United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R10-92/046
September 1992
&EPA Superfund
Record of Decision:
US DOE Idaho National
Engineering Lab (Operable
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NOTICE.
The appendices listed in the index that are not foulid in. this document have been removed at the request of .
the issuing agency. They contain matenaJ which supplement. but adds no further applk:abie information to
the content of the document. All supplemental material is, however, con1Bined in the administrative record
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REPORT DOCUMENTATION 11. REPORTNO.. 2. 3. Recipients Acceaaion No.
PAGE EPA/ROD/R10-92/046
4. Title and Subtille SUPERFUND RECORD OF DECISION 5. Report Date
US DOE Idaho National Engineering Laboratory 09/30/92
(Operable Unit 22), ID 6.
. " , Zl.rot- ; nn - "'..'- rn -rn'1nM
7. Author(a) 8. Perfonning Organization Rept. No.
9. Perfonning Orgainization Name and Adelle88 10. ProjectlTaaklWork Unit No.
11. Contract(C) or Grant(G) No.
(C)
(G)
12. Sponsoring Organization Name and Addre88 13. Type of Report & Period Covered
U.S. Environmental Protection Agency 800/000
401 M Street, S.W.
Washington, D.C. 20460 14.
1 S. SUpplementary Notea
PB93-964616
16. Abslract (Umit: 200 words)
The 890-square mile Idaho National Engineering Laboratory (INEL), located 32 miles west
of Idaho Falls, Idaho, is operated by the U.S. Department of Energy. Land use in the
area is predominantly industrial and mixed use. The site overlies a sole source Class
I aquifer, known as the Snake River Plain Aquifer. Within INEL, an area known as the
Power Burst Facility (PBF) operated from 1972 to 1985 and supported the testing of
pressurized-water fuel rods under hypothetical reactor accidents. This area contained
several site features, including a corrosive waste sump, an evaporation pond, and
discharge pipe. From 1978 to 1984, water containing a chromium-based algal and
corrosion inhibitor from the PBF reactor's secondary coolant system was discharged from
the corrosive waste sump (CWS) via a discharge pipe to an evaporation pond. To prevent
discharge of toxic hexavalent chromium to the sump, cooling water was treated in the
discharge pipe by bubbling sulfur dioxide through it to reduce the hexavalent chromium
to less toxic trivalent chromium, and the treated water was discharged to the sump and
neutralized using sodium hydroxide or sulfuric acid. As a result of these activities,
approximately 363 cubic yards of sediment in the evaporation pond have been
(See Attached Page)
17. Document Analysis L Descriptors
Record of Decision - US DOE Idaho National Engineering Laboratory (Operable Unit 22), ID
Fourth Remedial Action - Subsequent to follow
Contaminated Media: sediment, sludge, debris
Key Contaminants: metals (chromium), radioactive materials
b. klentifieralOpen-Ended Terms
c. COSA 11 FieIdIGroup
18. Avlilabitity Statement 19. Security Cla88 (Thia Report) 21. No. of Pages
None 34
20. Secl8i1y Claaa (Thia Page) 22. Price
None
SI- 2n(4-77)
50272-101
(See AN Z39.18)
See Instructions on Reverae
(Formetty NTl5-35)
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EPA/ROD/R10-92/046
us DOE Idaho National Engineering Laboratory
(Operable Unit 22), ID
Fourth Remedial Action - Subsequent to follow
Abstract (Continued)
contaminated by metals and radioactive materials. In 1987, the pond and sump were listed
as RCRA land disposal units; however, wastewater exhibiting the toxicity characteristic
(TC) for chromium is believed to have been discharged after the effective date of the TC
rule. The INEL site is currently divided into 10 Waste Area Groups (WAGs). Three
previous RODs signed in 1991 and 1992 addressed interim remedies for the warm waste pond
sediment in WAG 2, unexploded ordnance and contaminated soil in WAG 10, and ground water
contamination from the TS~05 injection well in WAG 1, respectively. This ROD provides an
interim remedy for the contaminated sediment and sludge in the evaporation pond,
discharge pipe, and waste sump as OU22 in WAG 5. A future ROD will address the
underlying aquifer and unsaturated zone. The primary contaminants of concern affecting
the sediment, debris, and sludge are metals, including chromium; and radioactive
naterials.
