Monday
May 18, 1998
Part III
Environmental
Protection Agency
40 CFR Part 194
Criteria for the Certification and
Recertification of the Waste Isolation
Pilot Plant's Compliance With the
Disposal Regulations: Certification
Decision; Final Rule
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ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Part 194
[FRL—6014-9]
RIN 2060-AG85
Criteria for the Certification and
Recertification of the Waste Isolation
Pilot Plant's Compliance With the
Disposal Regulations: Certification
Decision
AGENCY: Environmental Protection
Agency.
ACTION: Final rule.
SUMMARY: The Environmental Protection
Agency ("EPA") is certifying that the
Department of Energy's ("DOE") Waste
Isolation Pilot Plant ("WIPP") will
comply with the radioactive waste
disposal regulations set forth at
Subparts B and C of 40 CFR Part 191
(Environmental Standards for the
Management and Disposal of Spent
Nuclear Fuel, High-Level and
Transuranic Radioactive Waste). The
EPA is required to evaluate whether the
WIPP will comply with EPA's standards
for the disposal of radioactive waste by
the WIPP Land Withdrawal Act
("LWA") of 1992, as amended. EPA's
certification of compliance allows the
emplacement of radioactive waste in the
WIPP to begin, provided that all other
applicable health and safety standards,
and other legal requirements, have been
met. The certification constitutes final
approval under the WIPP LWA for
shipment of transuranic waste from
specific waste streams from Los Alamos
National Laboratory for disposal at the
WIPP. However, the certification is
subject to four specific conditions, most
notably that EPA must approve site-
specific waste characterization measures
and quality assurance programs before
other waste generator sites may ship
waste for disposal at the WIPP. The
Agency is amending the WIPP
compliance criteria (40 CFR Part 194) by
adding Appendix A that describes
EPA's certification, incorporating the
approval processes for waste generator
sites to ship waste for disposal at the
WIPP, and adding a definition for
"Administrator's authorized
representative." Finally, EPA is
finalizing its decision, also pursuant to
the WIPP LWA, that DOE does not need
to acquire existing oil and gas leases
near the WIPP to comply with the
disposal regulations.
EFFECTIVE DATE: This decision is
effective June 17, 1998. A petition for
review of this final action must be filed
no later than July 17, 1998, pursuant to
section 18 of the WIPP Land
Withdrawal Act of 1992 (Pub. L. 102-
579), as amended by the WIPP LWA
Amendments (Pub. L. 104-201).
FOR FURTHER INFORMATION CONTACT:
Betsy Forinash, Scott Monroe, or Sharon
White; telephone number (202) 564-
9310; address: Radiation Protection
Division, Center for the Waste Isolation
Pilot Plant, Mail Code 6602-J, U.S.
Environmental Protection Agency, 401
M Street S.W., Washington, DC 20460.
For copies of the Compliance
Application Review Documents
supporting today's action, contact Scott
Monroe. The Agency is also publishing
a document, accompanying today's
action, which responds in detail to
significant public comments that were
received on the proposed certification
decision. This document, entitled
"Response to Comments," may be
obtained by contacting Sharon White at
the above phone number and address.
Copies of these documents are also
available for review in the Agency's Air
Docket A-93-02.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. What is the WIPP?
II. What is the purpose of today's action?
III. With which regulations must the WIPP
comply?
IV. What is the decision on whether the
WIPP complies with EPA's regulations?
A. Certification Decision
B. Conditions
C. Land Withdrawal Act Section 4(b) (5) (B)
Leases
D. EPA's Future Role at the WIPP
(recertification, enforcement of
conditions)
V. What information did EPA examine to
make its decision?
VI. In making its final decision, how did EPA
incorporate public comments on the
proposed rule?
A. Introduction and the Role of Comments
in the Rulemaking Process
B. Significant Changes Made to the Final
Rule in Response to Comments
VII. How did EPA respond to general
comments on its proposed certification
decision?
VIII. How did EPA respond to major
technical issues raised in comments?
A. Content of Compliance Certification
Application (§194.14)
1. Site Characterization and Disposal
System Design
(a) Shaft Seals
(b) Panel Closure System
2. Results of Assessments, Input
Parameters to Performance Assessments,
Assurance Requirements, and Waste
Acceptance Criteria
3. Background Radiation, Topographic
Maps, Past and Current Meteorological
Conditions
4. Other Information Needed for
Demonstration of Compliance
5. Conclusion
B. Performance Assessment: Modeling and
Containment Requirements (§§ 194.14,
194.23, 194.31 through 194.34)
1. Introduction
2. Human Intrusion Scenarios
(a) Introduction
(b) Spallings
(c) Air Drilling
(d) Fluid Injection
(e) Potash Mining
(f) Carbon Dioxide Injection
(g) Other Drilling Issues
3. Geological Scenarios and Disposal
System Characteristics
(a) Introduction
(b) WIPP Geology Overview
(c) Rustler Recharge
(d) Dissolution
(e) Presence of Brine in the Salado
(f) Gas Generation Model
(g) Two-Dimensional Modeling of Brine
and Gas Flow
(h) Earthquakes
(i) Conclusion
4. Parameter Values
(a) Introduction
(b) Distribution Coefficient (Kd)
(c) Actinide Solubility
(d) Brine Pockets
(e) Permeability of Borehole Plugs
5. Other Performance Assessment Issues
(a) Sensitivity Analysis
(b) Performance Assessment Verification
Test
6. Conclusions
C. General Requirements
1. Quality Assurance (§ 194.22)
2. Waste Characterization (§ 194.24)
3. Future State Assumptions (§ 194.25)
4. Expert Judgment (§ 194.26)
5. Peer Re view (§194.27)
D. Assurance Requirements
1. Active Institutional Controls (§ 194.41)
2. Monitoring (§194.42)
3. Passive Institutional Controls (§ 194.43)
4. Engineered Barriers (§ 194.44)
5. Consideration of the Presence of
Resources (§194.45)
6. Removal of Waste (§ 194.46)
E. Individual and Ground-water Protection
Requirements (§§ 194.51-55)
IX. Does DOE need to buy existing oil and
gas leases near the WIPP?
X. Why and how does EPA regulate the
WIPP?
A. The WIPP Land Withdrawal Act
B. Limits of EPA's Regulatory Authority at
the WIPP
C. Compliance with Other Environmental
Laws and Regulations
XI. How has the public been involved in
EPA's WIPP activities?
A. Public Involvement Prior to Proposed
Rule
B. Proposed Certification Decision
C. Public Hearings on Proposed Rule
D. Additional Public Input on the Proposed
Rule
E. Final Certification Decision, Response to
Comments Document
F. Dockets
XII. How will the public be involved in
EPA's future WIPP activities?
XIII. Where can I get more information about
EPA's WIPP activities?
A. Technical Support Documents
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B. WIPP Information Line, Mailing List,
and Internet Homepage
XIV. Regulatory Analysis/Administrative
Requirements
A. Executive Order 12866
B. Regulatory Flexibility
C. Paperwork Reduction Act
D. Unfunded Mandates Reform Act
E. Executive Order 12898
F. Small Business Regulatory Enforcement
Fairness Act of 1996
G. National Technology Transfer &
Advancement Act of 1995
H. Executive Order 13045—Children's
Health Protection
I. What is the WIPP?
The Waste Isolation Pilot Plant
("WIPP") is a potential disposal system
for radioactive waste. Developed By the
Department of Energy ("DOE" or "the
Department"), the WIPP is located near
Carlsbad in southeastern New Mexico.
The DOE intends to bury radioactive
waste 2150 feet underground in an
ancient layer of salt which will
eventually "creep" and encapsulate
waste containers. The WIPP has a total
capacity of 6.2 million cubic feet of
waste.
Congress authorized the development
and construction of the WIPP in 1980
"for the express purpose of providing a
research and development facility to
demonstrate the safe disposal of
radioactive wastes resulting from the
defense activities and programs of the
United States." l The waste which may
be emplaced in the WIPP is limited to
transuranic ("TRU") radioactive waste
generated by defense activities
associated with nuclear weapons; no
high-level waste or spent nuclear fuel
from commercial power plants may be
disposed of at the WIPP. TRU waste is
defined as materials containing alpha-
emitting radio-isotopes, with half lives
greater than twenty years and atomic
numbers above 92, in concentrations
greater than 100 nano-curies per gram of
waste.2
Most TRU waste proposed for
disposal at the WIPP consists of items
that have become contaminated as a
result of activities associated with the
production of nuclear weapons (or with
the clean-up of weapons production
facilities), e.g., rags, equipment, tools,
protective gear, and organic or inorganic
sludges. Some TRU waste is mixed with
hazardous chemicals. Some of the waste
proposed for disposal at the WIPP is
currently stored at Federal facilities
1 Department of Energy National Security and
Military Applications of Nuclear Energy
Authorization Act of 1980, Pub. L. 96-164, section
213.
2WIPP Land Withdrawal Act, Pub. L. 102-579,
section 2(18), as amended by the 1996 WIPP LWA
Amendments, Pub. L. 104-201.
across the United States, including
locations in Colorado, Idaho, New
Mexico, Nevada, Ohio, South Carolina,
Tennessee, and Washington. Much of
the waste proposed for disposal at the
WIPP will be generated in the future.
II. What Is the Purpose of Today's
Action?
Before disposal of radioactive waste
can begin at the WIPP, the U.S.
Environmental Protection Agency
("EPA," or "the Agency") must certify
that the WIPP facility will comply with
EPA's radioactive waste disposal
regulations (Subparts B and C of 40 CFR
Part 191).3 The purpose of today's action
is to issue EPA's certification decision.
With today's action, EPA will add to
the Code of Federal Regulations a new
Appendix A to 40 CFR Part 194
describing EPA's certification decision
and the conditions that apply to the
certification. The Agency is adding a
new section, § 194.8, to the WIPP
compliance criteria (40 CFR Part 194)
that describes the processes EPA will
use to approve quality assurance and
waste characterization programs at
waste generator sites. The EPA is also
adding a definition of the term
"Administrator's authorized
representative" to the WIPP compliance
criteria. Except for these actions, the
certification decision does not otherwise
amend or affect EPA's radioactive waste
disposal regulations or the WIPP
compliance criteria.
Today's action also addresses the
provision of section 7(b)(2) of the WIPP
Land Withdrawal Act which prohibits
DOE from emplacing transuranic waste
underground for disposal at the WIPP
until, inter alia, it acquires specified oil
and gas leases, unless EPA determines
that such acquisition is not necessary.
III. With Which Regulations Must the
WIPP Comply?
The WIPP must comply with EPA's
radioactive waste disposal regulations,
located at Subparts B and C of 40 CFR
Part 191. These regulations limit the
amount of radioactive material which
may escape from a disposal facility, and
protect individuals and ground water
resources from dangerous levels of
radioactive contamination. In addition,
the compliance certification application
("CCA") and other information
submitted by DOE must meet the
requirements of the WIPP compliance
criteria at 40 CFR Part 194. The
compliance criteria implement and
interpret the general disposal
regulations specifically for the WIPP,
and clarify the basis on which EPA's
certification decision is made.
IV. What Is the Decision on Whether
the WIPP Complies With EPA's
Regulations?
A. Certification Decision
The EPA finds that DOE has
demonstrated that the WIPP will
comply with EPA's radioactive waste
disposal regulations at Subparts B and
C of 40 CFR Part 191. This decision
allows the WIPP to begin accepting
transuranic waste for disposal, provided
that other applicable environmental
regulations have been met and once a
30-day Congressionally-required waiting
period has elapsed.4 EPA's decision is
based on a thorough review of
information submitted by DOE,
independent technical analyses, and
public comments. The EPA determined
that DOE met all of the applicable
requirements of the WIPP compliance
criteria at 40 CFR Part 194. However, as
discussed below, DOE must meet
certain conditions in order to maintain
a certification for the WIPP and before
shipping waste for disposal at the WIPP.
B. Conditions
As noted above, EPA determined that
DOE met all of the applicable
requirements of the WIPP compliance
criteria. In several instances, however,
EPA found that it is necessary for DOE
to take additional steps to ensure that
the measures actually implemented at
the WIPP (and thus the circumstances
expected to exist there) are consistent
with DOE's compliance certification
application ("CCA") and with the basis
for EPA's compliance certification.
Regarding several requirements, DOE
demonstrated compliance with the
applicable compliance criteria for only
one category of waste at a single waste
generator site. To address these
situations, EPA is amending the WIPP
compliance criteria, 40 CFR Part 194,
and appending four explicit conditions
to its certification of compliance for the
WIPP.
Condition 1 of the certification relates
to the panel closure system, which is
intended over the long term to block
brine flow between waste panels in the
WIPP. In its CCA, DOE presented four
options for the design of the panel
closure system, but did not specify
which one would be constructed at the
WIPP. The EPA based its certification
decision on DOE's use of the most
robust design (referred to in the CCA as
"Option D"). The Agency found the
Option D design to be adequate, but also
3 WIPP LWA, section 8 (d).
i WIPP LWA, §7(b).
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determined that the use of a Salado
mass concrete—using brine rather than
fresh water—would produce concrete
seal permeabilities in the repository
more consistent with the values used in
DOE's performance assessment.
Therefore, Condition 1 of EPA's
certification requires DOE to implement
the Option D panel closure system at the
WIPP, with Salado mass concrete
replacing fresh water concrete. (For
more detail on the panel closure system,
refer to the preamble discussion of
§194.14.)
Conditions 2 and 3 of the final rule
relate to activities conducted at waste
generator sites that produce the
transuranic waste proposed for disposal
in the WIPP. The WIPP compliance
criteria (§§ 194.22 and 194.24) require
DOE to have in place a system of
controls to measure and track important
waste components, and to apply quality
assurance ("QA") programs to waste
characterization activities. At the time
of EPA's proposed certification
decision, the Los Alamos National
Laboratory ("LANL") was the only site
to demonstrate the execution of the
required QA programs and the
implementation of the required system
of controls. Therefore, EPA's
certification constitutes final approval
under the WIPP LWA for DOE to ship
waste for disposal at the WIPP only
from the LANL, and only for the
retrievably stored (legacy) debris at
LANL for which EPA has inspected and
approved the applicable system of
controls. Before DOE may ship any
mixed (hazardous and radioactive)
waste from the LANL—even if it is
encompassed by the waste streams
approved by EPA in this action—DOE
must obtain any other regulatory
approvals that may be needed,
including approval from the State of
New Mexico under the Resource
Conservation and Recovery Act to
dispose of such waste at the WIPP.
As described in the final WIPP
certification, before other waste may be
shipped for disposal at the WIPP, EPA
must separately approve the QA
programs for other generator sites
(Condition 2) and the waste
characterization system of controls for
other waste streams (Condition 3). The
approval process includes an
opportunity for public comment, and an
inspection (of a DOE audit) or audit of
the waste generator site by EPA. The
Agency's approval of waste
characterization systems of controls and
QA programs will be conveyed in a
letter from EPA to DOE. In response to
public comments on these conditions,
EPA's approval processes for waste
generator site programs have been
incorporated into the body of the WIPP
compliance criteria, in a new section at
§ 194.8. (For more information on this
change, see the preamble section
entitled, "Significant Changes to the
Final Rule Made in Response to Public
Comments." For further discussion of
Conditions 2 and 3, refer to the
preamble discussions of § 194.22 and
§ 194.24, respectively.)
Condition 4 of the certification relates
to passive institutional controls
("PICs"). The WIPP compliance criteria
require DOE to use both records and
physical markers to warn future
societies about the location and contents
of the disposal system, and thus to deter
inadvertent intrusion into the WIPP.
(§ 194.43) In its application, DOE
provided a design for a system of PICs,
but stated that many aspects of the
design would not be finalized for many
years (even up to 100) after closure. The
PICs actually constructed and placed in
the future must be consistent with the
basis for EPA's certification decision.
Therefore, Condition 4 of the
certification requires DOE to submit a
revised schedule showing that markers
and other measures will be
implemented as soon as possible after
closure of the WIPP. The DOE also must
provide additional documentation
showing that it is feasible to construct
markers and place records in archives as
described in DOE's certification
application. After closure of the WIPP,
DOE will not be precluded from
implementing additional PICs beyond
those described in the application. (See
the preamble discussion of § 194.43 for
more information on PICs.)
Although not specified in the
certification, it is a condition of any
certification that DOE must submit
periodic reports of any planned or
unplanned changes in activities
pertaining to the disposal system that
differ significantly from the most recent
compliance application. (§ 194.4(b)(3))
The DOE must also report any releases
of radioactive material from the disposal
system. (§ 194.4(b)(3)(iii), (v)) Finally,
EPA may request additional information
from DOE at any time. (§ 194.4(b)(2))
These reports and information will
allow EPA to monitor the performance
of the disposal system and evaluate
whether the certification must be
modified, suspended, or revoked for any
reason. (Modifications, suspensions,
recertification, and other activities are
also addressed in the preamble section
entitled, "EPA's Future Role at the
WIPP.")
C. Land Withdrawal Act Section
4(b)(5)(B) Leases
The EPA finds that DOE does not
need to acquire existing oil and gas
leases (Numbers NMNM 02953 and
02953C) (referred to as the "section
4(b)(5)(B) leases") in the vicinity of the
WIPP in order to comply with EPA's
final disposal regulations at 40 CFR Part
191, Subparts B and C. The EPA
concludes that potential activities at
these existing leases would have an
insignificant effect on releases of
radioactive material from the WIPP
disposal system and, thus, that they do
not cause the WIPP to violate the
disposal regulations.
D. EPA's Future Role at the WIPP
(recertification, enforcement of
conditions)
The EPA will continue to have a role
at the WIPP after this certification
becomes effective. As discussed above,
DOE must submit periodic reports on
any activities or conditions at the WIPP
that differ significantly from the
information contained in the most
recent compliance application. The EPA
may also, at any time, request additional
information from DOE regarding the
WIPP. (§ 194.4) The Agency will review
such information as it is received to
determine whether the certification
must be modified, suspended, or
revoked. Such action might be
warranted if, for example, significant
information contained in the most
recent compliance application were no
longer to remain true. The certification
could be modified to alter the terms or
conditions of certification—for example,
to add a new condition, if necessary to
address new or changed activities at the
WIPP. (§ 194.2) The certification could
be revoked if it becomes evident in the
future that the WIPP cannot or will not
comply with the disposal regulations.
Either modification or revocation must
be conducted by rulemaking, in
accordance with the WIPP compliance
criteria. (§§ 194.65-66) Suspension may
be initiated at the Administrator's
discretion, in order to promptly reverse
or mitigate a potential threat to public
health. For instance, a suspension
would take effect if, during
emplacement of waste, a release from
the WIPP occurred in excess of EPA's
containment limits. (See § 194.4(b)(3).)
In addition to reviewing annual
reports from DOE regarding activities at
the WIPP, EPA periodically will
evaluate the WIPP's continued
compliance with the WIPP compliance
criteria and disposal regulations. As
directed by Congress, this
"recertification" will occur every five
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years.5 For recertification, DOE must
submit to EPA for review the
information described in the WIPP
compliance criteria (although, to the
extent that information submitted in
previous certification applications
remains valid, it can be summarized and
referenced rather than resubmitted).
(§194.14) In accordance with the WIPP
compliance criteria, documentation of
continued compliance will be made
available in EPA's dockets, and the
public will be provided at least a 30-day
period in which to submit comments.
The EPA's decision on recertification
will be announced in the Federal
Register. (§ 194.64)
In the immediate future, the Agency
expects to conduct numerous
inspections at waste generator sites in
order to implement Conditions 2 and 3
of the compliance certification. Notices
announcing EPA inspections or audits
to evaluate implementation of quality
assurance ("QA") and waste
characterization requirements at
generator facilities will be published in
the Federal Register. The public will
have the opportunity to submit written
comments on the waste characterization
and QA program plans submitted by
DOE. As noted above, EPA's decisions
on whether to approve waste generator
QA program plans and waste
characterization systems of controls—
and thus, to allow shipment of specific
waste streams for disposal at the
WIPP—will be conveyed by a letter from
EPA to DOE. A copy of the letter, as
well as any EPA inspection or audit
reports, will be placed in EPA's docket.
(See the preamble sections entitled
"Dockets" and "Where can I get more
information about EPA's WIPP
activities?" for more information
regarding EPA's rulemaking docket.)
The procedures for EPA's approval have
been incorporated in the compliance
criteria at a new section, § 194.8.
As discussed previously, Condition 1
of the WIPP certification requires DOE
to implement the Option D panel
closure system at the WIPP, with Salado
mass concrete being used in place of
fresh water concrete. It will be possible
to evaluate the closure system only
when waste panels have been filled and
are being sealed. At that time, EPA
intends to confirm compliance with this
condition through inspections under its
authority at § 194.21 of the WIPP
compliance criteria.
Similarly, EPA will be able to
evaluate DOE's compliance with
Condition 4 of the certification only
5 WIPP LWA, § 8(f). Congress also directed that
this periodic recertification "shall not be subject to
rulemaking or judicial review."
when DOE submits a revised schedule
and additional documentation regarding
the feasibility of implementing passive
institutional controls. This
documentation must be provided to
EPA no later than the final
recertification application. Once
received, the information will be placed
in EPA's docket, and the Agency will
evaluate the adequacy of the
documentation. If necessary, EPA may
initiate a modification to the
certification to address DOE's revised
schedule; any such modification would
be undertaken in accordance with the
public participation requirements
described in the WIPP compliance
criteria, §§ 194.65-66. During the
operational period when waste is being
emplaced in the WIPP (and before the
site has been sealed and
decommissioned), EPA will verify that
specific actions identified by DOE in the
CCA and supplementary information
(and in any additional documentation
submitted in accordance with Condition
4) are being taken to test and implement
passive institutional controls. For
example, DOE stated that it will submit
a plan for soliciting archives and record
centers to accept WIPP information in
the fifth recertification application. The
Agency can confirm implementation of
such measures by examining
documentation and by conducting
inspections under its authority at
§194.21.
Finally, the WIPP compliance criteria
provide EPA the authority to conduct
inspections of activities at the WIPP and
at all off-site facilities which provide
information included in certification
applications. (§ 194.21) The Agency
expects to conduct periodic inspections,
both announced and unannounced, to
verify the adequacy of information
relevant to certification applications.
The Agency may conduct its own
laboratory tests, in parallel with those
conducted by DOE. The Agency also
may inspect any relevant records kept
by DOE, including those records
required to be generated in accordance
with the compliance criteria. For
example, EPA intends to conduct
ongoing inspections or audits at the
WIPP and at waste generator sites to
ensure that approved quality assurance
programs are being adequately
maintained and documented. The EPA
plans to place inspection reports in its
docket for public examination.
V. What Information Did EPA Examine
to Make its Decision?
The EPA made its certification
decision by comparing relevant
information to the WIPP compliance
criteria (40 CFR Part 194) and ensuring
that DOE satisfied the specific
requirements of the criteria in
demonstrating compliance with the
disposal regulations. The primary
source of information examined by EPA
was a compliance certification
application ("CCA") submitted by DOE
on October 29, 1996. (Copies of the CCA
were placed in EPA's Air Docket A-93-
02, Category II-G.) The DOE submitted
additional information after that time.
On May 22, 1997, EPA announced that
DOE's application was deemed to be
complete. (62 FR 27996-27998)
However, as contemplated by
Congress, EPA's compliance
certification decision is based on more
than the complete application. The EPA
also relied on materials prepared by the
Agency or submitted by DOE in
response to EPA requests for specific
additional information necessary to
address technical sufficiency concerns.
The Agency also considered public
comments on the proposed rule which
supported or refuted technical
positions. Thus, EPA's certification
decision is based on the entire record
available to the Agency, which is
contained in EPA's Air Docket A-93-02.
The record consists of the complete
CCA, supplementary information
submitted by DOE in response to EPA
requests for additional information,
technical reports generated by EPA and
EPA contractors, EPA audit and
inspection reports, and public
comments submitted on EPA's proposed
certification decision during the public
comment period.
In response to public comments
regarding the precise materials EPA
considered in reaching its certification
decision, the Compliance Application
Review Documents ("CARDs")
supporting today's decision reference
the relevant portion(s) of the October 29,
1996, CCA and any supplementary
information that the Agency relied on in
reaching a particular compliance
decision. (Docket A-93-02, Item V-B-2)
All materials which informed EPA's
proposed and final decisions have been
placed in the WIPP dockets or are
otherwise publicly available. A full list
of the supporting documentation for
EPA's certification decision and the
DOE compliance documentation
considered by the Agency is located at
Docket A-93-02, Item V-B-1. For
further information regarding the
availability of information EPA
examined, see the section entitled
"Dockets" in this preamble.
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VI. In Making its Final Decision, how
did EPA Incorporate Public Comments
on the Proposed Rule?
A. Introduction and the Role of
Comments in the Rulemaking Process
Congress directed that EPA's
certification decision for the WIPP be
conducted by informal (or "notice-and-
comment") rulemaking pursuant to
Section 4 of the Administrative
Procedure Act ("APA").6 Notice-and-
comment rulemaking under the APA
requires that regulatory agencies
provide notice of a proposed
rulemaking, an opportunity for the
public to comment on the proposed
rule, and a general statement of the basis
and purpose of the final rule.7 The
notice of proposed rulemaking required
by the APA must "disclose in detail the
thinking that has animated the form of
the proposed rule and the data upon
which the rule is based." (Portland
Cement Ass 'n v. Ruckelshaus, 486 F.2d
375, 392-94 (D.C. Cir. 1973)) The public
is thus enabled to participate in the
process by making informed comments
on the Agency's proposal. This provides
the Agency the benefit of "an exchange
of views, information, and criticism
between interested persons and the
agency." (Id.)
For the WIPP certification decision,
there are two primary mechanisms by
which EPA explains the issues that were
raised in public comments and the
Agency's reactions to them. First, broad
or major comments are discussed in the
succeeding sections of this preamble.
Second, EPA is publishing a document,
accompanying today's action and
entitled "Response to Comments,"
which contains the Agency's response
to all significant comments received
during the comment period on the
proposed certification decision. (The
EPA also responded to comments
received on its advance notice of
proposed rulemaking ("ANPR"); for
further information on the ANPR, see
the preamble section "Public
Involvement Prior to the Proposed
Rule.") The Response to Comments
document provides more detailed
responses to issues which are addressed
in the preamble, and addresses all other
significant comments on the proposal.
All comments received by EPA, whether
written or oral, were given equal
consideration in developing the final
rule.
6WIPPLWA, §8(d)(2).
'5U.S.C. 553
B. Significant Changes to the Final Rule
Made in Response to Public Comments
Today's action finalizes EPA's
proposed decision that the WIPP facility
will comply with the disposal
regulations and that DOE does not need
to acquire existing oil and gas leases in
the WIPP Land Withdrawal Area. (For
further information, refer to the
preamble section entitled, "What is the
decision on whether the WIPP complies
with EPA's regulations?") Beyond these
broad determinations, EPA's proposed
certification decision also included four
conditions related to the panel closure
system, quality assurance at waste
generator sites, waste characterization
measures at waste generator sites, and
passive institutional controls. The final
rule retains all of these conditions.
However, in response to comments
submitted on the proposal, the Agency
has made clarifying changes to Subpart
A of 40 CFR Part 194 to provide a
clearer explanation of the process for
determining compliance with the
conditions related to waste generator
sites.
Proposed Conditions 2 and 3 relate to
quality assurance ("QA") programs and
waste characterization programs,
respectively, at waste generator sites
intending to ship waste for disposal at
the WIPP. Except for removal of the
procedural sections of the proposed
conditions from the appendix (as
proposed) to Subpart A of 40 CFR Part
194, to provide for a clearer enunciation
of the process for determining
compliance with the conditions, these
conditions are retained with minor
clarifications in the final rule. The
conditions restrict DOE from shipping
waste to the WIPP from any sites other
than the Los Alamos National
Laboratory until EPA separately
approves the QA and waste
characterization plans at other waste
generator sites. For both QA and waste
characterization programs, the proposed
approval process included: placement
in the docket of site-specific
documentation submitted by DOE,
publication of a Federal Register notice
by EPA announcing a scheduled
inspection or audit, a period of at least
30 days for the public to comment on
information placed in the docket, and
the Agency's written decision regarding
the approval of these programs in the
form of a letter from EPA to DOE. The
EPA proposed to approve QA programs
on a site-wide basis. However, because
the features of waste streams can vary
widely and thus can require
significantly different characterization
techniques, EPA proposed to approve
waste characterization measures and
controls on the basis of waste streams
or, where multiple waste streams may
be characterized by the same waste
characterization processes and
techniques, groups of waste streams.
A number of commenters suggested
that in the waste generator site approval
process, EPA should delay the public
comment period until after completion
of an inspection or audit, and should
make the Agency's approval decision
explicitly subject to judicial review.
Other comments questioned the
authority for, and the value of, a
separate site approval process by EPA.
The EPA finds that it is both
necessary and within the Agency's
authority to evaluate and approve site-
specific QA and waste characterization
programs. The compliance criteria
expressly provide that any certification
of compliance "may include such
conditions as [EPA] finds necessary to
support such certification." (§ 194.4(a))
Before waste is shipped for disposal at
the WIPP, EPA must be confident that
the waste will conform to the waste
limits and other waste-related
assumptions incorporated in DOE's
performance assessment—that is, that
DOE adheres to the fundamental
information and assumptions on the
waste on which the certification of
compliance is based. Such confidence
can be assured only by confirmation
that the required QA and waste
characterization programs are in place
(i.e., established, implemented or
executed) at waste generator sites. The
EPA believes that an approval process
separate from DOE's internal procedures
is beneficial because DOE's process is
not geared solely to confirming that
programs adhere to EPA's compliance
criteria, and because DOE's process does
not provide for public participation.
Given the great public interest
regarding the WIPP, and waste
characterization in particular, EPA
believes it is important that the public
be informed of and have the opportunity
to be involved in the site approval
process. To that end, EPA's approval
process includes docketing information
relevant to site-specific approvals, and
allowing the public to comment on such
information.
The EPA's certification that the WIPP
will comply with the 40 CFR Part 191
radioactive waste disposal regulations is
based on the Agency's determination
that the WIPP will comply with the
containment requirements and other
requirements of 40 CFR Parts 191 and
194 for the waste inventory described
for purposes of the performance
assessment. In the CCA, DOE purported
to demonstrate that the WIPP would
meet the 40 CFR Part 191 release limits
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by modeling the WIPP's behavior in its
performance assessment. The
performance assessment incorporated
certain upper and lower limiting values
of specified waste components, as
required by 40 CFR 194.24(c). The EPA
confirmed the results of the
performance assessment using the same
upper and lower limiting values in the
performance assessment verification test
("PAVT"). Those upper and lower
limiting values apply to contact-
handled, remote-handled, and to-be-
generated waste from numerous
generator sites. Thus, in today's action,
EPA certifies that the WIPP will comply
with the 40 CFR Part 191 containment
requirements to the extent that
emplaced waste falls within the waste
envelope limits that were shown by the
performance assessment, and confirmed
by the PAVT, to be compliant with the
40 CFR Part 191 standards. Proposed
Conditions 2 and 3 change neither the
performance assessment assumptions
nor the terms on which the WIPP is
authorized for disposal, but rather
ensure that the assumptions on which
the compliance certification is based are
adhered to in practice.
Based on public comments, EPA also
finds it necessary to clarify that the
compliance criteria at § 194.22 and
§ 194.24 were not intended to require
that DOE address their requirements—
including QA measures, and the use of
process knowledge—for all waste
streams in the certification application
for the initial certification. Clearly, it
would be impossible to do so for the to-
be-generated waste. It is similarly
impossible for DOE to demonstrate
fully, in the initial certification
application, that the waste emplaced in
the disposal system actually conforms to
the waste envelope (i.e., upper and
lower waste limits) upon which the
certification is based, since waste
cannot be disposed of at the WIPP
before EPA grants an initial
certification. Confusion on these issues
arose because the compliance criteria at
40 CFR Part 194 apply to information in
compliance recertification applications
as well as the initial certification
application.
The fact that it was not EPA's intent
to require DOE to have implemented QA
or measurement programs for all waste
at every site prior to initial certification
is supported by numerous statements
made by the Agency at the time the
compliance criteria were issued. The
EPA had great discretion in setting the
waste characterization requirements,
since they were part of the general
requirements of the WIPP compliance
criteria and not derived directly from
the disposal regulations. In the
Response to Comments for 40 CFR Part
194, EPA emphasized that compliance
with the requirements would be
confirmed through inspections or audits
and would not serve to re-open the
certification rulemaking. (Docket A-92-
56, Item V-C-1, pp. 6-5, 6-8, and 6-20)
The Agency stated that the certification
rulemaking would address DOE's
analysis of waste characteristics and
components and documentation that a
system of controls had been established
at the WIPP to track the amount of
important waste components emplaced
in the disposal system. (Docket A-92-
56, Item V-C-1, p. 6-9) The certification
rulemaking has addressed these issues
and found DOE in compliance with the
requisite criteria. The EPA believes that
the comprehensive waste
characterization approach described by
DOE in the CCA—including the
approach to identification, limitation,
and confirmation of waste components
important to containment of waste in
the disposal system—is an appropriate
basis for granting an initial certification.
The EPA further believes that
confirmation of the QA and system of
controls at waste generator sites (i.e.,
measuring and tracking important waste
components) can be reasonably obtained
by a process of inspections and audits
in accordance with 40 CFR 194.21,
194.22(e), and 194.24(h).
The EPA declines to modify the
proposed approval process by delaying
the comment period until after the
issuance of EPA's inspection or audit
report. The EPA does not believe it is
prudent to commit to a strict sequence
of events that will be adhered to for
every approval. In some cases, the
Agency may place records of a
completed inspection or audit in the
docket prior to or during the public
comment period. However, in other
cases, the Agency believes that the
public comment period may better serve
members of the public if it allows them
to provide comments on DOE's
documentation prior to EPA's
inspection or audit. In this way, public
comments could inform EPA's
inspection criteria and process, or
provide information on which EPA may
take action to follow up in the
inspection or audit. Therefore, the
Agency does not believe that it is
prudent to specify when the comment
period may occur in relation to an
inspection or audit. Furthermore, EPA
declines to make any statement
regarding whether the approval
decisions are subject to judicial review.
Jurisdiction of U.S. Federal Courts is
governed by the enactments of the U.S.
Congress.
Nevertheless, in response to
comments requesting changes or
clarifications to EPA's waste generator
site and waste stream approval
processes, EPA made certain changes to
the proposed conditions. In order to
clarify EPA's original intent in the
compliance criteria regarding approval
of site-specific activities, EPA is
amending the compliance criteria at 40
CFR Part 194 to include the site-specific
approval process. (See 62 FR 58804,
58815) Thus, the procedures for
demonstrating compliance with the
proposed Conditions 2 and 3 are
incorporated in the final rule as a new
section at 40 CFR Part 194: § 194.8,
"Approval Process for Waste Shipment
from Waste Generator Sites for Disposal
at the WIPP." Also, in response to
comments advocating greater
transparency in the approval process,
EPA has clarified that scheduled
inspections or audits by EPA for the
purpose of approving quality assurance
programs at waste generator sites will be
announced by notice in the Federal
Register (§ 194.8(a)); this is consistent
with EPA's commitment to do so for
inspections and audits of waste
characterization programs at generator
sites (§ 194.8(b)). Providing notice of
such inspections will alert the public to
upcoming EPA approval activities and
allow for more informed public
participation. While public notice will
be provided for the scheduled initial
phase of an inspection or audit, should
it prove necessary for EPA to conduct
follow-up activities or continuations of
inspections and audits, EPA reserves the
right to do so without providing
additional public notice. Such follow-
up activities or continuations of audits
or inspections might be necessary to
obtain additional information or ensure
that corrective actions are being taken to
resolve initial findings. In no case will
EPA decide whether to approve site-
specific quality assurance or waste
characterization programs before
providing a minimum 30-day public
comment period on documentation of
the program plans, or before conducting
an inspection or audit at the relevant
site.
The Agency received some comments
related to Conditions 1 and 4 in the
proposed rule. EPA's responses to these
comments are discussed in the preamble
sections related to § 194.14 and
§ 194.43, respectively. Conditions 1 and
4 were retained without change in the
final rule. The response to comments
document accompanying today's action
provides more detailed responses
regarding the certification conditions
and all aspects of the final rule.
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The EPA received no significant
comments on its proposed actions to
slightly modify the criteria by revising
the authority citation and adding a new
definition for Administrator's
authorized representative. Therefore,
these actions take effect without change
from the proposed rule.
VII. How Did EPA Respond to General
Comments on Its Proposed Certification
Decision?
The EPA received many comments
which addressed broad issues related to
the proposed certification decision.
Many citizens simply expressed their
strong support for, or opposition to,
opening the WIPP. Some commenters
requested that EPA consider certain
factors in making its certification
decision. These factors include reviews
by organizations other than EPA, and
the political or economic motivations of
interested parties. The EPA's
certification decision must be made by
comparing the scope and quality of
relevant information to the objective
criteria of 40 CFR Part 194. Where
relevant, the Agency has considered
public comments which support or
refute technical positions taken by DOE.
Emotional pleas and comments on the
motives of interested parties are factors
that are not relevant to a determination
of whether DOE has demonstrated
compliance with the disposal
regulations and the WIPP compliance
criteria, and are therefore outside the
scope of this rulemaking.
A number of commenters suggested
that EPA should explore alternative
methods of waste disposal, such as
neutralizing radioactive elements,
before proceeding with a certification
decision. Others stated that the WIPP
should be opened immediately because
underground burial of radioactive waste
is less hazardous than the current
strategy of above-ground storage. Such
considerations are all outside the scope
of this rulemaking. Congress did not
delegate to EPA the authority to
abandon or delay the WIPP in favor of
other disposal methods. Congress
mandated that EPA certify, pursuant to
Section 4 of the APA, whether the WIPP
will comply with the radioactive waste
disposal regulations.8 Thus, EPA is
obligated to determine whether the
WIPP complies with the disposal
regulations, regardless of the relative
risks of underground disposal compared
to above-ground storage.
Many members of the public
expressed a desire for EPA to oversee
« WIPP Land Withdrawal Act ("WIPP LWA"),
Pub. L. 102-579, as amended by the 1996 WIPP
LWA Amendments, Pub. L. 104-201, Section 8(d).
other aspects of the WIPP's operation. In
particular, the public was concerned
with the risks of transporting
radioactive materials from waste
generator sites to the WIPP. All
transportation requirements for the
WIPP are established and enforced by
regulators other than EPA. (For further
discussion on the source and limitations
of EPA's authority to regulate the WIPP,
see preamble Section X, "Why and how
does EPA regulate the WIPP?") One
commenter stated that EPA should
survey electric and magnetic fields at
the WIPP. The EPA's disposal
regulations apply only to ionizing
radiation. They do not apply to non-
ionizing radiations such as electric and
magnetic fields. These issues are beyond
the scope of EPA's authority to regulate
waste disposal at the WIPP and are not
addressed in the certification
rulemaking.
The EPA received a number of
comments suggesting that the Agency
should have provided more or better
opportunities for public participation in
its decision making process. Comments
suggested, for example, that EPA should
have rescheduled public hearings,
responded more fully to comments
submitted prior to the proposed rule,
extended the public comment period,
and included the public in all meetings
between EPA and DOE. The EPA
provided numerous opportunities for
public participation in the WIPP
certification decision, including two
comment periods—one before and one
after the proposed decision—of at least
120 days (In fact, EPA accepted
comments on its advance notice of
proposed rulemaking announcing
receipt of DOE's CCA for over 250
days.), two sets of public hearings in
New Mexico, Federal Register notices,
and a number of meetings with various
stakeholders. These measures exceed
the basic requirements for notice-and-
comment rulemaking and are in full
compliance with the public
participation requirements of both the
WIPP compliance criteria and the
Administrative Procedure Act. Further
discussion on the measures taken by
EPA to involve the public can be found
in the preamble section entitled, "How
has the public been involved in EPA's
WIPP activities?"
Some members of the public
expressed doubt that EPA and its
contractors possessed the necessary
technical skills to evaluate DOE's
application or were free from conflicts
of interest. Many comments requested
that EPA release the names and
qualifications of individual contractor
employees who provided technical
support for EPA's certification
rulemaking. The EPA initially denied
this request because such information is
typically claimed as confidential
business information by federal
government contractors. (The Trade
Secrets Act prohibits EPA from
releasing confidential business
information, and imposes criminal
liability on federal employees for the
unauthorized disclosure of such
confidential information.9) However, in
response to the public interest regarding
this issue, EPA sought and obtained
from its contractors a limited waiver of
confidentiality to release the names and
qualifications of individual employees
who provided technical support related
to EPA's certification decision. In
January 1998, EPA provided this
contractor information to several
stakeholders and also placed it in the
rulemaking docket. (Docket A-93-02,
Items IV-C-13 and IV-C-14) The
Agency also sent to stakeholders (and
docketed) a description of the measures
EPA has taken to ensure that contractors
do not have any conflict of interest in
providing technical support on the
certification rulemaking. While EPA
agreed to release the above information
to allay public concerns, such
information is not relevant to EPA's
certification decision. Under notice-and-
comment rulemaking, it is the substance
and basis for EPA's decision that are at
issue.
Finally, several commenters stated
that EPA—by initially certifying the
WIPP to receive only certain waste from
the Los Alamos National Laboratory—is
granting a piecemeal certification, and
that such an action is illegal under
EPA's regulatory authority. The EPA
disagrees with the assertion that its
actions constitute a phased certification.
The EPA's certification is based on the
Agency's determination that the WIPP
will comply with the disposal
regulations for the inventory described
in the performance assessment.
Conditions 2 and 3 of the certification
(related to waste generator sites) change
neither the performance assessment
assumptions nor the terms on which the
WIPP is authorized for disposal, but
ensure that DOE adheres to the
assumptions on which compliance is
based. The EPA believes this approach
is consistent with Congressional intent
(as reflected in the WIPP LWA) and
with the disposal regulations and
compliance criteria. For further
discussion of comments related to the
proposed conditions of certification,
refer to the preceding preamble section
entitled, "Significant Changes Made to
918 U.S.C. 1905
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27361
the Final Rule in Response to
Comments."
VIII. How Did EPA Respond to Major
Technical Issues Raised in Comments?
A. Content of Compliance Certification
Applications (§ 194.14)
40 CFR Part 194 sets out those
elements which the Agency requires to
be in a complete compliance
application. In general, compliance
applications must include information
relevant to demonstrating compliance
with each of the individual sections of
40 CFR Part 194 to determine if the
WIPP will comply with the Agency's
radioactive waste disposal regulations at
40 CFR Part 191, Subparts B and C. The
Agency published the "Compliance
Application Guidance for the Waste
Isolation Pilot Plant: A Companion
Guide to 40 CFR Part 194" ("CAG")
which provided detailed guidance on
the submission of a complete
compliance application.10
Any compliance application must
include, at a minimum, basic
information about the WIPP site and
disposal system design, and must also
address all the provisions of the
compliance criteria; these requirements
are embodied in § 194.14. The
documentation required in the
compliance criteria is important to
enable a rigorous, thorough assessment
of whether the WIPP facility will
comply with the disposal regulations.
The EPA thoroughly reviewed DOE's
compliance certification application
("CCA") and additional information
submitted by DOE, and proposed that
DOE complies with each of the
requirements of § 194.14, conditioned
upon DOE's implementation of the most
robust panel closure system design
(designated as Option D) with slight
modification. The succeeding sections
address public comments related to
§ 194.14. (For more detailed
discussions, see Docket A-93-02, Item
V-B-2, CARD 14; and Item V-B-3.)
1. Site Characterization and Disposal
System Design
The EPA received numerous public
comments on issues related to the
requirements of §§ 194.14(a) and
194.14.(b), primarily related to the
geological features, disposal system
design and characteristics of the WIPP.
Since the geology and disposal system
characteristics are directly related to
10Section 194.11 provides that EPA's certification
evaluation would not begin until EPA notified DOE
of its receipt of a "complete" compliance
application. This ensures that the full one-year
period for EPA's review, as provided by the WIPP
LWA, shall be devoted to substantive, meaningful
review of the application. (61 FR 5226)
performance assessment modeling and
the containment requirements of 40 CFR
Part 191, a discussion of EPA's review
of the substantive comments (except for
those relating to shaft seals and panel
closures) can be found in the
Performance Assessment section of this
preamble. A discussion of the comments
on the engineered features related to
long term performance, specifically on
the shaft seal design and panel closure
system, are discussed below.
a. Shaft Seals. In the CCA, DOE
described the seals to be used in each
of the four shafts and included the
design plans and the material and
construction specifications for the seals.
(Docket A-93-02, Item II-G-1, CCA
Chapter 3.3.1, Chapter 8.1.1, and
Appendix SEAL) The purpose of the
shaft seal system is to limit fluid flow
within the shafts after the WIPP is
decommissioned and to ensure that the
shafts will not become pathways for
radionuclide release. The shaft seal
system has 13 elements that fill the shaft
with engineered materials possessing
high density and low permeability,
including concrete, asphalt, clay,
compacted salt, cementitious grout, and
earthen fill. The compacted salt column
component of the system within the
Salado is intended to serve as the
primary longterm barrier by limiting
fluid transport along the shaft during
the 10,000 year regulatory period. The
EPA proposed that DOE's shaft seal
design is adequate because the system
can be built and is expected to function
as intended. (Docket A-93-02, Item V-
B-2, CARD 14, Section 14.E; and Item
V-B-3)
Commenters expressed concern that
dissolution of the salt column could
occur because the overlying Rustler
aquifer has karst features and cannot be
relied upon to retard the migration of
radionuclides. (For more information on
karst, refer to the preamble sections on
Performance Assessment, Geological
Scenarios.) Dissolution of salt (halite) in
the WIPP shafts would require a source
of water that is not saturated with salt,
and a sink, i.e., some location for the
water to flow to after it has dissolved
the salt in the shafts. Since all of the
ground water from the top of the Salado
downward is saturated with salt (i.e., it
is "brine"), the unsaturated but highly
saline water would probably come
down the shaft from the Rustler
Formation. In order to reach the salt
component of the shaft seal, that water
would have to pass through or around
490 feet of concrete, asphalt, and
bentonite layers. Then, after flowing
through 550 feet of compacted salt
column, the saturated water would have
to flow through or around another
concreteasphalt water stop, another 100
feet of bentonite clay, and the shaft
station concrete plug. (Docket A-93-02,
Item V-B-2, CARD 14, Section 14.A)
Even if water were to pass through the
salt column, only a small fraction of the
salt column would be removed. Due to
the ongoing inward creep of the Salado
Formation, the salt column would still
be consolidated after such a dissolution
episode. Finally, DOE's PA calculations
do not include "credit" for bentonite
swelling, capture of water by clay, or the
adsorption of water into dry halite'all
processes that would tend to reduce
water predicted to reach the salt
column'and the PA results are therefore
conservative. Therefore, EPA concludes
that dissolution of the salt column is not
a concern. (Docket A-93-02, Item V-B-
2, CARD 14, Section 14.E; Item V-B-3,
Section F.2)
Commenters questioned the ability of
the shaft seals to perform as expected
because the material and construction of
the seals have not been tested. However,
EPA found that DOE performed and
referenced numerous tests and
experiments to establish the material
characteristics of importance to
containment of waste at the WIPP. The
characteristic of primary importance is
the material's permeability, the degree
to which fluids can travel through the
material. The permeability of concrete,
asphalt, and bentonite clay are well
documented, and DOE performed
numerous experiments to demonstrate
the applicability of these characteristics
to the WIPP's site specific conditions
(e.g., high brine concentration). The
DOE documented many laboratory and
insitu tests of the permeability of
compacted crushed salt including a
largescale field test to demonstrate the
feasibility of implementing such a seal
measure. (Docket A-93-02, Item II-G-2,
Appendices SEAL, PCS, DEL, and
MASS)
The technology planned for
constructing the shaft seals has been
tested in the real world. The
construction equipment and procedures
necessary to emplace the seal materials
are in large part the same as those used
to excavate the WIPP, but used in
reverse. Except for salt, the shaft seal
component materials are commonly
used in construction. Salt has been
extensively tested to determine its
properties and behavior in the
conditions which will exist in the shafts
after the WIPP is closed. The EPA finds
that the shaft seal design has undergone
extensive technical review and testing
by DOE that shows it is feasible to
construct and is expected to perform as
intended. (Docket A-93-02, Item V-B-
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2, CARD 14, Section 14.E; Item V-B-3,
Section F.2)
As commenters pointed out, and EPA
agrees, many changes may occur in
knowledge of construction materials
and in construction methods and
equipment during the 35 years before
the WIPP is expected to be closed. The
DOE provided a final design for the
shaft seals which could be constructed.
However, EPA recognizes the fact that
technology may change and expects the
shaft seal plans to be periodically
reviewed and revised to take full
advantage of new knowledge or
construction equipment in the future.
Acknowledgment of this circumstance
does not mean that the existing plans
are inadequate, or that major changes in
the design are anticipated. Periodic
review of the WIPP authorization(s) to
operate is required by the various
statutes and regulations applicable to
the WIPP, including EPA's review of
recertification applications every five
years, and the State of New Mexico's
review of the hazardous waste permit at
least every ten years. Shaft seal design
changes may be proposed by DOE and
perhaps approved by EPA several times
before the end of the WIPP disposal
operations phase. Significant changes in
the designs will be required to go
through public noticeandcomment
procedures before approval by EPA.
(§194.65-66)
b. Panel Closure System. Panel
closures are needed primarily during
active disposal operations at the WIPP
and during preparations for final closure
of the entire facility. Relative to long-
term performance, they can serve to
block the flow of brine between panels.
The DOE provided four options for a
panel closure system in the CCA, but
did not specify which panel closure
option would be used at WIPP. The EPA
reviewed the four panel closure system
options proposed by DOE and
considered that the intended purpose of
the panel closure system is to prevent
the existing disturbed rock zone
("DRZ") in the panel access drifts
(tunnels) from increasing in
permeability after panel closure (which
could allow greater brine flow). The
EPA considers the panel closure system
design identified as "Option D" to be
the most robust panel closure design.
(Docket A-93-02, Item II-G-1, CCA
Chapter 3 and Appendix PCS; Item V-
B-2, CARD 14, Section 14.E; Item V-B-
3, Section F.2) The EPA based its
evaluation of compliance for the
proposed rule on the Option D panel
seal design and proposed to establish a
certification condition requiring DOE to
implement the Option D design. The
EPA believes that the proposed design
on which compliance was based should
be actually implemented at the site. The
EPA also proposed to require DOE to
use Salado mass concrete (concrete
made with Salado salt) for construction
of the concrete barrier component of the
panel closure. This substitution
eliminates the potential for degradation
and decomposition of fresh water
concrete by infiltration of brine. The
EPA determined that implementation of
Option D is adequate to achieve the
long-term performance modeled in the
PA, since DOE shows that the use of a
concrete barrier component is capable of
providing resistance to inward
deformation of the surrounding salt and
prohibiting growth of the DRZ from its
initial state. (Docket A-93-02, Item V-
B-13)
Contrary to public comments, EPA
found that the panel closures can be
constructed using currently available
and widely used technology. Mixing
and transportation of concrete, using
special measures to prevent segregation
of fine and coarse particles (as required
in the Panel Closure System
construction specifications), and
placement in confined spaces by
pumping, is used routinely in bridge
and building foundations, dams, and in
water supply, subway and highway
tunnels. The steel forms in which the
concrete will be confined are somewhat
unusual in shape, but the methods of
construction are fairly simple and
standardized. The Salado mass concrete
mix is specially formulated for use in
the WIPP, but it has been extensively
tested to determine its properties (e.g.,
strength and resistance to chloride
degradation) as explained in
"Variability in Properties of Salado
Mass Concrete." (Docket A-93-02, Item
II-G-1, Ref. No. 662)
One commenter asked that EPA revise
its panel seal design condition so that
DOE may reassess the engineering of
panel closures when panels are to be
closed in the future. The EPA proposed
a certification condition (Condition 1)
requiring DOE to implement the panel
seal design that it designated as Option
D in the CCA. The Option D design shall
be implemented as described in the
CCA, except that DOE is required to use
Salado mass concrete rather than fresh
water concrete. Nothing in this
condition precludes DOE from
reassessing the engineering of the panel
seals at any time. Should DOE
determine at any time that
improvements in materials or
construction techniques warrant
changes to the panel seal design, DOE
must inform EPA. If EPA concurs, and
determines that such changes constitute
a significant departure from the design
on which certification is based, the
Agency is authorized under § 194.65 to
initiate a rulemaking to appropriately
modify the certification. The EPA has
retained the proposed Condition 1,
related to the panel closure system,
without change in the final rule. (See
also "Conditions" and "Significant
Changes to the Final Rule" sections of
this preamble.)
2. Results of Assessments, Input
Parameters to Performance Assessments,
Assurance Requirements, and Waste
Acceptance Criteria
Sections 194.14(c) through (f) require
DOE to submit the results of
assessments conducted in accordance
with 40 CFR Part 194; a description of
the input parameters associated with
such assessments and the basis for
selecting such parameters;
documentation of measures taken to
meet the assurance requirements of 40
CFR Part 194; and a description of the
waste acceptance criteria and actions
taken to assure adherence to such
criteria. The EPA proposed that DOE
complied with §§ 194.14(c) through (f)
based on EPA's finding that DOE
submitted the information required. The
EPA received numerous public
comments on the results of assessments,
input parameters to the PA, assurance
requirements, and the waste acceptance
criteria. A discussion of EPA's
responses to substantive comments can
be found in the corresponding sections
of the preamble. Based on these
responses, EPA finds that DOE complies
with §§ 194.14(c) through (f). For further
discussion, refer to CARD 14, Sections
14.C, 14.D, 14.E, 14.F (Docket A-93-02,
Item V-B-2) and Sections H.2, 1.2, J.2,
and K.2 of the technical support
document for § 194.14 (Docket A-93-02,
Item V-B-3).
3. Background Radiation, Topographic
Maps, Past and Current Meteorological
Conditions
For the CCA, DOE was required to
describe the background radiation in air,
soil and water in the vicinity of the
disposal system and the procedures
employed to determine such radiation
(§ 194.14(g)), provide topographic maps
of the vicinity of the disposal system
(§ 194.14(h)), and describe past and
current climatic and meteorological
conditions in the vicinity of the disposal
system and how these conditions are
expected to change over the regulatory
time frame (§ 194.14(1)). The EPA
proposed that DOE complied with the
requirements of §§ 194.14 (g), (h), and
(i). The EPA did not receive substantive
comments on these issues, except for
dissolution related to climate change. A
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27363
discussion of EPA's response to the
substantive comments on dissolution
can be found in the Performance
Assessment, Geological Scenarios and
Disposal System Characteristics section
of this preamble. The EPA finds that
DOE complies with §§194.14 (g)
through (i). For further discussion, refer
to Sections 14.K, 14.L, and 14.M of
CARD 14 (Docket A-93-02, Item V-B-
2) and Sections H.2, L.2, N.2 and N.4 of
the technical support document for
§194.14 (Docket A-93-02, ItemV-B-3).
4. Other Information Needed for
Demonstration of Compliance
The DOE was also required, under
§ 194.14(j), to provide additional
information, analyses, tests, or records
determined by the Administrator or the
Administrator's authorized
representative to be necessary for
determining compliance with 40 CFR
Part 194. After receipt of the CCA dated
October 29, 1996, EPA formally
requested additional information from
DOE in seven letters dated December 19,
1996, and February 18, March 19, April
17, April 25, June 6, and July 2, 1997.
(Docket A-93-02, Items II-I-l, II-I-9,
II-I-17, II-I-25, II-I-27, II-I-33, and II-
1-37, respectively) The information
requested in these letters was necessary
for EPA's completeness determination
and technical review. EPA staff and
contractors also reviewed records
maintained by DOE or DOE's
contractors (e.g., records kept at the
Sandia National Laboratories Records
Center in Albuquerque, New Mexico).
No additional laboratory or field tests
were conducted by DOE at EPA's
specific direction; however, DOE did
conduct and document laboratory tests
after October 29, 1996, in order to
present additional data to the
Conceptual Model Peer Review Panel.
(Docket A-93-02, Item II-A-39)
The EPA proposed that DOE complied
with § 194.14(j) because it responded
adequately to EPA's formal requests for
additional information, analyses, and
records. The EPA did not formally
request additional information from
DOE after publication of the proposed
rule. However, in response to
comments, EPA did verbally ask DOE
and Sandia National Laboratory for
information and other assistance in
calculations related to the Hartman
scenario, drilling into fractured
anhydrite, and the CCDFGF code and
quasi-static spreadsheet with regard to
air drilling. (Docket A-93-02, Items IV-
E-24, IV-E-25, IV-E-26, and IV-E-27)
In addition, DOE voluntarily submitted
information on the proposed rule that
was considered as comments.
All documents sent to EPA regarding
certification of the WIPP are available in
EPA Air Docket A-93-02. Additional
information relevant to EPA's
certification evaluation that was
reviewed by the Agency (e.g., DOE data
records packages, quality assurance
records, and calculations of actinide
solubility for americium, plutonium,
thorium and uranium) is also publicly
available. Documentation of peer review
panel meetings conducted after receipt
of the CCA has been placed in the EPA
docket. See Docket A-93-02, Item V-B-
1 for further information on the location
of all documentation reviewed by EPA.
5. Conclusion
The EPA received numerous public
comments on the proposed rule
regarding § 194.14. EPA has thoroughly
reviewed the public comments and
addressed all issues raised therein. On
the basis of its evaluation of the CCA
and supplementary information, and the
issues raised in public comments, EPA
finds that DOE complies with all
subsections of 40 CFR 194.14, with the
condition that DOE must fulfill the
requirements set forth in Condition 1 of
the final rule. For additional
information on EPA's evaluation of
compliance for § 194.14, see CARD 14.
(Docket A-93-02, Item V-B-2)
B. Performance Assessment: Modeling
and Containment Requirements
(§§194.14, 194.23, 194.31 through
194.34)
1. Introduction
The disposal regulations at 40 CFR
Part 191 include requirements for
containment of radionuclides. The
containment requirements at 40 CFR
191.13 specify that releases of
radionuclides to the accessible
environment must be unlikely to exceed
specific limits for 10,000 years after
disposal. At the WIPP, the specific
release limits are based on the amount
of waste in the repository at the time of
disposal. (§ 194.31) Assessment of the
likelihood that the WIPP will meet these
release limits is conducted through the
use of a process known as performance
assessment ("PA").
The WIPP PA process culminates in a
series of computer simulations that
attempts to describe the physical
attributes of the disposal system (site
characteristics, waste forms and
quantities, engineered features) in a
manner that captures the behaviors and
interactions among its various
components. The computer simulations
require the use of conceptual models
that represent physical attributes of the
repository. The conceptual models are
then expressed as mathematical
relationships, which are solved with
iterative numerical models, which are
then translated into computer code.
(§ 194.23) The results of the simulations
are intended to show the potential
releases of radioactive materials from
the disposal system to the accessible
environment over the 10,000-year
regulatory time frame.
The PA process must consider both
natural and man-made processes and
events which have an effect on the
disposal system. (§§ 194.32 and 194.33)
It must consider all reasonably probable
release mechanisms from the disposal
system and must be structured and
conducted in a way that demonstrates
an adequate understanding of the
physical conditions in the disposal
system. The PA must evaluate potential
releases from both human-initiated
activities (e.g., via drilling intrusions)
and natural processes (e.g., dissolution)
that would occur independently of
human activities. The DOE must justify
the omissions of events and processes
that could occur but are not included in
the final PA calculations.
The results of the PA are used to
demonstrate compliance with the
containment requirements in 40 CFR
191.13. The containment requirements
are expressed in terms of "normalized
releases." The results of the PA are
assembled into complementary
cumulative distribution functions
("CCDFs") which indicate the
probability of exceeding various levels
of normalized releases. (§ 194.34)
As described above, 40 CFR Part 194
contains several specific requirements
for the performance assessment of
WIPP. It is often difficult to discuss one
of the requirements in isolation from the
others. For example, several public
comments raised concern about the
CCA's screening of the fluid injection
scenario from the PA and EPA's
subsequent analysis. In order for EPA to
adequately address the fluid injection
issue, the Agency must discuss multiple
requirements related to geology and
other characteristics specific to the
WIPP site (§ 194.14), models and
computer codes (§ 194.23), and the
screening process for both human-
initiated releases and releases by natural
processes (§§ 194.32 and 194.33).
Because so many of the PA issues have
similarly overlapping requirements and
are often complex, EPA has chosen to
combine the discussions. Therefore, the
following discussions are framed in
terms of the PA issues raised in
comments, rather than according to
specific PA requirements of the
compliance criteria. The following
sections discuss the major PA issues
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that were raised during public hearings
and the public comment period. For
more information on performance
assessment and related issues, refer to
CARDs 14, 23, 32, and 33. (Docket A-
93-02, Item V-B-2)
2. Human Intrusion Scenarios
a. Introduction. Section 194.32
requires DOE to consider, in the PA,
both natural and man-made processes
and events which can have an effect on
the disposal system. Of all the features,
events, and processes ("FEPs") that are
considered for the PA calculations, the
human-intrusion scenarios related to
drilling have been shown to have the
most significant impact on the disposal
system and its ability to contain waste.
(§194.33)
In preparing the CCA, DOE initially
identified 1,200 potential FEPs, both
natural and human-initiated, for the
WIPP PA. These FEPs were reduced in
number in the final PA calculations.
The DOE may eliminate FEPs from
consideration in the PA for three
reasons:
• Regulatory—FEPs can be omitted
based on regulatory requirements. For
example, drilling activities that occur
outside the Delaware Basin do not have
to be considered in the PA, according to
§§194.33(b)(3)(i) and 194.33(b)(4)(i).
• Probability—FEPs can be omitted
because of the low probability that the
FEP will occur. For example, DOE
determined that the probability of a
meteorite landing in the vicinity of the
WIPP is so low that it does not need to
be considered in the PA. (§ 194.32(d))
• Consequences—FEPS can be
omitted because the consequences
resulting from the FEP, even if it does
occur, are so small. For example, there
would be no consequences on the
repository or the containment of waste
if an archeological excavation took place
on the surface in the vicinity of the
WIPP. (§194.32(a))
The following sections discuss the
major public comments on human
intrusion scenarios. Generally, public
comments related to whether or not the
scenario was appropriately screened by
DOE and to EPA's subsequent
evaluation of this screening. Some
comments addressed whether DOE's
modeling of events was appropriate.
The human intrusion scenarios
discussed below are: spallings releases,
air drilling, fluid injection, potash
mining, and carbon dioxide injection.
For more information on human
intrusion scenarios, refer to CARDs 32
and 33. (Docket A-93-02, Item V-B-2)
b. Spallings. The DOE's models for
the PA included five ways in which
radioactive waste could leave the
repository and escape to the accessible
environment: cuttings,11 cavings,12
spallings,13 direct brine release, and
transport of dissolved radionuclides
through the anhydrite interbeds (i.e.,
layers of rock immediately above the
repository). The first four of these
potential release pathways involve
direct releases of radiation to the earth's
surface in cases where people drill a
borehole while searching for resources.
The DOE's model for computing
releases of radiation due to spallings
was of particular concern to the
Conceptual Models Peer Review Panel
which reviewed each of the conceptual
models developed for the purposes of
the PA. (See Docket A-93-02, Item V-
B-2, CARD 23, Section 7.) The peer
review panel found the spallings
conceptual model inadequate because it
did not fully model all potential
mechanisms that may cause pressure-
driven solid releases to the accessible
environment. (Docket A-93-02, Item II-
G-12, p. 74) The DOE presented
additional experimental evidence and
the results of other modeling to the peer
review panel and requested that it
consider whether the spallings volumes
predicted by the original inadequate
spallings model were reasonable for use
in the PA. (Docket A-93-02, Items II-G-
22 and II-G-23) After considering this
additional information, the peer review
panel concluded that the spallings
values in the CCA are reasonable for use
in the PA. The panel concluded that,
while the spallings model does not
accurately represent the future state of
the repository, its inaccuracies are
conservative and, in fact, may
overestimate the actual waste volumes
that would be expected to be released by
a spallings event. (Docket A-93-02,
Item II-G-22, Section 4, p. 18)
The spallings conceptual model
relates to the following requirements of
§ 194.23: documentation of conceptual
models used in the PA (§ 194.23(a)(l));
consideration and documentation of
alternative conceptual models
(§ 194.23(a)(2)); and reasonable
representation of future states of the
repository in conceptual models
(§ 194.23(a)(3)(i)). The EPA proposed
that DOE met the requirements of
§ 194.24(a)(l) and (a)(2), and, for all
conceptual models except the spallings
11 "Cuttings" refers to material, including waste,
that is cut by a drill bit during drilling and is
carried to the surface by the drilling fluid as it is
pumped out of the borehole.
12 "Cavings" refers to material that falls from the
walls of a borehole as a drill bit drills through.
Cavings are carried to the surface by the drilling
fluid as it is pumped out of the borehole.
13 "Spallings" refers to releases of solids pushed
up and out by gas pressure in the repository during
a drilling event.
conceptual model, § 194.24(a)(3)(i). The
EPA did not propose, however, to
determine that the spallings model
incorporated in the CCA PA "reasonably
represents possible future states of the
repository," as stated in § 194.24(a)(3)(i).
The EPA proposed to accept the
spallings model for the purposes of
demonstrating compliance with
§ 194.23(a)(3)(i) on the basis that it has
been determined to produce
conservative overestimates of potential
spallings releases. (62 FR 58807) The
Agency now concludes that DOE has
met the requirements of § 194.23 in its
final rule. (See Docket A-93-02, Item
V-B-2, CARD 23, Section 7.4.)
The public commented on four
aspects of DOE's spallings modeling and
EPA's evaluation of that modeling:
adequacy of DOE's spallings modeling,
purpose and approach of EPA's
spallings modeling, use of DOE's
GASOUT code for modeling spallings,
and the need to include additional
spallings mechanisms.
Some commenters expressed concern
that DOE's conceptual model for
spallings used in the PA did not
adequately represent spallings releases,
as stated initially by the Conceptual
Model Peer Review Panel. However,
others indicated that DOE had worked
on the spallings model extensively since
the peer review panel's review, and that
the spallings model demonstrated that
the volume of releases due to spalling
would be small.
The EPA agrees that the spallings
conceptual model was inadequate to
represent possible future states of the
repository. In response to the
Conceptual Models Peer Review Panel,
DOE did substantial additional work,
developed a separate mechanistically-
based model and provided supporting
experimental data. The peer review
panel concluded that the spallings
model used in the CCA PA calculated
release volumes that were reasonable
and probably conservative. (Docket A-
93-02, Item II-G-22) On the basis of
this additional work, EPA concludes
that the spallings release volumes
calculated by the CCA spallings model
are acceptable. Based upon this work,
the Agency also agrees with those
commenters who stated that spallings
would result in only a small volume of
waste being released to the accessible
environment through spallings.
Commenters asked for clarification of
EPA's purpose in producing its
spallings evaluation reports for the
proposed rule. (Docket A-93-02, Items
III-B-10 and III-B-11) They also
questioned EPA's technical approach in
these reports, particularly the
discretization (time and space intervals).
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Discretization is important because if
intervals are too large, modeling may
not calculate or may incorrectly
calculate some important events, and if
intervals are too small, modeling will be
time-consuming and inefficient.
The EPA prepared its Spallings
Evaluation and Supplemental Spallings
Evaluation for the proposed rule in
order to model simplistically the
transport of spallings releases up a
borehole during blowout. The spallings
model used in the CCA PA did not
examine transport; rather, DOE's
spallings model took the approach that
all waste broken loose and able to move
would actually reach the earth's surface.
The Agency used an independent model
to investigate if DOE's spallings
conceptual model would give
conservative estimates of spallings
releases. The EPA believed this would
determine if the calculated spallings
releases were potentially acceptable for
use in PA, despite the flaws in DOE's
model. The EPA undertook these
studies early in its own review, and in
the Conceptual Models Peer Review
Panel's review of the spallings
conceptual model, when both the Panel
and the Agency were concerned about
the results of the model.
After EPA completed its own
modeling, DOE performed additional
studies using an alternative,
mechanistic conceptual model for
spallings. (Hansen et al., Spallings
Release Position Paper, Docket A-93-
02, Item II-G-23) DOE's additional
studies showed that its original
spallings conceptual model always
predicted a greater volume of releases
than the mechanistic spallings
conceptual model that used a more
realistic approach to calculate spallings
releases. As a result, both the
Conceptual Models Peer Review Panel
and EPA concluded that released
volumes estimated using the original
CCA spallings conceptual model were
reasonable and conservative. The EPA
found DOE's analysis in the Spallings
Release Position Paper to be more
conclusive than the Agency's studies in
its Spallings Evaluation and
Supplemental Spallings Evaluation.
DOE's analysis was an improvement
over EPA's analysis because it was more
thorough, it used much finer
discretization (smaller time and space
intervals) which allowed more specific
predictions, and it predicted both
volumes and activity of spallings
releases. As described in the proposed
rule, EPA examined the Spallings
Release Position Paper and concluded
that the spallings release volumes
calculated by the spallings model used
in the PA are conservative and,
therefore, acceptable to demonstrate
compliance with the waste containment
requirements of 40 CFR 191.13. (62 FR
58807) This conclusion is based not on
the EPA's spallings reports prepared for
the proposed rule, which have been
questioned by commenters, but on the
additional spallings analysis performed
by DOE, presented to the Conceptual
Models Peer Review Panel, and found
by EPA to demonstrate that the spallings
release volumes used in the CCA PA are
conservative. (Docket A-93-02, Item III-
B-2; Item V-B-2, CARD 23; and Item V-
C-l)
Some commenters expressed concern
about the stability of Sandia National
Laboratory's GASOUT computer code
that calculates spallings releases. One
individual had used this code to
calculate spallings releases due to air
drilling, but other commenters stated
that it was not appropriate to apply the
GASOUT code to the air drilling
scenario. (Air drilling refers to the
practice of using air or other substances
lighter than mud as a drilling fluid.)
The EPA agrees that the GASOUT
code may not be stable under some
conditions. GASOUT was designed to
model blowout of waste during the first
few seconds after borehole penetration,
where the driller uses mud in the
borehole to reduce friction during
drilling. The GASOUT code was only
intended to be used under specific
conditions of waste tensile strength14
and permeability. (Docket A-93-02,
Item II-E-9) Within its range of
applicability, GASOUT produces results
that are consistent with results obtained
by other modeling approaches, such as
the quasi-static model and the coupled
numerical model. (Docket A-93-02,
Item II-G-23) However, if GASOUT is
not used as designed, it may well be
unstable or may calculate invalid
results. In particular, EPA agrees with
those commenters stating that it is
inappropriate to use GASOUT to
analyze the releases of spallings due to
air drilling. The programmer of the
GASOUT code himself has said that this
code was not designed to model drilling
using compressible fluids such as air.
(Docket A-93-02, Item II-E-9) For
further discussion of the GASOUT code,
see the discussion of air drilling below
in this preamble.
Some commenters stated that DOE
had erroneously excluded from the PA
the stuck pipe 15 and gas erosionl6
spallings mechanisms, two additional
ways by which high gas pressure
conditions in the repository could result
in releases of solid radioactive waste to
the accessible environment. In
particular, commenters asserted that
DOE had selected an incorrect value for
the threshold waste permeability,17
above which the gas erosion and stuck
pipe mechanisms would not occur.
They also stated that DOE's assumptions
did not take into consideration the
presence of magnesium oxide (MgO)
backfill, which would affect both waste
permeability and tensile strength. These
commenters suggested that EPA should
do further analysis, should require DOE
to do more analysis, or should reject
DOE's spallings models and mandate
new models. Other commenters
countered that stuck pipe and gas
erosion would not occur because of the
physical and mechanical properties of
the waste.
The EPA has analyzed the validity of
DOE's decision to exclude stuck pipe
and gas erosion mechanisms from the
PA. In order for these mechanisms to
occur, there must be a combination of
high gas pressure, low waste
permeability, and low waste strength.
First, the gas pressure in the repository
must be sufficiently high to move waste
to and up the borehole. Low waste
permeability is necessary to maintain
the high pressure during the drilling
event. Finally, low waste tensile
strength is necessary to allow the waste
to break off and move toward the
borehole. The DOE has fabricated
simulated samples of waste that have
corroded or degraded and have
generated gas, as is expected to occur in
the WIPP once waste is emplaced, and
has measured the porosity18 of these
samples. Waste porosity and gas
pressure are related. This is because a
greater porosity means a greater volume
of spaces that gas can fill. By the ideal
gas law, when the same number of gas
molecules fill a larger volume, they will
have a lower gas pressure. The waste
porosity also affects waste permeability,
14 Tensile strength is resistance to being pulled
apart.
15 "Stuck pipe" means a situation where high gas
pressures in the repository would break off
radioactive waste and press it against a drill string
hard enough to stop or greatly reduce drilling. In
order to continue drilling, a drill operator would
raise and lower the drill string and, in the process,
could transport waste to the surface.
16 "Gas erosion" means a situation where
radioactive waste breaks off slowly due to high gas
pressures in the repository, enters drilling mud
surrounding the drill, and is transported to the
earth's surface in the mud.
17 "Waste permeability" is the degree to which
fluid can move through the waste.
18 "Porosity" is the fraction of space present that
is open and can store gases or liquids, as opposed
to space filled by solid matter.
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since more open space in waste means
more space where a liquid or gas can
penetrate. Based upon DOE's
measurements of the porosity of
surrogate waste samples, EPA found
that it is extremely unlikely that the
required conditions of high gas pressure
and low waste permeability will exist in
the WIPP. The high pressure necessary
to support gas erosion or stuck pipe
mechanisms would expand the WIPP
waste, creating a higher porosity (and
higher permeability). Thus, for the
characteristics of the WIPP waste, the
permeability would not become low
enough (less than 10~l6 square meters)
to create a gas erosion or stuck pipe
event. (Docket A-93-02, Item V-B-2,
CARD 23, Section 7.4) If the
permeability is not low enough for gas
erosion or stuck pipe, releases may still
occur, but the release mechanism will
be a short-lived blowout (spallings)
rather than gas erosion or stuck pipe.
Therefore, EPA concludes that DOE
correctly modeled only the "blowout"
process in its spallings model and
appropriately excluded stuck pipe and
gas erosion.
c. Air Drilling. Shortly before
publication of the proposed certification
decision, and after EPA's cutoff date for
addressing ANPR comments, EPA
received a comment containing a
technical report stating that DOE should
have included the human intrusion
scenario of air drilling in the PA, rather
than screening it out. (Docket A-93-02,
Item IV-D-01) Normally, oil drillers
will use mud in the borehole to reduce
friction and to carry away solids that
break free as the drill bit bores into the
ground. However, in some cases, drillers
might instead use air, mist, foam, dust,
aerated mud or light weight solid
additives as the fluid in the borehole.
Public comments noted that the air
drilling19 scenario was not included by
DOE in the CCA, and raised the
following issues:
• Air drilling technology is currently
successfully used in the Delaware Basin.
• Air drilling is thought to be a viable
drilling technology under the
hydrological and geological conditions
at the WIPP site.
• Air drilling could result in releases
of radionuclides that are substantially
greater than those considered by DOE in
the CCA.
In response to these concerns, EPA
prepared a study on air drilling and its
likely impact on the WIPP (Docket A-
93-02, Item IV-A-1), placed it in the
docket, and allowed for a public
19 In this discussion, the term "air drilling" refers
to all forms of drilling using drilling substances
lighter than mud.
comment period of 30 days. (63 FR
3863; January 27, 1998) The EPA's study
examined the frequency of air drilling
near the WIPP, the likelihood that
drillers would use air drilling under the
conditions at the WIPP, and the
potential volume of radioactive waste
that could be released using air drilling.
In the report, the Agency concluded that
air drilling is not a common practice in
the Delaware Basin, and that air drilling
through the Salado, the geologic salt
stratum where the WIPP is located, is
not presently used in the Delaware
Basin near the WIPP. Because the use of
air as a drilling fluid is not current
practice in the Delaware Basin, EPA
found that DOE is not required to
include air drilling in the PA.
(§ 194.33(c)(l)) Nevertheless, the
Agency also modeled potential releases
of radioactive waste during air drilling,
and found that any releases would be
within the range calculated in the CCA
PA for mud-based drilling.
The EPA received a number of
comments on its air drilling report.
Some members of the public stated that
air drilling is a proven technology and
the frequency of its use by the oil and
gas industry is increasing. They
suggested that air drilling techniques are
not currently being used more widely
because of the limited knowledge of
new developments and the industry's
resistance to changing methods. The
commenters implied that if these
obstacles are overcome, air drilling will
occur widely in the future. One
commenter recommended that the
Agency require DOE to consider air
drilling using a frequency of 30% of all
wells, based upon a projected estimate
from DOE of the use of air drilling in the
entire U.S. in the year 2005. In contrast,
other commenters stated that air drilling
would be less economic than mud
drilling if the driller encountered any
interruption in the air drilling process.
The Agency recognizes that air
drilling is a proven technology for
extraction of oil and gas under
appropriate conditions. However, EPA
believes that it is inappropriate to use
speculative projections of future
practices in the oil and gas industry
across the U.S. in the PA or to guess that
a practice will be used more in the
future because some drillers may
currently misunderstand the
technology. The EPA's compliance
criteria require DOE to assume that
future drilling practices and technology
will remain consistent with practices in
the Delaware Basin at the time a
compliance application is prepared.
(§ 194.33(c)(l)) The EPA included this
requirement in the compliance criteria
to prevent endless speculation about
future practices, and to model situations
that are representative of the Delaware
Basin, rather than a wider area that is
not representative of conditions at the
WIPP site. (61 FR 5234; Docket A-92-
56, V-C-1, p. 12-12) The Agency chose
to use current drilling practices for
resources exploited in the present and
past as a stand-in for potential future
resource drilling practices. (61 FR 5233)
The specific frequency suggested by the
commenter is arbitrary because it
applies to the entire U.S. rather than the
Delaware Basin and because the
commenter provides no reason for
selecting an estimated frequency of air
drilling in 2005 rather than in some
other year. The DOE must abide by the
requirement of § 194.33(c)(l) to assume
that future drilling practices remain
consistent with practices in the
Delaware Basin at the time the CCA was
prepared (1996). Thus, the pertinent
issues are whether air drilling
constitutes current practice in the
Delaware Basin and, if so, how it could
affect potential releases from the WIPP.
Some commenters said that air
drilling is already occurring in the
Delaware Basin, and thus, should be
considered in the PA. One commenter
noted that EPA should look at the
frequency of air drilling in the Texas
portion of the Delaware Basin, as well
as in the New Mexico portion of the
Delaware Basin, consistent with
§ 194.33(c)(l). Commenters also raised a
concern that EPA's examination of well
files might underestimate the
occurrence of air drilling because
information on the drilling fluid used is
not always clear in the records. Another
commenter suggested that air drilling
could be left out of the PA only if it has
a probability of less than one chance in
ten thousand, under § 194.32(d).
The EPA agrees that the frequency of
air drilling needs to be examined in the
entire Delaware Basin. In response to
these public comments, EPA
supplemented the analysis in its initial
air drilling report by conducting a
random sample of wells drilled in the
New Mexico and Texas portions of the
Delaware Basin and has determined the
frequency of air drilling in the entire
Delaware Basin. (The initial report is
located at Docket A-93-02, Item IV-A-
1; the supplemented report is located at
Docket A-93-02, Item V-B-29.) The
Agency found that air drilling is not
used more frequently in the Delaware
Basin as a whole than in the New
Mexico portion of the Basin. At the 95%
statistical confidence level, EPA found
that, at most, only 1.65% of all wells in
the Delaware Basin may have been
drilled with air. In those records
examined, none of the wells were
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27367
drilled through the salt-bearing geologic
formation, as would be required to
penetrate the WIPP. This additional
information confirms the Agency's
conclusion (as stated initially in Docket
A-93-02, Item IV-A-1) that air drilling
is not a current practice in the Delaware
Basin.
The EPA agrees that the well drilling
records examined in its random sample
may not by themselves be conclusive
about whether air drilling was used at
specific wells. As an independent
confirmation of the extent of air drilling
in the Delaware Basin (and near the
WIPP specifically), EPA also
interviewed knowledgeable industry
contacts, many of whom were
experienced in air drilling. These
individuals independently confirmed
that air drilling is rarely practiced in the
Delaware Basin and that it is virtually
nonexistent in the vicinity of WIPP.
(Docket A-93-02, Item V-B-29) The
DOE also found similar results in an
exhaustive analysis of 3,349 wells in the
Delaware Basin. (Docket A-93-02, IV-
G-7) These independent sources of
information further verify EPA's
conclusion that air drilling is not a
current practice in the Delaware Basin.
In particular, air drilling through the
salt section (where the waste is present)
is not consistent with current drilling
practices in the Delaware Basin.
The EPA disagrees that the frequency
of air drilling must be less than one in
ten thousand wells in order for DOE to
leave it out of the PA. Section
194.33(c)(l) requires DOE to look at
"drilling practices at the time a
compliance application is prepared."