~he selected interim remedial action for this site includes removing and
solidifying/stabilizing the 100 cubic yards of contaminated sediment from the evaporation
pond by grouting, followed by onsite disposal in the Radioactive Waste Management Complex
(RWMC) at INEL along with existing low-level waste containers; removing sludge and
sediment from the waste sump; treating the sludge by grouting, if feasible, based on the
results of treatability studies, and disposing of the treated sludge onsite in RWMC;
decontaminating the discharge pipe; and sampling the remaining sediment to verify
residual contaminant concentrations. The estimated total cost for this remedial action
is $480,000. No O&M costs were provided for this remedial action.
PERFORMANCE STANDARDS OR GOALS:
Sediment
scenario
future.
and sludge excavation goals are based on a site-specific residential use
for a population that begins residence at the site within 100 years in the
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. .'" .-'.. - ""~" .'
Power Burst Facility Corrosive Waste Sump
and Evaporation Pond
Operable Unit 5-13
Waste Area Group 5
Idaho National Engineering Laboratory
Idaho Falls, Idaho
'.,. '., -... .:.., -, "; :."." . '.' ~.~. .".
.' . . ~ '. ' . - .: :",. .'
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DECLARATION OF. TIlE RECORD OF DECISION
Site Name and Location
Power Burst Facility Corrosive Waste Sump and Evaporation Pond
Operable Unit 5-13
Waste Area Group 5
Idaho National Engineering Laboratory
Idaho Falls, Idaho
Statement or Basis and Purpose
This decision document presents the selected interim remedial action for the Power Burst
Facility (pBF) Evaporation Pond, Corrosive Waste Sump, and discharge pipe at the Idaho National
Engineering Laboratory (INEL), Operable Unit (OU) 5-13. luis alternative was chosen in
accordance with the Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA) as amended by the Superfund Amendments and Reauthorization Act, and to the extent
practicable the National Oil and Hazardous Substances Pollution Contingency Plan. This decision is
based on information in the Administrative Record for the site, which is located in the INEL
Technical Library, 1776 Science Center Drive, Idaho Falls, Idaho.
The lead agency in this decision is the U.S. Department of Energy. The U.S. Environmental
Protection Agency approves of this decision and, along with the Idaho Department of Health and
Welfare (IDHW),has participated in the evaluation of the interim action alternatives. The IDHW
concurs with the selected remedy.
Assessment or the Site
Actual or threatened releases of hazardous substances from this site, if not addressed by
implementing the response action selected in this Record of Decision (ROD), may present an
imminent and substantial endangerment to human health and welfare or the environment due to the
presence of chromium in the Evaporation Pond sediments.
Description or the Selected Remedy
This ROD for OU 5-13 addresses the contamination of the sediments of the Evaporation Pond
and the sludge and sediment contained within the Corrosive Waste Sump and discharge pipe at the
PBF. This interim remedial action involves:
.
The removal of the identified areas of high contaminant concentration in the Evaporation
Pond
.
Stabilization of contaminated material from the pond by grouting and disposal at the
Radioactive Waste Management Complex (RWMC) at the INEL
.
Removal of the sludge and sediment present within the Corrosive Waste Sump
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.
Treatment of materials and sediments removed from the sump by grouting, if feasible
based on treatability studies, and disposal at the RWMC.