This requirement refers to typical
industry practices in the Delaware Basin
at the time a compliance application is
prepared. (See 61 FR 5230; Docket A-
92-56, Item V-C-1, p. 12-18; Docket A-
93-02, Item II-B-29, p. 50.) It was not
intended to apply to experimental
procedures, emergency procedures, or
conjectured future practices. The
Agency finds it unrealistic to consider a
specific deep drilling method to be
current practice or typical of drilling in
the Delaware Basin when it is used for
only a small percentage of all wells in
the Basin. As indicated in § 194.32,
deep drilling and shallow drilling are
events to be considered in the PA. The
Agency believes that DOE has correctly
implemented the requirements of
§ 194.32(d) by including the general
technique of deep drilling as a scenario
in the PA, rather than separately
analyzing the probability of each
potential kind of deep drilling.
One commenter stated that air drilling
is a viable technique under the
conditions in the vicinity of the WIPP
site. This commenter said that drilling
with air may even become the method
of choice in the WIPP area, since a
driller will prefer to use a technology
such as air drilling, which avoids loss
of circulation. Another commenter
expressed concern about the
conclusions of EPA's Analysis of Air
Drilling at WIPP (Docket A-93-02, Item
IV-A-1) that water inflow upon drilling
would prevent air drilling near the
WIPP and that air drilling is not an
economically feasible drilling method
near the WIPP. This commenter also
stated that EPA's estimates of the water
flow rate that can be tolerated during air
drilling were too low.
The EPA examined a report from a
commenter that found that water
inflows from the Culebra would not
prevent air drilling at the WIPP site. The
report based this premise on the
transmissivity in some parts of the WIPP
site. However, EPA disagrees that the
transmissivity threshold mentioned in
the report would provide sufficient
reason to conclude that air drilling was
currently practical in that area. The
range of transmissivities at the WIPP
site shows that air drilling is definitely
not feasible in some parts of the site,
and is unsuitable in other portions of
the site. The EPA also found that the
possibility of excessive water inflow
was only one of the reasons mentioned
by industry contacts as to why air
drilling was not used in the vicinity of
WIPP. Other reasons, cited in EPA's Air
Drilling Report, include sections of
unconsolidated rock above the salt
section and the potential for hitting
brine pockets in the Castile Formation.
(Docket A-93-02, Item V-B-29)
Because of the reasons industry contacts
gave for not conducting air drilling near
the WIPP, the Agency disagrees that air
drilling would ever become a preferred
method of drilling at the WIPP site.
Commenters were concerned that
there might be greater releases of waste
with air drilling than with mud drilling.
This is because air and foam are less
dense than mud, so it would take less
pressure inside the repository to push
waste toward the surface as solid waste
(spallings) or as waste dissolved in brine
(direct brine release). One individual
calculated spallings releases due to air
drilling using DOE's GASOUT computer
code, and found that releases due to air
drilling were several orders of
magnitude higher than the releases
computed in the CCA PA. (Docket A-
93-02, ItemII-D-120) Other
commenters countered that the
GASOUT code was not designed to
model spallings using air drilling, and
therefore, that the GASOUT code could
not be applied in this situation.
Although EPA concluded that there
was no need to include air drilling in
the PA, the Agency conducted its own
modeling of spallings due to air drilling
to respond to public concerns. (Docket
A-93-02, Item V-B-29, Section 6 and
Appendix A) The EPA used the quasi-
static model developed by DOE as a
mechanistic model of spallings, an
approach that provides greater modeling
flexibility than with the GASOUT code.
The quasi-static model tends to
overestimate releases of radioactive
waste because it predicts the total
volume of waste that is available for
transport. The total volume available for
transport would not all be released in
actuality because pressurized gas would
not be able to lift large, heavy particles
up to the earth's surface. Studies have
shown that the quasi-static model
generally predicts larger spalled
volumes than the model incorporated in
the GASOUT code. (Docket A-93-02,
Item II-G-23, Table 3-3) For air drilling
conditions, EPA estimated volumes of
releases to be within the range of
spallings values predicted by the CCA
and used in the PAVT evaluation.
The EPA also examined the effects of
air drilling on the combined,
complementary cumulative distribution
functions ("CCDFs") used to show
graphically whether the WIPP meets
EPA's containment requirements for
radioactive waste. (Docket A-93-02,
Item V-B-29, Section 6) The EPA found
that the CCDFs produced by DOE were
not significantly different from those
produced in the PAVT. In fact, releases
from the WIPP were still below the
containment requirements of § 191.13
by more than an order of magnitude
when air drilling is included as a
scenario.
The EPA determines that DOE does
not need to include air drilling in the
PA because it is not current practice in
the Delaware Basin. Further analyses,
conducted by EPA solely to allay the
public's concerns on this issue, showed
that spallings releases calculated in the
CCA and the PAVT encompass the
potential impacts of air drilling (were it
to occur) on compliance with the
containment requirements.
See CARD 32 for further discussion of
the screening of features, events, and
processes. (Docket A-93-02, Item
V-B-2)
d. Fluid Injection Commenters stated
that DOE should not have screened out
the human intrusion scenario of fluid
injection 20 from the final PA
20 The fluid injection discussed here refers to
either (1) brine disposal from oil activities, (2)
maintenance of pressure in existing oil production,
Continued
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calculations. Brine could be injected
into existing boreholes, enter the
repository, become contaminated and
flow to various release points. In
§ 194.32(c), EPA's compliance criteria
specifically require DOE to analyze the
effects of boreholes or leases that may be
used for fluid injection activities near
the disposal system soon after disposal.
The fluid injection scenario has been
of particular concern to the public
because of events that occurred in the
Rhodes-Yates oil field, about 40 miles
east of WIPP but outside the Delaware
Basin in a different geologic setting. An
oil well operator, Mr. Hartman
encountered a brine blowout in an oil
development well while drilling in the
Salado Formation in the Rhodes-Yates
Field. In subsequent litigation, the court
found that the source of the brine flow
was injection water from a long-term
waterflood borehole located more than a
mile away. A fluid injection scenario
causing the movement of fluid under
high pressure is referred to as "the
Hartman Scenario" after this case.
The DOE initially screened out this
activity from the PA because the
Department's modeling of fluid
injection indicated that it would result
in brine inflow values within the range
calculated in the CCA PA where there
is no human intrusion. (Docket A-93-
02, Item II-A-32) Both EPA and public
commenters on the Advance Notice of
Proposed Rulemaking did not believe
that DOE had performed sufficient
analyses to rule out the potential effects
of fluid injection related to oil
production on the disposal system.
Therefore, the Agency required DOE to
model fluid injection using more
conservative geologic assumptions
about the ability of Salado anhydrite to
transmit fluid. (Docket A-93-02, Item
II-I-17) This more conservative
modeling showed that fluid injection
would have little impact on the results
of the PA. (Docket A-93-02, Item II-I-
36) Based on this modeling and other
information submitted by DOE on the
frequency of fluid injection well
failures, EPA proposed that DOE's
screening was sufficient and realistic.
(62 FR 58806, 58822) Thus, EPA
concluded that fluid injection could be
screened out of the final PA calculations
based on low consequences to the
disposal system.
The EPA performed its own
independent review of fluid injection,
which showed that the injection
analysis must include the nature of
anhydrites, duration of injection
activities, and presence of leaking
boreholes. (Docket A-93-02, Item V-B-
22) As part of its analysis, the Agency
performed additional modeling of the
injection well scenario. The EPA
concluded that, although scenarios can
be constructed that move fluid to the
repository via injection, the probability
of such an occurrence, given the
necessary combination of natural and
human-induced events, is very low.
Several commenters stated that either
EPA or DOE needed to model the
Hartman Scenario. One commenter
stated that it should be proven that
DOE's BRAGFLO21 code can reproduce
what is believed to have happened in
the Hartman case. Some members of the
public also referred to modeling
performed by Bredehoeft and by
Bredehoeft and Gerstle which found
that the Hartman scenario could cause
releases in excess of the disposal
regulations (Docket A-93-02, Item II-D-
116 Attachment (b)); these commenters
stated that neither EPA nor DOE had
satisfactorily modeled the Hartman
Scenario.
The EPA examined Bredehoeft and
Gerstle's modeling of fluid injection at
the WIPP and finds their assumptions
highly unrealistic. In particular, the
report assumes that all brine is directly
injected into one anhydrite interbed in
the Salado Formation. The anhydrite
interbeds in the Salado are only a few
feet thick. Therefore, a driller would
need to plan specifically to deliberately
inject brine into the anhydrite interbeds
to have such a situation occur at the
WIPP. Also, well operators using fluid
injection for oil or gas recovery would
be attempting to inject brine into
formations where petroleum and gas
reserves are found, which are thousands
of feet below the Salado. If flooding due
to fluid injection occurred accidentally
in the vicinity of the WIPP, the flow of
fluid would not be limited to the narrow
band of one anhydrite interbed in the
Salado. Also, Bredehoeft and Gerstle's
report assumes that fractures in the
anhydrite will extend for three or more
kilometers and will remain open. This
would require extremely high pressures
to be generated by the brine injection
process. The EPA agrees that under very
unrealistic conditions, modeling can
show fluid movement toward the WIPP
under an injection scenario. However,
when using more realistic but still
conservative assumptions in the
modeling, fluid movement sufficient to
or (3) water flooding to increase oil recovery. In the
Delaware Basin, the fluid would most likely be
brine.
21 BRAGFLO predicts gas generation rates, brine
and gas flow, and fracturing within the anhydrite
marker beds in order to calculate the future of the
repository.
mobilize radioactive waste in the
disposal system does not occur.
In response to public comments, the
Agency tried to reproduce several of the
results obtained with Bredehoeft's
model using DOE's BRAGFLO model. In
two cases, EPA's modeling produced
flows similar to those in the March 1997
Bredehoeft report. (Docket A-93-02,
Item II-D-116) However, because the
Agency's study looked at flows in
multiple locations and Bredehoeft's
study does not specify the location of its
predicted flows, the results are not
directly comparable. The EPA also
attempted to replicate Bredehoeft's
modeling of high pressure conditions
that would be mostly likely to cause a
catastrophic event. However, the
Agency found that critical aspects of
Bredehoeft's work are not documented
sufficiently to make meaningful
comparisons using the BRAGFLO
computer code. In particular, the grid
spacing used in the model predictions
were unclear. This information is
necessary in order to recreate
Bredehoeft's simulation. Also, EPA was
unable to determine whether the length
to which fractures grow are based on
completely opened or partially opened
fractures. The Agency contacted the
primary author of the paper in order to
obtain additional critical information.
However, the author was not certain
how they had treated these aspects of
modeling and had no further
documentation. (Docket A-93-02, Item
IV-E-23) Because of insufficient
documentation of vital aspects of
modeling, the Agency could not
replicate Bredehoeft's results. In
addition, due to lack of proper
documentation it was not clear to EPA
that Bredehoeft's modeling represented
the Hartman Scenario. Therefore, EPA
finds that lack of agreement between the
Bredehoeft model and BRAGFLO does
not indicate that DOE's modeling is
inadequate. (Docket A-93-02, Item V-
B-22)
Several commenters had concerns
about EPA's Fluid Injection Analysis,
including its conclusions that the
geology and the current well
construction practices near the WIPP are
extremely different from the geology
and well construction practices that
occurred in the Hartman case. In
contrast, other commenters stated that
fluid injection is unlikely to occur near
WIPP and current well construction
practices in the area will prevent
injection well leakage. Some
commented that EPA's probability
estimates for the chain of events that
could lead to a blowout caused by fluid
injection were overly optimistic and
that the probability estimate ignores
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27369
experience with severe water flows in
New Mexico.
The EPA concluded that current well
construction practice makes it unlikely
that there could be a well failure of the
nature of the "Hartman scenario" that
occurred in the Rhodes-Yates field
outside the Delaware Basin. This is
because regulatory requirements for
drilling are much more rigorous near the
WIPP than was the case at the Rhodes-
Yates field at the time of the Hartman
case. Also, the Agency reiterates that
there are significant differences in the
geology near the WIPP and in the
Rhodes-Yates field where the Hartman
case occurred, that should not be
ignored. The vertical distance between
the formation where brine would be
injected for disposal and the formation
where the repository is located is greater
than the vertical distance that fluid is
believed to have traveled in the
Hartman case. This distance, and effects
of friction, would make it more difficult
for fluids to travel vertically upward at
the WIPP than in the Hartman case.
Interbeds near the WIPP site are more
numerous and are likely to be thinner
than in the Hartman case, thereby
reducing the likelihood of flow between
the repository and the WIPP boundary.
The Agency concludes that the geology
in the WIPP area will play an active role
in reducing fluid movement, or in an
extreme case, preventing a massive well
blowout. (Docket A-93-02, Item V-B-
22)
While EPA accepted DOE's argument
that the fluid injection scenario can be
screened out of the PA on the basis of
low consequence, DOE presented
supplemental information that also
indicated that the probability of a
catastrophic well failure would be low.
The EPA's Fluid Injection Analysis for
the proposed rule also examined the
chain of events necessary to cause
catastrophic failure for a well. The EPA
estimated that the probability of this
chain of events occurring for a given
well in the vicinity of the WIPP was
low'within the range of one in 56,889 to
one in 667 million. (Docket A-93-02,
Item III-B-22) These estimates of
probability were intended to illustrate
in this hypothetical failure scenario the
chain of events that must all occur for
an injection well to impact the WIPP.
The commenters objected to the lowest
probability estimate, but did not state
which probabilities or assumptions in
the chain of events that they believed
EPA had incorrectly selected. The EPA
notes that this estimate of low
probability was only one of many
reasons cited in the technical support
document for EPA's proposed
determination that fluid injection could
be screened from the PA. (Docket A-93-
02, Item III-B-22) After considering
geologic information, well history and
age, construction standards, and
operating practices, the Agency
concludes that reported water flows in
the Salado Formation in other areas of
New Mexico are not representative of
conditions in the vicinity of the WIPP.
(Docket A-93-02, Item V-B-22) Even if
an injection event takes place, the
predicted low consequence is sufficient
reason to remove it from consideration
in the PA.
One commenter stated that EPA
should require DOE to revise its PA
model to include the Hartman Scenario
and perform another PA. In contrast,
another commenter stated that fluid
injection events will not impact
repository performance, even with
conservative assumptions, so fluid
injection can be excluded from the PA.
The Agency finds that:
• Commenters'modeling of fluid
injection that predicted potential
releases exceeding EPA standards was
based upon unrealistic assumptions that
would maximize releases.
• The EPA tried to replicate scenarios
similar to the Hartman case using DOE's
BRAGFLO model. Some results were
similar in magnitude to modeling
results presented by commenters, but
not directly comparable.
• Modeling by DOE predicts that
fluid injection will cause low flows that
will not significantly impact the results
of PA.
• Well construction procedures near
the WIPP have changed due to
regulatory requirements; therefore, it is
unreasonable to assume that the same
well procedures from the Hartman case
will occur near the WIPP.
• There are significant geological
differences between the WIPP site and
the Rhodes-Yates field in the Hartman
case.
For all of these reasons, EPA
concludes that it is not necessary to
repeat the PA using the scenario of fluid
injection. (Docket A-93-02, Item V-B-
22; Also, see Docket A-93-02, Item V-
B-2, CARDs 23 and 32 for further
discussion of fluid injection.)
A related issue raised by commenters
was DOE's modeling of fractures in the
anhydrite interbeds directly above the
WIPP. Such fractures could allow
injected brine to enter the repository, to
dissolve waste, and to release
radioactivity outside the WIPP.
Commenters stated that DOE's model for
anhydrite fracturing was inadequate to
describe observed changes at the WIPP
and was not based on sufficient
experimental data. Some commenters
stated that DOE's model significantly
understates the length of fractures
compared to another modeling
technique, Linear Elastic Fracture
Mechanics ("LEFM"). Shorter fractures
would mean that contaminated brine
does not travel as easily, which lessens
releases.
The Agency disagrees that DOE's
modeling of anhydrite fracturing is
inadequate. The independent
Conceptual Models Peer Review Panel
found that the "type of fracture
propagation and dilation used in the
conceptual model has been
substantiated by in situ tests." The
Panel also found that the conceptual
model was adequate. (Docket A-93-02,
Item II-G-1, Appendix PEER.l) The
EPA finds that the mathematical
"porosity model" used in the CCA PA
adequately implements the conceptual
model for anhydrite fracturing. This
mathematical model used a combination
of field test data at lower pressures and
the theory of continuum mechanics at
higher pressures.
Some features of LEFM are not
appropriate for representing the
anhydrite interbeds. LEFM predicts that
a single, long fracture hundreds of feet
long will be created in a homogeneous
medium. The Agency finds that this
approach is inappropriate for the
anhydrite interbeds in the Salado at the
WIPP, which already contain numerous
small fractures. (Docket A-93-02, Item
IV-G-34, Attachment 5; Item V-C-1,
Section 194.23) Field tests found that
fractures branched into a series of
fractures following preexisting fractures
or weaknesses near the injection hole,
rather than producing a single, long-
distance fracture. In the case of fluid
injection, these fractures would store
fluid, which would slow down and
shorten further fractures. The pre-
existing fractures will produce a fracture
front, such as that modeled by
BRAGFLO, rather than a single fracture
radius, as modeled by an LEFM. Two
studies cited by commenters as support
for use of LEFM in fact question the
applicability of LEFM to WIPP
anhydrites and recommend that DOE
consider alternative conceptual models.
(e.g., Docket A-93-02, Item IV-G-38)
The EPA concludes that BRAGFLO is
more appropriate to use for WIPP than
a pure linear elastic fracture mechanics
model because there are pre-existing
fractures in the anhydrite layers that
must be accounted for in the conceptual
model. The EPA finds that the
conceptual model based on a single
fracture is fundamentally flawed for
application in WIPP anhydrites. The
Agency also finds that the model
incorporated in the PA is appropriate,
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and that further modeling with revised
computer codes is not necessary.
e. Potash Mining. Public comments
raised concerns about DOE's estimates
of the potash reserves in the vicinity of
the WIPP and DOE's evaluation of the
solution mining scenario. The primary
effects that mining could have on the
repository are opening existing fractures
in the geologic formations above the
WIPP and increasing hydraulic
conductivity as a result of subsidence.
These effects could change the flow and
path of ground water through the
Culebra dolomite.
Several commenters stated that DOE
underestimated the amount of potash in
the vicinity of the WIPP and therefore
underestimated the impact that
extracting the additional potash would
have on the performance of the
repository. In the CCA, DOE provided
estimates of the mineable potash
reserves both outside and within the
WIPP Land Withdrawal Area. The
compliance criteria require DOE to
consider excavation mining of only
those mineral resources which are
extracted in the Delaware Basin.
(§ 194.32(b)) Therefore, potash resources
of a type or quality that are currently not
mineable for either technological or
economic reasons need not be addressed
in DOE's analysis. The EPA determined,
through an independent analysis, that
the CCA appropriately represents the
extent of currently mined resources, in
accordance with the criteria. The EPA
also determined that DOE appropriately
considered the impact that such
resources and excavation mining could
have on the performance of the
repository. (Docket A-93-02, Item V-B-
2, CARD 32)
Additional comments were received
on DOE's screening of solution mining
from the PA. The DOE determined that
solution mining of potash is not
occurring in the vicinity of the WIPP
and can be omitted from the PA based
on the regulatory requirement that only
currently occurring (or near-future)
practices be considered in the PA.
(§ 194.32(c)) The EPA agrees with DOE
that solution mining is not a current
practice and can be omitted from the PA
on regulatory grounds.
The DOE submitted supplemental
information which related to the
potential effects of solution mining for
potash. (Docket A-93-02, Item II-I-31)
The DOE concluded that the impacts of
solution mining for potash would be the
same as those for room and pillar
mining, and that the potential
subsidence-induced hydraulic effects in
the Culebra would be similar to those
for typical mining practices. Some
comments disputed this conclusion,
stating that the effects of solution
mining on the repository would be
substantially different than those from
conventional mining and could cause
the WIPP to exceed the containment
requirements. After examining these
comments, EPA concluded that the
scenarios set forth in the comments
were not realistic and that the
commenter's conclusion was based on
an extreme example of subsidence from
solution mining. The EPA disagrees
with the comments and concludes that
subsidence in the vicinity of the WIPP
would not vary significantly with
solution mining compared to
conventional mining.
The EPA concludes that solution
mining for potash is appropriately
omitted from the PA because it is not a
current practice, and therefore, is not an
activity expected to occur prior to or
soon after disposal. As added assurance,
the Agency also finds that even if
solution mining of potash were to occur
in the vicinity of the WIPP, the potential
effects of such mining are consistent
with those from conventional
techniques and are therefore already
accounted for in the PA. (Docket A-93-
02, Item V-C-1, Section 8)
f. Carbon Dioxide Injection. Public
comments raised concerns that carbon
dioxide (CO2) injection is a current
drilling practice in the Delaware Basin
that DOE inappropriately omitted from
the PA calculations. Carbon dioxide
flooding is the injection of CO2 into an
oil reservoir to improve recovery. CO2
injection is typically used in tertiary
recovery processes after the economic
limits for waterflooding have been
reached. When CO2 is injected and
mixing occurs, the viscosity of the crude
oil in the reservoir is reduced. The CO2
increases the bulk and relative
permeability of the oil, and increases
reservoir pressure so that the resulting
mixture flows more readily toward the
production wells. When CO2 begins to
appear at the producing well, it is
typically recovered, cleaned of
impurities, pressurized and re-injected.
The use of CO2 flooding for enhanced
oil recovery in west Texas and southern
New Mexico began in 1972. In this area,
most CO2 injection activity is located on
the Central Basin Platform and on the
Northwest Shelf. A limited number of
CO2 flooding projects have occurred in
the Texas portion of the Delaware Basin.
Economy of scale, oil prices, proximity
to CO2 supply and reservoir
heterogeneity are several of the
controlling factors that strongly
influence whether this technique is
applied at a given well. (Docket A-93-
02, Item V-C-1, Section 8)
In the CCA (Appendix SCR), DOE
determined that CO2 injection is not a
current drilling practice in the Delaware
Basin and therefore omitted it from
consideration in the PA. For the
proposed rule, EPA concurred with DOE
that CO2 injection was not a current
practice. However, as a result of the
public comments, EPA reviewed the
issue and determined that CO2 injection
does occur in the Texas portion of the
Delaware Basin. In responding to
comments, EPA found no evidence of
CO2 injection practices in the New
Mexico portion of the Delaware Basin.
(Docket A-93-02, Item V-C-1, Section
8) All CO2 injection projects found in
New Mexico occurred outside the
Delaware Basin. The EPA found that
CO2 injection has only limited potential
for use around WIPP because of site-
specific concerns related to reservoir
size, proximity to existing pipelines and
reservoir heterogeneity. However,
because EPA confirmed that CO2
injection is practiced in the Delaware
Basin, EPA conducted an analysis of the
consequences that CO2 injection could
have on the PA calculations.
In order to investigate the potential
effect of CO2 injection should it occur in
the future, EPA conducted some
bounding calculations. (Docket A-93-
02, Item V-C-1, Section 8) Using
numerous conservative assumptions,
EPA estimated the rate of CO2 flow
through a hypothetical wellbore
annulus into an anhydrite interbed at
the depth of the WIPP repository. For
example, grout in the wellbore annulus
is expected to degrade only along
portions of the wellbore; however, EPA
assumed that such degradation would
occur along the entire wellbore, thus
providing a continuous pathway for CO2
migration. Other conservative
assumptions included a long time frame
for injection, constant CO2 pressures at
the point of injection and at the
intersection of the interbed with the
borehole, and a high permeability in the
interbed. The EPA's calculations also
assumed that CO2 would be injected
into the Delaware Mountain Group
below WIPP and readily migrate to
Marker Bed 139, through which CO2 is
assumed to flow toward the repository.
These assumptions increase the
potential effect of the gas injection and
therefore increase the predicted
radionuclide releases that are calculated
for the performance of the WIPP
repository.
These simple but conservative
calculations for a hypothetical CO2
flood indicate that, even if it were to
occur, CO2 injection does not pose a
threat to WIPP. For the very
conservative assumptions specified in
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this study, even for long periods of time,
there is little potential for injected CO2
to ever reach the repository. In
summary, DOE determined that CO2
injection was not a current drilling
practice in the Delaware Basin and
therefore screened it from the PA based
on regulatory requirements. Based on
public comments, EPA identified
limited CO2 injection activities in the
Delaware Basin. The EPA conducted an
analysis of the effects of CO2 injection
on the repository and found that CO2
injection can be omitted from the PA
because of the minimal consequences
that would occur as a result of CO2
injection.
g. Other Drilling Issues. A few public
comments raised concerns about other
human intrusion related scenarios. For
example, some comments disagreed
with the drilling rates that were set forth
in the CCA. Other comments contended
that natural gas storage exists in the
Delaware Basin and should be
considered in the PA.
Several public comments stated that
the CCA did not provide drilling rates
that are consistent with the extensive
drilling throughout the area. The EPA
required DOE to include the effects of
drilling into a WIPP waste panel in the
PA. The DOE was required to separately
examine the rate of shallow and deep
drilling. Shallow drilling is defined in
§ 194.2 as drilling events that do not
reach a depth of 2,150 feet below the
surface and therefore do not reach the
depth of the WIPP repository. Deep
drilling is defined in § 194.2 as drilling
events that reach or exceed the depth of
2,150 feet and therefore reach or exceed
the depth of the repository. Both types
of drilling events include exploratory
and developmental wells. (See Docket
A-93-02, Item V-B-2, CARD 33 for
further discussion of drilling rates.)
The EPA accepted DOE's finding that
shallow drilling would not be of
consequence to repository performance
and was therefore not included in the
PA. (Docket A-93-02, Item V-B-2,
CARD 32, Section 32.G) The future rate
of deep drilling was considered in
DOE's PA. The deep drilling rate set
forth in the CCA for the Delaware Basin
is 46.775 boreholes per square kilometer
per 10,000 years.
Several commenters suggested that
DOE should use other, higher deep
drilling rates in the PA. Comments
stated that these higher rates, based on
drilling over limited areas near the
WIPP or on time periods shorter than
100 years (such as the last year or the
last 50 years), would be more consistent
with current drilling rates. The EPA's
criteria require that the deep drilling
rate be based on drilling in the Delaware
Basin over the 100-year period
immediately prior to the time that the
compliance application is prepared.
(§ 194.33(b)(3)) Although the drilling
rate dictated by EPA's requirements may
be lower than the current drilling rate,
the use of a 100-year drilling rate more
adequately reflects the actual drilling
that may be expected to take place over
the long term. (See Response to
Comments for 40 CFR Part 194, Docket
A-92-56, Item V-C-1, p. 12-11.) The
future rate of deep drilling in the PA
was set equal to the average rate at
which that type of drilling has occurred
in the Delaware Basin during the 100-
year period immediately prior to the
time that the compliance application
was prepared. Commenters did not
suggest that DOE had failed to include
known drilling events or had calculated
the rate inconsistently with EPA's
requirements. Therefore, EPA finds that
the approach taken by DOE meets the
regulatory requirements set forth in
§ 194.33(b). (Docket A-93-02, Item V-
B-2, CARD 33)
Natural gas storage facilities, in
underground cavities, are known to
exist in the Salado Formation outside
the Delaware Basin. However, neither
EPA nor DOE is aware of any natural gas
storage in the Salado Formation of the
Delaware Basin. Because there is no
known gas storage in the Delaware
Basin, DOE is permitted to omit it from
the PA according to the requirements of
§194.32(c).
In addition to determining that there
is no known gas storage in the Delaware
Basin, EPA conducted an analysis of the
effects that this activity would have on
the repository. The EPA's analysis,
presented in the response to comments,
shows that natural gas storage would
not affect the ability of the WIPP
repository to successfully isolate waste
because the migration potential of the
gas would be minimal.
3. Geological Scenarios and Disposal
System Characteristics
a. Introduction. 40 CFR 194.14(a)
requires DOE to describe the natural and
engineered features that may affect the
performance of the disposal system.
Among the features specifically required
to be described are potential pathways
for transport of waste to the accessible
environment. This information is
crucial to the conceptual models and
computer modeling that is done to
determine compliance with the
containment requirements and the
individual and ground-water protection
requirements. In addition to a general
understanding of the site, EPA required
specific information on hydrologic
characteristics with emphasis on brine
pockets, anhydrite interbeds, and
potential pathways for transport of
waste. The EPA also required DOE to
project how geophysical, hydrogeologic
and geochemical conditions of the
disposal system would change due to
the presence of waste. Geology also
relates to criteria at §§ 194.32 and
194.23, which require DOE to model
processes which may affect the disposal
system, and to use models that
reasonably represent possible future
states of the disposal system.
The EPA examined the CCA and the
supplemental information provided by
DOE and proposed to find that it
contained an adequate description of
the WIPP geology, geophysics,
hydrogeology, hydrology and
geochemistry of the WIPP disposal
system and its vicinity, and how these
conditions change over time. (62 FR
58798-58800) Several commenters
suggested that the WIPP site geology
and disposal system characteristics have
been incorrectly assessed or
inaccurately modeled. Commenters
expressed concern with the WIPP site
regarding Rustler recharge; dissolution,
including karst; presence of brine in the
Salado; use of two dimensional
modeling with the BRAGFLO computer
code instead of modeling the disposal
system using a three-dimensional
representation (2D/3D BRAGFLO),
earthquakes, and the gas generation
conceptual model. The EPA's response
to these comments is discussed below.
b. WIPP Geology Overview. The WIPP
is located in the Delaware Basin of New
Mexico and Texas and is approximately
26 miles southeast of Carlsbad, New
Mexico. This area of New Mexico is
currently arid, but potential future
precipitation increases were accounted
for in the PA. The Delaware Basin
contains thick sedimentary deposits
(over 15,000 feet, or 4572 meters, thick)
that overlay metamorphic and igneous
rock (1.1 to 1.5 billion years old). The
WIPP repository is a mine constructed
approximately 2,150 feet (655 meters)
below ground surface in the Permian
age (6200-250 million years old) Salado
Formation, which is composed
primarily of salt (halite).
The DOE considered the primary
geologic units of concern to be (from
below the repository to the surface): (1)
the Castile Formation ("Castile"),
consisting of anhydrite and halite with
pressurized brine pockets found locally
throughout the vicinity of the WIPP site;
(2) the Salado Formation ("Salado"),
consisting primarily of halite with some
anhydrite interbeds and accessory
minerals and approximately 2,000 feet
(600 meters) thick; (3) the Rustler
Formation ("Rustler"), containing salt,
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anhydrite, elastics, and carbonates
(primarily dolomite), with the Culebra
dolomite member of the Rustler as the
unit of most interest; and (4) the Dewey
Lake Red Beds Formation ("Dewey
Lake"), consisting of sandstone,
siltstone and silty claystone. The
geologic formations below these were
included in the screening of features,
events, and processes, but were not
included in the PA calculations because
they did not affect the performance of
the disposal system. See CARD 32,
Sections 32.A and 32.F, for a detailed
discussion of screening of features,
events, and processes. (Docket A-93-02,
Item V-B-2)
c. Rustler Recharge. Numerous
comments on the proposed rule were
related to whether the Rustler
Formation, primarily the Culebra
dolomite member, would be recharged;
that is, whether water will infiltrate
through the soil and underlying rock
and into the Culebra. Commenters
linked high infiltration to the potential
dissolution of the Culebra and other
members of the Rustler, concluding that
karst has been formed and contributes to
ground water flow. Commenters
claimed that the presence of karst
features would render DOE's ground
water flow models invalid. Site
characterization data and DOE's ground
water modeling indicate that infiltration
is very low and limited, if any,
dissolution is ongoing, contrary to
commenters statements.
The DOE indicated that the units
above the Salado (i.e., the Rustler, the
Dewey Lake and the Santa Rosa) are
classified as a single hydrostratigraphic
unit (i.e., equivalent to a geologic unit
but for ground water flow) for
conceptual and computer modeling. The
Rustler is of particular importance for
WIPP because it contains the most
transmissive units above the repository
(i.e., has the highest potential rate of
ground water flow). In particular, the
Culebra dolomite member of the Rustler
Formation is considered to be the
primary ground water pathway for
radionuclides because it has the fastest
ground water flow in the Rustler
Formation. The Culebra dolomite is
conceptualized as a confined aquifer in
which the water flowing in the Culebra
is distinct from rock units above or
below it and interacts very slowly with
other rock units. In general, fluid flow
in the Rustler is characterized by DOE
as exhibiting very slow vertical leakage
through confining layers and faster
lateral flow in conductive units. (Docket
A-93-02, Item V-B-2, CARD 14,
Sections 14.B.4 and 14.B.5) The DOE
stated that the Culebra member
conceptually acts as a "drain" for the
units around it, but that it takes up to
thousands of years for the Culebra to
respond to changes in the environment.
DOE's modeling indicates that the
Culebra ground water is still responding
to changes in precipitation from the
latest ice age. DOE's explanation for the
ground water flow in the units above the
Salado is embodied in the ground water
basin model which was introduced in
Chapter 2 of the CCA. The EPA did not
consider treatment of this issue in the
CCA to be adequate and requested
additional information. (Docket A-93-
02, Item II-I-17) The DOE provided
additional information in response to
this request. (Docket A-93-02, Item II-
1-31)
The ground water basin model, which
simulates recharge passing slowly
through the overlying strata before
reaching the portion of the Culebra
within the boundaries of the WIPP site
recognizes the possibility of localized
infiltration. (Docket A-93-02, Item V-
B-2, CARD 23) The DOE included
ground water recharge in its ground
water basin modeling for the Culebra
Member of the Rustler formation. The
DOE also acknowledged the water-
bearing capabilities of the Dewey Lake
and considered this possibility in the
PA evaluations. The DOE assumed that
the water table would rise in response
to increased recharge caused by up to
twice the current site precipitation.
Essentially, DOE's conceptual model
of flow in the Culebra assumes that the
Culebra is a confined aquifer in which
the flow slowly changes directions over
time, depending on climatic conditions.
The ground water basin model also
accounts for the current ground water
chemistry. Current geochemical
conditions are the result of past climatic
regimes and ground water responses to
those changes; because the ground water
chemistry is still adjusting to the current
conditions, it does not reflect the
current ground water flow direction in
the Culebra. This new interpretation
allows for limited but very slow vertical
infiltration to the Culebra through
overlying beds, although the primary
source of ground water will be lateral
flow from the north of the site. The EPA
reviewed DOE's conceptualization of
ground water flow and recharge, and
believes that it provides a realistic
representation of site conditions
because it plausibly accounts for the
inconsistencies in the current ground
water flow directions and the
geochemistry. The EPA examined this
treatment of recharge in the PA
modeling and determined it to be an
appropriate approach that reasonably
bounds and accounts for the impact of
potential future recharge. (See Docket
A-93-02, Item V-B-2, CARD 14,
Sections 14.B.4 and 14.B.5; CARD 23,
Section 2.4; and CARD 32, Section
32.F.4 for detailed discussions of
hydrogeology.)
Commenters also stated that DOE's
estimate of the age of ground water is
based on an unreliable methodology and
that the stable isotopic compositions of
most samples of ground water from the
Rustler Formation were found to be
similar to the composition of other,
verifiably young, ground water in the
area. The age of the ground water is
important because the ground water
basin model is based on the assumption
that the Rustler water is "fossil" water,
having been recharged under climatic
conditions significantly different from
the present. Because the isotopic data
can be interpreted differently, EPA
examined the entire spectrum of data
that could be used to assess infiltration
rates, including DOE's ground water
basin model, Carbon-14 data, and
tritium data. Based on these data, EPA
concluded that the ground water basin
model provides a plausible description
of ground water conditions in the
Culebra. The EPA also points out that
recent Carbon-14 data indicate that a
minimum age of 13,000 years is
appropriate for Culebra waters. Further,
different geochemical zones in the WIPP
are explained by differences in regional
recharge and long residence time.
(Docket A-93-02, Item II-I-31) The EPA
examined all data pertaining to ground
water flow in the Rustler, and believes
the DOE's total conceptualization
adequately described system behavior
for the purposes of the PA.
d. Dissolution. In the CCA, DOE
indicated that the major geologic
process in the vicinity of the WIPP is
dissolution. The DOE proposed that
three principal dissolution mechanisms
may occur in the Delaware Basin:
lateral, deep and shallow. (Docket A-
93-02, Item V-B-2, CARD 14, section
14.B.4) Deep dissolution refers to that at
the base of or within the salt section
along the Bell Canyon Castile
Formation; lateral dissolution occurs
within the geological units above the
Salado (progressing eastward from Nash
Draw); and shallow dissolution,
including the development of karst and
dissolution of fracture fill in Salado
marker beds and the Rustler, would
occur from surface-down infiltration of
undersaturated water. Lateral, strata-
bound dissolution can occur without
shallow dissolution from above.
To the west, the slight dip in the beds
has exposed the Salado to near-surface
dissolution processes; however, DOE
estimated that the dissolution front will
not reach the WIPP site for hundreds of
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27373
thousands of years. Near-surface
dissolution of evaporitic rocks (e.g.,
gypsum) has created karst topography
west of the WIPP site, but DOE
contended that karst processes do not
appear to have affected the rocks within
the WIPP site itself. The DOE indicated
that while deep dissolution has
occurred in the Delaware Basin, the
process of deep dissolution would not
occur at such a rate near the WIPP that
it would impact the waste containment
capabilities of the WIPP during the
regulatory time period. The DOE
concluded that the potential for
significant fluid migration to occur
through most of these pathways is low.
However, DOE also concluded that fluid
migration could occur within the
Rustler and Salado anhydrite marker
beds and included this possibility in PA
calculations. In the proposed rule, EPA
concluded that deep, lateral, and
shallow dissolution (including karst
features and breccia pipes) will not
serve as significant potential
radionuclide pathways and that the
potential for significant fracture-fill
dissolution during the regulatory time
period is low. (Docket A-93-02, Item V-
B-2, CARD 14, Section 14.B.5; Item V-
B-3, Section B.S.t)
Comments on the proposed rule
stated that shallow dissolution and karst
features occur at WIPP and will affect its
containment capabilities. The EPA does
not agree with DOE's assertion that the
distribution of salt in the Rustler is
solely a depositional feature because
Rustler transmissivity (which is related
to fracture occurrence in the Rustler)
corresponds somewhat to the
occurrence of salt in the Rustler. This
implies that some post-Rustler
dissolution has occurred which impacts
the fracturing in Rustler rocks. However,
the evidence observed by EPA indicate
many Rustler features were formed
millions of years ago (e.g., the breccia
zone in the exhaust shaft, or at WIPP-
18, where anhydrite/clay-rich strata may
be halite dissolution residues). Other
Rustler features (e.g., salt distribution in
the Rustler) could have occurred
sometime after the Rustler was
deposited, but there is no evidence to
indicate that ongoing dissolution of
soluble material in the Rustler or at the
Rustler-Salado contact will modify the
existing transmissivity to the extent that
the results of PA will be affected.
(Docket A-93-02, ItemV-B-2, CARD
14, Section 14.B.5)
The EPA concurs that the presence of
fractures and related fracture fill that
could be attributed to dissolution or
precipitation could significantly impact
ground water transport in the Rustler.
The DOE modeled the presence of
fractures using a dual porosity model,
and has accounted for permeability
variability by developing transmissivity
fields based upon measured field data
which reflect the varying transmissivity
values. This dual porosity conceptual
model recognizes that fluid may flow
through both the rock matrix and
fractures at the site. The use of dual
porosity assumes ground water flows
through fractures, but allows solutes to
diffuse into the matrix. The EPA
concludes that while fractures are
present in Rustler Formation units and
slow vertical infiltration does occur,
there is no evidence that indicates
fractures are conduits for immediate
dissolution of Rustler or Salado salts, or
that pervasive infiltration and
subsequent dissolution of the Salado
Formation or Rustler is a rapid, ongoing
occurrence at the WIPP site. Further,
ground water quality differences
between the more permeable units of
the Rustler Formation support relative
hydrologic isolation (i.e., the water in
the Magenta member interacts very little
with the water in the Culebra member),
or at least they support very slow
vertical infiltration that has not allowed
for extensive geochemical mixing of
ground waters in these units.
Many commenters suggested that
WIPP cannot contain radionuclides
because WIPP is in a region of karst
(topography created by the dissolution
of rock). Karst terrain typically exhibits
cavernous flow, blind streams, and
potential for channel development that
would enhance fluid and contaminant
migration. Numerous geologic
investigations have been conducted in
the vicinity and across the WIPP site to
assess the occurrence of dissolution
(karst) and the presence of dissolution-
related features. The EPA reviewed
information and comments submitted
by DOE, stakeholders, and other
members of the public regarding the
occurrence and development of karst at
the WIPP. (Docket A-93-02, Item V-B-
2, CARD 14, section 14.B.5) The EPA
acknowledges that karst terrain is
present in the vicinity of the WIPP site
boundary near the surface. Near-surface
dissolution of evaporitic rocks (e.g.,
gypsum) have created karst topography
west of the WIPP site. Nash Draw,
which (at its closest to WIPP) is
approximately one mile west of the
WIPP site, is attributed to shallow
dissolution and contains karst features.
(Docket A-93-02, Item V-B-3, Section
B.S.t) The EPA also recognizes the
potential importance of karst
development on fluid migration.
The EPA agrees that karst features
occur in the WIPP area but concluded
that karst features are not pervasive over
the disposal system itself. The EPA
examined hydrogeologic data (e.g.,
transmissivity and tracer tests) from
DOE's wells at and near the WIPP site
and found no evidence of cavernous
ground water flow typical of karst
terrain at the WIPP site. Similarly, a
field investigation conducted by EPA
during the summer of 1990 to assess the
occurrence of karst features showed no
evidence of significant karst features,
such as large channels, dolines,
sinkholes, or collapsed breccias (other
than those at, for example, at WIPP-33
and Nash Draw) in the immediate WIPP
vicinity. (55 FR 47714) Available data
suggest that dissolution-related features
occur in the immediate WIPP area (e.g.,
WIPP-33 west of the WIPP site), but
these features are not pervasive and are
not associated with any identified
preferential ground water flow paths or
anomalies at the WIPP site. (Docket A-
93-02, Item V-B-2, CARD 14, Section
14.B.5) Therefore, the groundwater
modeling in the PA is adequate.
Several commenters stated that poor
Rustler Formation core recovery at
WIPP indicates the presence of karst.
The commenters state that fragmented
core samples containing dissolution
residues are a clear indication of
unconsolidated or cavernous zones
capable of transmitting water with little
resistance. However, core recovery is
related to rock strength, and does not
necessarily have an association with
local hydrologic conditions. In the case
of WIPP, cores that were attempted
through fractured material, including
the Culebra, exhibited poor recoveries.
The EPA agrees that fractured Rustler is
'present at test well H-3. However, EPA
does not believe that the presence of
fractured material in the Rustler
indicates that karst processes are active.
In fact, the development of fractures can
occur for various reasons unrelated to
dissolution (e.g., removal of overlying
rock due to erosion). The DOE
recognized the presence of fractures
within the Culebra, and included this
dual porosity system in the PA
modeling. In addition, core loss is a
common occurrence in the drilling of all
kinds of rocks, sometimes associated
with fracture and other causes related to
drilling technology, as well as the
occurrence of soft or incompetent rock.
The EPA concludes that to interpret all
zones of lost core as zones of karst is
inappropriate, as other rock features
contribute to core loss which have
nothing to do with cavernous porosity.
The EPA reviewed information
pertinent to the potential development
of karst in the WIPP area and believes
that the near continuous presence of the
more than half-million year old
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Mescalero Caliche over the WIPP site is
a critical indicator that recharge from
the ground surface to the bedrock
hydrologic regime has not been
sufficient to dissolve the caliche at the
site. If active dissolution of the
evaporites in the subsurface were
occurring in the WIPP area, it would be
expected that collapse features would be
evident in the Mescalero above the area
where the dissolution is, or has
occurred. As noted above, EPA has
found no evidence of direct
precipitation-related flow increases
typical of karst terrain, and no field
evidence of large channels or other karst
features. The relative pervasiveness of
the Mescalero Caliche over a long
period of time is also an indication that
there has been an arid climate and very
low recharge conditions over a long
period of time at the WIPP site. This,
combined with DOE's near-future
precipitation assumptions, led EPA to
conclude that karst feature development
will neither be pervasive nor impact the
containment capabilities of the WIPP
during the 10,000 year regulatory
period. (Docket A-93-02, ItemV-B-2,
CARD 14, Section 14.B.5; Item V-B-3,
Section S.B.t)
The EPA concludes that dissolution
has occurred in the WIPP area outside
of the WIPP site, as evidenced by karst
features like Nash Draw. It is possible
that dissolution has occurred at the
WIPP site sometime in the distant past
(i.e., millions of years ago for strata-
bound features) associated with a
geologic setting other than that currently
present at WIPP; however dissolution in
the Culebra is not an ongoing process at
the WIPP site. Thus EPA finds that
DOE's modeling (which assumes no
karst within the WIPP site boundary) is
consistent with existing borehole data
and other geologic information.
e. Presence of Brine in the Salado.
Numerous commenters stated the
Salado Formation will be wet and that
brine is weeping into the repository at
a slow but significant rate, leading to a
wet repository which will corrode the
waste containers. This, the commenters
stated, would invalidate the basic
premises of the WIPP that dry salt beds
would creep and encapsulate the waste
canisters.
The EPA agrees that brine will enter
the repository from the Salado
Formation via anhydrite marker beds.
The EPA also notes that the presence of
brine within the Salado is a key element
of the PA modeling; brine inflow is
assumed to occur and the impact of
brine inflow on gas generation is
assessed. Brine is necessary for both of
the processes that may cause gas
generation: either drum corrosion or
microbial respiration. If there is no
inflow of brine into the repository,
neither corrosion of iron drums nor
survival of microbes would occur, so gas
generation would not occur. Therefore,
although the commenters correctly
noted that initial WIPP studies did
assume the salt to be "dry," the
presence of interstitial brine has long
been recognized and is accounted for in
the PA. (Docket A-93-02, Item V-B-2,
CARD 14, Section 14.E.5; Item V-B-3,
Section F.2)
In the CCA discussion of the gas
generation conceptual model, DOE
indicates that brine is expected to be
present in the repository due to a
natural inflow of brine. Corrosion of the
waste containers, generation of gases
resulting from waste corrosion and
microbial degradation, and the effects of
these processes on the disposal system
components have been addressed in the
DOE PA and the EPA-mandated PAVT.
(Docket A-93-02, Item V-B-2, CARD
14, Section 14.D; Item V-B-2, CARD 23,
Section 2.4; Item V-B-3, Section E.2)
The DOE also considered that additional
brine could be introduced to the waste
area if a drilling event passed through
the waste and subsequently hit a brine
pocket. The presence of a pressurized
brine pocket beneath WIPP was
addressed in the PA under the Human
Intrusion Scenarios whereby the
reservoir is penetrated by a borehole
and brine is subsequently released into
and mixed with the waste and
eventually discharged either into the
Culebra or at the ground surface. The
EPA concludes that DOE adequately
considered the presence of brine in PA
modeling because it included the
possibility of encountering a brine
pocket in its intrusion scenarios, and
because the potential effects of brine on
corrosion rates and gas generation were
incorporated in PA models. For more
information on brine pocket parameter
values, see the subsequent discussion of
Parameter Values in the Performance
Assessment sections of this preamble.
f. Gas Generation Model. Some
chemical reactions could occur in the
WIPP because metal containers holding
waste may corrode and waste made
from organic materials such as rubber
may decompose if water is available and
if other conditions are conducive to
such decomposition. The corrosion
reaction would create hydrogen gas
(H2). The decomposition of organic
waste would create carbon dioxide (2)
and methane (CH4). These gases would
build up in the repository after it is
sealed, increasing pressure inside the
waste rooms.
The DOE developed a gas generation
conceptual model to describe this
situation. The Department's gas
generation conceptual model
incorporates the following basic
premises:
• Gas is generated primarily by metal
corrosion and microbial processes;
• Gas generation is closely linked to
other processes;
• Gas generation from microbial
processes will not always occur;
• High gas pressures in the repository
can cause the Salado anhydrite
interbeds to fracture; and
• High gas pressure is necessary
before spalling and direct brine releases
can begin.
The DOE performed experiments on
gas generation rates for the 1992 PA and
updated these experiments more
recently. (Telander, M.R. and R.E.
Westerman, 1997. "Hydrogen
Generation by Metal Corrosion in
Simulated Waste Isolation Pilot Plant
Environments," SAND96-2538; see
Docket A-93-02, Item V-B-1.) The gas
generation rates are important in The
PA because build-up of high gas
pressures increases the chance for
releases if a drill bores into the
repository.
During the public comment period,
commenters questioned the gas
generation rates used in the gas
generation conceptual model. One
commenter stated that calculated
corrosion rates were too low because
they are based upon long-term tests that
show lower rates than short-term tests,
they assume a high pH, and they
include a minimum rate of zero,
perhaps by assuming that salt
crystallization will prevent corrosion.
The commenter also stated that
corrosion rates used in the model
should account for the fact that direct
contact with salt and backfill increases
the rate. The commenter further stated
that DOE seemed to use the observed
data to set the upper limit of a
distribution of corrosion rates, rather
than the midpoint of such a
distribution, which would
systematically understate the corrosion
rate because most values would be less
than the values taken from DOE's
observed data. Finally, the commenter
stated that aluminum corrosion is as
significant as corrosion of steel, and that
it is likely to take place in the repository
because CO2 and iron will be present
and will enhance aluminum corrosion.
The EPA examined DOE's studies on
gas generation rates. The EPA disagrees
that the assumptions of long-term rates,
pH, and minimum corrosion rate are not
well-founded. Since the results of the
corrosion testing are used to develop a
long-term hydrogen gas generation rate
for the repository that applies over
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27375
hundreds of years, it is appropriate that
DOE developed the rate based on
hydrogen generation over a longer time
(12 to 24 months) rather than for a
shorter time. Data indicate that during
the first few months of the test, the
corrosion reaction had not yet stabilized
at equilibrium, producing more
hydrogen gas than would have been
expected at equilibrium for the amount
of iron present. (Docket A-93-02, Item
II-G-1, CCA Reference #622) Therefore,
the higher rate of gas generation
observed in the short-term is unlikely to
represent what happens in the
repository over hundreds of years.
The DOE's assumption of high pH
(about 10) is consistent with data on the
use of magnesium oxide (MgO) backfill.
Because DOE has committed to using
MgO backfill in the repository in the
CCA, EPA finds it reasonable to assume
this pH in the repository. (See the
preamble section "Engineered Barriers"
for further discussion of MgO backfill.)
Furthermore, even if the MgO were not
fully effective and the pH were to drop
from near 10 to between 7 and 8, the
enhanced corrosion rate expected at that
lower pH is already reflected in the
probability distribution for the corrosion
rate parameter. DOE's experimental data
show that MgO backfill will function as
assumed in the CCA. Therefore, EPA
concludes that DOE considered the
issue of pH and realistically
incorporated it into the model.
The DOE took its minimum corrosion
rate of zero from studies on steel
corrosion rates when the steel is in a
humid environment and also when steel
is submerged in brine. The DOE found
that virtually no corrosion occurred and
no hydrogen gas was generated under
humid conditions. Also, the studies
show that the steel has an extremely low
corrosion rate when it is submerged in
brine at the higher pH expected in the
WIPP. Some DOE studies also found
that salt films may prevent corrosion, as
the commenter mentioned. (Docket A-
93-02, Item II-G-1, CCA Appendix
MASS, Attachment MASS 8-2) Based
on all these studies, EPA concludes that
DOE's minimum corrosion rate is
supported and appropriate.
The DOE assumed that the corrosion
rates of steel submerged in brine were
uniformly distributed from zero to 0.5
micrometers per year. The EPA believes
that the bases for the parameter
assumptions are adequately
documented and the use of the
particular parameter distribution is
consistent with demonstrating the
concept of reasonable expectation for
the H2 gas generation rates used in the
CCA. However, EPA was concerned that
the maximum corrosion rate value
selected by DOE did not fully reflect
other uncertainties. These uncertainties
included the accelerated corrosion of
steel in reactions with other materials
such as backfill and aluminum. Data
from DOE tests indicated that corrosion
rates might be twice as high as those
used in the PA. (Docket A-93-02, Item
V-B-14) Thus, in the PAVT, EPA
required DOE to double the maximum
corrosion rate to assure that these other
uncertainties were more fully reflected.
(Docket A-93-02, Item II-G-28)
(Doubling the corrosion rate would be
expected to cause the gas generation rate
to rise but not necessarily double, since
other factors such as microbial
degradation also influence gas
generation.) This and other changes
made in the PAVT showed that the
repository remained in compliance with
the standards.
The commenter correctly notes that
the corrosion data from DOE's studies
were used to set the upper limit of a
uniform distribution of corrosion, rather
than a mid-point. (Telander, M.R. and
R.E. Westerman, 1997. See Docket A-
93-02, Item V-B-1.) However, EPA does
not agree that this practice would
systematically understate the corrosion
rate under the conditions expected to
occur in the repository. The
experimental rate was obtained under
pH conditions substantially lower than
those expected in the repository (i.e., 7.4
to 8.4 versus 9.2 to 9.9). The corrosion
rate is expected to be at least an order
of magnitude lower at the higher pH
than at the pH expected in the
repository in the presence of MgO.
(Docket A-93-02, Item V-B-14)
Therefore, the higher corrosion values
(i.e., those based on the study) represent
extreme conditions, rather than those
expected in the repository, and the
parameter range would account for all
values that are likely to occur. In
addition, as noted above, EPA required
that the maximum corrosion rate be
doubled in the PAVT to account for
uncertainties in this parameter. The
Agency believes that this addresses the
concerns raised by the commenter.
The commenter notes that CO2 and
iron will enhance the corrosion of
aluminum. Although EPA agrees this is
true, the Agency believes it does not
affect the results of the PA. Carbon
dioxide reacts with MgO, so CO2 will
not be available to reduce the brine pH
and to enhance corrosion. Second,
accelerated corrosion of aluminum is
not a significant factor in the WIPP's
performance, since brine will be
consumed in corrosion reactions and
will lead to smaller direct brine releases.
(This is also discussed in the following
preamble section concerning two
dimensional modeling of brine and gas
flow.) The results of DOE's modeling
show that iron is consistently left over
after reacting with all available brine.
(Docket A-93-02, Item II-G-7, Fig.
2.2.9) Based upon data on these
reactions, the Agency concludes that
enhanced corrosion of aluminum due to
CO2 and iron will not increase releases
of radioactivity because brine will not
be left over to go to the surface as direct
brine releases. (Docket A-93-02, Item
V-C-1)
g. Two-Dimensional Modeling of Brine
and Gas Flow. The DOE modeled the
flow of brine and gases within the
repository in the BRAGFLO computer
code. The DOE simplified this model by
representing the repository as a space in
two dimensions rather than in three
dimensions, as it is in reality. The
Department made this simplification in
order to speed up computer calculations
significantly. The DOE performed a
screening analysis titled SI: Verification
of 2D-Radial Flaring Using 3D Geometry
to see if the two-dimensional BRAGFLO
model would predict similar results to
a three-dimensional model. (WPO
#30840) In Appendix MASS,
Attachment 4-1 of the CCA, DOE
explained that the results of the
screening analysis showed that a three-
dimensional model would not give
significantly different results from the
two-dimensional model used in the PA.
The EPA examined DOE's
documentation to determine if the CCA
complied with EPA's requirements for
documentation of conceptual models
and consideration of alternative
conceptual models under §§ 194.23(a)(l)
and (a) (2). The EPA reviewed the
screening analysis and concluded in the
proposal that DOE sufficiently
documented its rationale and approach
behind using a two-dimensional model
for brine and gas flow in the repository.
(62 FR 58808)
One commenter stated that DOE's
screening analysis suggested that the
two-dimensional ("2D") BRAGFLO
model might underestimate releases of
radionuclides to the surface under
higher gas pressures. The commenter
stated that several three-dimensional
("3D") BRAGFLO simulations of the
repository should be performed using
parameter values from the CCA PA. The
recommended analysis would include
calculations of direct brine releases
(releases of brine contaminated with
radioactive waste) and spallings
(releases of solid waste pushed out of
the repository under high pressure), and
an assessment of how much brine
would be consumed by chemical
reactions. Another commenter stated
that the screening analysis had been
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misinterpreted because details of the
assumptions used in the original
screening analysis had not been
considered. This commenter also stated
that results of additional analysis
submitted by DOE as comments showed
that the two-dimensional BRAGFLO
code used in the CCA PA results in a
conservative estimate of the releases
when compared to results from a three-
dimensional code.
The EPA examined the screening
analysis mentioned by the commenters.
The Agency found that the divergence
between the results of the two-
dimensional and three-dimensional
versions of BRAGFLO occurred only at
very high (lithostatic 22) pressures that
would occur seldom if ever in the
repository. (Docket A-93-02, Item V-C-
1, Section 5) For simulations at the gas
generation rates used in the CCA PA,
the two-dimensional BRAGFLO code
predicted greater brine inflows than the
three-dimensional code. (Greater brine
inflows could potentially lead to greater
direct brine releases.)
The EPA also considered how much
brine would be consumed in chemical
reactions. One of DOE's studies showed
that brine is consumed by corroding
steel barrels and leaves behind at least
20 percent of the original steel at the
end of 10,000 years for 99 percent of the
sets of simulated conditions tested in
the CCA PA. (Docket A-93-02, Item II-
G-7, p. 2-12) Based on this study, EPA
concluded that even if the 3D model
predicted additional brine inflow
(beyond that predicted in the current 2D
model), this brine will simply be
consumed in chemical reactions (i.e.,
corrosion of metal drums), and will not
go to the surface as direct brine releases.
In addition, the Agency looked at results
of additional simulations that DOE
conducted to compare BRAGFLO 2D
and 3D results. (Docket A-93-02, Item
IV-G-34, Attachment 1 and February
25, 1998, memorandum) DOE's results
show that the use of a two dimensional
representation does not result in an
underestimate of direct brine release
during human intrusion. In all cases
investigated, the two dimensional
simulations consistently predict either
the same or higher repository pressures
and brine saturations than their
corresponding three-dimensional
simulations, leading to larger releases.
The Agency, therefore, concludes that
the two-dimensional BRAGFLO code
results in conservative estimates of
releases from the repository compared
to results from a three-dimensional
model.
22 Lithostatic pressure is the pressure exerted by
overlying rock layers.
In addition, EPA found that DOE
sufficiently documented its
development of conceptual models and
scenarios, including alternative
conceptual models considered, in the
CCA and additional documentation
submitted to the Agency. Therefore,
EPA finds DOE in compliance with the
requirements of §§ 194.23(a)(l) and
(a) (2) with respect to modeling of brine
and gas flow.
h. Earthquakes. Several public
comments raised concerns about the
effect that earthquakes could have on
the repository and the containment of
waste. Several commenters refer to a
recent (January 4, 1998) earthquake in
New Mexico, over 100 miles from the
WIPP site, as an indication of the
weakness of the WIPP site for disposal
purposes.
In the CCA, DOE examined seismicity
as part of its features, events, and
processes, analyses, and concluded
earthquakes could be excluded from the
PA calculations based on low
consequences. This conclusion is drawn
from a wealth of knowledge about the
seismic activity and processes in the
region, but is based primarily on the fact
that the intensity of ground shaking (the
primary cause of destruction from an
earthquake) is significantly less
underground than at the surface. In
addition, the ductile nature of a salt
deposit makes it deform differently than
typical hard rocks, so the displacement
due to rupture (if any) will be less. The
EPA reviewed DOE's earthquake
(seismic) scenario in the Technical
Support Document for 194.14: Content
of Compliance Application, Section
IV.B.4.f. (Docket A-93-02, Item V-B-3)
The EPA concurs with DOE's analysis,
that the probability of a release of
radionuclides from the repository due to
the opening of fracture pathways caused
by an earthquake is very small.
Many years of seismological
monitoring, microseismal studies and
geologic study demonstrate that there
are no probable sources of large
earthquakes at or near the WIPP site.
(Docket A-93-02, Item II-G-1, Chapter
2.6) The only sources of significant
earthquakes in the region lie far to the
west of the site along the Rio Grande rift
or to the south along major plate
tectonic features in Mexico, although
measurable earthquakes have occurred
closer to the WIPP. (Docket A-93-02,
Item II-G-1, Chapter 2 and Appendix
SCR) Micro-earthquakes (magnitude 3.0
or smaller on the Richter scale), most of
which are too small to be felt, or small,
shallow teleseismal ground motion
related to distant earthquakes are the
only seismicity expected at the WIPP
site during the very short period that the
repository will persist as an
underground opening. The EPA notes
that the site of the January 4, 1998,
earthquake is located in the Rio Grande
Rift—over 100 miles east of WIPP—and
seismic activity in that area, including
the January 4, 1998 earthquake, was too
small to have an impact at WIPP.
Therefore, EPA finds that the effects of
earthquakes need not be considered in
performance assessments. (See Docket
A-93-02, Item V-B-2, CARD 32,
Section G)
i. Conclusion. The EPA finds that
DOE adequately assessed the site
characteristics for the purposes of the
PA and use in comparison with EPA's
radioactive waste disposal standards
and WIPP compliance criteria. The
results of EPA's review of the CCA and
additional information provided by DOE
is provided in CARDs 14, 23, 32 and 33.
(Docket A-93-02, Item V-B-2)
4. Parameter Values
a. Introduction. Parameters are
numerical values or ranges of numerical
values used in the PA to describe
different physical and chemical aspects
of the repository, the geology and
geometry of the area surrounding the
WIPP, and possible scenarios for human
intrusion. Some parameter values are
well-established physical constants,
such as the Universal Gas Constant or
atomic masses of radionuclides.
Parameters also can be physical,
chemical or geologic characteristics that
DOE established by experimentation.
The DOE has also assigned parameters
to aspects of human intrusion scenarios,
such as the diameter of a drill bit used
to drill a borehole that might penetrate
the repository.
Section 194.23(c)(4) requires detailed
descriptions of data collection
procedures, data reduction and analysis,
and code input parameter development.
Section 194.14(d) requires DOE to
describe the input parameters to the PA
and to discuss the basis for their
selection. Section 194.14(a) requires
DOE to describe the characteristics of
the WIPP site, including the natural and
engineered features that may affect the
performance of the disposal system,
which is part of the process of
parameter development.
The Agency reviewed the CCA,
parameter documentation, and record
packages for approximately 1,600
parameters used as input values to the
CCA PA calculations. The EPA further
reviewed parameters record packages
and documentation in detail for 465
parameters important to performance of
the disposal system. The Agency
selected parameters to review in depth
based on the following criteria:
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• Parameters that were likely to
contribute significantly to releases or
seemed to be poorly justified;
• Parameters that control various
functions of the CCA PA computer
codes that were likely to be important
to calculations of releases and important
to compliance with the containment
requirements of § 191.13; and
• Other parameters EPA used to
evaluate the overall quality of Sandia
National Laboratory's ("SNL")
documentation traceability.
After its initial review, EPA found
that DOE had a great deal of
documentation available in the SNL
Records Center supporting most of the
parameters used in the CCA PA.
However, EPA had some concerns about
the completeness of the list of CCA PA
parameters in the CCA and the SNL
Records Center, the description and
justification to support the development
of some code input parameters, and the
traceability of data reduction and
analysis of parameter-related records.
The Agency did not agree with the
technical justification of some
parameter values and probability
distributions.
The Agency later required DOE to
perform additional calculations in a
Performance Assessment Verification
Test ("PAVT") in order to verify that the
cumulative impact of all required and
other corrections to input parameters,
conceptual models, and computer codes
used in the PA was not significant
enough to necessitate a new PA. The
EPA directed DOE to incorporate
modified values or distributions for
twenty-four parameters in the PAVT.
(Docket A-93-02, Item II-I-27) The
PAVT showed that the calculated
releases may increase by up to three
times from those in the original CCA
PA, but that the WIPP is still an order
of magnitude below the containment
requirements in § 191.13. The DOE
satisfied EPA's concerns about the
parameters by incorporating EPA's
changes to the parameter values and
parameter distributions in the PAVT.
During the public comment period on
the proposed rule, members of the
public expressed concern about a few
specific parameters used in the PAVT:
distribution coefficients (Kd), the
permeability of borehole plugs, the
characteristics of a potential brine
pocket, and the solubility of different
actinide ions in brine. Commenters
stated these particular parameters could
have an especially great impact on
releases, and therefore, on the results of
the PA.
b. Distribution Coefficient (Kd). As the
primary radionuclide pathway during
an intrusion, the Culebra was the
subject of many public comments,
especially related to distribution
coefficients23 (Kd values). In DOE's
conceptual model the Culebra is
characterized as a fractured dolomite
that has dual-porosity and acts to
physically retard movement of
contaminants. In a dual-porosity rock
unit, ground water is believed to flow
through the fractures, but water and
contaminants can access the pore space
within the rock matrix away from the
fractures. Movement of water and
contaminants into the pore space slows
(retards) their respective forward
movement. This physical retardation is
necessary in order to have chemical
retardation. In the process of chemical
retardation, contaminants diffuse from
the fractures into the pore space where
they can adsorb onto the rock mass.
This adsorption is described by
distribution coefficients, or Kd values.
The CCA indicated that there were no
contributions to total releases from the
ground water pathway. (Docket A-93-
02, Item II-G-1, Chapter 2) This was
due to the limited amount of
contaminated brine predicted to reach
the Culebra and the fact that
radionuclides adsorbed into the Culebra
dolomite did not move with the ground
water flow. That is, the movement of the
radionuclides were retarded with
respect to the ground water flow. The
estimate of the extent of the retardation
(i.e., the Kd value) was based on
laboratory tests using crushed rocks and
small columns of rock. (CCA, Docket A-
93-02, Item II-G-1, Chapter 6)
The EPA reviewed DOE's Kd values in
detail. (Docket A-93-02, Item V-B-4)
Based upon the review of DOE's data,
methodologies, and conclusions, EPA
proposed that the Kd ranges suggested
by DOE were sufficient for the PA. (62
FR 58799) The EPA also concluded that
the laboratory tests were conducted
appropriately and that the Kd values
DOE derived from this testing are
reasonable, given the experimental
evidence, and sufficient for PA
purposes. (Docket A-93-02, Item V-B-
2, CARD 14, Section 14.B.5)
Commenters stated that DOE's
experiments did not produce Kd values
that are representative of conditions in
the Culebra. The DOE data on actinide
23 Dissolved waste migrating out of the disposal
site would migrate as atoms with a positive
electrical charge, or cations; these could be cation
species such as Pu+4 or U + 6. When liquid such as
brine carries the cations through sediment or rock,
some of the cations become attached to the surface
of these solids. Therefore, the cations travel more
slowly than the liquid as a whole. The rate of
advance of the cation as the liquid migrates can be
described with a number called a retardation factor.
Distribution coefficients, or Kd's, are used in
calculating the retardation factor.
Kd values are derived directly from the
results of a number of experiments (e.g.,
crushed rock, column tests) conducted
with brine solutions that are
representative of brines in the disposal
system. The DOE used samples of the
Culebra Dolomite and brine solutions
that are considered to be representative
of the field situation. These data were
supplemented by experiments with
other natural dolomites and column
experiments, in which the effects of a
field-realistic solid to solution ratio
could be investigated. The laboratory-
derived Kd values are expected to
overestimate the mobilities of the
actinides, making them reflective of
upper bounds for predicting the
maximum possible rates of actinide
migration in the PA calculations.
Therefore, it is reasonable to expect that
the range of actinide Kd values obtained
from the DOE experiments are inclusive
of any scale-effects that might produce
a different average Kd value than the
experimental average in either the
greater or lesser directions. Docket A-
93-02, Item V-B-4, Section 4.4 presents
EPA's analysis of field Kd testing.
The DOE's experimental results show
that each of the actinides tested is
adsorbed to the rock matrix to varying
extents; hence, they will not migrate as
fast as the overall rate of horizontal
water flow (i.e., the actinides will be
attenuated). These results are consistent
with general theories of the adsorptive
behavior of cationic solutes under
alkaline pH conditions.
The EPA reviewed DOE's actinide Kd
values and concluded that the
population of Kd values determined in
DOE experiments was not well-
represented by a uniform distribution.
The Agency recommended that a
loguniform distribution be used in the
PA calculations. In the PAVT,
loguniform distributions for the actinide
Kd values were used. (WPO# 47258;
Docket No A-93-02, Item II-G-39) The
results of PAVT still resulted in
compliance with regulatory release
limits. Therefore, EPA determined that
the CCA PA was adequate for the
purpose of determining compliance.
(Docket A-93-02, Item V-B-4)
The DOE also performed bounding
calculations using the minimum Kd
values necessary to achieve compliance
with EPA limits. The bounding
estimates were obtained for plutonium
(239Pu) and americium (241Am), which
are critical actinides with respect to
releases to the accessible environment.
Results of DOE's bounding assumptions
(whereby all other factors are set to the
least favorable value) indicate that a Kd
of 3 milliliter per gram (ml/g) is
sufficient for compliance for 239Pu and
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241 Am. Estimates based on typical CCA
sample sets indicate that Kd values
greater than 1 ml/g are sufficient for
compliance. (A higher Kd value
indicates greater retardation—or less
movement—of radionuclides.) The Kd
ranges determined from DOE column
experiments, conducted since
submission of the CCA, for 239Pu and
241 Am are typically greater than 100 ml/
g, thus inferring that Kd values used in
the PA are more than sufficient to
ensure compliance with EPA limits with
respect to accessible environment
release through the Culebra. For these
reasons, the actinide Kd values
developed by DOE are considered to be
adequate for representing actinide
mobilities in the PA calculations.
(Docket A-93-02, ItemV-B-2, CARD
14, Section 14.G.5)
The EPA reviewed and responded to
the public comments on Kd values and
finds the Kd values used in the PA are
sufficient. Refer to EPA Technical
Support Document for Section 194.14:
Assessment of Kd Values Used in the
CCA for EPA's detailed review. (Docket
A-93-02, Item V-B-4)
c. Actinide Solubility. Actinide
solubilities are used in the computer
codes to calculate the actinide
concentrations released from the
repository. They are important because
as radionuclides dissolve in brine, they
are more easily released from the
disposal system through direct brine
release mechanisms. Commenters
questioned the analysis of certain
chemical conditions in the disposal
system relating to backfill, ligands,
uncertainty, and oxidation state
analogy.
An important factor influencing
actinide solubility is the magnesium
oxide (MgO) backfill DOE proposed to
emplace in the WIPP. The DOE
indicated that MgO backfill emplaced
with transuranic waste would mitigate
the solubility-enhancing effects of
carbon dioxide from waste degradation.
The DOE proposed to emplace a large
amount of MgO in and around waste
drums in order to provide an additional
factor of safety and thus account for
uncertainties in the geochemical
conditions that would affect CO2
generation and MgO reactions.
Commenters stated that DOE has not
shown the predicted MgO chemical
processes will take place. The DOE
provided documentation in the CCA
and supplementary information that
MgO can effectively reduce actinide
solubility in the disposal system. While
the conceptual model peer review panel
initially rejected DOE's
conceptualization of the Chemical
Conditions Model, DOE provided
additional information on MgO
processes and the peer review panel
later concluded that MgO processes will
indeed take place as initially postulated
by DOE. The EPA concluded that DOE's
qualitative justification was sufficient to
show that the emplacement of MgO
backfill in the repository will help
prevent or substantially delay the
movement of radionuclides toward the
accessible environment by helping to
maintain alkaline conditions in the
repository, which in turn favors lower
actinide solubilities. Furthermore,
DOE's bounding of pH levels to a
narrow range greatly reduces the
uncertainty associated with pH and
actinide solubility in the PA. Refer to
CARD 24, Section 24.B.6, and CARD 44
for further discussion of the effects of
MgO. (Docket A-93-02, Item V-B-2)
The EPA received numerous
comments regarding DOE's lack of a
sensitivity analysis on the effects of
organic ligands and that organic ligands
other than ethylene diaminetetraacetic
acid ("EOTA") should have been
considered. Organic ligands are
important since they can increase more
mobile fractions, i.e., can make more
radionuclides available for transport.
Organic chemicals are expected to be
part of the waste, especially because
many were used in the separation of
actinides during chemical processing of
nuclear materials. DOE's bounding
calculations and incorporation of
uncertainty ranges to represent actinide
concentrations in the PA calculations
indicate that organic ligands will have
only a minor effect on the solubilities of
actinide solids under the expected
repository conditions. The EPA found,
through independent calculations, that
there is no substantive information that
could be gained by conducting a
sensitivity analysis on the effects of
organic ligands or conducting the
calculations with citrate rather than
EDTA, since EDTA provides a
conservative assessment of the effects of
ligands on solubility of actinide solids.
(Docket A-93-02, Item V-B-2, CARD
24, Section 24.E.5) The EPA agrees with
the conclusions of the Waste
Characterization Independent Review
Panel "that under the conditions of
MgO backfill, chelating agents (e.g.,
organic ligands) will have a negligible
effect on repository performance. The
Panel notes that, even at the basic pH in
the repository, the availability of
transition metals may be enhanced due
to the formation of soluble halo
complexes, making an even stronger
case that base metals control ligand
chemistry."
Commenters also expressed concern
about the solubility uncertainty range
used in the PA computer codes. The
DOE determined that the available
experimental data for the oxidation state
+IV actinides (i.e., plutonium, uranium,
and neptunium) were insufficient for
making such comparisons. However, the
experimental procedures for
determining the solubilities of +IV
actinide solids are not substantially
different from those used to determine
the solubilities of+III and +V actinide
solids. Therefore, EPA concluded that
the uncertainties determined for the +III
and +V actinide solids would be
inclusive of those that would be
obtained for +IV actinide solids, which
are based on experimental
measurements of thorium oxide. This
expectation is based on the fact that
DOE used the outermost limits of the
differences between model results and
experimental results for all data
examined to define the breadth of the
uncertainty limits. This procedure
greatly expands the size of the
uncertainty bounds beyond what might
be calculated from statistical treatment
of the distribution of the differences.
(Docket A-93-02, Item V-B-2, CARD
24, Section 24.B.6; and Item V-B-17)
The EPA therefore finds that the
uncertainty bounds on actinide
solubility are adequate for use in the
PA.
Finally, commenters raised issues
regarding the limitations of the
oxidation state analogy in the Actinide
Source Term Dissolved Species Model.
In short, the actinide oxidation analogy
means that actinides of the same
oxidation state tend to have similar
chemical properties under similar
conditions. The oxidation state analogy
is based on standard inorganic
chemistry principles. This
generalization can be made because
chemical reactions involving ionic
species are related primarily to the
charge densities of the reacting species.
Actinides with the same oxidation state
have the same core electronic structure;
hence they have similar ionic radii and
charge densities, which in turn leads to
analogous chemical behavior in
solubility and aqueous speciation
reactions. In addition to the theoretical
basis, DOE conducted experimental
studies that confirmed the validity of
the oxidation state analogy, and
subsequently employed it in its
representation of the solubilities of
actinides. The EPA finds that the
actinide oxidation state is adequate for
use in the PA. (Docket A-93-02, Item
V-B-2, CARD 24, Section 2.B.6)
For details regarding chemical
reactions of MgO, see CARD 24 (Waste
Characterization) and CARD 44
(Engineered Barriers). For further
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27379
information regarding the PA modeling
of solubility and chemical conditions in
the repository, see CARD 23 (Models
and Computer Codes). CARDs can be
found in Docket A-93-02, Item V-B-2.
d. Brine Pockets. The Castile
Formation lies underneath the Salado
Formation, where the WIPP is located.
This stratum contains pockets of brine
under pressure. One of the parameters
in the PA that commenters believed to
be important is the probability that a
driller will hit a brine pocket in the
Castile. The CCA PA models the
possibility that a drill bit could
penetrate a brine pocket in the Castile
Formation, allowing brine to rise up the
borehole and into the repository. The
brine could then dissolve radioactive
waste and could carry it to the earth's
surface if another driller bored a hole
into the repository. This could increase
the amount of radioactive waste
reaching the accessible environment.
Some commenters expressed concern
that brine from brine pockets in the
Castile Formation could travel up to the
level of the repository, or even to the
earth's surface. The EPA believes that
this is not a problem unless the
repository is disturbed by human
intrusion. Because it is difficult for
water to travel in the Salado and Castile
formations (i.e., they have low
permeability), there is no natural
connection between a Castile brine
pocket and the waste panel area under
undisturbed conditions. These brines
are also either saturated or nearly
saturated with soluble minerals such as
salt (halite), and thus, the brine in
pockets will not dissolve the
surrounding material. (Docket A-93-02,
Item II-G-1, CCA Chapter 2, Table 2-5)
However, in the case of a deep drilling
intrusion that goes through a waste
panel and into the Castile, it is possible
that the driller will intercept brine in
the Castile and create a pathway for
Castile brine to flow into the repository
and interact with the waste. The
probability of human intrusion through
the WIPP repository to an underlying
Castile brine pocket is a key component
of the PA.
The 1992 draft PA considered the
probability of a driller hitting a brine
pocket under the waste area with a
range of 25 percent to 62 percent, based
on geophysical work that suggested
brine may be present. (Docket A-93-02,
Item II-G-1, Reference #563) In the CCA
PA, DOE assigned a probability of
hitting a brine pocket of 8 percent,
based upon a geostatistical analysis of
oil and gas wells in the vicinity of
WIPP. The Agency believed that the
assigned probability was low, based
upon data from one particular DOE
study using the Time Domain
Electromagnetic ("TDEM") method. In
addition, EPA found there was
considerable uncertainty in this
parameter. Therefore, in the PAVT the
Agency required DOE to change the
constant value of this parameter to a
uniform probability distribution from 1
percent to 60 percent, based upon data
in the TDEM study. (Docket A-93-02,
Item II-I-27)
Many commenters questioned the use
of a uniform distribution from 1 percent
to 60 percent as the range for the
probability of hitting a brine pocket that
EPA specified be used in the PAVT.
Some believed that EPA should require
DOE to examine a probability of 100
percent for hitting a brine pocket, based
upon data from DOE's WIPP-12
borehole, which suggested that a large
reservoir of brine might lie in the Castile
Formation under the WIPP Land
Withdrawal Area. Others recommended
that EPA require DOE to repeat the PA
assuming a constant probability of 60
percent.
The EPA carefully evaluated the
potential occurrence of brine pockets
below the WIPP. The EPA agrees that
there is significant uncertainty
concerning the existence of a brine
pocket beneath the repository. For this
reason, EPA required DOE to reevaluate
the probability of hitting a brine pocket
in the PAVT using a probability
distribution rather than a constant
value.
The EPA also considered the
possibility that the brine pocket
indicated by WIPP-12 data may
underlie 100 percent of the repository.
Based on reservoir volume and
thickness data from WIPP-12,
commenters found that a cylindrically-
shaped reservoir could underlie the
entire repository. However, EPA
considers this unlikely because brine in
the Castile does not reside in
homogeneous and well-defined
reservoirs. Instead, it is believed to
reside in vertical or subvertical fracture
systems, which may be extensive and
contain significant volumes of brine.
(Docket A-93-02, Item II-G-1,
Appendix MASS, Attachment 18-6)
Although EPA agrees that part of the
WIPP-12 reservoir may underlie part of
the repository, the time-domain
electromagnetic ("TDEM") survey data
do not support speculation of a 100%
probability of an encounter. (Docket A-
93-02, Item II-G-1, Chapter 2.2.1.2.2,
Item V-B-3, section IV; Item V-B-14,
Sections 4.1, 4.4, and 4.5) In addition,
as pointed out by one of the commenters
recommending a probability of 60
percent, some boreholes adjacent to
brine-producing boreholes near the
WIPP site are known to be dry. In view
of the lack of support from the TDEM
data and the other concerns expressed
above, EPA concludes that available
data do not support a 100 percent
probability of hitting a brine pocket.
The EPA established its 1 percent to
60 percent range of probability for
hitting a brine pocket based upon data
from the TDEM survey. The Agency
examined the data and found that the
probability distributions for
encountering brine under the WIPP
varied widely, depending on whether or
not one assumed that brine pockets exist
below the bottom of the Anhydrite III
layer near the top of the Castile
Formation. Using the base of the
anhydrite layer as the cutoff, EPA's
simulations showed that the fraction of
the excavated area of the repository
underlain by brine varies from 1 to 6
percent of the excavated area. Using the
base of the Castile as the cutoff, the
fraction of the excavated area of the
repository underlain by brine would
range from about 35 to 58 percent.
According to the 1992 WIPP PA, Castile
Formation brines are generally found in
the uppermost anhydrite layer (usually
Anhydrite III), rather than all the way
through the Castile. (Docket A-92-03,
Item II-G-1, CCA Reference #563, Vol.