Removing the areaS of high contaminant concentration reduces the potential risk to human
health by reducing the potential for exposure to chromium by inhalation and cesium-137 by direct
ionizing radiation. Cleanup levels which have been determined to be protective of human health for
this remedial action are 800 mglkg for total chromium and 30 pCi/g for cesium-137. Cesium-137
does not present an unacceptable risk, but will be used as an indicator for chromium during the
interim action. All contaminant concentrations above these levels will be removed from the pond.
Declaration
This interim action is protective of human health and the enviroIlt-nent. It complies with
federal and state appliC3ble or relevant and appropriate requirements directly associated with this
interim action and is cost-effective. This interim action is not intended to fully address the statutory
mandate for permanence and treatment to the maximum extent pract.icable. 1t does, however, use
treatment, and is in furtherance of that mandate by utilizing permanent solutions and alternative
treatment technology to the maximum extent practicable given the limited scope of this action. As
mandated by CERCLA, a review will be conducted within 5 yrs to assess the risk remaining at the
site.
Because this action may not constitute the final remedy for the Evaporation Pond, Corrosive
Waste Sump, and discharge pipe, the statutory preference for remedies that employ treatment that
reduces toxicity, mobility, or volume as the principal element will be addressed at the time of the
final response action. Subsequent actions may be necessary to fully address the principal threats
posed by the site. Because the interim remedy will result in some contaminants remaining onsite, the
effectiveness of the interim action as a final action will be evaluated in the Waste Area Group 5
Comprehensive Remedial InvestigationIFeasibility Study (OU 5-12), scheduled to begin in 1996.
\
"":'~:"I
IV
"'.""'-...<"" -"
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Signature sheet for the foregoing Record of Decision for Operable Unit 5-13 interim action at the
Idaho National Engineering Laboratory between the United States Department of Energy and the
United States Environmental Protection Agency, with concurrence by the Idaho Department of Health
and Welfare. The Operable Unit 5-13 interim action consists of cleanup of the Power Burst Facility
Evaporation Pond, Corrosive Waste Sump, and discharge pipe at the Idaho National Engineering
Laboratory .
~~
Augustme - Pltrolo
Manager
Department of Energy Idaho Field Office
r~wc
Date
-------
Signarure sheet for the foregoing Record of Decision for Operable Unit 5-13 interim action at the
Idaho National Engineering Laboratory between the United States Department of Energy and the
United States Environmental Protection Agency, with concurrence by the Idaho Department of Health
and Welfare. The Operable Unit 5-13 interim action consists of cleanup of the Power Burst Facility
Evaporation Pond, Corrosive Waste Sump, and discharge pipe at the Idaho National Engineering
Laboratory .
~~
Dana Rasmussen
Regional Administrator, Region 10
Environmental Protection Agency
113019~
Date
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Signature sheet for the foregoing Record of Decision for Operable Unit 5-13 interim action at the
Idaho National Engineering Laboratory between the United States Deparunent of Energy and the
United States Environmental Protection Agency, with concurrence by the Idaho Department of Health
and Welfare. The Operable Unit 5-13 interim action consists of cleanup of the Power Burst Facility
Evaporation Pond, Corrosive Waste Sump, and discharge pipe at the Idaho National Engineering
Laboratory .
~Pi2~A
Richard Donovan. ,.,.
Director
Idaho Department of Health and Welfare
9/30/C;z
Date I ,
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CONTENTS
DECLARATION OF THE RECORD OF DECISION. . . . . . . . . . . . . . . . . . . . . . . . . . .. iii
ACRONYMS
. . .. .. .. ... .. .. .. .. .. ... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. : . .. .. ... .. .. .. .. .. .. .. .. .. ... ... .. .. .. .. .. .. ..
Xll
DECISION SUMMARY
1. SITE NAME, LOCATION AND DESCRIPTION. . . . . . . . . . . . . . . . . . . . . .. I
2. SITE HISTORY AND ENFORCEMENT ACTIVITiES. . . . . . . . . . . . . . . . . . .. 1
3. HIGHLIGHTS OF COMMUNITY PARTICIPATION. . . . . . . . . . . . . . . . . . . .. 5
4. SCOPE AND ROLE OF OPERABLE UNIT AND RESPONSE ACTION. . . . . . . .. 6
5. SUMMARY OF SITE CHARACTERISTICS. . . . . . . . . . . . . . . . . . . . . . . . ., 7
6. SUMMARY OF SITE RISKS. . . . . . . . . . . . . . . . . . . .. ~ . . . . . . . . . . . . .. 7
7. DESCRIPTION OF AL TERNA TIYES ............................. II
8. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES. . . . . . . . .. 12
9. SELECTED REMEDY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 17
10. STATUTORY DETERMINATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 19
11. DOCUMENTATION OF SIGNIFICANT CHANGES. . . . . . . . . . . . . . . . . . .. 21
APPENDIX A - RESPONSIVENESS SUMMARY. . . . . . . . ; . . . . . . . . . . . . . . . . . . . A-I
APPENDIX B - PUBLIC COMMENTIRESPONSE LIST INDEX. . . . . . . ~ . . . . . . . . . . . B-1
APPENDIX C -- ADMINISTRATIVE RECORD INDEX. . . . . . . . . . . . . . . . . . . . . . . . . C-l
FIGURES
1. Location of INEL and PBF facilities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ., 2
2. Map of the PBF area showing au 5-13: the PBF Corrosive Waste Sump (PBF-8) and Evaporation
Pond (PBF-IO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3
3. Sample locations and contaminant concentrations collected during the 1989 sampling effort at the
PBF Evaporati.on Pond. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9
4. spatial relationship of total chromium t() cesium-137 in the PBF Evaporation Pond using.og
transformed data from Table I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 13
TABLES
1. Cesium-137 and chromium concentrations found in PBF Evaporation Pond samples. . . . . .. 10
2. Summary of risk from preliminary risk assessment for the PBF Evaporation Pond. . . . . . .. 12
3. Cost Estimation for the Alternatives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 18
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ARARs
ACRONYMS
appl icable or relevant and appropriate requirements
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
CFR Code of Federal Regulations
COCA Consent Order and Compliance Agreement
DOE
EPA
FF.I\/CO
FR
HWMA
IDHW
INEL
u .S. Department of Energy
U .S. Environmental Protection Agency
Federal Facility Agreement and Consent Order
Federal Register
Hazardous Waste Management Act - State of Idaho
Idaho Department of Health and Welfare
Idaho National Engineering Laboratory
NCP National Oil and Hazardous Substances Pollution Contingency Plan
NESHAP National Emission Standards for Hazardous Air Pollutants
NPL National Priorities List
OU
PBF
pCi/g
RCRA
RIfFS
ROD
RWMC
SARA
TRA
WAG
Operable Unit
Power Burst Facility
picocuries per gram
Resource Conservation and Recovery Act
Remedial InvestigationlFeasibility Study
Record of Decision
Radioactive Waste Management Complex
Superfund Amendments and Reauthorization Act
Test Reactor Area
Waste Area Group
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DECISION SlTh'lMARY
1. SITE NAME, WCATION, AND DESCRIPTION
The Idaho National Engineering Laboratory (INEL) is located in southeastern Idaho on the
northeast portion of the Eastern Snake River Plain and encompasses approximately 890 square miles
of desert. The closest major community is Idaho Falls (population 46,(00), located 42 miles
southeast of the lNEL. The Power Burst Facility (pBF) is located in the south-central portion of the
INEL (Figure 1). This Record of Decision (ROD) documents the interim action decision for the PBF
Evaporation Pond, Corrosive Waste Sump, and discharge pipe [Operable Unit (OU) 5-13], which are
located within the PBF area, east. of the Reactor Building (pBF-620) (Figure 2).
The PBF Corrosive Waste Sump is an unlined concrete structure that was used during the
neutralization of spent reactor secondary coolant water prior to discharge to the Evaporation Pond.