3, p. 5-4) If brine is confined to the
upper (Anhydrite III) layer, which is the
more probable case based on geologic
information, the maximum fraction of
the repository area underlain by brine is
6 percent. However, in order to examine
the possible effects of the more
conservative case, EPA chose to assume
an equal probability that a driller would
hit a brine pocket in either the upper
Anhydrite III layer or the base of the
Castile. Therefore, EPA used a
probability range in the PAVT with a
low value of 1 percent based on the
upper anhydrite layer and the high
value of 60 percent derived by rounding
up the highest value from the TDEM
survey. The EPA believes that existing
information supports the range used in
the PAVT as valid, and probably
conservative, values for the probability
of hitting a brine pocket.
The Agency also notes that a
sensitivity analysis of the PA parameters
submitted in comments showed that the
final results of the PA were not
significantly affected by increasing the
probability of hitting a brine pocket.
Even when the Castile brine encounter
probability was increased to 100
percent'the highest possible
probability'there was no significant
difference between the resulting mean
CCDF and the mean CCDF in the CCA,
which was based upon a brine
encounter probability of 8 percent.
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(Docket A-93-02, Item IV-G-43) The
EPA believes that 100 percent is an
unrealistically high probability. The
results of this study confirm that
examining such a probability in more
detail would provide little added
information about the performance of
the WIPP.
Commenters stated that the range of
the compressibility of rock surrounding
a Castile brine pocket used in the CCA
PA was too wide. They also believed
that the brine pocket volume values
used in the PA were too small. Castile
rock compressibility is one of several
parameters that affects the volume of
brine pockets in the Castile. This is
important because a drill bit would be
more likely to hit a large brine pocket
than a small one.
The EPA agrees with commenters that
DOE's parameters for rock
compressibility in the Castile and
representation of brine pocket size/
volume in the CCA PA were not
consistent with available information.
The EPA also believes that the
parameters of the Castile brine pockets
are highly uncertain. In order to capture
this uncertainty, the Agency believed it
would be appropriate to sample from a
range of parameter values, rather than to
use a single estimate, as DOE did in the
CCA PA. In the PAVT, EPA required
DOE to use a range of possible brine
pocket volumes. (WPO#41887. See
Docket A-93-02, Item V-B-1. See also
Docket A-93-02, Item V-B-14.)
Changing the rock compressibility of the
Castile and the Castile porosity
effectively modified the sampled brine
pocket volume to include, more
representatively, the possibility of larger
brine pocket volumes like those
expected based on data from the WIPP-
12 borehole. The EPA found that
modification of these parameters in the
PAVT did not result in releases that
exceed EPA's containment standards.
Based on these results, EPA has
concluded that the CCA PA was
adequate for the purpose of
demonstrating compliance.
e. Permeability of Borehole Plugs. In
the PA modeling, DOE assumed that
people drilling for resources would
follow standard practice and plug the
boreholes left behind. As long as these
borehole plugs remain intact, the
pressure of gases generated from the
waste will build up inside the
repository. The more permeable the
borehole plugs are, the more gas will be
capable of escaping from the repository.
This would reduce pressure in the
repository and therefore would reduce
the potential for releases of radioactivity
through spallings or direct brine release
from a future drilling event. In the CCA
PA, DOE modeled a situation in which
borehole plugs between the Castile and
Bell Canyon Formations would remain
impermeable, and most borehole plugs
closer to the earth's surface would
disintegrate after two hundred years and
would become more permeable.
One commenter stated that the CCA
does not model the gas buildup which
would result from impermeable plugs.
The EPA does not agree that the CCA
does not model gas buildup. In the CCA
PA and PAVT, gas pressure is allowed
to build up in the undisturbed
repository. Pressure would be released if
a borehole is drilled into the repository.
In some of the PA simulations, pressure
builds up again, although not to
undisturbed levels, after it is released
during a borehole intrusion. (Docket A-
93-02, ItemII-G-7, Figure 3.3.1)
However, EPA was concerned about
DOE's assumption that a relatively small
number of borehole plugs would have
low permeability. In the CCA PA, DOE
assumed that 98 percent of the
boreholes would be plugged with either
two or three plugs, where the top plug
would degrade and become more
permeable, and 2 percent of the
boreholes were plugged with a single
low permeability plug. The EPA was
concerned that an assumption that only
2 percent of the boreholes had low
permeability might not be conservative.
Therefore, EPA required that the
permeability range for borehole plugs in
the PAVT be broadened to include
lower values (at which gas will not
escape at a significant rate). This
parameter change ensured that the
PAVT would more frequently
incorporate low borehole permeability
and gas pressure buildup for more
simulations than in the CCA PA,
providing a more conservative result.
Other commenters expressed concern
that the borehole plug permeabilities
used in the CCA PA and the PAVT were
too high, and might underestimate
releases of radioactive material from the
WIPP. One commenter pointed out that
EPA retained the permeability used by
DOE as a high value and then added a
range of permeabilities extending to
lower values after the Agency rejected
DOE's initial value as too high.
In the PAVT, EPA required that two
changes be made regarding the
permeability of the borehole plugs.
First, the Agency required that the
permeability of the intact plugs during
the first two hundred years of the plug
lifetime be treated as a variable or
probability distribution rather than as a
fixed parameter, with a range bounded
by values found in the literature. The
range of values included borehole plug
permeabilities both higher and lower
than the constant permeability used in
the CCA. In addition, EPA required DOE
to use a range of permeability values to
represent the permeability of borehole
plugs that have started to degrade. The
upper end of the new range was the
same permeability as that used in the
CCA, but the lower end of the range was
reduced by three orders of magnitude
and the median was reduced by an
order of magnitude. The Agency
believed that the upper end of the range
chosen by DOE, based upon the
permeability of silty sand, was
reasonable because an abandoned
borehole plug could degrade to this type
of debris over long periods of time.
Since the permeability of the actual
borehole fill material at some time well
into the future is unknowable, the
Agency believes that the use of data
based on natural materials is a
reasonable approach. However, the
Agency was not satisfied with the
rationale for the lower end of the range
originally chosen by DOE. The EPA
believes that there is some probability
that the concrete borehole plugs will not
degrade as assumed in the CCA PA.
Consequently, in the PAVT, EPA set the
lower end of the range at a permeability
value consistent with intact concrete.
One commenter stated that DOE had
not sufficiently accounted for
uncertainty in the lifetime of a borehole
plug before it degrades. (A borehole
plug with a longer lifetime would take
longer to become more permeable and
would allow more gas to build up in the
repository.) This commenter stated that
DOE should perform additional
calculations to investigate how borehole
plug lifetimes could influence
repository conditions and compliance
with the containment requirements.
The EPA also initially had concerns
that uncertainty about the lifetime of
borehole plugs had not been sufficiently
represented in the CCA PA. In order to
reflect this uncertainty, the Agency
required DOE to use a probability
distribution of borehole plug
permeabilities for intact plugs during
the first two hundred years of their
lifetime in the PAVT, rather than a
constant value. The sampled range of
permeabilities includes values
representing the permeability of both
intact (newer) plugs and disintegrating
(older) plugs. Therefore, EPA believes
that this change made in the PAVT
adequately addresses the effects of
uncertainty in borehole plug life.
5. Other Performance Assessment Issues
The EPA used many methods to
analyze specific scenarios or
characteristics that DOE included in the
PA. Commenters had concerns about
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27381
these methods, since the soundness of
EPA's conclusions would depend upon
the soundness of the methods used to
reach those conclusions. Commenters
disagreed with aspects of a few types of
analyses in particular: sensitivity
analysis, and the PA verification test
("PAVT"). Sensitivity analysis is a
computer modeling technique that
examines whether results of computer
modeling will change significantly if a
particular parameter value is changed.
The EPA's approach to sensitivity
analysis is documented in EPA's
Technical Support Document for
Section 194.23: Sensitivity Analysis.
(Docket A-93-02, V-B-13) The PAVT
was a set of 300 simulations of
additional performance assessment
calculations required by EPA. The
PAVT implemented DOE's PA modeling
using the same sampling methods as the
CCA PA, but incorporating parameter
values that were selected by EPA.
Because some commenters disagreed
with DOE's approach to the PA and
EPA's approach to its analysis, they
recommended that the Agency require
DOE to repeat the PA using different
scenarios or characteristics of the WIPP
and its surroundings; these issues are
discussed in preceding sections of this
preamble related to the PA.
a. Sensitivity Analysis. Computer
modelers perform a sensitivity analysis
for a parameter in a model to find out
if results of modeling are sensitive to
(significantly affected by) that
parameter. If the results of modeling are
not sensitive to the parameter, then the
exact value of the parameter is not
important to the results of modeling.
The compliance criteria require DOE
to document the development of input
parameters for the PA under
§§194.14(d), 194.23(c)(4), and
194.34(b). As part of its parameter
development, DOE conducted a
sensitivity analysis of parameters used
in the CCA PA. (Docket A-93-02, Item
II-G-1, Appendix SA, Volume XVI) The
EPA reviewed this and supplementary
information that documents DOE
sensitivity analysis of the parameters
sampled in the PA. (Docket A-93-02,
Item II-G-7) As the Agency continued
in its review of the CCA and supporting
documentation, EPA found that there
were three categories of parameters not
fully documented in the CCA
documents or in the Sandia National
Laboratory WIPP Records Center. These
categories were: (1) parameters lacking
supporting evidence; (2) parameters
having data records that support values
other than those selected by DOE; and
(3) parameters that are not explicitly
supported by the relevant data or
information. The EPA expressed
concern about 58 parameters of the 465
parameters that EPA reviewed in detail.
(Docket A-93-02, Item II-I-17) For
these 58 parameters, EPA evaluated
whether changing the parameter values
would have a significant impact on the
results of computer modeling, primarily
through the use of a sensitivity analysis.
(Docket A-93-02, Item V-B-13)
(Distribution coefficients, or Kd values,
were examined in separate calculations
and analyses conducted by EPA.
(Docket A-93-02, Items V-B-4, V-B-7,
and V-B-8)) In its sensitivity analysis,
the Agency examined changes in output
from the PA models' major submodels
that calculate releases and solubility of
actinides: BRAGFLO24, BRAGFLO—
DBR25, CUTTINGS—S 26, SOURCE
TERM 27, and CCDFGF^. The EPA
found that 27 of the 58 parameters have
a significant impact on the results of
modeling and that 31 of the 58
parameters did not have a significant
impact. Some of these parameters (both
significant and insignificant to results)
were subsequently determined to be
adequately supported based on
additional documentation provided by
DOE or Sandia National Laboratory.
(Docket A-93-02, Items II-I-25 and II-
1-27) For parameters that might have an
impact on the results of the PA and
were found not to be adequately
supported, EPA required DOE to
perform a Performance Assessment
Verification Test with revisions to the
significant parameters.
Commenters stated that they had
concerns about the submodel approach
used in EPA's sensitivity analysis. One
commenter stated that EPA had not
justified this approach, beyond stating
that it was "a more sensitive method"
than examining the final results of the
complete PA model. Another
commenter stated that EPA had not
shown that the submodel approach for
24 BRAGFLO predicts gas generation rates, brine
and gas flow, and fracturing within the anhydrite
marker beds in order to predict the future state of
the repository.
25 BRAGFLO—DBR calculates the amount of
waste that dissolves in brine and travels in the
contaminated brine as a direct brine release.
26 CUTTINGS—S predicts the volume of solid
waste released from the repository because of
human intrusion drilling. This includes releases
from cavings (material that falls from the walls as
a drill bit drills through), cuttings (material that is
actually cut by a drill bit during drilling, including
any waste), and spallings (releases of solids pushed
up and out by gas pressure in the repository).
27 SOURCE TERM calculates actinide solubilities
within the repository. The solubility values are then
used in the NUTS and PANEL codes to calculate
the actinide concentrations in brine released from
the repository.
28 CCDFGF calculates the complementary,
cumulative distribution functions ("CCDFs") used
to show compliance with EPA's containment
requirements.
testing sensitivity related in any
particular way to the compliance
demonstration with the containment
requirements. This commenter also
stated that EPA had not explained or
justified why the analysis used the
average of changes in the outputs of the
submodels, and that averaging output
changes might disguise the significance
of a parameter value change if some
outputs change in direct response and
others change inversely.
The DOE's PA model uses almost
1600 parameters. Even an important
parameter may change the final results
of the PA by a relatively small
percentage because so many parameters
contribute to the final results. The
different submodels contain far fewer
parameters than the complete PA.
Therefore, a change in any one
parameter will cause a greater
percentage change in the output from a
submodel than in the final result of the
entire PA modeling. It is for this reason
that EPA chose to use submodels. This
approach provided intermediate results
that would be a more sensitive measure
of reactions of a model to changes in
input parameters than the resultant
complementary cumulative distribution
functions ("CCDFs") used to determine
compliance.
The submodel outputs that EPA
analyzed for sensitivity included the
outputs most closely linked with
radionuclide release and the ability of
the WIPP to meet EPA's containment
requirements. Examples of submodel
outputs are gas pressure in the
repository; cumulative brine release into
the Culebra dolomite; cumulative
cavings release and cumulative
spallings release to the earth's surface;
and brine flow into the anhydrite
interbeds away from the repository. If a
parameter changes the submodel
outputs significantly, it may have a
significant impact on the final results of
the PA; however, if a parameter does not
change the submodel output
significantly, then it cannot change the
final results of the PA significantly. In
addition, EPA notes that the nature of
the testing—which included three
model runs at low, average, and high
parameter values—means that it is not
practical to develop mean CCDFs. It
would be necessary to run all of the PA
codes for each parameter change a
hundred times to create a single CCDF.
Therefore, except for those parameters
included in the CCDFGF code, it would
have been extremely cumbersome and
time-consuming to perform a sensitivity
analysis on the final results of the PA.
The Agency disagrees that averaging
the submodel outputs disguises the
significance of a parameter value change
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if some outputs change in direct
response and others change inversely.
The EPA used absolute values 29 of the
percent changes in computing the
average percent changes. If two
parameters had inverse relationships,
those relationships would not cancel
each other out because the final results
would be an average of the absolute
values. Averaging of the percent
changes in the key submodel outputs
was a significant step only for the
parameters in the BRAGFLO code,
where average changes to output were
developed based on 11 model outputs.
The EPA averaged the results of these
eleven outputs in order to give equal
weight to each in determining the
sensitivity of BRAGFLO parameters.
Several members of the public
commented that most of the sensitivity
analyses varied only one parameter,
rather than varying several parameters
at a time, which potentially could show
a significant combined result. The EPA
varied single parameters in most of the
analyses to identify those parameters
that were most important to the PA
results. One of the problems with
varying multiple parameters
simultaneously is that it is difficult to
determine which parameter (or
parameters) led to the observed result.
Analysis of groups of parameters
requires the Agency to find that the
entire group of parameters is sensitive
or not sensitive. In addition, if some
parameters in a group increase releases
while others reduce releases, a group
analysis may not detect actual
sensitivity for individual parameters.
This is because the sensitivity analysis
typically looks at low, high, and average
values for all parameters in the group
simultaneously. Without examining the
sensitivity of individual parameters, the
analyst would not always know enough
about the parameters to be able to
predict the most extreme situation with
the greatest consequences of releases.
The ability to determine the significance
of individual parameters is important
because this allows one to improve the
model's predictive capability by
focusing resources on those parameters
that are most sensitive and have the
greatest impact on results. It is true that
EPA did not perform a separate
sensitivity analysis run on groups of
parameters that it determined were
insensitive through individual
parameter tests. The Agency believes
that this is not necessary because the
cumulative calculated sensitivity of
29 Absolute value is the magnitude of a number,
without a positive or negative sign. For example,
positive three and negative three both have an
absolute value of three.
these insensitive parameters is so small
compared to the sensitive parameters.
For example, the sum of the percent
changes for all 33 insensitive parameters
in BRAGFLO together was 47 percent
(ranging from 0 percent to 10 percent
each), while the percent change for the
individual sensitive parameters ranged
from 101 percent to 103,611 percent
each. (Docket A-93-02, Item V-B-13,
Table 3.1-1) Therefore, EPA concluded
that those parameters it found
insensitive through analysis of
individual parameters will not have a
significant effect on results of the PA
and do not need to be re-analyzed in
groups.
In addition to performing its own
sensitivity analysis on parameters, the
Agency required DOE to complete a
comprehensive recalculation of the
entire PA in the Performance
Assessment Verification Test ("PAVT").
The purpose of the PAVT was to
perform a complete evaluation of the
synergistic effects of changing important
and questionable parameters on the
outcome of the PA calculations. The
results of the PAVT indicate that the
calculated releases would increase
when changes are made to the sensitive
parameters identified by the Agency,
but the revised results of the PA with
these more conservative parameter
values would still be an order of
magnitude less than the containment
requirements of 40 CFR 191.13.
A commenter stated that EPA's
sensitivity analysis did not vary
conceptual models. The Agency agrees
that this is true. The objective of EPA's
sensitivity analysis was to determine the
importance of selected individual
parameters and groups of parameters to
the PA results. The purpose of a
sensitivity analysis on conceptual
models would be to determine if model
results would change significantly using
different assumptions or using
alternative conceptual models. The EPA
examined the conceptual models and
alternatives, under §§ 194.23(a)(l) and
(a) (2). As a result of this review, EPA
required DOE to conduct a sensitivity
analysis on Culebra transmissivity and
to examine the assumption that the
Culebra acts as a fully confined system
as it pertains to hydrogeochemistry of
the Culebra. (Docket A-93-02, Item II-
1-17) The EPA found that the sensitivity
analysis results supported DOE's
treatment of Culebra transmissivity and
treatment of the Culebra as a confined
system because of the minimal impact
on results when changing assumptions.
(Docket A-93-02, Item II-I-31) In
addition, the Conceptual Models Peer
Review Panel reviewed the conceptual
models, as required by §§ 194.27 and
194.23(a)(3)(v). The Agency finds that it
is not necessary to perform further
sensitivity analysis on conceptual
models because both the Agency's and
the Panel's reviews accomplished the
purpose of evaluating the impact of
using different assumptions or using
alternative conceptual models. These
reviews found all the conceptual models
except the spallings model to be
adequate for use in the PA, and
concluded that the spallings values used
in the CCA PA are reasonable for use in
the PA. (Docket A-93-02, Item V-B-2,
CARD 23, Section 7)
The EPA determined that DOE
adequately provided a detailed listing of
the code input parameters; listed
sampled input parameters; provided a
description of parameters and the codes
in which they are used; discussed
parameters important to releases;
described data collection procedures,
sources of data, data reduction and
analysis; and described code input
parameter development, including an
explanation of quality assurance
activities. The DOE also documented
the probability distribution of these
parameters, as required by § 194.34(b).
The Agency analyzed parameter values
used in the CCA, including DOE's
documentation of the values and EPA's
sensitivity analysis. The EPA also
required DOE to change these parameter
values in the PAVT and found that the
WIPP is still an order of magnitude
below the containment requirements in
§ 191.13. (For further discussion of
values for several specific parameters,
refer to the preceding preamble
discussion, "Parameter values." See also
Docket A-93-02, Item V-B-2, CARD 23,
Sections 8 and 9.) Therefore, the Agency
determines that the CCA complies with
§§194.14(d), 194.23(c)(4) and 194.34(b).
b. Performance Assessment
Verification Test. The containment
requirements at § 191.13 indicate that a
disposal system is to be tested through
a PA that predicts the likelihood of
occurrence of all significant processes
and events that may disturb the disposal
system and affect its performance, and
that predicts the ability of the disposal
system to contain radionuclides. Section
191.13 requires that a disposal system
be designed so that there is reasonable
expectation that cumulative releases (1)
have a probability of less than one in ten
(0.1) of exceeding the calculated release
limits, and (2) have no more than a one
in one thousand (0.001) chance of
exceeding ten times the calculated
release limits.
In the process of reviewing the CCA,
the Agency found problems with some
computer codes and with
documentation of parameter
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development. Commenters also voiced
concerns about some parameters used in
the CCA PA during the public comment
period for the Advanced Notice of
Proposed Rulemaking. The Conceptual
Models Peer Review Panel initially
found that one of the conceptual models
used for the PA, the spallings
conceptual model, was not adequate.
The DOE itself found some problems
with some of its codes, particularly
concerning code stability. Because of
these many concerns, the Agency
required DOE to perform additional
calculations in a Performance
Assessment Verification Test ("PAVT")
in order to verify that the cumulative
impact of all changes to input
parameters, conceptual models, and
computer codes used in the PA was not
significant enough to necessitate a new
PA. (PAVT, Docket A-93-02, Items II-
G-26 and II-G-28) The PAVT used
modified parameter values and ranges,
selected by EPA, in DOE's PA model.
Many of these parameter values were
suggested by public comments. The
PAVT results showed releases that were
higher, on average, than DOE's original
calculations in the CCA. However, the
PAVT results were still well within the
EPA release limits stated in 40 CFR
191.13.
During the public comment period on
EPA's proposed certification decision
for the WIPP, commenters raised several
issues about the PAVT and about the PA
in general. Some commenters stated that
the PAVT incorporated extremely
conservative ranges for 24 critical
parameters, and that the PA in general
was done in a conservative fashion.
Other commenters stated that specific
parameter values needed to be changed
in order to make more conservative
assumptions. In particular, the public
mentioned parameters for actinide
solubility, distribution coefficients (Kd),
the probability of hitting a brine pocket,
and the permeability of borehole plugs.
(These parameters are discussed above.)
Commenters also said that DOE needed
to investigate possible human intrusion
scenarios more thoroughly. Among the
human intrusion scenarios commenters
identified for further study were air
drilling, fluid injection, CO2 injection,
and potash mining. Members of the
public commented that DOE had
incorrectly assessed geology of the WIPP
site and the future state of the waste to
go into the WIPP. They stated concerns
about the potential for dissolution, for
the recharge of ground water in the
Rustler Formation with contaminated
brine, for earthquakes, and for water
entering the Salado layer and the
modeling of gas generation and flow of
brine and gas in the repository. Many
commenters stated that the Agency
should require DOE to run another PA
using different assumptions about these
topics.
The EPA initially had many of the
same concerns as those mentioned by
the public, particularly concerning
parameters and human intrusion
scenarios. As discussed in the above
preamble sections on the PA, EPA
questioned the values and distributions
of many values of the parameters. The
Agency even required DOE to revise
some parameter values for the PAVT.
The EPA also asked DOE to investigate
fluid injection further. After receiving
public comments, the Agency did
independent work on the possible
impacts of fluid injection and air
drilling, as well as analysis of the
likelihood of air drilling and CO2
injection in the Delaware Basin. (Docket
A-93-02, Item V-C-1, Sections 5 and 8)
After reviewing the information
available, the Agency concludes that
DOE's PA incorporates the appropriate
human intrusion scenarios and geologic
and disposal system characteristics. The
PAVT and additional analyses of
intrusion scenarios by both DOE and
EPA have adequately addressed
concerns raised by commenters.
Based upon results of the CCA PA (as
confirmed by the PAVT), EPA finds that
the WIPP complies with the
containment requirements by a
comfortable margin, even when using
more conservative parameter values that
were changed significantly from those
in the CCA PA. This modeling shows
that the WIPP will contain waste safely
under realistic scenarios, and even in
many extreme cases. The EPA found
that the scenarios and parameter
changes suggested by commenters either
had already been adequately addressed
by DOE, were inappropriate for the
Delaware Basin, would impact neither
releases nor the results of the PA
sufficiently to justify further analysis, or
were not realistic. Therefore, the Agency
concludes that no further PA is required
to determine if the WIPP is safe or to
make its certification decision.
Many comments were based on a
philosophy that DOE should use an
unrealistically conservative approach to
the PA. For example, a commenter
stated that air drilling should be
incorporated in the PA at the most
conservative rate predicted by DOE in
the near future for the entire U.S., even
if air drilling is not currently a standard
practice in the Delaware Basin. Another
commenter suggested using the most
conservative value from the PAVT for
the probability of hitting a brine pocket,
even after the commenter's own
sensitivity analysis showed that this
parameter did not have a significant
impact on WIPP compliance at still
higher values. A different commenter
stated that DOE and EPA should analyze
actinide solubilities as if DOE were not
adding MgO to reduce those solubilities,
even though the Department has
committed to adding MgO. The Agency
found all of these suggestions to be
inappropriate, either because they were
unrealistic or because they required
additional analysis when the change
had already been demonstrated to have
little or no impact on the PA results.
The Agency believes that the PA should
be a reasonable assessment with some
conservative assumptions built in,
rather than an assessment comprised
entirely of unrealistic assumptions and
worst-case scenarios. The disposal
regulations at 40 CFR Part 191 require
the PA to show there is a reasonable
expectation that cumulative releases
will meet the containment
requirements. This philosophy is
reflected elsewhere in EPA's
requirements, such as in the
requirement for the mean CCDF to
comply with the containment
requirement, rather than for every CCDF
to comply. If unrealistically
conservative assumptions were used in
the PA, then results of the PA would not
reflect reality and would not be a
reasonable measure of the WIPP's
capability to contain waste.
6. Conclusions
Section 194.23 sets forth specific
requirements for the models and
computer codes used to calculate the
results of performance assessments
("PA") and compliance assessments. In
order for these calculations to be
reliable, DOE must properly design and
implement the computer codes used in
the PA. To that end, § 194.23 requires
DOE to provide documentation and
descriptions of the PA models,
progressing from conceptual models
through development to mathematical
and numerical models, and finally to
their implementation in computer
codes.
The CCA and supporting documents
contain a complete and accurate
description of each of the conceptual
models used and the scenario
construction methods used. The
scenario construction descriptions
include sufficient detail to understand
the basis for selecting some scenarios
and rejecting others and are adequate for
use in the CCA PA calculations. Based
on information provided in the CCA,
together with supplementary
information provided by DOE in
response to specific EPA requests, EPA
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concluded that DOE provided an
adequate and complete description of
alternative conceptual models seriously
considered but not used in the CCA.
The information on peer review in the
CCA and in supplementary information
demonstrates that all conceptual models
have undergone peer review consistent
with the requirements of § 194.27.
Related issues discussed above in
today's preamble include spallings,
fluid injection, air drilling, CO2
injection, and the gas generation
conceptual model. The Agency
determines that the DOE has
demonstrated compliance with the
requirements of §§ 194.23 (a)(l), (a)(2)
and (a) (3) (v).
The Conceptual Models Peer Review
Panel found all the conceptual models
to reasonably represent possible future
states of the repository and to be
adequate for use in the PA except the
spallings conceptual model. However,
as discussed above in this preamble,
additional modeling conducted by DOE,
and additional data presented by DOE,
provide a substantial basis for EPA to
conclude that the results of the spallings
model are adequate and useful for the
purpose for which conceptual models
are intended, i.e., to aid in the
determination of whether the WIPP will
comply with the disposal regulations
during the regulatory time period.
Public comments received on this issue
are discussed above in the preamble
section on spallings. Because the
spallings model produces reasonable
and conservative results, and because
the Peer Review Panel found that all
other conceptual models reasonably
represent possible future states of the
repository, EPA finds DOE in
compliance with § 194.23(a)(3)(i).
Based on information contained in the
CCA and supporting documentation for
each code, EPA concludes that the
mathematical models used to describe
the conceptual models incorporate
equations and boundary conditions
which reasonably represent the
mathematical formulation of the
conceptual models. Some of the specific
issues related to this criterion are in the
section of the preamble entitled, "Two-
dimensional modeling of brine and gas
flow." Based on the CCA and
supplementary information provided by
DOE, the Agency determines that DOE
provided sufficient technical
information to document the numerical
models used in the CCA. Based on
verification testing, EPA also
determined that the computer codes
accurately implement the numerical
models and that the computer codes are
free of coding errors and produce stable
solutions. The DOE resolved coding
error problems and stability problems
identified in numerical models by
completing code revisions and
supplementary testing requested by the
Agency. Therefore, the Agency
concludes that DOE has demonstrated
compliance with §§ 194.23(a)(3) (ii), (iii)
and (iv).
Based on EPA audits and CCA review,
EPA found that code documentation
meets the quality assurance
requirements of ASME NQA-2a-1990
addenda, part 2.7, to ASME NQA-2-
1989 edition. Thus, the Agency finds
that DOE complies with § 194.23(b).
Based on DOE's documentation for
each code and supplementary
information requested by EPA, the
Agency found that DOE provided
adequate documentation so that
individuals knowledgeable in the
subject matter have sufficient
information to judge whether the codes
are formulated on a sound theoretical
foundation, and whether the code has
been used properly in the PA. The EPA
found that the CCA and supplementary
information included an adequate
description of each model used in the
calculations; a description of limits of
applicability of each model; detailed
instructions for executing the computer
codes; hardware and software
requirements to run these codes; input
and output formats with explanations of
each input and output variable and
parameter; listings of input and output
files from sample computer runs; and
reports of code verification, bench
marking, validation, and QA
procedures. The EPA also found that
DOE adequately provided a detailed
description of the structure of the
computer codes and supplied a
complete listing of the computer source
code in supplementary documentation
to the CCA. The documentation of
computer codes describes the structure
of computer codes with sufficient detail
to allow EPA to understand how
software subroutines are linked. The
code structure documentation shows
how the codes operate to provide
accurate solutions of the conceptual
models. The EPA finds that DOE did not
use any software requiring licenses.
Therefore, EPA determines that DOE has
complied with the requirements of
§§194.23(c) (1),(2),(3) and (5).
The EPA determined that DOE, after
additional work and improvement of
records in the SNL Record Center,
adequately provided a detailed listing of
the code input parameters; listed
sampled input parameters; provided a
description of parameters and the codes
in which they are used; discussed
parameters important to releases;
described data collection procedures,
sources of data, data reduction and
analysis; and described code input
parameter development, including an
explanation of QA activities. The EPA
determined that the CCA and
supplementary information adequately
discussed how the effects of parameter
correlation are incorporated, explained
the mathematical functions that
describe these relationships, and
described the potential impacts on the
sampling of uncertain parameters. The
CCA also adequately documented the
effects of parameter correlation for both
conceptual models and the formulation
of computer codes, and appropriately
incorporated these correlations in the
PA. Public comments regarding
parameters are discussed above in the
preamble in the section titled
"Parameter Values." The Agency finds
that DOE has demonstrated compliance
with the requirements of § 194.23(c) (4)
and (6).
Because DOE provided EPA with
ready access to the necessary tools to
permit EPA to perform independent
simulations using computer software
and hardware employed in the CCA,
EPA finds DOE in compliance with
§194.23(d).
Section 194.31 of the compliance
criteria requires DOE to calculate release
limits for radionuclides in the WIPP in
accordance with 40 CFR Part 191,
Appendix A. Release limits are to be
calculated using the activity, in curies,
from radioactive waste that will exist in
the WIPP at the time of disposal. The
CCA PA and the PAVT were calculated
using release limits calculated according
to Appendix A of 40 CFR Part 191 using
DOE's projected inventory of waste
radioactivity at the time of disposal.
Therefore, EPA concludes that DOE has
met the requirements of § 194.31.
Section 194.32 requires DOE to
consider, in the PA, both natural and
man-made processes and events which
can have an effect on the disposal
system. The EPA expected DOE to
consider all features, events and
processes ("FEPs") that may have an
effect on the disposal system, including
both natural and human-initiated
processes. The Department is not
required to consider FEPs that have less
than one change in 10,000 of occurring
over 10,000 years.
The EPA concluded that the initial
FEP list assembled by DOE was
sufficiently comprehensive, in
accordance with §§ 194.32(a) and (e)(l).
Based on quantitative and qualitative
assessments provided in the CCA and
supporting documents, EPA concluded
that DOE appropriately rejected those
FEPs that exhibit low probability of
occurrence during the regulatory period,
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in accordance with § 194.32(d). In
addition, EPA found DOE's inclusion of
various scenarios in the PA to be
reasonable and justified, and meets the
requirement of § 194.32 (e) (2). The DOE
provided documentation and
justification for eliminating those FEPs
that were not included in the PA. In
some cases (e.g., fluid injection, CO2
injection, potash mining and
dissolution), the CCA did not initially
provide adequate justification or
convincing arguments to eliminate FEPs
from consideration in the PA. However,
DOE provided supplemental
information and analyses, which EPA
determined was sufficient to
demonstrate compliance with
§194.32(e)(3).
The EPA verified, through review of
the CCA and supporting documents,
that DOE included, in the PA,
appropriate changes in the hydraulic
conductivity values for the areas
affected by mining. The area considered
to be mined for potash in the controlled
area is consistent with the requirement
of § 194.32(b), that the mined area be
based on mineral deposits of those
resources currently extracted from the
Delaware Basin. Thus, EPA finds that
DOE complies with § 194.32(b).
In accordance with § 194.32(c), DOE
considered the possibility of fluid
injection, identified oil and gas
exploration and exploitation, and water
and potash exploration as the only near
future human-initiated activities that
need to be considered in the PA. The
EPA's review of the CCA and supporting
documents referenced in the CCA with
respect to § 194.32(c), indicated that
DOE adequately analyzed the possible
effects of current and future potential
activities on the disposal system. In
response to concerns expressed by EPA
and stakeholders, DOE conducted
additional analyses and submitted
follow-up information. In addition, EPA
has performed its own analysis of fluid
injection. Public comments concerning
human intrusion FEPs are discussed in
the preamble sections above titled,
"Fluid injection," "Potash mining," and
"CO2 injection." The collected
information provided by DOE was
adequate. Therefore, EPA concludes that
DOE's analysis meets the requirements
of§194.32(c).
Section 194.33 requires DOE to make
specific assumptions about future deep
and shallow drilling in the Delaware
Basin. The EPA found that the
documentation in the CCA
demonstrated that DOE thoroughly
considered deep and shallow drilling
activities and rates within the Delaware
Basin in accordance with § 194.33 (a)
and (b). The EPA found that DOE
appropriately screened out shallow
drilling from consideration in the PA.
The EPA also found that DOE
appropriately incorporated the
assumptions and calculations for
drilling into the PA as stipulated in
§§ 194.33 (b) and (c). In accordance with
§ 194.33(c), DOE evaluated the
consequences of drilling events
assuming that drilling practices and
technology remain consistent with
practices in the Delaware Basin at the
time the certification application was
prepared. Public comments concerning
this issue are discussed in the preamble
section above titled, "Air drilling." The
EPA determined that the PA models did
not incorporate the effects of techniques
used for resource recovery, as allowed
by § 194.33(d). The EPA further
concludes that the drilling information
in the CCA is consistent with available
data. Therefore, the Agency finds DOE
in compliance with the requirements of
§194.33.
Section 194.34 of the compliance
criteria provides specific requirements
for presenting the results of the PA for
the WIPP. Section 194.34 requires DOE
to use complementary cumulative
distribution functions ("CCDFs") to
express the results of the PA. The
Department also must document the
development of probability
distributions, and the computational
techniques used for drawing random
samples from these probability
distributions, for any uncertain
parameters used in the PA. The PA must
include a statistically sufficient number
of CCDFs. The CCA must display the
full range of CCDFs generated. Finally,
the CCA must demonstrate that the
mean of the population of CCDFs meets
the containment requirements of
§ 191.13 with at least a 95 percent level
of statistical confidence.
The CCA presented the results of the
PA in the form of CCDFs. The PA used
Latin Hypercube Sampling to sample
values randomly from probability
distributions of uncertain parameters.
Parameter values and their distributions
were documented in the CCA and in
Sandia National Laboratory's Records
Center. The CCA presented the full
range of the 300 CCDFs generated in the
PA, as well as mean CCDF curves. The
CCDFs showed that the mean CCDF
curve met the containment requirements
of § 191.13. Less than one percent of
CCDF curves in the CCA PA exceeded
one times the release limit, and no
CCDF curves exceeded ten times the
release limit. Based on these results,
DOE concluded that the WIPP met
EPA's requirements.
The EPA also examined the results of
the PAVT in light of the requirements of
§ 194.34. The PAVT presented the
results of the PA in CCDFs, and
presented the complement of 300
CCDFs. DOE's documentation and
EPA's separate analysis demonstrated
that 300 CCDFs are sufficient,
statistically speaking. The PAVT used
the same random sampling technique of
Latin Hypercube Sampling that the PA
model used for the CCA PA. The DOE
used parameter values assigned by EPA,
as well as other parameter values and
their distributions documented earlier
for the CCA PA. The mean CCDF curve
for the PAVT showed that releases were
roughly three times those calculated in
the CCA PA, but releases still met the
containment requirements of § 191.13
by more than an order of magnitude at
the required statistical confidence level.
Less than ten percent of CCDF curves in
the PAVT exceeded one times the
release limit, and no CCDF curves
exceeded ten times the release limit.
The PAVT confirmed that the CCA PA
was adequate for determining
compliance. Therefore, EPA concludes
that the CCA PA meets EPA's
containment requirements and that DOE
complies with the requirements of
§194.34.
C. General Requirements
1. Quality Assurance (§ 194.22)
Section 194.22 establishes quality
assurance ("QA") requirements for the
WIPP. QA is a process for enhancing the
reliability of technical data and analyses
underlying DOE's CCA. Section 194.22
requires DOE to (a) establish and
execute a QA program for all items and
activities important to the containment
of waste in the disposal system, (b)
qualify data that were collected prior to
implementation of the required QA
program, (c) assess data for their quality
characteristics, to the extent practicable,
(d) demonstrate how data are qualified
for their use, and (e) allow verification
of the above measures through EPA
inspections/audits. The DOE's QA
program must adhere to specific Nuclear
Quality Assurance ("NQA") standards
issued by the American Society of
Mechanical Engineers ("ASME").
The EPA assessed compliance with
the QA requirements in two ways. First,
EPA reviewed general QA information
submitted by DOE in the CCA and
reference documents. The EPA's second
level of review consisted of visits to the
WIPP site, as well as WIPP-related
facilities, to perform independent audits
and inspections to verify DOE's
compliance with the QA requirements.
The proper establishment and execution
of a QA program is verified strictly by
way of inspections and audits.
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Therefore, EPA conducted audits to
verify the proper execution of the QA
program at DOE's Carlsbad Area Office
("CAO"), Sandia National Laboratories
("SNL"), and Westinghouse's Waste
Isolation Division ("WID") at the WIPP
facility. The EPA auditors observed
WIPP QA activities, interviewed WIPP
personnel, and reviewed voluminous
records required by the NQA standards,
but not required to be submitted as part
of the CCA.
Section 194.22(a)(l) requires DOE to
adhere to a QA program that
implements the requirements of the
following: (1) ASMENQA-1-1989
edition; (2) ASME NQA-2a-1990
addenda, part 2.7, to ASME NQA-2-
1989 edition; and (3) ASME NQA-3-
1989 edition (excluding Section 2.1 (b)
and (c), and Section 17.1). The EPA
verified that DOE established these
requirements in the Quality Assurance
Program Document ("QAPD") contained
in the CCA. The QAPD is the
documented QA program plan for the
WIPP project, as a whole, to comply
with the NQA requirements. The QAPD
is implemented by DOE's CAO, which
has the authority to audit all other
organizations associated with waste
disposal at the WIPP (such as WID, SNL
and waste generator sites) to ensure that
their lower-tier QA programs establish
and implement the applicable
requirements of the QAPD. The EPA
audited DOE's QA program at CAO and
determined that DOE properly adhered
to a QA program that implements the
NQA standards. Therefore, EPA finds
DOE in compliance with § 194.22(a)(l).
Section 194.22(a)(2) requires DOE to
include information in the CCA that
demonstrates that the requisite QA
program has been "established and
executed" for a number of specific
activities. Section 194.22(a)(2)(i)
requires DOE to include information
which demonstrates that the QA
program has been established and
executed for waste characterization
activities and assumptions. In the CCA,
DOE provided the QAPD, which is
DOE's central QA document program
plan that then must be incorporated into
site-specific QA program plans. The
DOE generator sites will prepare site
certification Quality Assurance Plans
("QAPs") that, together with Quality
Assurance Project Plans ("QAPjPs"),
will constitute site-specific QA program
plans.30 The EPA finds that the QAPD,
as it applies to waste characterization, is
in conformance with the NQA
requirements and that DOE's QA
organization can properly perform
audits to internally check the QA
programs of the waste generator sites.
However, as discussed below, the
Agency will verify the establishment
and execution of site-specific QA
programs.
The compliance criteria require that
QA programs be established and
executed specifically with respect to the
use of process knowledge and a system
of controls for waste characterization.
(§§194.22(a)(2)(i) and 194.24(c)(3)
through (5)) To accomplish this, waste
generator site-specific QA programs and
plans must be individually examined
and approved by EPA to ensure
adequate QA programs are in place
before EPA allows individual waste
generator sites to transport waste for
disposal at the WIPP. Since waste
characterization activities have not
begun for most TRU waste generator
sites and storage facilities, EPA has not
yet evaluated the compliance of many
site-specific QA plans and programs.