The Corrosive Waste Sump dimensions are 11 x 11 x 21 ft deep. The sump walls are 12 in. thick,
and the floor is 15 in. thick. The discharge pipe (approximately 6 in. in diameter) that leads from the
Corrosive Waste Sump to the Evaporation Pond may also be contaminated.
The PBF Evaporation Pond is a 140- x 140-ft lined surface impoundment enclosed by a 6-ft
high cyclone fence. The pond is used to receive reactor secondary cooling water from the PBF
reactor following neutralization in the Corrosive Waste Sump. The Evaporation Pond was
constructed in 1978 by borrowing native soil from a source located east of the pond. This material
was used to form a 4.5-ft high. berm containing a Hypalon liner, which was covered by 6 in. of
sediments for protection.
2. SITE msroRY AND ENFORCEMENT ACTIVITIES
The PBF reactor, which operated from 1972 to 1985, was built to support the Thermal Fuel
Behavior Program's testing of pressurized-water reactor fuel rods under hypothetical reactor
accidents. The discharge from the regeneration of the demineralizers and secondary coolant system
waste was released to the Corrosive Waste Injection Well (OU 5-08) from 1972 to 1978. From 1978
to 1984, water containing a chromium-based algal and corrosion inhibitor from the PBF reactor's
secondary coolant system was discharged into the Evaporation Pond via the Corrosive Waste Sump,
along with discharges associated with the regeneration of demineralizers. In 1984, a phosphate-based
corrosion inhibitor replaced the chromium-based inhibitor, thereby eliminating further discharge of
chromium. .
The Corrosive Waste Sump and discharge piping from the Waste Sump to the Evaporation
Pond are part of a system whose prime function was to transfer secondary coolant water from the
PBF secondary coolant system to the Evaporation Pond. The secondary coolant system was drained 2
to 4 times per yr when the.reactor was operational. To prevent discharge of toxic hexavalent
chromium to the Corrosive Waste Sump, the secondary coolant water was treated by bubbling sulfur
dioxide through it to. reduce the hexavalent chromium to less toxic trivalent chromium. The coolant
was discharged to the Corrosive Waste Sump, where the liquid was neutralized using sodium
hydroxide or sulfuric acid. The pH of the sump effluent was monitored for only a short period in late
1984 and was normally between 6.5 and 7.0. Because the process did not change, these results are
assumed to be representative of all effluent discharged through the sump.
The Corrosive Waste Sump also received water from the demineralizer system. The
demineral izer system contains ion exchange resin col urnns that were used for purifying primary and
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Figure L Location of the INEL and PBF facilities.
2
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secondary reactor cool ing water and for treatment of wastewater. After the majority of the exchange
capacity is used, the resin, which is in the form of beads, is regenerated.
During regeneration of the resin columns, backflushing operations allowed some resin beads
to flow to the Corrosive Waste Sump and then to the Evaporation Pond. Because ion exchange resin
beads selectively bind to meuI ions such as chromium and cesium-137, the highest concentrations of
chromium and cesium-137 would most likely occur in areas of the pond where the resin beads.
accumulate. Results from sampling done in 1989 support the concept that chromium and cesium-137
are associated as mentioned above.
As a result of the evaporation of secondary coolant water discharged to the pond, chromium
and cesium-137 contamination is found in the 9,800 cubic feet (363 cubic yards) of sediments located
on top of the Hypalon liner. The lNEL's waste management records indicate, on the average: a touI
of 33 Ib/yr trivalent chromium was discharged to the Evaporation Pond. There is no leak detection
system under the liner, and no samples have been collected from beneath the liner to determine if
ieakage and subsequent conumillation of the sediment:; ben~t.1t the Hner have occurred. However,
the pond does retain water, which has been introduced to control the emission of particulate material.
The PBF Evaporation Pond sediments have been sampled several times. In 1988, six
random grab samples were collected from the Evaporation Pond. Chemical analyses were performed
to quantify the types and concentrations of meuIs, volatile organics, semi-volatiles, pesticides, and
polychlorinated biphenyls present. In September 1989, six biased grab samples were collected from
the Evaporation Pond and analyzed for the presence of gamma-emitting radionuclides. A combination
of biased and systematic random samples (a touI of 20 samples) were collected to characterize the
pond and sump contents in November of 1989... The laboratory data from these sampling efforts and
the pr~liminary risk evaluation based on those data, provide the basis for this interim action.
The release of radioactive or hazardous contaminants to the Evaporation Pond was identified
and evaluated during investigations conducted in accordance with the Resource Conservation and
Recovery Act (RCRA) Corrective Action Requirements of the July 1987 Consent Order and .
Compliance Agreement (COCA) signed by the U.S. EnvironmenuI Protection Agency (EPA), U.S.
Department of Energy (DOE), and U.S. G~logical Survey. The sump and pond were listed as
COCA units PBF-Q8 and PBF-lO, respectively, in that agreement.
Under the COCA, the pond and sump were listed as RCRA Land Disposal Units because
there was information indicating wastewater exhibiting the toxicity characteristics for chromium was
discharged to the pond after the effective date of the relevant RCRA regulations. These units have
since been incorporated into the Federal Facility Agreement and Consent Order (FF A/CO) and are
being addressed under the CERCLA process. The 1989 EP Toxicity tests show Evaporation Pond
sediments do not exhibit the toxicity characteristic for chromium, and therefore are not RCRA
hazardous. The material in the Corrosive Waste Sump has not been subjected to toxicity
characteristic leach test. However, much lower concentrations of cOntaminants were detected in the
waste sump. These low concentrations in a medium consisting mostly of resin heads, which
aggressively binds chromium and other metal ions, indicates that the sump materials are not RCRA
hazardous waste. Consistent with the FFA/CO Action Plan, Section 1.3.1, the final action for this
OU will meet the applicable substantive requirements of RCRA/Hazardous Waste Management Act -
State of Idaho (HWMA) in the event an unacceptable risk to human health and the environment is
demonstrated .
The INEL was proposed for listing on the National Priorities List (NPL) in the Federal
Register (FR) on July 14, 1989 (54 FR 29820). The listing was proposed by the EPA under the
authority of the Comprehensive Environmental Response, Compensation, and Liabil ity Act of 1980
4
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(CERCLA) as amended by the Superfund Amendments and Reauthorization Act of 1986 (SARA).
The final rule, which listed the INEL on the NPL, was published on November 21, 1989, in
54 FR 44184.
In December 1991, the EPA, DOE, and Idaho Department of Health and Welfare (IDHW)
signed the FF A/CO that superseded the COCA. This agreement provides the process and schedule to
facilitate cleanup of the areas identified in the FFA/CO Action Plan, in accordance with CERCLA,
RCRA, and HWMA.
The FFA/CO lists OU 5-13 as an interim action requiring investigation and/or remediation.
This ROD documents the decision to perform an interim action on OU 5-13 and the remedy selected.
The OU 5-13 interim action will be evaluated for adequacy as a final remedial action in the Waste
Area Group (WAG) 5 Comprehensive Remedial Investigation/Feasibility Study (RIIFS), which is
scheduled to begin in 1996.
3. IllGHLIGIITS OF COMMUNITY PARTICIPATION
In accordance with CERCLA, sections 1 1 3 (k:)(2)(B)(i-v) and 117, the public was given the
opportunity to participate in the remedy selection process. In accordance with CERCLA, section
113(k)(1), an Administrative Record was established to provide the basis for the selection of the
remedial action. The Notice of Availability for the Proposed Plan was published in the Post Register
(Idaho Falls), Idaho Stale Journ.aI (pocatello), and Tunes News ([win Falls) on April 3, 1992; in the
Idaho Statesman (Boise) and Daily News (Moscow) on March 21; and in the South Idaho Press
(Burley) on March 27 and April 3. .