To date, one WIPP waste generator
site, Los Alamos National Laboratory
("LANL"), has been approved by EPA to
have established an adequate QA
program plan and to have properly
executed its QA program in accordance
with the plan. Prior to approval of
LANL's site-specific QA program, EPA
conducted an audit of DOE's overall
WIPP QA program and approved its
capability to perform audits in
accordance with the requirements of
NQA-1. The EPA then inspected three
DOE audits of LANL's QA program.
Based on the results of the inspections,
the EPA inspectors determined that the
QA program had been properly
executed at LANL.31 Therefore, EPA
finds that the requirements of
§ 194.22(a)(2)(i) have been met for waste
characterization activities at LANL.
30 NQA-1 (Element II-2) requires that
organizations responsible for activities affecting
quality (in the case of the WIPP, affecting the
containment of waste in the disposal system) must
have documented QA programs in accordance with
the applicable NQA requirements. The
documentation for such programs is commonly
referred to as a "quality assurance program plan,"
or "QAPP." For WIPP waste generator sites, the role
of the QAPP is fulfilled by documents with other
titles, such as the QAP and the QAPjP. The "TRU
QAPP" referenced by DOE in the CCA is not a
QAPP as described by the NQA standards; rather,
it is a technical document that describes the quality
control requirements and performance standards for
characterization of TRU waste coming to the WIPP
facility. The TRU QAPP is addressed more
specifically in the preamble discussion of § 194.24,
Waste Characterization.
31 The terms "audits" and "inspections" are not
synonymous. At waste generator sites, EPA may
either conduct its own audits or inspect audits
conducted by DOE. (The DOE-CAO conducts audits
to evaluate waste characterization programs at
waste generator sites.) The difference is that for an
inspection, EPA's role is to review DOE's QA
checks, and not actually conduct all of the checks
itself.
With respect to other waste generator
sites, EPA will verify compliance with
§ 194.22(a)(2) (i) conditioned on
separate, subsequent approvals from
EPA that site-specific QA programs for
waste characterization activities and
assumptions have been established and
executed in accordance with applicable
NQA requirements at each waste
generator site.
As waste generator facilities establish
QA programs after LANL, EPA will
assess their compliance with NQA
requirements. The approval process for
site-specific QA programs includes a
Federal Register notice, public
comment period, and on-site EPA audits
or inspections to evaluate
implementation. For further information
on EPA's approval process, see
Condition 2 and § 194.8. For further
discussion of waste characterization
programs and approval of the processes
used to characterize waste streams from
generator sites, see the discussion of
§ 194.24 below in this preamble.
Section 194.22(a)(2)(ii) requires DOE
to include information which
demonstrates that the QA program has
been established and executed for
environmental monitoring, monitoring
of performance of the disposal system
and sampling and analysis activities.
Westinghouse's WID was responsible for
establishing this requirement under the
WID QAPD described in the CCA. The
EPA conducted an audit of the WID and
found that the requisite QA program
had been established and executed for
environmental monitoring, sampling
and analysis activities. The EPA also
finds that Chapter 5 of the CCA and
referenced documents contain a
satisfactory description of compliance
with this section. Therefore, EPA finds
the WIPP in compliance with
§194.22(a)(2)(ii).
Section 194.22(a)(2)(iii) requires DOE
to include information which
demonstrates that the QA program has
been established and executed for field
measurements of geologic factors,
ground water, meteorologic, and
topographic characteristics. WID is
responsible for conducting field
measurements of geologic factors,
ground water, meteorologic and
topographic characteristics. The EPA
conducted an audit of the WID QA
program and found it to be properly
established and executed in accordance
with the applicable NQA requirements.
The EPA also finds that Chapter 5 of the
CCA and referenced documents contain
a satisfactory description of compliance
with this section. Therefore, EPA finds
DOE in compliance with
§194.22(a)(2)(iii).
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Section 194.22(a)(2)(iv) requires DOE
to include information to demonstrate
that the QA program has been
established and executed for
computations, computer codes, models
and methods used to demonstrate
compliance with the disposal
regulations. SNL and WID are
responsible for computations and
software items. The EPA reviewed
information in the CCA and conducted
audits of both SNL and WID Q A
programs. The Agency found that
computer codes were documented in a
manner that complies with the
applicable NQA requirements, and that
software QA procedures were
implemented in accordance with ASME
NQA-2a, part 2.7. The EPA also finds
that Chapter 5 of the CCA and
referenced documents contain a
satisfactory description of compliance
with this section. The EPA therefore
finds that DOE complies with
§194.22(a)(2)(iv).
Section 194.22(a)(2)(v) requires DOE
to include information which
demonstrates that the QA program has
been established and executed for
procedures for implementation of expert
judgment elicitation. CAO and CAO's
Technical Assistance Contractor were
responsible for developing the
procedures for the expert elicitation that
was conducted (after the publication of
the CCA). The EPA found that the
requirements of this regulation were met
by the development and
implementation of CAO Team
Procedure 10.6 (Revision 0), CAO Team
Plan for Expert Panel Elicitation
(Revision 2), and CAO Technical
Assistance Contractor Experimental
Programs Desktop Instruction No.l
(Revision 1). The EPA finds DOE in
compliance with § 194.22(a)(2)(v). The
process of expert judgment elicitation is
discussed in further detail in the section
of this preamble related to § 194.26 of
the compliance criteria.
Section 194.22(a)(2)(vi) requires DOE
to include information which
demonstrates that the QA program has
been established and executed for
design of the disposal system and
actions taken to ensure compliance with
the design specifications. Most of the
WIPP's design was conducted before the
EPA required a QA program. Design
work for the repository sealing system
was conducted under the SNL QA
program. The QA procedures
established and implemented by SNL
and WID address the requirements of
the NQA standards; design verification
was accomplished by a combination of
NQA-1 Supplement 3S-1 methods. The
EPA audits of SNL and WID showed
that the QA programs are properly
established and executed. The EPA also
finds that Chapter 5 of the CCA and
referenced documents contain an
adequate description of compliance
with this section. Therefore, EPA finds
DOE in compliance with
§194.22(a)(2)(vi).
Section 194.22(a)(2)(vii) requires DOE
to include information which
demonstrates that the QA program has
been established and executed for the
collection of data and information used
to support compliance applications.
SNL was responsible for this activity.
SNL adequately addressed these
requirements by implementing
numerous QA procedures to ensure the
quality of data and information
collected in support of the WIPP. The
EPA's audit of SNL concluded that the
QA program is properly established and
executed. Therefore, EPA finds DOE in
compliance with § 194.22(a)(2)(vii).
Section 194.22(a)(2)(viii) requires
DOE to include information which
demonstrates that the QA program has
been established for any other item or
activity not listed above that is
important to the containment of waste
in the disposal system. The DOE has not
identified any other item or activity
important to waste isolation in the
disposal system that require QA
controls to be applied as described in
the CAO QAPD. To date, the EPA has
also not identified any other items or
activities which require controls. The
EPA audits determined that the QA
organizations of CAO, WID, and SNL
have sufficient authority, access to work
areas, and organizational freedom to
identify other items and activities
affecting the quality of waste isolation.
Therefore, EPA finds DOE in
compliance with § 194.22(a)(2)(viii).
Section 194.22(b) requires DOE to
include information which
demonstrates that data and information
collected prior to the implementation of
the QA program required by
§ 194.22(a)(l) have been qualified in
accordance with an alternate
methodology, approved by the
Administrator or the Administrator's
authorized representative, that employs
one or more of the following methods:
peer review; corroborating data;
confirmatory testing; or a QA program
that is equivalent in effect to
§ 194.22(a)(l) ASME documents.
The EPA conducted two audits that
traced new and existing data to their
qualifying sources. The two audits
found that equivalent QA programs and
peer review had been properly applied
to qualify existing data used in the PA.
The EPA also concluded that the use of
existing data from peer-reviewed
technical journals was appropriate,
since the level of such reviews was
equivalent to NUREG-1297 peer
reviews conducted by DOE. Therefore,
EPA finds DOE in compliance with
§ 194.22(b). Furthermore, the Agency is
approving the use of any one of the
following three methods for
qualification of existing data: (1) peer
review, conducted in a manner that is
compatible with NUREG-1297; (2) a QA
program that is equivalent in effect to
ASME NQA-1-1989 edition, ASME
NQA-2a-1990 addenda, part 2.7, to
ASME NQA-2-1989 edition, and ASME
NQA-3-1989 edition (excluding Section
2.1(b) and (c) and Section 17.1); or (3)
use of data from a peer-reviewed
technical journal.
Sections 194.22(c)(l) through (5)
require DOE to provide information
which describes how all data used to
support the compliance application
have been assessed, to the extent
practicable, for specific data quality
characteristics ("DQCs"). In the CCA,
DOE stated that in most cases it was not
practicable to document DQCs for
performance assessments, but asserted
that the intent of DQCs was fulfilled by
other QA programs and quality control
measures.
The Agency agrees with DOE that it
is not appropriate to apply DQCs
retroactively to all of the parameters and
existing data used in the PA, but
believes that they can and should be
applied to measured data (i.e., field
monitoring and laboratory experiments)
as they are developed and used. The
EPA found that, because DOE deemed it
impractical to apply DQCs in some
instances, the CCA and supplementary
information did not systematically or
adequately address DOE's consideration
of DQCs for measured data related to the
PA. Therefore, EPA reviewed parameter
records to determine whether DOE
could in fact show that various data
quality characteristics had been
considered for measured data. The
Agency reviewed additional materials,
primarily data record packages at the
SNL records center, to independently
determine whether DQCs had been
assessed for data used in the PA. The
EPA found that for recent data (five to
ten years old), DOE's experimental
program plans in the data record
packages generally addressed data
quality in measured data, including
accuracy, precision, representativeness,
completeness, and comparability during
measurement and collection.
For older existing data, EPA found
less documentation of assessment of
DQCs. However, laboratory
notebooks'which provide first-hand
documentation of measurement
procedures and results'supporting data
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record packages provided some
information related to the quality of
measurements (e.g., how well DOE's
measured values compared with values
found in peer-reviewed publications).
Many existing data were also subject to
peer review in order to qualify them for
use in the CCA; EPA concluded that the
peer review panels considered the use
of DQCs in determining that such data
were adequate. The EPA also agreed
with DOE's argument in supplementary
information that for most of the existing
data, collection under a program
equivalent to the NQA standards in
§ 194.22(a)(l) provided adequate
evidence that the quality of data had
been evaluated and controlled. Finally,
EPA concurred with DOE's conclusion
that the uncertainties in measured data
reflected in DQCs have a small effect on
compliance certainty, compared to other
uncertainties in the PA (such as
extrapolation of processes over 10,000
years).
The EPA found that data quality
received considerable attention from
peer reviewers and Independent Review
Teams assembled by DOE, and was
subject to NQA requirements as
specified in the Quality Assurance
Program Document ("QAPD"). Section
§ 194.22(a) requires DOE to implement
NQA-3-1989 in its quality assurance
program. NQA-3-1989 states, "Planning
shall establish provisions for data
quality evaluation to assure data
generated are valid, comparable,
complete, representative, and of known
precision and accuracy." This
requirement was satisfactorily
incorporated in the QAPD, which is the
quality assurance "master" document
that establishes QA requirements for all
activities overseen by the DOE Carlsbad
Area Office. The EPA determined by
means of audits that DOE adequately
implemented the requirements of the
QAPD, and also determined that DOE
adequately qualified existing data in
accordance with Section § 194.22(b).
(See Docket A-93-02, Item V-B-2,
CARD 22, Sections 22.A.6 and 22.J.5.)
Therefore, EPA finds that DOE's data
qualification was sufficiently rigorous to
account for the DQCs identified in the
WIPP compliance criteria.
Based on its review of data record
packages and the QAPD, the Agency
finds that DOE has assessed DQCs, to
the extent practicable, for data used in
the CCA. The EPA thus finds that DOE
complies with § 194.22(c). The Agency
expects that DOE will assess DQCs for
future waste characterization and
monitoring activities.
Section 194.22(d) requires DOE to
provide information which describes
how all data are qualified for use. SNL
generated a table providing information
of how all data in the PA were qualified.
The EPA audited the existing QA
programs and determined that the data
were qualified for use by independent
and qualified personnel in accordance
with NQA requirements. On this basis,
EPA finds DOE in compliance with
§194.22(d).
Section 194.22(e) allows EPA to verify
execution of QA programs through
inspections, record reviews, and other
measures. As discussed above, EPA has
conducted numerous audits of DOE
facilities, and intends to conduct future
inspections of waste generator site-
specific QA plans under its authority.
The Agency also intends to conduct
inspections or audits to confirmed
DOE's continued adherence to QA
requirements for which EPA is
certifying compliance.
In summary, EPA finds DOE in
compliance with the requirements of
§ 194.22 subject to the condition that
EPA separately approve the
establishment and execution of site-
specific QA programs for waste
characterization activities at waste
generator sites. (See Condition 2 of the
proposed Appendix A to 40 CFR Part
194.)
The EPA received many public
comments on § 194.22, but the most
significant issue identified by
commenters was the lack of objective
evidence in the CCA to justify meeting
the requirements at § 194.22(a)(2). The
comments posed the fundamental
question of whether or not EPA could
certify, based solely on information
provided by DOE in the CCA, that DOE
established and executed a QA program
for the eight areas considered important
to the containment of waste in the
disposal system. In response to such
concerns, EPA believes it is necessary to
explain and clarify the verification of
these QA requirements.
The CCA does not alone provide all
the documentation to verify compliance
with the requirement of § 194.22(a)(2).
Section § 194.22(e) requires EPA to
verify that DOE has established and
executed a QA program for the areas
indicated in § 194.22(a)(2). The
"objective evidence" for determining
whether or not a QA program has been
established and executed exists at the
WIPP-related facilities and generator
sites, and is gathered in the field audits
and inspections. The function of the
audits and inspections is to gather
objective evidence to determine
compliance of the QA programs with
the applicable NQA standards.
Several WIPP organizations are
responsible for establishing and
executing the activities and items listed
in the eight areas of § 194.22(a) (2). The
CCA states that DOE provides the
overall QA program requirements for
WIPP via the CAO QAPD. The CAO
QAPD requirements are further
supported and amplified by the next tier
of QA program documents, which
includes the SNL quality assurance
procedures (SNL QAPs), the WID
Quality Assurance Program Description,
and the individual site quality
assurance program plans (e.g., QAPjPs).
More documentation is found in DOE,
WID and SNL implementing procedures
and QA records. For example,
"Corrective Action Reports" and "Audit
Reports" provide objective evidence of
implementation of certain NQA
elements. Therefore, EPA finds that
sufficient information for compliance
with § 194.22(a)(2)(ii)-(viii), and for QA
program implementation for waste
characterization activities at LANL
(§ 194.22(a)(2)(i)) was provided in the
CCA and supporting documents to the
extent practical.
The EPA verified that QA programs
were established in accordance with
§ 194.22 through the CAO QAPD and
supporting documents. The EPA
expected to find objective evidence of
compliance or noncompliance with the
QA requirements within the QA records
and activities of the WIPP organizations,
including CAO, SNL, and WID. In
accordance with § 194.22(e), the Agency
conducted audits of these WIPP
organizations to verify the appropriate
execution of QA programs. (Docket A-
93-02; Items II-A-43, II-A-44, II-A-45,
II-A-46, II-A-47, II-A-48, and II-A-49)
Documentation of evidence of audits
that verified the execution of the Q A
programs is found in EPA's audit
reports. The EPA's audits of CAO, SNL,
and WID covered all aspects of the
programs including, but not limited to:
the adoption of the requirements of
§ 194.22 through the CAO QAPD,
quality assurance procedures ("QAPs"),
reports from previous audits,
surveillance reports, and corrective
action reports ("CARs"). The audits
assessed the adequacy and
implementation of the SNL and WID
quality assurance programs in
accordance with the requirements of
§ 194.22(a)(l). For example, for
§ 194.22(a)(2)(iv), the "computations,
computer codes, models and methods
used to demonstrate compliance with
the disposal regulations," EPA
conducted audits of the SNL and WID
quality assurance programs for
computations, computer codes, methods
and models. For all of the other areas in
§ 194.22(a)(2), CARD 22 (Section 22.B)
should be consulted for information and
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27389
citations to audit reports. (Docket A-93-
02, ItemV-B-2)
In summary, EPA certifies compliance
with the eight areas in § 194.22(a)(2)
through inspections and audits. Most of
the evidence demonstrating compliance
is found at the WIPP-related facilities
and generator sites. Such evidence was
unreasonable to include in the CCA due
to the voluminous nature of the
information.
2. Waste Characterization (§ 194.24)
Section 194.24, waste
characterization, generally requires DOE
to identify, quantify, and track the
chemical, radiological and physical
components of the waste destined for
disposal at the WIPP that can influence
disposal system performance.
Section 194.24(a) requires DOE to
describe the chemical, radiological and
physical composition of all existing and
to-be-generated waste, including a list of
waste components and their
approximate quantities in the waste.
The DOE provided the required
information on existing waste (35% of
the total WIPP inventory) by combining
similar waste streams into waste stream
profiles. The waste stream profiles
contain information on the waste
material parameters, or components,
that could affect repository
performance. For to-be-generated waste
(65% of the total WIPP inventory), DOE
extrapolated information from the
existing waste streams to determine the
future amount of waste. The EPA
reviewed this information and
determined that DOE's waste stream
profiles contained the appropriate
specific information on the components
and their approximate quantities in the
waste. Therefore, EPA finds DOE in
compliance with § 194.24(a).
Section 194.24(b) requires DOE to
analyze waste characteristics and waste
components for their impact on disposal
system performance. Waste components
affect waste characteristics and are
integral to disposal system performance.
The DOE identified waste-related
elements pertinent to the WIPP as part
of its screening for features, events, and
processes. The features, events, and
processes used in the performance
assessment ("PA") served as the basis
from which characteristics and
associated components were identified
and further analyzed. (For further
information on features, events, and
processes, see Docket A-93-02, Item V-
B-2, CARD 32; and the above preamble
sections related to the PA.)
The DOE concluded that six
characteristics were expected to have a
significant effect on disposal system
performance and were used in the PA as
parameters or in conceptual models:
solubility, formation of colloidal
suspensions containing radionuclides,
gas generation, shear strength of waste,
radioactivity of specific isotopes, and
transuranic ("TRU") activity at disposal.
The DOE identified eight waste
components influencing the six
significant waste characteristics: ferrous
metals, cellulose, radionuclide
identification, radioactivity of isotopes,
TRU activity of waste, solid waste
components, sulfates, and nitrates.
Finally, DOE provided a list of waste
characteristics and components
assessed, but determined not to be
significant for various reasons such as
negligible impact on the PA. The EPA
found that DOE used a reasonable
methodology to identify and assess
waste characteristics and components.
The analysis appropriately accounted
for uncertainty and the quality of
available information. Therefore, EPA
finds DOE in compliance with
requirements in § 194.24(b).
Section 194.24(c)(l) requires DOE to
specify numeric limits on significant
waste components and demonstrate
that, for those component limits, the
WIPP complies with the numeric
requirements of §§ 194.34 and 194.55.
Either upper or lower limits were
established for components that must be
controlled to ensure that the PA results
comply with the containment
requirements. The DOE explicitly
included numeric limits, identified as
fixed values with no associated
uncertainty, for four waste components.
Lower limits were established for (1)
ferrous and (2) non-ferrous metals (not
included in DOE's original list of
components, but added later due to its
binding effect on organic ligands); upper
limits were established for (3)
cellulosics and (4) free water (not
included in DOE's original list of
components, but added later due to its
inclusion in the Waste Acceptance
Criteria).
The three components related to
radioactivity (radionuclide
identification, radioactivity of isotopes,
TRU activity of waste) were effectively
limited by the inventory estimates used
in the PA and the WIPP LWA fixed-
value limits. Both the PA inventory
estimates and the WIPP LWA fixed-
value limits were included in the PA
calculations through parameters closely
related to these components, and the
results demonstrated compliance with
EPA's standards.
Explicit limits were not identified for
solid waste, sulfates, and nitrates, even
though DOE identified these as
components significant to performance.
For solid waste, EPA determined that in
the PA, DOE took no credit for the
potential gas-reducing effects of solid
waste (i.e., assumed a lower limit of
zero) and demonstrated that the WIPP
would still comply. For nitrates and
sulfates, EPA determined that these
components would not significantly
affect the behavior of the disposal
system as long as cellulosics were
limited. Thus, EPA concurred that it is
unnecessary to specify limits for
nitrates, sulfates, and solid waste.
The EPA finds DOE in compliance
with § 194.24(c)(l). The EPA concurred
with DOE that it was not necessary to
provide estimates of uncertainty for
waste limits, so long as the PA
demonstrated compliance at the fixed
limits. However, since DOE's waste
limits do not address uncertainty, the
Department must account for
uncertainty in the quantification of
waste components when tracking
compliance with the waste limits. That
is, the fixed waste limits essentially
constitute an upper confidence level (in
the case of limits on the maximum
amount of a waste component) or a
lower confidence level (in the case of
limits on the minimum amount of a
component) for measurements or
estimates of waste components that
must be tracked. The DOE must
demonstrate that the characterized
waste components, including associated
uncertainty (i.e., margin of error), meet
the fixed waste component limits.
Section 194.24(c)(2) requires DOE to
identify and describe the methods used
to quantify the limits of important waste
components identified in § 194.24(b)(2).
The DOE proposed to use non-
destructive assay ("NDA"), non-
destructive examination ("NDE"), and
visual examination ("VE") as the
methods used to quantify various waste
components. (See Docket A-93-02, Item
V-B-2, CARD 24, Section 24.F.I for
further information about the methods.)
The DOE described numerous NDA
instrument systems and described the
equipment and instrumentation found
in NDE and VE facilities. The DOE also
provided information about
performance demonstration programs
intended to show that data obtained by
each method could meet data quality
objectives established by DOE. The EPA
found that these methods, when
implemented appropriately, would be
adequate to characterize the important
waste components. Therefore, EPA finds
DOE in compliance with § 194.24(c)(2).
Section 194.24(c)(3) requires DOE to
demonstrate that the use of process
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knowledge 32 to quantify components in
waste for disposal conforms with the
quality assurance ("QA") requirements
found in § 194.22. The DOE did not
submit site-specific information on the
process knowledge to be used at waste
generator sites as part of the CCA. The
EPA requires such information to
conduct proper review of whether use of
the process knowledge is appropriate
and reliable. The DOE provided some
information on its overall plans for
using process knowledge in the CCA.
The DOE did not, however, provide
specific information on the use of
process knowledge or Acceptable
Knowledge ("AK"—hereafter only "AK"
is used; process knowledge is a subset
of acceptable knowledge) at any waste
generator site in the CCA, nor did it
provide information demonstrating
establishment of the required Q A
programs.
After submission of the CCA, EPA
subsequently received information
regarding AK to be used at the Los
Alamos National Laboratory ("LANL").
The EPA determined that DOE
adequately described the use of AK for
legacy debris waste at LANL. The EPA
has confirmed establishment and
execution of the required QA programs
at that waste generator site through
inspections. Therefore, EPA finds that
DOE has demonstrated compliance with
the § 194.24(c)(3) QA requirement for
LANL. The EPA does not find, however,
that DOE has adequately described the
use of AK for any waste at LANL other
than the legacy debris waste which can
be characterized using the processes
examined in EPA's inspection. (See
Docket A-93-02, Item V-B-15 for
further information on the conclusions
of EPA's inspection. See Docket A-93-
02, Item II-I-70 for a list of the items
and processes inspected by EPA.)
Furthermore, DOE has not demonstrated
compliance with § 194.24(c)(3) for any
other waste generator site. For any
LANL waste streams using other
characterization processes or any other
waste generator site, before waste can be
shipped to the WIPP, EPA must
determine that the site has provided
information on how AK will be used for
waste characterization of the waste
stream(s) proposed for disposal at the
WIPP. Condition 3 of the final rule
32 Process knowledge refers to knowledge of waste
characteristics derived from information on the
materials or processes used to generate the waste.
This information may include administrative,
procurement, and quality control documentation
associated with the generating process, or past
sampling and analytic data. Usually, the major
elements of process knowledge include information
about the process used to generate the waste,
material inputs to the process, and the time period
during which the waste was generated.
embodies this limitation. The site-
specific use of process knowledge must
conform with QA requirements, as
addressed by Condition 2. (For further
information on EPA's approval process,
see § 194.8, "Approval Process for
Waste Shipment from Waste Generator
Sites for Disposal at the WIPP.")
Sections 194.24(c) (4) and (5) require
DOE to demonstrate that a system of
controls has been and will continue to
be implemented to confirm that the
waste components emplaced in the
WIPP will not exceed the upper limit or
fall below the lower limit calculated in
accordance with § 194.24(c)(l) and that
the system of controls conforms to the
QA requirements specified in § 194.22.
The DOE described a system of controls
over waste characterization activities,
such as the requirements of the TRU QA
Program Plan ("TRU QAPP") and the
Waste Acceptance Criteria ("WAC").
The EPA found that the TRU QAPP
established appropriate technical
quality control and performance
standards for sites to use in developing
site-specific sampling plans. Further,
DOE outlined two phases in waste
characterization controls: (1) waste
stream screening/verification (pre-
shipment from waste generator site);
and (2) waste shipment screening/
verification (pre-receipt of waste at the
WIPP). The tracking system for waste
components against their upper and/or
lower limits is found in the WIPP Waste
Information System ("WWIS"). The EPA
finds that the TRU QAPP, WAC, and
WWIS are adequate to control important
components of waste emplaced in the
WIPP. The EPA audited DOE's QA
programs at Carlsbad Area Office,
Sandia National Laboratory and
Westinghouse Waste Isolation Division
and determined that DOE properly
adhered to QA programs that implement
the applicable Nuclear Quality
Assurance standards and requirements.
(See the preamble discussion of
§ 194.22, Quality Assurance, for further
information.) However, in the CCA,
DOE did not demonstrate that the WWIS
is fully functional and did not provide
information regarding the specific
system of controls to be used at
individual waste generator sites.
After submission of the CCA, EPA
subsequently received information
regarding the system of controls
(including measurement techniques) to
be used at LANL. The Agency
confirmed through inspections that the
system of controls—and in particular,
the measurement techniques—is
adequate to characterize waste and
ensure compliance with the limits on
waste components for some waste
streams, and also confirmed that a QA
program had been established and
executed at LANL in conformance with
Nuclear Quality Assurance
requirements. Moreover, DOE
demonstrated that the WWIS is
functional with respect to LANL—i.e.,
that procedures are in place at LANL for
adding information to the WWIS
system, that information can be
transmitted from LANL and
incorporated into the central database,
and that data in the WWIS database can
be compiled to produce the types of
reports described in the CCA for
tracking compliance with the waste
limits. At the same time, DOE
demonstrated that the WWIS is
functional with respect to the WIPP
facility—i.e., that information
incorporated into the central database
can be retrieved at the WIPP and
compiled to produce reports for tracking
compliance with the waste limits.
Therefore, EPA finds DOE in
compliance with §§ 194.24(c)(4) and (5)
for legacy debris waste at LANL. (Docket
A-93-02, Items V-B-15 and V-B-2,
CARD 24) The EPA's decision is limited
to the waste that can be characterized
using the systems and processes audited
by DOE, inspected by EPA, and found
to be adequately implemented at
LANL.33 The EPA does not find,
however, that DOE has demonstrated
compliance with § 194.24(c)(4) for any
other waste stream at LANL, or with
§§ 194.24(c)(4) and (5) at any other
waste generator site.
For any LANL waste streams using
other characterization processes or any
other waste generator site, before waste
can be shipped to the WIPP, EPA must
determine that the site has implemented
a system of controls at the site, in
accordance with § 194.24(c)(4), to
confirm that the total amount of each
waste component that will be emplaced
in the disposal system will not exceed
the upper limiting value or fall below
the lower limiting value described in
the introductory text of paragraph (c) of
§ 194.24. The implementation of such a
system of controls shall include a
demonstration that the site has
procedures in place for adding data to
the WWIS, and that such information
can be transmitted from that site to the
WWIS database; and a demonstration
that measurement techniques and
control methods can be implemented in
accordance with § 194.24(c)(4) for the
33See Docket A-93-02, Item II-I-70 for a list of
the systems and processes audited by DOE. See
Docket A-93-02, Item II-I-51 for a description of
the waste identifier and a discussion of the items
and activities inspected by EPA. They include
characterization methodologies and relevant
procedures, such as that used for entering data into
the WWIS database.
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waste stream(s) proposed for disposal at
the WIPP. Condition 3 prohibits DOE
from shipping waste for disposal at
WIPP until EPA has approved site-
specific waste characterization programs
and controls. The system of controls
must also be implemented in
accordance with the QA requirements of
40 CFR 194; see Condition 2. (For
further information on EPA's approval
process, see § 194.8, "Approval Process
for Waste Shipment from Waste
Generator Sites for Disposal at the
WIPP.")
Section 194.24(d) requires DOE either
to include a waste loading scheme
which conforms to the waste loading
conditions used in the PA and in
compliance assessments, or to assume
random placement of waste in the
disposal system. The DOE elected to
assume that radioactive waste would be
emplaced in the WIPP in a random
fashion. The DOE examined the possible
effects of waste loading configurations
on repository performance (specifically,
releases from human intrusion
scenarios) and concluded that the waste
loading scheme would not affect
releases. The DOE incorporated the
assumption of random waste loading in
its performance and compliance
assessments (pursuant to §§ 194.32 and
194.54, respectively).
The EPA determined that, because the
DOE had assumed random waste
loading, a final waste loading plan was
unnecessary. The EPA determined that,
in the PA, DOE accurately modeled
random placement of waste in the
disposal system. Since EPA concurred
with DOE that a final waste loading plan
was unnecessary, DOE does not have to
further comply with § 194.24(1),
requiring DOE to conform with the
waste loading conditions, if any, used in
the PA and compliance assessment.
Therefore, EPA finds that DOE complies
with§§194.24(d) and (f).
Section 194.24(e) prohibits DOE from
emplacing waste in the WIPP if its
disposal would cause the waste
component limits to be exceeded.
Section 194.24(g) requires DOE to
demonstrate that the total inventory
emplaced in the WIPP will not exceed
limitations on TRU waste described in
the WIPP LWA. Specifically, the WIPP
LWA defines limits for: surface dose
rate for remote-handled ("RH") TRU
waste, total amount (in curies) of RH-
TRU waste, and total capacity (by
volume) of TRU waste to be disposed.
(WIPP LWA, Section (7) (a)) In order to
meet the §§ 194.24(e) and (g) limits,
DOE intends to rely on the TRU QAPP,
WAC, and a two-phase system of
controls for waste characterization—pre-
shipment (at waste generator sites) and
pre-receipt (at the WIPP). The DOE
stated that the WWIS will be used to
track specific data related to each of the
WIPP LWA limits; by generating routine
WWIS reports, DOE will be able to
determine compliance with the imposed
limits. The WWIS will also be used to
track information on each of the
important waste components for which
limits were established. The EPA finds
that the WWIS is adequate to track
adherence to the limits, and that the
WWIS has been demonstrated to be
fully functional at the WIPP facility; as
discussed above, waste generator sites
will demonstrate WWIS procedures
before they can ship waste for disposal
at the WIPP. Therefore, EPA finds DOE
in compliance with §§ 194.24(e) and (g).
Section 194.24(h) allows EPA to
conduct inspections and record reviews
to verify compliance with the waste
characterization requirements. As
discussed above, EPA intends to
monitor execution of waste
characterization and QA programs at
waste generator sites through
inspections and record reviews.
In summary, EPA finds that DOE is in
compliance with § 194.24, and that
LANL has demonstrated compliance
with §§ 194.24(c)(3) through (5) for
legacy debris waste and may therefore
ship TRU waste for disposal at the WIPP
(as such shipments relate solely to
compliance with EPA's disposal
regulations; other applicable
requirements or regulations still may
need to be fulfilled before disposal may
commence). The EPA's final
determination of compliance is limited
to the EPA's decision is limited to the
legacy debris waste that can be
characterized using the systems and
processes audited by DOE, inspected by
EPA, and found to be adequately
implemented at LANL. It is important to
note that EPA's LANL approval does not
imply that DOE's internal certification
processes can substitute for EPA's
approval of waste generator sites or
processes used to characterize waste
stream(s)—including QA measures, use
of process knowledge, and the system of
controls (other than LANL's legacy
debris waste approved in today's
action). The EPA will inspect the
individual certification process for each
waste generator site and for one or more
waste stream(s). (For further information
on EPA's approval process, see § 194.8,
"Approval Process for Waste Shipment
from Waste Generator Sites for Disposal
at the WIPP.")
The DOE may not ship other waste
streams for emplacement at the WIPP
until EPA determines that (1) DOE has
provided adequate information on how
process knowledge will be incorporated
into waste characterization activities for
a particular waste stream (or group of
waste streams) at a generator site, and
(2) DOE has demonstrated that the
system of controls described in
§ 194.24(c)(4) and (5) has been
established for the site. In particular,
DOE must demonstrate that the WWIS
system is functional for any waste
generator site before waste may be
shipped, and that the system of controls
(including measurement techniques)
can be implemented for each waste
stream which DOE plans to dispose in
the WIPP. As discussed in the preamble
for § 194.22, DOE must also demonstrate
that sites have established and executed
the requisite QA programs described in
§§194.22(a)(2)(i) and 194.24(c)(3) and
(5).
The EPA received many public
comments on § 194.24. The majority of
the comments focused primarily on
whether or not DOE could adequately
characterize waste to be sent to the
WIPP. In response to such concerns,
EPA believes it is useful to explain and
clarify the general process of waste
characterization as required by § 194.24,
and to describe the activities EPA
expects to monitor for future waste
characterization. First, § 194.24(a)
requires DOE to describe the chemical,
radiological, and physical composition
of the wastes to be emplaced in the
WIPP. Second, DOE must conduct an
analysis that substantiates that: (1) all
characteristics of the wastes which may
influence containment in the repository
have been identified and assessed
(§ 194.24(b)(l)); (2) all components of
the wastes which influence such waste
characteristics have been identified and
assessed (§ 194.24(b)(2)); and (3) any
decision not to consider a waste
characteristic or component on the basis
that it will not significantly influence
containment of the waste.
(§ 194.24(b)(3)) Third, for each waste
component identified as being
significant, DOE is to specify a "limiting
value" of the total inventory of such
waste components to be emplaced in the
repository. (§ 194.24(c)) Fourth, DOE
must demonstrate that, for the total
inventory of waste proposed to be
emplaced in the disposal system, the
WIPP will comply with the numeric
requirements of §§ 194.34 and 194.55
for the upper and lower limiting values
of the identified waste components.
(§ 194.24(c)(l)) Fifth, DOE must identify
and describe the methods used to
quantify the limits of waste
components. (§ 194.24(c)(2))
At this point, § 194.24 imposes
requirements that shift the focus from
information on, and assessment of, the
total waste inventory to procedures for
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characterization of the waste at
individual waste generator sites and
accurate assessment of the waste
inventory. First, DOE must show that
the AK used to quantify the waste
components at the waste generator sites
will conform with QA requirements of
§ 194.22. Then, to ensure that the
generator sites ship only waste that
conforms with the waste component
limits, a system of controls must be
implemented that tracks and measures
the waste components destined for the
WIPP. This system of controls must also
comply with the QA requirements of
§194.22.
The approval process for site-specific
waste characterization controls and QA
programs includes a Federal Register
notice, public comment period, and on-
site EPA audits or inspections to
evaluate implementation. (See
Condition 2, Condition 3, and § 194.8.)
Prior to an EPA audit or inspection, EPA
expects to receive certain documents
from DOE. To determine that the
procedures used to characterize waste
(e.g., measuring and testing, sample
control, equipment assessments) are
based on good technical practices, and
the personnel are qualified to perform
the task, EPA expects to receive the
following general documents which
conform with the requirements of
§ 194.22: Site-Specific Quality
Assurance Program Plan ("QAPP") and
a report or reports from CAO's QA
organization that verifies the
establishment and implementation of
the Nuclear Quality Assurance
requirements identified in § 194.22.
Likewise, DOE will provide technical
documents prior to an audit or
inspection to verify the methods for
characterizing, quantifying, and tracking
waste. Such technical documents will
include information on the use of both
process knowledge and measurement
methods for waste characterization.
First, for measurement equipment such
as NDA, NDE, and VE, DOE may
provide information on measuring and
testing, equipment assessments, sample
control, data documentation, and
software control. For AK, DOE may
provide the AK package which provides
information on the areas and buildings
from which the waste stream was
generated, the waste stream volume and
time period of generation, the waste
generating process described for each
building, the process flow diagrams, and
the material inputs or other information
that identifies the chemical and
radionuclide content of the waste
stream and the physical waste form. In
addition, the following supplemental
information may be provided for AK
records: process design documents,
standard operating procedures,
preliminary and final safety analysis
reports and technical safety
requirements, waste packaging logs, site
databases, information from site
personnel, standard industry
information, previous analytical data
relevant to the waste stream, material
safety data sheets or other packaging
information, sampling and analysis data
from comparable or surrogate waste
streams, and laboratory notebooks that
detail the research processes and raw
materials used in experiments.
The fundamental objective of EPA's
review of DOE's waste characterization
at waste generator sites is to ensure that
the proposed system of controls can
quantify and track both the
radionuclides and the four waste
component limits identified as
important for the repository
performance. Because DOE's defense
missions varied at the sites, the waste
generated and the methods to
characterize waste vary accordingly.
These variations in practices and
methods result in the need to review
two general areas: (1) AK packages and
(2) the system of controls, including
measurement methods and tracking
procedures. Therefore, EPA finds that it
is important to clarify what is entailed
by both general areas.
Thirty-five percent of WIPP waste is
currently classified as "retrievably
stored waste," which is TRU waste
generated after the 1970's but before the
implementation of the TRU Waste
Characterization Quality Assurance
Program Plan ("QAPP"). Retrievably
stored waste containers will be
classified into waste streams using
acceptable knowledge.34 All retrievably
stored waste containers will be
examined using radiography or visual
examination to confirm the physical
waste form (or "Summary Category
Group"), to verify the absence of
prohibited items, and to determine the
waste characterization techniques to be
used. To confirm the results of
radiography, a statistically selected
number of the Contact-Handled
Transuranic waste container population
will be visually examined by opening
the containers to inspect waste contents
to verify the radiography results. If
visual examination results for a drum
conflict with the results of radiography,
the drum and possibly the entire waste
stream is reclassified, and a higher
percentage of future drums will be
required to undergo visual examination.
Representativeness of containers
selected for visual examination will be
validated by reviewing documents that
show that true random samples were
collected. Repackaged retrievably stored
waste may be handled as newly
generated waste, with the Summary
Category Group confirmed by using
visual examination instead of
radiography. Retrievably stored waste
will be assayed using Non Destructive
Assay ("NDA") 35, and will undergo
headspace-gas sampling and analysis for
volatile organic compound
concentrations.36
Sixty-five percent of all WIPP waste is
to-be-generated TRU waste. To-be-
generated waste characterization will
begin with verification that processes
generating the waste have operated
within established written procedures.
Waste containers will be classified into
waste streams using acceptable
knowledge. Hazardous and radioactive
constituents in to-be-generated wastes
will be documented and verified at the
time of generation to provide acceptable
knowledge for the waste stream.
Verifying that the physical form of the
waste (Summary Category Group)
corresponds to the physical form of the
assigned waste stream is accomplished
by visual examination during packaging
of the waste into the drums. This
process consists of operator
confirmation that the waste is assigned
to a waste stream that has the correct
Summary Category Group for the waste
being packaged into the drums. If
confirmation cannot be made, corrective
actions will be taken. A second
operator, who is equally trained to the
requirements of the WAC and TRU
Waste Characterization QAPP, will
provide additional verification by
reviewing the contents of the waste
34 AK is used by DOE to (1) delineate waste
streams to facilitate further characterization; (2)
identify radionuclide content as a basis for further
radioassay ("NDA") determinations, and identify
the combustible and metal content to determine the
radionuclide content as a basis for radiography and/
or visual examination ("NDE/VE"); and (3) make
hazardous waste determinations for wastes
regulated under the Resource Conservation and
Recovery Act.
35 All waste containers will undergo NDA
techniques to allow an item to be tested without
altering its physical or chemical form. NDA
techniques approved for use on WIPP containers
can be classified as active or passive. Passive NDA
methods measure spontaneously emitted radiations
produced through radioactive decay of isotopes
inside the waste containers. Active NDA methods
measure radiations produced by artificially
generated reactions in waste material.
36 Results of head-space gas sampling and
chemical analyses are compared with acceptable
knowledge determinations to assess the accuracy of
acceptable knowledge. Additional analysis of head-
space gas for volatile organic compounds, and
additional use of NDA, radiography, and other
characterization methods may be employed to
further characterize waste to meet regulations that
apply to the hazardous (but not necessarily
radioactive) portions of the WIPP waste. The
requirements for hazardous waste are enforced by
the State of New Mexico.
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container to ensure correct reporting. If
the second operator cannot provide
concurrence, corrective actions will be
taken. To-be-generated waste will not
undergo radiography, as the waste will
be identified by visual examination
during packaging. All to-be-generated
waste containers will undergo
headspace-gas analysis for volatile
organic compound and their
concentrations, and NDA for
radioisotopes and their activities.
Acceptable knowledge, visual
examination during packing, NDA and
headspace-gas sampling and analysis
are used to further characterize
homogeneous solids, soils/gravel, and
debris waste. In addition, newly
generated streams of such wastes will be
randomly sampled a minimum of once
per year and analyzed for total volatile
and semi-volatile organic compounds
and metals.
A system of controls is used to
confirm that the total amount of each
waste component that will be emplaced
in the disposal system does not exceed
the upper limiting value or fall below
the lower limiting value for the
component. The system of controls for
WIPP waste has two phases for DOE's
internal process. Phase I entails Waste
Stream Screening and Verification,
which will occur before waste is
shipped to the WIPP, and is a three-step
process. First, an initial audit of the site
will be conducted by DOE's Carlsbad
Area Office as part its audit program
before the WIPP could begin the process
of accepting waste from a site. The audit
provides on-site verification of
characterization procedures, data
package preparation and recordkeeping.
Second, the generator site personnel
perform the waste characterization data
package completeness/accuracy review
and either accept or reject the data.
Third, if the data are accepted, the site
waste characterization data are
transferred manually or electronically
via the WWIS to the WIPP. At the WIPP,
screening includes verification that all
of the required elements of a waste
characterization data package are
present and that the data meet
acceptance criteria required for
compliance. Waste stream approval or
rejection to ship to the WIPP is the
outcome of Phase I.
Phase II includes examination of a
waste shipment after it has arrived at
the WIPP, and is a three-step process.
First, upon receipt of a waste shipment,
the WIPP personnel determine manifest
completeness and sign the manifest
before the driver may depart. Second,
WIPP personnel determine waste
shipment completeness by checking the
bar-coded identification number found
on each TRU waste container. The bar-
coded identification number is noted
and checked against the WWIS. The
WWIS maintains waste container
receipt and emplacement information.
Third, waste shipment irregularities or
discrepancies are identified and
resolved. If there are discrepancies, the
generator site is contacted for
resolution. Finally, WIPP personnel
compare the container identification
number with a list of those approved for
disposal at the WIPP. Waste shipment
approval or rejection for disposal at the
WIPP is the outcome of Phase II. (For
further information on the system of
controls, see Docket A-93-02, Item V-
B-2, CARD 24, Section 24.H.2.)
In summary, all waste sent to WIPP
will be appropriately and thoroughly
characterized. First, the acceptable
knowledge provides essential waste
content information that later
determines the waste categories. The AK
process undergoes quality assurance
checks to confirm good technical
practices and qualified personnel. Then,
the measurement techniques (NDA,
NDE, VE) confirm the AK data, and
further define the content and limits of
the waste. Further confirmation of the
accuracy of the waste characterization is
provided by the extensive tracking
system. Again, quality assurance checks
are applied to the tracking and
measurement controls. The waste
characterization process, if
implemented accordingly, provides
complete and thorough characterization
of the waste. The DOE has committed to
implement this process. No waste
generator site will be allowed to ship
proposed waste streams to the WIPP
until the waste characterization process
detailed above is met at that generator
site for the given waste stream(s).
3. Future State Assumptions (§ 194.25)
Section 194.25 stipulates that
performance assessments ("PA") and
compliance assessments "shall assume
that characteristics of the future remain
what they are at the time the
compliance application is prepared,
provided that such characteristics are
not related to hydrogeologic, geologic or
climatic conditions." Section 194.25
also requires DOE to provide
documentation of the effects of potential
changes of hydrogeologic, geological,
and climatic conditions on the disposal
system over the regulatory time frame.
The purpose of the future state
assumptions is to avoid unverifiable and
unbounded speculation about possible
future states of society, science,
languages, or other characteristics of
mankind. The Agency has found no
acceptable methodology that could
make predictions of the future state of
society, science, languages, or other
characteristics of mankind. However,
the Agency does believe that established
scientific methods can make plausible
predictions regarding the future state of
geologic, hydrogeologic, and climatic
conditions. Therefore, § 194.25 focuses
the PA and compliance assessments on
the more predictable significant features
of disposal system performance, instead
of allowing unbounded speculation on
all developments over the 10,000-year
regulatory time frame.
The EPA proposed to find DOE in
compliance with the requirements of
§ 194.25 because the future state
assumptions that DOE made and
documented in the CCA were inclusive
of all relevant elements of the PA and
compliance assessments and were
consistent with the requirements of
§ 194.25. (62 FR 58816-7) The Agency
reviewed the future state assumptions
DOE made about hydrogeologic and
geologic characteristics and found that
DOE accurately characterized, screened,
and modeled the potential changes from
current conditions. For climatic
changes, EPA found DOE's approach to
be conservative and consistent with the
compliance criteria, since DOE
examined the worst-case scenario of
increased precipitation at the WIPP
rather than the potential effects of global
warming, which could be beneficial to
the WIPP. (§ 194.25(b)(3)) The EPA
found that DOE's incorporation of these
changes into the PA was adequate.
Finally, EPA found that the CCA's
approach to dealing with uncertainty,
including use of conservative
assumptions to compensate for
uncertainty, are consistent with the
features, events, and processes list,
screening arguments, and model
descriptions.
The EPA received no public
comments on this topic beyond those
addressed in the proposal, and so finds
DOE in compliance with the
requirements of § 194.25. For further
information concerning EPA's
evaluation of compliance with § 194.25,
see CARD 25. (Docket A-93-02, Item V-
B-2) For additional information on the
features, events, and processes included
in the PA and compliance assessments,
see CARD 32 (Docket A-93-02, Item V-
B-2) and the preamble discussion of
performance assessment issues (Section
VIII.B). For additional information on
both geologic and hydrogeologic
conditions of the WIPP, see the
preamble discussion of § 194.14.
4. Expert Judgment (§ 194.26)
The requirements of 40 CFR 194.26
apply to expert judgment elicitation.
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Expert judgment is typically used to
elicit two types of information:
numerical values for parameters
(variables) that are measurable only by
experiments that cannot be conducted
due to limitations of time, money, and
physical situation; and essentially
unknowable information, such as which
features should be incorporated into
passive institutional controls to deter
human intrusion into the repository. (61
FR 5228) Quality assurance
requirements (specifically
§ 194.22(a)(2)(v)) must be applied to any
expert judgment to verify that the
procedures for conducting and
documenting the expert elicitation have
been followed.
The requirements of 40 CFR Part 194
prohibit expert judgment from being
used in place of experimental data,
unless DOE can justify that the
necessary experiments cannot be
conducted. Expert judgment may
substitute for experimental data only in
those instances in which limitations of
time, resources, or physical setting
preclude the successful or timely
collection of data.
The CCA did not identify any formal
expert elicitation activities. During the
Agency's review of performance
assessment ("PA") parameters, EPA
found inadequate explanation and
information for 149 parameters that
DOE claimed had been derived using
professional judgment. The compliance
criteria do not provide for utilization of
"professional judgement.'' Input
parameters are to be derived from data
collection, experimentation, or expert
elicitation. The EPA requested that DOE
provide additional information on the
derivation of the 149 parameters.
(Docket A-93-02, Items II-I-17, II-I-25,
and II-I-27)
The DOE responded to EPA's requests
by adding information to and improving
the quality of the records stored in the
Sandia National Laboratory ("SNL")
Records Center in order to enhance the
traceability of parameter values. The
EPA deemed the documentation
provided by DOE adequate to
demonstrate proper derivation of all but
one of the "professional judgment"
parameters—the waste particle size
distribution parameter. For a
comprehensive discussion of the
technical review of PA parameters, see
the preamble discussion of performance
assessment, CARD 23 (Section 12.0),
and EPA's "Parameter Report" and
"Parameter Justification Report."
(Docket A-93-02, Items V-B-2, V-B-
12, V-B-14) The EPA required DOE to
use the process of expert elicitation to
develop the value for the waste particle
size distribution parameter. (Docket A-
93-02, Item II-I-27)
The waste particle size parameter is
important in performance assessments
because the distribution of waste
particle diameters affects the quantity of
radioactive materials released in
spallings from inadvertent human
intrusion. Because particle diameters
are uncertain and cannot be estimated
either directly from available data or
from data collection or experimentation,
the waste particle size parameter had to
be based on an elicitation of expert
judgment.
The DOE conducted the expert
judgment elicitation on May 5-9, 1997.
The results of the expert elicitation
consisted of a model for predicting
waste particle size distribution as a
function of the processes occurring
within the repository, as predicted by
the PA. The DOE completed a final
report entitled, "Expert Elicitation on
WIPP Waste Particle Size
Distributions(s) During the 10,000-Year
Regulatory Post-closure Period."
(Docket A-93-02, Item II-I-34) The
particle size distribution derived from
the expert elicitation was incorporated
in the PA verification test ("PAVT")
calculations.
The EPA's review of DOE's
compliance with the requirements of
§ 194.26 principally focused on the
conduct of the elicitation process, since
§ 194.26 sets specific criteria for the
performance of an expert judgement
elicitation. The EPA observed DOE's
elicitation process and conducted an
audit of the documentation prepared in
support of DOE's compliance with
§ 194.26. The scope of the audit covered
all aspects of the expert judgment
elicitation process, including: panel
meetings, management and team
procedures, curricula vitae of panel
members, background documents, and
presentation materials. The EPA also
assessed compliance with the quality
assurance requirements of
§ 194.22(a)(2)(v). The EPA found that
the documentation was appropriate, that
the panel members were appropriately
qualified, and that the results of the
elicitation were used consistent with the
stated purpose; EPA, therefore,
proposed to find DOE in compliance
with § 194.26. (62 FR 58817-18)
Comments on EPA's proposed
decision for § 194.26 related to two
main issues: (1) Commenters questioned
DOE's statement that it did not conduct
any expert judgement activities in
developing the CCA; and (2)
commenters questioned the use or role
of "professional judgement" in the
development of input parameters used
in the CCA. The DOE's understanding of
expert judgment was consistent with
EPA's use of the term "expert
judgment" in the compliance criteria,
namely a formal, highly structured
elicitation of expert opinion. (Response
to Comments for 40 CFR Part 194,
Docket A-92-56, Item V-C-1, p. 8-4)
However, EPA agrees that the CCA
initially did not contain adequate
information to ascertain whether a large
number of the input parameters had
been properly derived. The DOE
subsequently provided additional
information, and substantially improved
the quality of the records at the SNL
Records Center, which enabled EPA to
confirm that all but one of the
parameters were adequately supported.
In regard to the use of professional
judgement in the development of input
parameters, the compliance criteria in
§ 194.26 do not provide for derivation of
input parameters through "professional
judgement." Input parameters used in
the PA are to be derived from data
collection, experimentation, or expert
elicitation. The Agency, however,
recognizes that raw data resulting from
data collection or experimentation may
require "professional judgment" in the
development of input parameters.
Professional scientific judgment may be
used to interpolate, extrapolate,
interpret, and apply data to develop
parameter values but cannot substitute
for data. (Expert judgment may
substitute for data, but only when
information cannot reasonably be
obtained through data collection or
experimentation.) The applicability of
§ 194.26 does not extend to professional
scientific judgment used in such
circumstances. (Docket A-92-56, Item
V-C-1, p. 8-5)
Based on its review of documentation
developed by DOE and its contractors,
the results of EPA's audit, and
consideration of public comments, EPA
concludes that DOE complied with the
requirements of § 194.26 in conducting
the required expert elicitation. For
further information on EPA's evaluation
of compliance with § 194.26, see CARD
26. (Docket A-93-02, Item V-B-2)
5. Peer Review (§194.27)
Section 194.27 requires DOE to
conduct peer review evaluations related
to conceptual models, waste
characterization analyses, and a
comparative study of engineered
barriers. A peer review involves an
independent group of experts who are
convened to determine whether
technical work was performed
appropriately and in keeping with the
intended purpose. The required peer
reviews must be performed in
accordance with the Nuclear Regulatory
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Commission's NUREG-1297, "Peer
Review for High-Level Nuclear Waste
Repositories," which establishes
guidelines for the conduct of a peer
review exercise. Section 194.27 also
requires DOE to document in the
compliance application any additional
peer reviews beyond those explicitly
required.
The EPA proposed to find DOE in
compliance with the requirements of
§ 194.27 because EPA's independent
audit established that DOE had
conducted and documented the
required peer reviews in a manner
compatible with NUREG-1297. The
Agency also proposed that DOE
adequately documented additional peer
reviews in the CCA. The EPA received
no public comments on this topic
beyond those addressed in the proposal
(62 FR 58818), and so finds DOE in
compliance with the requirements of
§ 194.27. For further information
concerning EPA's evaluation of
compliance with § 194.27, see CARD 27.
(Docket A-93-02, Item V-B-2)
D. Assurance Requirements
1. Active Institutional Controls
(§194.41)
Section 194.41 implements the active
institutional controls ("AICs")
assurance requirement. The disposal
regulations define AICs as "controlling
access to a disposal site by any means
other than passive institutional controls,
performing maintenance operations or
remedial actions at a site, controlling or
cleaning up releases from a site, or
monitoring parameters related to
disposal system performance." (40 CFR
191.12) Section 194.41 requires AICs to
be maintained for as long a period of
time as is practicable after disposal;
however, contributions from AICs for
reducing the rate of human intrusion in
the PA may not be considered for more
than 100 years after disposal.
The DOE proposed to: construct a
fence and roadway around the surface
footprint of the repository; post warning
signs; conduct routine patrols and
surveillance; and repair and/or replace
physical barriers as needed. The DOE
also identified other measures that
function as AICs, such as DOE's
prevention of resource exploration at
the WIPP and DOE's construction of
long-term site markers. The DOE will
maintain the proposed AICs for at least
100 years after closure of the WIPP, and
the WIPP PA assumed that AICs would
prevent human intrusion for that period.
The EPA reviewed the proposed AICs
in connection with the types of
activities that may be expected to occur
in the vicinity of the WIPP site during
the first 100 years after disposal (i.e.,
ranching, farming, hunting, scientific
activities, utilities and transportation,
ground water pumping, surface
excavation, potash exploration,
hydrocarbon exploration, construction,
and hostile or illegal activities) and
examined the assumptions made by
DOE to justify the assertion that AICs
will be completely effective for 100
years. The DOE stated in the CCA that
the proposed AICs will be maintained
for 100 years, and that regular
surveillance could be expected to detect
a drilling operation in a prohibited area
that is set up in defiance or ignorance
of posted warnings.
The EPA received public comments
on its proposed certification decision
stating that it was unreasonable to
assume that AICs could be completely
effective for 100 years. While EPA
recognizes that 100 percent
effectiveness of AICs over 100 years
cannot be established with certainty, the
proposed AICs are fully within DOE's
present capability to implement and
may be expected to be enforceable for a
period of 100 years. Therefore, EPA
found it reasonable for DOE to assume
credit in the PA for 100 years. The EPA
found the assumptions regarding
longevity and efficacy of the proposed
AICs to be acceptable based on the fact
that the types of inadvertent intrusion
which AICs are designed to obviate are
not casual activities, but require
extensive resources, lengthy procedures
for obtaining legal permission, and
substantial time to set up at the site
before beginning.
Contributions from AICs in the PA are
considered as a reduction in the rate of
human intrusion. The EPA reviewed the
CCA and the parameter inputs to the PA
and determined that DOE did not
assume credit for the effectiveness of
active institutional controls for more
than 100 years after disposal. The EPA
found DOE's assumptions to be
sufficient to justify DOE's assertion that
AICs will completely prevent human
intrusion for 100 years after closure.
Because DOE adequately described the
proposed AICs and the basis for their
assumed effectiveness and did not
assume in the PA that AICs would be
effective for more than 100 years, EPA
finds DOE in compliance with § 194.41.
For further information on EPA's
evaluation of compliance for § 194.41,
refer to CARD 41. (Docket A-93-02,
Item V-B-2)
2. Monitoring (§194.42)
Section 194.42 requires DOE to
monitor the disposal system to detect
deviations from expected performance.
The monitoring requirement
distinguishes between pre-and post-
closure monitoring because the
monitoring techniques that may be used
to access the repository during
operations (pre-closure) and after the
repository has been backfilled and
sealed (post-closure) are different.
Monitoring is intended to provide
information about the repository that
may affect the predictions made about
the PA or containment of waste. The
EPA proposed that DOE was in
compliance with this requirement. (62
FR 58827)
Public comments on EPA's proposed
decision stated that the monitoring plan
presented by DOE does not comply with
certain hazardous waste (Resource
Conservation and Recovery Act) and
Nuclear Regulatory Commission
("NRC") requirements. However, the
monitoring techniques and parameters
suggested by commenters are not
required by § 194.42, which requires
only that the post-closure monitoring
plan be complementary to certain
applicable hazardous waste monitoring
requirements. The purpose of this
language is to eliminate potential
overlap with hazardous waste
monitoring requirements while ensuring
that monitoring will be conducted even
if not required by the applicable
hazardous waste regulations. (Response
to Comments for 40 CFR Part 194,
Docket A-92-56, Item V-C-1, p. 14-7)
One commenter stated that DOE
should monitor additional parameters
and perform remote monitoring to
prolong the length of time that data is
gathered. The EPA determined that
monitoring the additional parameters
would provide no significant benefit
because these parameters were not
identified as significant to the
containment of waste or to verifying
predictions made about the repository.
The EPA also determined that
additional remote monitoring of the
panel rooms would neither provide
significant information on the
performance of the repository nor verify
predictions about its performance.
The plans in the CCA addressed both
pre-closure and post-closure monitoring
and included the information required
by the compliance criteria. Therefore,
EPA finds that DOE is in compliance
with the requirements of § 194.42.
Under its authority at § 194.21, EPA
intends to conduct inspections of DOE's
implementation of the monitoring plans
that DOE has set forth. For further
information on EPA's evaluation of
compliance for § 194.42, see CARD 42.
(Docket A-93-02, Item V-B-2)
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3. Passive Institutional Controls
(§194.43)
The compliance criteria at § 194.43
require a description of passive
institutional controls ("PICs") that will
be implemented at the WIPP. The EPA
defined PICs in the disposal regulations
as markers, public records and archives,
government ownership of and
restrictions on land use at a site, and
any other means of preserving
knowledge of a site. (40 CFR 191.12)
PICs are intended to deter unintentional
intrusions into a disposal system by
people who otherwise might not be
aware of the presence of radioactive
waste at the site.
Section 194.43 requires DOE to: (1)
identify the controlled area with
markers designed, fabricated, and
emplaced to be as permanent as
practicable; (2) place records in local
State, Federal, and international
archives and land record systems likely
to be consulted by individuals in search
of resources; and (3) employ other PICs
intended to indicate the location and
dangers of the waste. In accordance with
§ 194.43(b), DOE also must indicate the
period of time that PICs are expected to
endure and be understood by potential
intruders. Finally, DOE is permitted to
propose a credit for PICs in the PA, as
explained in § 194.43(c). This credit
must be based on the proposed
effectiveness of PICs over time, and
would take the form of reduced
likelihood in the PA of human intrusion
over several hundred years. The
compliance criteria prohibit DOE from
assuming that PICs could entirely
eliminate the likelihood of future
human intrusion into the WIPP.
The EPA proposed that DOE complied
with § 194.43(a) and (b) because the
measures proposed in the CCA are
comprehensive, practicable, and likely
to endure and be understood for long
periods of time. The EPA also proposed
a condition that DOE submit additional
information concerning the schedule for
completing PICs, the fabrication of
granite markers, and commitments by
various recipients to accept WIPP
records. (62 FR 58827-29) The EPA did
not receive any comments disputing this
decision, and so finds DOE in
compliance with § 194.43(a) and (b).
However, DOE must fulfill Condition 4
of Appendix A to 40 CFR Part 194 no
later than the final recertification
application. For further information on
EPA's evaluation of compliance with
§ 194.43, see CARD 43. (Docket A-93-
02, ItemV-B-2)
Some commenters expressed the
concern that PICs in general, and DOE's
plan in particular, would not be
sufficient to prevent drilling or other
intrusions into the WIPP over 10,000
years. The EPA has never asserted that
PICs, as an assurance measure, could or
must be sufficient to prevent human
intrusion into a site entirely or for a
specified period (such as 10,000 years).
In fact, the WIPP compliance criteria
prohibit DOE from assuming that PICs
can completely eliminate the likelihood
of human intrusion. (§ 194.43(c)) DOE's
design incorporates features that will
serve to promote the endurance and
comprehensibility of PICs over time,
such as: redundant markers, highly
durable materials with low intrinsic
value, messages in multiple languages,
and record storage in multiple locations.
Also, the CCA clearly discusses the
manner in which DOE accounted in the
design for possible, realistic failures.
The Agency believes that the existence
of site-specific markers and records,
designed to be durable over long periods
of time, will greatly improve the
chances that future generations will
retain knowledge of the hazard posed by
waste stored at the WIPP.
The EPA proposed to deny DOE's
request under § 194.43(c) that the
likelihood of human intrusion into the
WIPP during the first 700 years after
closure be reduced by 99 percent based
on the anticipated effectiveness of PICs.
The EPA denied the credit because DOE
did not use an expert judgment
elicitation to derive the credit, as
explicitly envisioned by the Agency.
The EPA expected that an expert
judgment elicitation that makes use of
the best available information and
expertise would be used to account for
the considerable uncertainties
associated with a prediction of the
ability of PICs to prevent human
intrusion hundreds of years into the
future. Since the WIPP is located in an
area of resource exploitation, the
uncertainty was not sufficiently
reflected in the near 100 percent credit
proposed in the CCA.
The Agency received comments both
supporting and refuting this decision.
Comments supporting EPA's proposed
decision tended to reflect the position
that any PICs credit would be too
uncertain for use in the PA. In
opposition to EPA's decision, comments
stated that EPA drew improper
conclusions about DOE's use of expert
judgment and treatment of uncertainty.
These comments requested that EPA
reverse its denial of PICs credit, or at
least consider future credit proposals,
but did not identify why EPA's
conclusions were incorrect other than to
reiterate positions taken in the CCA that
were explicitly assessed by EPA in the
proposal. (62 FR 58828) Therefore, EPA
sees no cause to reverse its decision to
deny DOE's request for PICs credit
under § 194.43(c). However, EPA's final
decision today applies only to the credit
proposal in the CCA and should not be
interpreted as a judgment on the use of
PICs credit in performance assessments
generally. In the future, DOE may
present to EPA additional information
derived from an expert elicitation of
PICs credit. Any future PICs credit
proposals will be considered in the
context of a modification rulemaking,
and will be subject to public
examination and comment.
4. Engineered Barriers (§ 194.44)
Section 194.44 requires DOE to
conduct a study of available options for
engineered barriers at the WIPP and
submit this study and evidence of its
use with the compliance application.
Consistent with the assurance
requirement found at 40 CFR 191.14,
DOE must analyze the performance of
the complete disposal system, and any
engineered barrier(s) that DOE
ultimately implements at the WIPP must
be considered in the PA and EPA's
subsequent evaluation. Based on the
comparative study that constitutes
Appendix BBS of the CCA, DOE
proposed magnesium oxide (MgO)
backfill as an engineered barrier and
proposed to emplace bags of MgO
between and around waste containers in
the repository. The EPA proposed to
find DOE in compliance with § 194.44
because DOE conducted and
documented the required study in a
manner consistent with the WIPP
compliance criteria and proposed to
implement an engineered barrier to
delay the movement of water or
radionuclides. (62 FR 58829)
Public comments on the proposal
stated that the waste should be treated
before being placed in the repository.
Commenters stated that treatment of
waste could serve to provide additional
confidence in the safety of the disposal
system beyond that demonstrated by the
performance assessment, based on the
assumption that waste treatment would
reduce the potential effects of a
repository breach. Commenters
therefore urged EPA to encourage DOE
to treat the waste in order to add
additional assurance in the predicted
performance of the WIPP.
Section 194.44 of the compliance
criteria requires DOE to perform a
comparison of the benefits and
detriments of waste treatment options
(referred to as "engineered barriers" by
EPA and as "engineered alternatives" by
DOE). DOE's evaluation incorporated
such treatment methods as vitrification
and shredding. Based on this
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evaluation, DOE selected the use of
MgO as an engineered barrier. The EPA
determined that MgO will be an
effective barrier, based on DOE's
scientific evaluation of the proposed
barrier's ability to prevent or
substantially delay the movement of
radionuclides toward the accessible
environment.
Section 194.44 does not require
specific engineered barriers or the
implementation of more than one
engineered barrier. Since DOE will
employ the use of a barrier as required
by this section, and since the
performance assessment results showed
compliance with the containment
requirements with the use of this
barrier, EPA does not consider it
necessary to require DOE to treat waste
prior to emplacement. However, EPA
agrees that waste treatment or additional
barriers may further enhance the
containment ability of the WIPP. In the
future, if DOE were to select a new
treatment option (such as vitrification)
that differs significantly from the option
in the most recent compliance
application, DOE must inform EPA prior
to making such a change.
(§ 194.4(b)(3)(i) and (vi)) The EPA will
evaluate the information provided by
DOE and determine if the certification
warrants modification.
Other commenters expressed concern
that DOE failed to consider alternatives
to the proposed 55-gallon steel waste
drums that could reduce releases or the
formation of gas in the repository due to
the degradation of carbon. Commenters
further stated that DOE failed to
consider adequately how engineered
barriers could reduce releases from four
human intrusion scenarios: fluid
injection, air drilling, stuck pipe, and
direct brine release.
The EPA recognized that gas
production from waste drum
degradation was a relevant issue and so
included consideration of "improved
waste containers" in the list of factors
for DOE to consider when evaluating
engineered barriers. (40 CFR 194.44(b))
The DOE did, in fact, consider various
aspects of waste packages in the
engineered barrier study. Appendix A of
Appendix BBS (p. A-10) states that the
"improved waste container" options
scored low in a qualitative assessment
because of their minimal ability to
improve conditions with respect to
waste solubility and shear strength. As
explained in CARD 44 (Docket A-93-
02, Item V-B-2), DOE also examined the
effects of engineered barriers on the
long-term performance of the WIPP
using the Design Analysis Model
("DAM"), which provided a relative
comparison of the potential benefits of
the different barriers on the performance
of the repository. There was no attempt
to determine the absolute effect of the
barriers on the performance of the
repository since the objective of the
study (in accordance with the WIPP
compliance criteria) was only to provide
DOE with information for use in the
selection or rejection of additional
engineered barriers. (Docket A-93-02,
Item V-B-2, CARD 44, Section 44.C.4)
It was not necessary for DOE to show
the absolute effect of each barrier on the
WIPP's performance in the face of a
specific human intrusion scenario such
as air drilling. Rather, it was sufficient
for DOE to consider the relative ability
of barriers to prevent or delay
radionuclide migration in the event of
human intrusion.
Other comments expressed concern
that the "containment" and "assurance"
requirements were not kept separate, as
was intended by EPA's disposal
standards. The separation of the
requirements is valid only to the extent
that engineered barriers may be used to
meet the containment requirements, but
must be used to meet the assurance
requirements. The effects of all
engineered barriers employed at the
WIPP must be considered in
performance assessments. Excluding
such barriers from consideration would
result in inaccurate modeling of the
disposal system, which is defined in
§ 191.12 (a) to include engineered
barriers. (Response to Comments for 40
CFR Part 194, Docket A-92-56, Item V-
C-l, pp. 16-10, 16-13) Although not
required to comply with § 194.44, DOE
and others performed calculations
showing that the WIPP can comply with
the containment requirements with or
without the use of MgO as an
engineered barrier. (Docket A-93-02,
Items IV-D-12 and IV-G-7)
The EPA finds that DOE complies
with § 194.44. The EPA found that DOE
conducted the requisite analysis of
engineered barriers and selected an
engineered barrier designed to prevent
or substantially delay the movement of
water or radionuclides toward the
accessible environment. The DOE
provided sufficient documentation to
show that MgO can effectively reduce
actinide solubility in the disposal
system. The DOE proposed to emplace
a large amount of MgO around waste
drums in order to provide an additional
factor of safety and thus account for
uncertainties in the geochemical
conditions that would affect CO2
generation and MgO reactions. For
further information on EPA's evaluation
of compliance for § 194.44, see CARD
44. (Docket A-93-02, Item V-B-2) For
further information regarding the PA
modeling of solubility and chemical
conditions in the repository, see CARD
23—Models and Computer Codes.
(Docket A-93-02, Item V-B-2)
5. Consideration of the Presence of
Resources (§194.45)
Section 194.45 implements the
assurance requirement that the disposal
system be sited so that the benefits of
the natural barriers of the disposal
system will compensate for any
increased probability of disruptions to
the disposal system resulting from
exploration and development of existing
resources. (61 FR 5232) In issuing the
WIPP compliance criteria, EPA
determined that the performance
assessment ("PA") is the appropriate
tool to weigh the advantages and
disadvantages of the WIPP site because
the PA demonstrates whether potential
human intrusion will cause
unacceptably high releases of
radioactive material from the disposal
system. Comments on § 194.45 for the
proposed certification decision did not
address the question of compliance with
this requirement but instead focused on
the criterion itself, stating that it was
inconsistent with the original basis for
the assurance requirements to be
qualitative in nature. The EPA believes
that the presence of resources
requirement is reasonable because the
performance assessment must account
for the increased potential for human
intrusion into the disposal system due
to the presence of known resources,
based on historical rates of drilling and
mining in the vicinity of the WIPP.
(Docket A-92-56, ItemV-C-1, p. 17-1)
In any case, it is beyond the scope of the
certification rulemaking to
fundamentally re-examine or change the
disposal regulations or compliance
criteria as they relate to the presence of
resources.
Because the PA incorporated human
intrusion scenarios and met EPA's
release limits in accordance with the
WIPP compliance criteria, EPA
determines that DOE has demonstrated
compliance with § 194.45. For
discussion of comments on human
intrusion scenarios, results, and other
aspects of the PA, refer to Section B
("Performance Assessment: Modeling
and Containment Requirements") of this
preamble. For further information on
EPA's evaluation of compliance for
§ 194.45, refer to CARD 45. (Docket A-
93-02, Item V-B-2)
6. Removal of Waste (§ 194.46)
Section 194.46 requires DOE to
provide documentation that the removal
of waste from the disposal system is
feasible for a reasonable period of time
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after disposal. In the proposed
certification decision on WIPP, EPA
proposed that DOE was in compliance
with this requirement.
Public comments on EPA's proposed
decision expressed concern that there
would be no way to remove the waste
once the WIPP repository is sealed. The
technology used to dispose of the waste
is substantially the same as the
technology that would be used to
remove it. This technology may
reasonably be expected to remain
available for at least 100 years after the
repository is sealed. Public comments
also stated that EPA and DOE should
identify the limitations of DOE's
removal of waste plan. In Appendix
WRAC of the CCA, DOE acknowledges
the expense and hazard of removing the
waste from the repository. The purpose
of the requirement at § 194.46 is to
demonstrate that the removal of waste
remains possible, not necessarily simply
or inexpensive, for a reasonable period
of time after disposal. (50 FR 38082)
The DOE demonstrated that it is
possible to remove waste from the
repository for a reasonable period of
time after disposal. Therefore, EPA
determines that DOE is in compliance
with § 194.46. For further information
on EPA's evaluation of compliance with
§ 194.46, see CARD 46. (Docket A-93-
02, ItemV-B-2)
E. Individual and Ground-water
Protection Requirements (§§ 194.51-55)
Sections 194.51 through 194.55 of the
compliance criteria implement the
individual protection requirements of
40 CFR 191.15 and the ground-water
protection requirements of Subpart C of
40 CFR Part 191. Assessment of the
likelihood that the WIPP will meet the
individual dose limits and radionuclide
concentration limits for ground water is
conducted through a process known as
compliance assessment. Compliance
assessment uses methods similar to
those of the PA (for the containment
requirements) but is required to address
only undisturbed performance of the
disposal system. That is, compliance
assessment does not include human
intrusion scenarios (i.e., drilling or
mining for resources). Compliance
assessment can be considered a
"subset" of performance assessment,
since it considers only natural
(undisturbed) conditions and past or
near-future human activities (such as
existing boreholes), but does not include
the long-term future human activities
that are addressed in the PA.
Section 194.51 requires DOE to
assume in compliance assessments that
an individual resides at the point on the
surface where the dose from
radionuclide releases from the WIPP
would be greatest. The EPA required
that the CCA identify the maximum
annual committed effective dose and the
location where it occurs, and explain
how DOE arrived at those results.
In DOE's analysis, an individual
receives the highest dose if one assumes
that the individual takes drinking water
directly from the Salado Formation at
the subsurface boundary of the WIPP
area. The DOE assumed that an
individual would receive the maximum
estimated dose regardless of location on
the surface and calculated the resultant
doses accordingly. EPA found this
approach to be conservative and
proposed that DOE complied with
§ 194.51. The Agency received no public
comments on this topic beyond those
addressed in the proposal (62 FR
58831), and so finds DOE in compliance
with the requirements of § 194.51.
Section 194.52 requires DOE to
consider in compliance assessments all
potential exposure pathways for
radioactive contaminants from the
WIPP. The DOE must assume that an
individual consumes two liters per day
of drinking water from any underground
source of drinking water outside the
WIPP area.
The DOE considered the following
pathways: an individual draws drinking
water directly from the Salado
Formation; an individual ingests plants
irrigated with contaminated water or
milk and beef from cattle whose stock
pond contained contaminated water
from the Salado; and an individual
inhales dust from soil irrigated with
contaminated water from the Salado.
Intended to result in the maximum
dose, DOE's assumption that water is
ingested directly from the Salado
actually is so conservative as to be
unrealistic, since Salado water is highly
saline and would have to be greatly
diluted in order to function as drinking
or irrigation water.
The EPA proposed that DOE complied
with § 194.52 because DOE considered
all potential exposure pathways and
assumed that an individual consumes
two liters of Salado water a day,
following dilution. The Agency received
no public comments on this topic
beyond those addressed in the proposal
(62 FR 58831), and so finds DOE in
compliance with the requirements of
§ 194.52. For further information
concerning EPA's evaluation of
compliance for §§ 194.51 and 194.52,
see CARD 51/52. (Docket A-93-02, Item
V-B-2)
Section 194.53 requires DOE to
consider in compliance assessments
underground sources of drinking water
("USDWs") near the WIPP and their
interconnections. A USDW is defined at
40 CFR 191.22 as "an aquifer or its
portion that supplies a public water
system, or contains a sufficient quantity
of ground water to do so and (i)
currently supplies drinking water for
human consumption or (ii) contains
fewer than 10,000 mg per liter of total
dissolved solids."
The DOE identified three potential
USDWs near the WIPP—the Culebra
Member of the Rustler Formation, the
Dewey Lake Red Beds, and the Santa
Rosa Sandstone of the Dockum Group—
despite incomplete data showing that
they meet the regulatory definition of a
USDW. The DOE did not analyze
underground interconnections among
these water bodies, instead assuming
conservatively that people would draw
water directly from the Salado
Formation, bypassing other USDWs
closer to the surface and thus resulting
in greater exposure.
The EPA proposed that DOE complied
with § 194.53 because DOE adequately
considered potential USDWs near the
WIPP. The Agency received a few
public comments that raised questions
about DOE's approach to evaluating
USDWs. For example, some commenters
questioned DOE's assertion that USDWs
such as Laguna Grande de la Sal would
not be contaminated if the WIPP is left
undisturbed. In fact, the compliance
assessments assumed that water in the
Salado Formation constituted a
hypothetical USDW that would provide
drinking water after being diluted.
Radionuclide concentrations would be
expected to be greatest in the Salado at
the subsurface boundary of the WIPP,
since the disposal system is located in
that geologic formation. Thus, by
demonstrating that EPA's drinking
water standards would be met where
radioactive contamination would be
greatest, DOE also showed that other,
more distant potential aquifers also
would comply. This conservative
approach compensates for substantial
uncertainties that would otherwise be
involved in the calculation of
radionuclide transport to potential
USDWs.
Even using an analysis that was
designed to maximize radionuclide
releases, DOE showed that the WIPP
will comply with EPA's limits for
radionuclides in ground water by a wide
margin. The EPA therefore finds DOE in
compliance with § 194.53. For further
information concerning EPA's
evaluation of compliance with § 194.53,
see CARD 53. (Docket A-93-02, Item V-
B-2)
Sections 194.54 and 194.55 relate to
the scope and results of compliance
assessments conducted to determine
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27399
compliance with the individual dose
and ground-water protection
requirements. The EPA found that DOE
appropriately evaluated and screened
out natural features, processes, and
events related to undisturbed
performance, and proposed to find DOE
in compliance with § 194.54. (62 FR
58832) The Agency received no specific
comments on this decision. Comments
on issues that could affect predictions of
undisturbed performance, such as site
characterization or ground-water
modeling, are discussed separately in
this preamble and did not necessitate
changes to compliance assessments.
(See "Geologic Scenarios and Disposal
System Characteristics" under the
Performance Assessment sections of this
preamble.) The EPA therefore finds that
DOE complies with § 194.54. For further
information on EPA's evaluation of
compliance with § 194.54, see CARD 54.
(Docket A-93-02, Item V-B-2)
The EPA found that compliance
assessments conducted by DOE
appropriately documented uncertainty,
documented probability distributions
for uncertain parameters, randomly
sampled across the distributions, and
generated and displayed a sufficient
number of estimates of radiation doses
and ground-water concentrations.
Further, the resulting estimates of
radiation doses and radionuclide
concentrations in ground water (and
independent calculations by EPA) were
well below the limits in § 191.15 and
Subpart C of 40 CFR Part 191. In its
proposal, the Agency found that DOE is
in compliance with the requirements of
§ 194.55, and received no comments
disputing this decision, which is
therefore finalized. For further
information on EPA's evaluation of
compliance for § 194.55, see CARD 55.
(Docket A-93-02, Item V-B-2)
IX. Does DOE Need to Buy Existing Oil
and Gas Leases Near the WIPP?
The EPA finds that DOE does not
need to acquire existing oil and gas
leases in the vicinity of the WIPP in
order to comply with EPA's disposal
regulations. These existing leases, and
EPA's need to evaluate their effects on
the WIPP, are addressed by the 1992
WIPP Land Withdrawal Act ("LWA")
which provides for EPA's regulatory
authority at the WIPP.37 (See Section X
of this preamble, entitled "Why and
How Does EPA Regulate the WIPP," for
more information on the WIPP LWA.)
The 1992 WIPP LWA withdrew the
geographic area containing the WIPP
facility from all forms of entry,
appropriation, and disposal under
3'Pub. L. 102-579, sections 4(b)(5) and 7(b)(2).
public land laws. The WIPP LWA
transferred jurisdiction of the land to
the Secretary of Energy explicitly for the
use of constructing, operating, and
conducting other authorized activities
related to the WIPP. The WIPP LWA
prohibits all surface or subsurface
mining or oil or gas production is
prohibited at all times on or under the
land withdrawal area. (WIPP LWA,
section 4(b)(5)(A)) However, section
4 (b) (5) (B) states that existing rights
under two oil and gas leases (Numbers
NMNM 02953 and 02953C) (referred to
as "the section 4(b)(5)(B) leases") shall
not be affected unless the Administrator
determines, after consultation with DOE
and the Department of the Interior, that
the acquisition of such leases by DOE is
required to comply with EPA's final
disposal regulations.
Before DOE can emplace waste in the
WIPP, DOE must acquire the leases,
unless EPA determines that such
acquisition is not required. (WIPP LWA,
section 7(b)(2)) This determination is
separate and apart from the WIPP LWA
requirement for EPA to conduct the
certification decision by notice-and-
comment rulemaking. (WIPP LWA,
section 8(d)). Nonetheless, the Agency
chose to address this matter as part of
the certification process because the
determination of whether potential
drilling on the leases could possibly
affect the integrity of the WIPP is closely
related to similar determinations that
must be made to determine compliance
with the disposal regulations and WIPP
compliance criteria. (See §§ 194.32(c),
194.54(b))
As discussed in the proposed
certification decision, EPA examined
DOE's analysis of a number of potential
activities in the life cycle of a well-
drilling, fluid injection (for both
waterflooding and brine disposal), and
abandonment—that could affect the
WIPP disposal system. The Agency
agreed with DOE that the effects of
drilling a borehole would be highly
localized, due to well casing procedures
and borehole plugging practices. The
EPA found that the effects of fluid
injection can also be expected to be
localized, due to underground injection
control requirements. Finally, even
abandoned boreholes would have little
consequence on waste panels more than
a meter away. Because the closest
possible approach of a borehole drilled
from the section 4(b)(5)(B) leases is over
2400 meters (8000 feet) from the WIPP
waste disposal rooms, EPA determined
that such a borehole would have an
insignificant effect on releases from the
disposal system (and in turn, on
compliance with the disposal
regulations). (62 FR 58835-58836)
For the reasons discussed above, EPA
concluded in its proposed rule that the
Secretary of Energy does not need to
acquire Federal Oil and Gas Leases No.
NMNM 02953 and No. NMNM 02953C.
(62 FR 58836) A number of comments
on the proposed rule suggested that
DOE conducted inadequate performance
assessment analyses on drilling
activities occurring prior to or soon after
disposal in the vicinity of the WIPP, but
only one commenter took issue directly
with EPA's decision to not require the
Secretary of Energy to acquire the
Section 4(b)(5)(B) leases. This
commenter questioned the impact of
drilling activities by lease holders.
The DOE's analysis of drilling for the
performance assessment indicated that
wells drilled into the controlled area,
but away from the waste disposal room
and panels, will not adversely affect the
disposal system's capability to contain
radionuclides. A slant-drilled borehole
from outside the Land Withdrawal Area,
into the section 4(b)(5)(B) lease area at
least 6000 feet below the surface, would
be at least 2400 meters (8000) feet away
from the WIPP disposal rooms and
would thus have an insignificant effect
on releases from the disposal system or
compliance with the disposal
regulations. The EPA finds that
potential activities at the section
4(b)(5)(B) leases will not cause the WIPP
to violate the disposal regulations. (For
more information on drilling scenarios,
see the preamble discussions related to
performance assessment.) Therefore,
EPA determines that it is not necessary
for the Secretary of Energy to acquire
the Federal Oil and Gas Leases No.
NMNM 02953 and No. NMNM 02953C.
X. Why and How Does EPA Regulate
the WIPP?
The WIPP Land Withdrawal Act is the
statute that provides EPA the authority
to regulate the WIPP. The EPA's
obligations and the limitations on EPA's
regulatory authority under that law are
discussed below.
A. The WIPP Land Withdrawal Act
The EPA's oversight of the WIPP
facility is governed by the WIPP Land
Withdrawal Act ("LWA"), passed
initially by Congress in 1992 and
amended in 1996. (Prior to the passage
of the WIPP LWA in 1992, DOE was
self-regulating with respect to the WIPP;
that is, DOE was responsible for
determining whether its own facility
complies with applicable regulations for
radioactive waste disposal.) The WIPP
LWA delegates to EPA three main tasks,
to be completed sequentially, for
reaching a compliance certification
decision. First, EPA must finalize
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general regulations which apply to all
sites—except Yucca Mountain—for the
disposal of highly radioactive waste.38
These regulations, located at Subparts B
and C of 40 CFR Part 191 ("disposal
regulations"), were published in the
Federal Register in 1985 and 1993.39
Second, EPA must develop, by
rulemaking, criteria to implement and
interpret the general radioactive waste
disposal regulations specifically for the
WIPP. The EPA issued the WIPP
compliance criteria, which are found at
40 CFR Part 194, in 1996.40
Third, EPA must review the
information submitted by DOE and
publish a certification decision.41
Today's action constitutes EPA's
certification decision as required by
section 8 of the WIPP LWA.
Today's action also addresses the
requirement at section 7(b)(2) that,
before DOE can emplace waste in the
WIPP, DOE must acquire existing oil
and gas leases near the WIPP unless
EPA determines that such acquisition is
not required in order for DOE to comply
with the disposal regulations. The EPA
determines that acquisition of the leases
is not necessary. For further discussion
of this requirement, refer to the
preamble section entitled, "Does DOE
need to buy existing oil and gas leases
near the WIPP?"
Besides requiring EPA to issue a
certification decision, the WIPP LWA
also requires the Agency to conduct
periodic recertifications, if the facility is
initially certified. Every five years, EPA
must determine whether documentation
submitted by DOE demonstrates that the
WIPP continues to be in compliance
with the disposal regulations.42
Recertifications are not conducted
through rulemaking, and are not
addressed by today's action. However,
the WIPP compliance criteria address
the process by which EPA intends to
conduct recertifications, including
publishing public notices in the Federal
Register and providing a public
comment period. (§ 194.64) For further
information on recertification, refer to
the preamble sections entitled, "EPA's
Future Role at the WIPP" and "How
will the public be involved in EPA's
future WIPP activities?"
B. Limits of EPA's Regulatory Authority
at the WIPP
As discussed above, the WIPP LWA
conveys specific responsibilities on EPA
as WIPP LWA, section 8 (b).
3950 FR 38066-38089 (September 19, 1985) and
58 FR 66398-66416 (December 20, 1993).
4061 FR 5224-5245 (February 9, 1996).
" WIPP LWA, section 8 (d).
«WIPP LWA, section 8(f).
to ensure the safety of the WIPP as a
permanent disposal facility. The
Agency's primary responsibility,
described in section 8 of the WIPP
LWA, is to determine whether the WIPP
facility will comply with EPA's disposal
regulations. Members of the public have
expressed, in written comments and in
oral testimony on the proposed rule, a
desire for the Agency to oversee other
aspects of the WIPP's operation. In
response to such concerns, EPA must
clarify that its authority to regulate DOE
and the WIPP is limited by the WIPP
LWA and other statutes which delineate
EPA's authority to regulate radioactive
materials in general. The limitations on
EPA's authority necessarily limit the
scope of the present rulemaking.
A number of commenters suggested
that EPA should explore alternative
methods of waste disposal, such as
neutralizing radioactive elements,
before proceeding with a certification
decision. Others stated that the WIPP
should be opened immediately because
underground burial of radioactive waste
is less hazardous than the current
strategy of above-ground storage. In the
WIPP LWA, Congress did not delegate
to EPA the authority to abandon or
delay the WIPP because future
technologies might evolve and eliminate
the need for the WIPP. Also, Congress
did not delegate to EPA the authority to
weigh the competing risks of leaving
radioactive waste stored above ground
compared to disposal of waste in an
underground repository. These
considerations are outside the authority
of EPA as established in the WIPP LWA,
and thus outside the scope of this
rulemaking. However, as technologies
evolve over the operating period of the
WIPP, DOE may incorporate them into
the facility design through a
modification or during the required
recertification process. The EPA will
evaluate how any such changes in
design or activities at the WIPP may
affect compliance with the radioactive
waste disposal regulations.
Some commenters requested that EPA
consider certain factors in making its
certification decision. These factors
include reviews by organizations other
than EPA, and the political or economic
motivations of interested parties. The
EPA's certification decision must be
made by comparing the scope and
quality of relevant information to the
objective criteria of 40 CFR Part 194.
Where relevant, the Agency has
considered public comments which
support or refute technical positions
taken by DOE. Emotional pleas and
comments on the motives of interested
parties are factors that are not relevant
to a determination of whether DOE has
demonstrated compliance with the
disposal regulations and WIPP
compliance criteria, and are therefore
outside the scope of this rulemaking.
Finally, the hazards of transporting
radioactive waste from storage sites to
the WIPP is of great concern to the
public. Transportation is entirely
outside EPA's general authority for
regulating radioactive waste. Moreover,
in the WIPP LWA, Congress did not
authorize any role for EPA to regulate
transportation. Instead, the WIPP LWA
reiterated that DOE must adhere to
transportation requirements enforced by
the U.S. Nuclear Regulatory
Commission and the U.S. Department of
Transportation. (WIPP LWA, section 16)
Because all transportation requirements
for the WIPP are established and
enforced by other regulators, EPA does
not address the issue further in today's
action.
The preamble section entitled, "What
is EPA's response to general comments
received on the certification decision?"
provides further discussion of general
issues, including several related to the
scope of EPA's certification rulemaking.
C. Compliance With Other
Environmental Laws and Regulations
The WIPP must comply with a
number of other environmental and
safety regulations in addition to EPA's
disposal regulations—including, for
example, the Solid Waste Disposal Act
and EPA's environmental standards for
the management and storage of
radioactive waste. Various regulatory
agencies are responsible for overseeing
the enforcement of these Federal laws.
For example, the WIPP's compliance
with EPA's radioactive waste
management regulations, found at
Subpart A of 40 CFR Part 191, is
addressed by an EPA guidance
document which describes how EPA
intends to implement Subpart A at the
WIPP. (Copies of the WIPP Subpart A
Guidance are available by calling the
WIPP Information Line atj^^^^^^|
www.epa/gov/radiation/wipp.)
Enforcement of some parts of the
hazardous waste management
regulations has been delegated to the
State of New Mexico. The State's
authority for such actions as issuing a
hazardous waste operating permit for
the WIPP is in no way affected by EPA's
certification decision. It is the
responsibility of the Secretary of Energy
to report the WIPP's compliance with all
applicable Federal laws pertaining to
public health and the environment.43
Compliance with environmental or
«WIPP LWA, sections 7(b)(3) and 9.
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27401
public health regulations other than
EPA's disposal regulations and WIPP
compliance criteria is not addressed by
today's action.
XI. How Has the Public Been Involved
in EPA's WIPP Activities?
Section 8(d)(2) of the WIPP LWA
requires that the Administrator's
certification decision be conducted by
informal (or "notice-and-comment")
rulemaking pursuant to Section 4 of the
Administrative Procedure Act ("APA").
Notice-and-comment rulemaking under
the APA requires that an agency provide
notice of a proposed rulemaking, an
opportunity for the public to comment
on the proposed rule, and a general
statement of the basis and purpose of
the final rule.44
The WIPP compliance criteria, at
Subpart D of 40 CFR Part 194,
established a process of public
participation that exceeds the APA's
basic requirements, and provides the
public with the opportunity to
participate in the regulatory process at
the earliest opportunity. The WIPP
compliance criteria contain provisions
that require EPA to: publish an advance
notice of proposed rulemaking
("ANPR") in the Federal Register; allow
public comment on DOE's compliance
certification application ("CCA") for at
least 120 days, prior to proposing a
certification decision; hold public
hearings in New Mexico, if requested,
on the CCA; provide a minimum of 120
days for public comment on EPA's
proposed certification decision; hold
public hearings in New Mexico on
EPA's proposal; produce a document
summarizing the Agency's
consideration of public comments on
the proposal, and maintain
informational dockets in the State of
New Mexico to facilitate public access
to the voluminous technical record,
including the CCA. The EPA has
complied with each of these
requirements.
A. Public Involvement Prior to Proposed
Rule
The EPA received DOE's CCA on
October 29, 1996. Copies of the CCA
and all the accompanying references
submitted to EPA were placed in EPA's
dockets in New Mexico and
Washington, DC. On November 15,
1996, the Agency published in the
Federal Register (61 FR 58499) an
ANPR announcing that the CCA had
been received, and announcing the
Agency's intent to conduct a rulemaking
to certify whether the WIPP facility will
comply with the disposal regulations.
"5U.S.C. 553.
The notice also announced a 120-day
public comment period, requested
public comment "on all aspects of the
CCA," and stated EPA's intent to hold
public hearings in New Mexico.
The EPA published a separate notice
in the Federal Register announcing
hearings to allow the public to address
all aspects of DOE's certification
application. (62 FR 2988) Public
hearings were held on February 19, 20
and 21, 1997, in Carlsbad, Albuquerque
and Santa Fe, New Mexico, respectively.
In addition to the public hearings, EPA
held three days of meetings in New
Mexico, on January 21, 22 and 23, 1997,
with the principal New Mexico
Stakeholders. Detailed summaries of
these meeting were placed in Docket A-
93-02, Category II-E.
The Agency received over 220 sets of
written and oral public comments in
response to the ANPR. The Agency
reviewed all public comments
submitted during the ANPR 120-day
comment period or presented at the
preliminary meetings with stakeholders.
The EPA provided responses to these
comments in the preamble to the
proposed certification as well as in the
compliance application review
documents ("CARDs") for the proposed
certification decision. The CARDs also
addressed late comments—and
comments on the completeness of DOE's
CCA—received after the close of the
public comment period (on March 17,
1997) but before August 8, 1997. (62 FR
27996-27998) All relevant public
comments, whether received in writing,
or orally during the public hearings,
were considered by the Agency as the
proposed certification decision was
developed. For further discussion of
EPA's completeness determination and
other pre-proposal activities, see the
preamble to the proposed certification
decision, 62 FR 58794-58796.
B. Proposed Certification Decision
On October 30, 1997, EPA published
a Notice of Proposed Rulemaking in the
Federal Register, fulfilling the
requirements of the WIPP compliance
criteria at § 194.62. (62 FR 58792-
58838) The notice announced the
Administrator's proposed decision,
pursuant to section 8(d)(l) of the WIPP
LWA, as amended, to issue a
certification that the WIPP facility will
comply with the disposal regulations,
and solicited comment on the proposal.
The notice also marked the beginning of
a 120-day public comment period on
EPA's proposed certification decision.
Finally, the notice announced that
public hearings would be held in New
Mexico during the public comment
period.
C. Public Hearings on Proposed Rule
Further information on the hearings
was provided in a Federal Register
notice published on December 5, 1997.
(62 FR 64334-64335) The Agency
conducted hearings in three cities in
New Mexico—Carlsbad, Albuquerque,
and Santa Fe—on January 5 through 9,
1998. The EPA took a number of steps
to ensure that citizens were aware of the
hearings and to accommodate requests
to testify before the EPA panel. For
example, EPA placed forty-six notices in
newspapers across the State to advertise
the hearings and provided a manned,
toll-free telephone line for pre-
registration. The Agency also allowed
on-site registration, and extended the
hours of the hearings in both
Albuquerque and Santa Fe in order to
allow everyone present who wished to
testify the opportunity to do so.
D. Additional Public Input on the
Proposed Rule
In addition to the public hearings,
EPA held two days of meetings in New
Mexico, on December 10-11, 1997, with
the principal New Mexico stakeholders,
including the New Mexico Attorney
General's Office, the New Mexico
Environmental Evaluation Group
("EEC"), Concerned Citizens for Nuclear
Safety, Citizens for Alternatives to
Radioactive Dumping, and Southwest
Research and Information Center.
Detailed summaries of these meetings
were placed in Docket A-93-02, Item
IV-E-8. Additional meetings were also
held in January 1998 in New Mexico
and Washington, DC with the New
Mexico EEC (IV-E-10 and IV-E-11) and
other stakeholders (IV-E-11).
In response to concerns expressed in
meetings with stakeholders and in
public hearings, EPA performed
additional analyses of air drilling (a
specialized drilling method which
stakeholders raised as an issue which
could potentially affect the WIPP if it
occurred near the site). In light of the
significant public interest in this issue,
EPA conducted its analysis and released
its report during the comment period on
the proposed rule, in order to allow an
opportunity for the public to comment
on EPA's technical analysis. The
Agency published a Federal Register
notice of availability for the report and
provided a 30-day public comment
period. (63 FR 3863; January 27, 1998)
The report was placed in the public
docket and also sent electronically to a
number of interested stakeholders,
including the New Mexico Attorney
General, the New Mexico
Environmental Evaluation Group,
Citizens for Alternatives to Radioactive
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Dumping, Concerned Citizens for
Nuclear Safety, and Southwest Research
and Information Center.
E. Final Certification Decision, Response
to Comments Document
Today's notice of EPA's final
certification decision pursuant to
section 8(d)(l) of the WIPP LWA fulfills
the requirement of the WIPP compliance
criteria at § 194.63(a). Also in
accordance with § 194.63(b), EPA is
publishing a document, accompanying
today's action and entitled "Response to
Comments," which contains the
Agency's response to all significant
comments received during the comment
period on the proposed certification
decision. (Docket A-93-02, Item V-C-1)
(For further discussion of EPA's
treatment of ANPR and other pre-
proposal comments, refer to the
preamble to the proposed rule, 62 FR
58794-58796.) All comments received
by EPA, whether written or oral, were
given equal consideration in developing
the final rule. All comments received by
the Agency were made available for
public inspection through the public
docket. (Docket A-93-02, Categories IV-
D, IV-F, and IV-G)
F. Dockets
In accordance with 40 CFR 194.67,
EPA maintains a public docket (Docket
A-93-02) that contains all information
used to support the Administrator's
proposed and final decisions on
certification. The Agency established
and maintains the formal rulemaking
docket in Washington, D.C., as well as
informational dockets in three locations
in the State of New Mexico (Carlsbad,
Albuquerque, and Santa Fe). The docket
consists of all relevant, significant
information received to date from
outside parties and all significant
information considered by the
Administrator in reaching a certification
decision regarding whether the WIPP
facility will comply with the disposal
regulations. The EPA placed copies of
the CCA in Category II-G of the docket.
The Agency placed supplementary
information received from DOE in
response to EPA requests in Categories
II-G and II-I.
The final certification decision and
supporting documentation can be found
primarily in the following categories of
Docket A-93-02: Category V-A (final
rule and preamble), Category V-B
(Compliance Application Review
Documents and Technical Support
Documents), and Category V-C
(Response to Comments document).
The hours and locations of EPA's
public information dockets are as
follows: Docket No. A-93-02, located in
room 1500 (first floor in Waterside Mall
near the Washington Information
Center), U.S. Environmental Protection
Agency, 401 M Street, S.W.,
Washington, D.C., 20460 (open from
8:00 a.m. to 4:00 p.m. on weekdays); 2)
EPA's docket in the Government
Publications Department of the
Zimmerman Library of the University of
New Mexico located in Albuquerque,
New Mexico, (open from 8:00 a.m. to
9:00 p.m. on Monday through Thursday,
8:00 a.m. to 5:00 p.m. on Friday, 9:00
a.m. to 5:00 p.m. on Saturday, and 1:00
p.m. to 9:00 p.m. on Sunday); 3) EPA's
docket in the Fogelson Library of the
College of Santa Fe in Santa Fe, New
Mexico, located at 1600 St. Michaels
Drive (open from 8:00 a.m. to 12:00
midnight on Monday through Thursday,
8:00 a.m. to 5:00 p.m. on Friday, 9:00
a.m. to 5:00 p.m. on Saturday, 1:00 p.m.
to 9:00 p.m. on Sunday); and 4) EPA's
docket in the Municipal Library of
Carlsbad, New Mexico, located at 101 S.
Halegueno (open from 10:00 a.m. to 9:00
p.m. on Monday through Thursday,
10:00 a.m. to 6:00 p.m. on Friday and
Saturday, and 1:00 p.m. to 5:00 p.m. on
Sunday). As provided in 40 CFR Part 2,
a reasonable fee may be charged for
photocopying docket materials.
XII. How Will the Public be Involved in
EPA's Future WIPP Activities?
The EPA's regulatory role at the WIPP
does not end with its initial certification
decision. The Agency's future WIPP
activities will include periodic
recertifications, review of DOE reports
on activities at the WIPP, assessment of
waste characterization and QA programs
at waste generator sites, announced and
unannounced inspections of the WIPP
and other facilities, and possibly
modification, revocation, or suspension
of the certification for cause. These
activities are described above in the
preamble section entitled "EPA's Future
Role at the WIPP." The EPA has
provided for public involvement in
these activities through rulemaking
procedures, Federal Register notices
and public comment periods, and by
making information available in its
public dockets. (See the preamble
sections entitled "Dockets" and "Where
can I get more information about EPA's
WIPP activities?" for more information
regarding EPA's rulemaking docket.)
While a suspension may be initiated
at the discretion of the Administrator in
order to promptly reverse or mitigate a
potential threat to public health, any
modification or revocation of the
certification will be conducted through
rulemaking. (§§ 194.65-66) To modify
or revoke the certification, EPA will first
publish a Notice of Proposed
Rulemaking in the Federal Register.
This notice will announce EPA's
proposed action, describe the basis for
the decision, and provide the
opportunity for public comment on the
proposal. Documentation related to the
decision will be made available to the
public through EPA's docket. Any final
rule on modification or revocation will
also be published in the Federal
Register. In addition, EPA will release a
document which summarizes and
responds to significant public comments
received on its proposal.
The recertification process—EPA's
periodic review of the WIPP's continued
compliance with the disposal
regulations and WIPP compliance
criteria—will include many of the same
elements as notice-and-comment
rulemaking. For example, EPA will
publish a Federal Register notice
announcing its intent to conduct such
an evaluation. The certification
application for recertification will be
placed in the docket, and at least a 30-
day period will be provided for
submission of public comments. The
Agency's decision on whether to
recertify the WIPP facility will again be
announced in a Federal Register notice.
(§194.64)
Although not required by the APA,
the WIPP LWA, or the WIPP compliance
criteria, EPA intends to place in the
docket all inspection or audit reports
and annual reports by DOE on
conditions and activities at the WIPP.
The Agency also plans to docket
information pertaining to the
enforcement of certification conditions.
For the enforcement of Conditions 2 and
3 (regarding quality assurance ("QA")
and waste characterization programs at
waste generator sites), a number of
additional steps will be taken. As
described in § 194.8 of the WIPP
compliance criteria, before approving
QA and waste characterization controls
at generator sites, EPA will publish a
Federal Register notice announcing
EPA inspections or audits. The requisite
plans and other appropriate inspection
or audit documentation will be placed
in the docket, and the public will be
allowed the opportunity to submit
written comments. A comment period of
at least 30 days will be provided. Thus,
EPA's decisions on whether to approve
waste generator QA program plans and
waste characterization controls'—and
thus, to allow shipment of specific
waste streams for disposal at the
WIPP'—will be made only after EPA has
conducted an inspection or audit of the
waste generator site and after public
comment has been solicited on the
matter. The Agency's decisions will be
conveyed by a letter from EPA to DOE.
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A copy of the letter, as well as the
results of any inspections or audits, will
be placed in EPA's docket.
XIII. Where Can I Get More
Information About EPA's WIPP
Activities?
The EPA's docket functions as the
official file for Agency rulemakings. The
EPA places all information used to
support its proposed and final decisions
in the docket, which is available for
review by the public. For the WIPP
certification rulemaking, information is
placed in Air Docket Number A-93-02.
The official docket is located in
Washington, DC, and informational
dockets are provided in three cities in
New Mexico. (See the "Dockets" section
of this preamble for more information
on the location and hours of EPA's
WIPP dockets.) The contents of the
docket include technical information
received from outside parties and other
information considered by EPA in
reaching a certification decision, as well
as the Agency's rationale for its
decision. The technical support
documents which describe the basis for
EPA's certification decision are
discussed below; sources of more
general information on EPA's WIPP
activities are also addressed.
A. Technical Support Documents
For more specific information about
the basis for EPA's certification
decision, there are a number of
technical support documents available.
The Compliance Application Review
Documents, or CARDs, contain the
detailed technical rationale for EPA's
certification decision. This document is
found at Docket A-93-02, Item V-B-2.
The CARDs discuss DOE's
compliance with the individual
requirements of the WIPP compliance
criteria. Each CARD is a section in the
document which is numbered according
to the section of 40 CFR Part 194 to
which it pertains. For example, CARD
23 addresses § 194.23, "Models and
Computer Codes." Each CARD: restates
the specific requirement, identifies
relevant information expected in the
CCA, explains EPA's compliance review
criteria, summarizes DOE's approach to
compliance, and describes EPA's
compliance review and decision. The
CARDs also list additional EPA
technical support documents and any
other references used by EPA in
rendering its decision on compliance.
All technical support documents and
references are available in Docket A-93-
02 with the exception of generally
available references and those
documents already maintained by DOE
or its contractors in locations accessible
to the public. (Instructions for obtaining
access to DOE documents can be found
at Docket A-93-02, Item V-B-1.)
B. WIPP Information Line, Mailing List,
and Internet Homepage
For more general information and
updates on EPA's WIPP activities,
interested citizens may contact EPA's
toll-free WIPP Information Line atj
^^^•^^^J. The hotline offers a
recordedmessage, in both English and
Spanish, about current EPA WIPP
activities, upcoming meetings, and
publications. Callers are also offered the
option of joining EPA's WIPP mailing
list. Periodic mailings, including a WIPP
Bulletin and fact sheets related to
specific EPA activities, are sent to
members of the mailing list (currently
numbering over 800). The WIPP internet
homepage, at www.epa.gov/radiation/
wipp, provides general information on
EPA's regulatory oversight of the WIPP.
Federal Register notices are also
announced on the homepage, and a
number of documents (ranging from
outreach materials and hearings
transcripts to technical support
documents) are available to review or
download.
XIV. With What Regulatory and
Administrative Requirements Must
This Rulemaking Comply?
A. Executive Order 12866
Under Executive Order 12866, (58 FR
51735; October 4, 1993), the Agency
must determine whether the regulatory
action is "significant" and therefore
subject to OMB review and the
requirements of the Executive Order.
The Order defines "significant
regulatory action" as one that is likely
to result in a rule that may: (1) have an
annual effect on the economy of $100
million or more or adversely affect in a
material way the economy, a sector of
the economy, productivity, competition,
jobs, the environment, public health or
safety, or State, local, or tribal
governments or communities; (2) create
a serious inconsistency or otherwise
interfere with an action taken or
planned by another agency; (3)
materially alter the budgetary impact of
entitlements, grants, user fees, or loan
programs or the rights and obligations of
recipients thereof; or (4) raise novel
legal or policy issues arising out of legal
mandates, the President's priorities, or
the principles set forth in the Executive
Order. Pursuant to the terms of
Executive Order 12866, it has been
determined that this final rule is a
"significant regulatory action" because
it raises novel policy issues which arise
from legal mandates. As such, this
action was submitted to OMB for
review. Changes made in response to
OMB suggestions or recommendations
are documented in the public record.
B. Regulatory Flexibility
The Regulatory Flexibility Act
("RFA") generally requires an agency to
conduct a regulatory flexibility analysis
of any rule subject to notice and
comment rulemaking requirements
unless the agency certifies that the rule
will not have a significant economic
impact on a substantial number of small
entities. Small entities include small
businesses, small not-for-profit
enterprises, and small governmental
jurisdictions. This final rule will not
have a significant impact on a
substantial number of small entities
because it sets forth requirements which
apply only to Federal agencies.
Therefore, I certify that this action will
not have a significant economic impact
on a substantial number of small
entities.
C. Paperwork Reduction Act
The EPA has determined that this
proposed rule contains no information
collection requirements as defined by
the Paperwork Reduction Act (44 U.S.C.
3501 etseq).
D. Unfunded Mandates Reform Act
Title II of the Unfunded Mandates
Reform Act of 1995 ("UMRA"), Pub. L.
104-4, establishes requirements for
Federal agencies to assess the effects of
their regulatory actions on State, local
and tribal governments and the private
sector. Pursuant to Title II of the UMRA,
EPA has determined that this regulatory
action is not subject to the requirements
of sections 202 and 205, because this
action does not contain any "federal
mandates" for State, local, or tribal
governments or for the private sector.
The rule implements requirements that
are specifically set forth by the Congress
in the Waste Isolation Pilot Plant Land
Withdrawal Act (Pub. L. 102-579) and
that apply only to Federal agencies.
E. Executive Order 12898
Pursuant to Executive Order 12898
(59 FR 7629, February 16, 1994),
entitled "Federal Actions to Address
Environmental Justice in Minority
Populations and Low-Income
Populations," the Agency has
considered environmental justice
related issues with regard to the
potential impacts of this action on the
environmental and health conditions in
low-income, minority, and native
American communities. The EPA has
complied with this mandate. The
requirements specifically set forth by
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the Congress in the Waste Isolation Pilot
Plant Land Withdrawal Act (Pub. L.
102-579), which prescribes EPA's role
at the WIPP, did not provide authority
for EPA to examine impacts in the
communities in which wastes are
produced, stored, and transported, and
Congress did not delegate to EPA the
authority to consider alternative
locations for the WIPP.
The EPA involved minority and low-
income populations early in the
rulemaking process. In 1993 EPA
representatives met with New Mexico
residents and government officials to
identify the key issues that concern
them, the types of information they
wanted from EPA, and the best ways to
communicate with different sectors of
the New Mexico public. The feedback
provided by this group of citizens
formed the basis for EPA's WIPP
communications and consultation plan.
To help citizens, including a significant
Hispanic population in Carlsbad and the
nearby Mescalero Indian Reservation,
stay abreast of EPA's WIPP-related
activities, the Agency developed many
informational products and services.
The EPA translated into Spanish many
documents regarding WIPP, including
educational materials and fact sheets
describing EPA's WIPP oversight role
and the radioactive waste disposal
standards. The EPA also established a
toll-free WIPP Information Line,
recorded in both English and Spanish,
providing the latest information on
upcoming public meetings,
publications, and other WIPP-related
activities. The EPA also developed a
vast mailing list, which includes many
low-income, minority, and native
American groups, to systematically
provide interested parties with copies of
EPA's public information documents
and other materials. Even after the final
rule, EPA will continue its efforts
toward open communication and
outreach.
F. Small Business Regulatory
Enforcement Fairness Act of 1996
The Congressional Review Act, 5
U.S.C. 801 et seq., as added by the Small
Business Regulatory Enforcement
Fairness Act of 1996, generally provides
that before a rule may take effect, the
agency promulgating the rule must
submit a rule report, which includes a
copy of the rule, to each House of the
Congress and to the Comptroller General
of the United States. Section 804,
however, exempts from section 801 the
following types of rules: rules of
particular applicability; rules relating to
agency management or personnel; and
rules of agency organization, procedure,
or practice that do not substantially
affect the right or obligations of non-
agency parties. (5 U.S.C. 804(3)) The
EPA is not required to submit a rule
report regarding today's action under
section 801 because this is a rule of
particular applicability.
G. National Technology Transfer &
Advancement Act of 1995
Section 12 of the National Technology
Transfer & Advancement Act of 1995 is
intended to avoid "re-inventing the
wheel." It aims to reduce the costs to
the private and public sectors by
requiring federal agencies to draw upon
any existing, suitable technical
standards used in commerce or
industry. To comply with the Act, EPA
must consider and use "voluntary
consensus standards," if available and
applicable, when implementing policies
and programs, unless doing so would be
"inconsistent with applicable law or
otherwise impractical." The EPA has
determined that this regulatory action is
not subject to the requirements of
National Technology Transfer &
Advancement Act of 1995 as this
rulemaking is not setting any technical
standards.
H. Executive Order 13045—Children's
Health Protection
This final rule is not subject to E.O.
13045, entitled "Protection of Children
from Environmental Health Risks and
Safety Risks" (62 FR 19885, April 23,
1997), because it does not involve
decisions on environmental health risks
or safety risks that may
disproportionately affect children.
List of Subjects in 40 CFR Part 194
Environmental protection,
Administrative practice and procedure,
Nuclear materials, Radionuclides,
Plutonium, Radiation protection,
Uranium, Transuranics, Waste treatment
and disposal.
Dated: May 13, 1998.
Carol M. Browner,
Administrator.
For the reasons set out in the
preamble, 40 CFR Part 194 is amended
as follows.
PART 194—CRITERIA FOR THE
CERTIFICATION AND RE-
CERTIFICATION OF THE WASTE
ISOLATION PILOT PLANT'S
COMPLIANCE WITH THE 40 CFR PART
191 DISPOSAL REGULATIONS
1. The authority citation for part 194
is revised to read as follows:
Authority: Pub. L. 102-579, 106 Stat. 4777,
as amended by Pub. L. 104-201,110 Stat.
2422; Reorganization Plan No. 3 of 1970, 35
FR 15623, Oct. 6, 1970, 5 U.S.C. app. 1;
Atomic Energy Act of 1954, as amended, 42
U.S.C. 2011-2296 and 10101-10270.
2. In § 194.2, a definition is added in
alphabetical order to read as follows:
§ 194.2 Definitions.
* * * * *
Administrator's authorized
representative means the director in
charge of radiation programs at the
Agency.
3. Section 194.8 is added to subpart
A to read as follows:
§ 194.8 Approval Process for Waste
Shipment from Waste Generator Sites for
Disposal at the WIPP
(a) Quality Assurance Programs at
Waste Generator Sites. The Agency will
determine compliance with
requirements for site-specific quality
assurance programs as set forth below:
(1) Upon submission by the
Department of a site-specific quality
assurance program plan the Agency will
evaluate the plan to determine whether
it establishes the applicable Nuclear
Quality Assurance (NQA) requirements
of § 194.22(a)(l) for the items and
activities of §§ 194.22(a)(2)(i),
194.24(c)(3) and 194.24(c)(5). The
program plan and other documentation
submitted by the Department will be
placed in the dockets described in
§194.67.
(2) The Agency will conduct a quality
assurance audit or an inspection of a
Department quality assurance audit at
the relevant site for the purpose of
verifying proper execution of the site-
specific quality assurance program plan.
The Agency will publish a notice in the
Federal Register announcing a
scheduled inspection or audit. In that or
another notice, the Agency will also
solicit public comment on the quality
assurance program plan and appropriate
Department documentation described in
paragraph (a)(l) of this section. A public
comment period of at least 30 days will
be allowed.
(3) The Agency's written decision
regarding compliance with the requisite
quality assurance requirements at a
waste generator site will be conveyed in
a letter from the Administrator's
authorized representative to the
Department. No such compliance
determination shall be granted until
after the end of the public comment
period described in paragraph (a) (2) of
this section. A copy of the Agency's
compliance determination letter will be
placed in the public dockets in
accordance with § 194.67. The results of
any inspections or audits conducted by
the Agency to evaluate the quality
assurance programs described in
paragraph (a)(l) of this section will also
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be placed in the dockets described in
§194.67.
(4) Subsequent to any positive
determination of compliance as
described in paragraph (a) (3) of this
section, the Agency intends to conduct
inspections, in accordance with
§§ 194.21 and 194.22(e), to confirm the
continued compliance of the programs
approved under paragraphs (a) (2) and
(a) (3) of this section. The results of such
inspections will be made available to
the public through the Agency's public
dockets, as described in § 194.67.
(b) Waste Characterization Programs
at Waste Generator Sites. The Agency
will determine compliance with the
requirements for use of process
knowledge and a system of controls at
waste generator sites as set forth below:
(1) For each waste stream or group of
waste streams at a site, the Department
must:
(i) Provide information on how
process knowledge will be used for
waste characterization of the waste
stream(s) proposed for disposal at the
WIPP; and
(ii) Implement a system of controls at
the site, in accordance with
§ 194.24(c)(4), to confirm that the total
amount of each waste component that
will be emplaced in the disposal system
will not exceed the upper limiting value
or fall below the lower limiting value
described in the introductory text of
paragraph (c) of § 194.24. The
implementation of such a system of
controls shall include a demonstration
that the site has procedures in place for
adding data to the WIPP Waste
Information System ("WWIS"), and that
such information can be transmitted
from that site to the WWIS database;
and a demonstration that measurement
techniques and control methods can be
implemented in accordance with
§ 194.24(c)(4) for the waste stream(s)
proposed for disposal at the WIPP.
(2) The Agency will conduct an audit
or an inspection of a Department audit
for the purpose of evaluating the use of
process knowledge and the
implementation of a system of controls
for each waste stream or group of waste
streams at a waste generator site. The
Agency will announce a scheduled
inspection or audit by the Agency with
a notice in the Federal Register. In that
or another notice, the Agency will also
solicit public comment on the relevant
waste characterization program plans
and Department documentation, which
will be placed in the dockets described
in § 194.67. A public comment period of
at least 30 days will be allowed.
(3) The Agency's written decision
regarding compliance with the
requirements for waste characterization
programs described in paragraph (b)(l)
of this section for one or more waste
streams from a waste generator site will
be conveyed in a letter from the
Administrator's authorized
representative to the Department. No
such compliance determination shall be
granted until after the end of the public
comment period described in paragraph
(b) (2) of this section. A copy of the
Agency's compliance determination
letter will be placed in the public
dockets in accordance with § 194.67.
The results of any inspections or audits
conducted by the Agency to evaluate the
plans described in paragraph (b)(l) of
this section will also be placed in the
dockets described in § 194.67.
(4) Subsequent to any positive
determination of compliance as
described in paragraph (b) (3) of this
section, the Agency intends to conduct
inspections, in accordance with
§§ 194.21 and 194.24(h), to confirm the
continued compliance of the programs
approved under paragraphs (b) (2) and
(b) (3) of this section. The results of such
inspections will be made available to
the public through the Agency's public
dockets, as described in § 194.67.
4. Appendix A to Part 194 is added
to read as follows:
Appendix A to Part 194—Certification
of the Waste Isolation Pilot Plant's
Compliance With the 40 CFR Part 191
Disposal Regulations and the 40 CFR
Part 194 Compliance Criteria
In accordance with the provisions of the
WIPP Compliance Criteria of this part, the
Agency finds that the Waste Isolation Pilot
Plant ("WIPP") will comply with the
radioactive waste disposal regulations at part
191, subparts B and C, of this chapter.
Therefore, pursuant to Section 8(d)(2) of the
WIPP Land Withdrawal Act ("WIPP LWA"),
as amended, the Administrator certifies that
the WIPP facility will comply with the
disposal regulations. In accordance with the
Agency's authority under § 194.4(a), the
certification of compliance is subject to the
following conditions:
Condition 1: § 194.14 (b), Disposal system
design, panel closure system. The
Department shall implement the panel seal
design designated as Option D in Docket A-
93-02, Item II-G-1 (October 29, 1996,
Compliance Certification Application
submitted to the Agency). The Option D
design shall be implemented as described in
Appendix PCS of Docket A-93-02, Item II-
G-1, with the exception that the Department
shall use Salado mass concrete (consistent
with that proposed for the shaft seal system,
and as described in Appendix SEAL of
Docket A-93-02, Item II-G-1) instead of
fresh water concrete.
Condition 2: §194.22: Quality Assurance.
The Secretary shall not allow any waste
generator site other than the Los Alamos
National Laboratory to ship waste for
disposal at the WIPP until the Agency
determines that the site has established and
executed a quality assurance program, in
accordance with §§ 194.22(a)(2)(i),
194.24(c)(3) and 194.24(c)(5) for waste
characterization activities and assumptions.
The Agency will determine compliance of
site-specific quality assurance programs at
waste generator sites using the process set
forth in §194.8.
Condition 3: § 194.24: Waste
Characterization. The Secretary may allow
shipment for disposal at the WIPP of legacy
debris waste at the Los Alamos National
Laboratory ("LANL") that can be
characterized using the systems and
processes inspected by the Agency and
documented in Docket A-93-02, Item II—I—
70. The Secretary shall not allow shipment
of any waste from any additional LANL
waste stream (s) or from any waste generator
site other than LANL for disposal at the WIPP
until the Agency has approved the processes
for characterizing those waste streams for
shipment using the process set forth in
§194.8.
Condition 4: § 194.43, Passive institutional
controls.
(a) Not later than the final recertification
application submitted prior to closure of the
disposal system, the Department shall
provide, to the Administrator or the
Administrator's authorized representative:
(1) a schedule for implementing passive
institutional controls that has been revised to
show that markers will be fabricated and
emplaced, and other measures will be
implemented, as soon as possible following
closure of the WIPP. Such schedule should
describe how testing of any aspect of the
conceptual design will be completed prior to
or soon after closure, and what changes to the
design of passive institutional controls may
be expected to result from such testing.
(2) documentation showing that the granite
pieces for the proposed monuments and
information rooms described in Docket A-
93-02, Item II-G-1, and supplementary
information may be: quarried (cut and
removed from the ground) without cracking
due to tensile stresses from handling or
isostatic rebound; engraved on the scale
required by the design; transported to the
site, given the weight and dimensions of the
granite pieces and the capacity of existing
rail cars and rail lines; loaded, unloaded, and
erected without cracking based on the
capacity of available equipment; and
successfully joined.
(3) documentation showing that archives
and record centers will accept the documents
identified and will maintain them in the
manner identified in Docket A-93-02, Item
II-G-1.
(4) documentation showing that proposed
recipients of WIPP information other than
archives and record centers will accept the
information and make use of it in the manner
indicated by the Department in Docket A—
93-02, Item II-G-1 and supplementary
information.
(b) Upon receipt of the information
required under paragraph (a) of this
condition, the Agency will place such
documentation in the public dockets
identified in § 194.67. The Agency will
determine if a modification to the
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compliance certification in effect is
necessary. Any such modification will be
conducted in accordance with the
requirements at §§ 194.65 and 194.66.
[FR Doc. 98-13100 Filed 5-15-98; 8:45 am]
BILLING CODE 6560-50-P
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