Public jnvolv~1DeDt opportunities for Lie PBF au 5-13 Interim Action were. annout1c~ via the
lNEL News newsletter, which is distributed to approxiInately 14,000 members of the general public.
Newspaper and radio advertisements and an INEL press release were utilized to inform the public of
this proposed action. Personal phone calls were made to key individuals, environmental groups, and
organizations by the lNEL outreach offices in Pocatello, Twin Falls, and Boise and by the
Community Re!ations office in Idaho Falls. The Proposed Plan for the interim action for the PBF
Evaporation Pond and the PBF Corrosive Waste Sump was mailed to the public on March 19, 1992.
The Proposed Plan was mailed to approximately 6,500 individuals on the INEL mailing list with a
cover letter from the Director of the Environmental Restoration Division of the DOE, Field Office
Idaho, urging citizens to comment on the Proposed Plan and to attend public meetings. Copies of the
Proposed Plan and the Administrative Record are available to the public in six regional lNEL
information repositories: the INEL Technical Library in Idaho Falls; and city libraries in Idaho Falls,
Pocatello, Twin Falls, and Boise; and the University of Idaho Library in Moscow. The city library in
Moscow originally received the material, but the material has since been moved to the University of
Idaho Library. Copies of the Administrative Record file for the PBF Evaporation Pond and
Corrosive Waste Sump Interim Action were placed in the information repositories sections or at the
reference desk in each of the libraries on March 19, 1992.
The public comment period was initially scheduled from March 25 to April 24, 1992. Two
public meetings were held on April 8 and 9, 1992, in Idaho Falls and Burley, respectively.
Representatives from the DOE, IDHW, and EG&G Idaho, were present to discuss the Proposed Plan.
answer questions, and receive public comment. The EP A was available via teleconference to assist in
answering questions and receiving comments. Verbatim transcripts were prepared by a court reporter
at each public meeting. Written comment forms were also available at each meeting. A telephone
technical briefing was held for the League of Women Voters and other citizens of Moscow on
May 7, 1992, at the University of Idaho Education Building.
5
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During the initial comment period a written request was received for an extension, and the
public comment period was extended an additional 30 days, to May 24. The reason for the requested
extension was the delay in some of the public receiving the Proposed Plan due to mailing problems.
The extension announcement was made in the Post Register on April 24, the Idaho State Journal on
April 26, the Tunes News on April 26, the Idaho StaIesman on April 27, the Daily News on Aprir 24,
the SOUlh Idaho Press on April 24, and the Morning Tribune (Lewiston) on April 26.
All verbal comments given at the public meetings and all submitted written comments are
recorded verbatim in the Administrative Record for the ROD. Responses to the public Comments
received during the public comment period are included in the Responsiveness Summary
(Appendix A) and were considered during the development of this ROD. Public comments on the
Proposed Plan are annotated to indicate which response in the Responsiveness Summary addresses
each comment. Tne information used as L.'1e basis of the decision for this interim action is included in
the Administrative Record.
Predominant public opinions on the preferred alternative, as described in the Proposed Plan,
are that any potentially contaminated sediments beneath the pond should be removed, in addition to
removal of all the sediments within the pond and the liner itself. Others who believe the risk to
human health and the environment is minimal, suggested the "No Action" alternative should be
implemented.
4. SCOPE AND ROLE OF OPERABLE UNIT AND RESPONSE ACTION
To better manage the investigations needed to determine appropriate remedial actions, the
INEL has been divided into 10 WAGs. Within each WAG, known or s'Jspected are.as of
. contamination are assigned to an OU as a means of managing and controlling investigation and
cleanup activity. This strategy allows the EPA, IDHW, and DOE to focus available cleanup
resources on those areas that could potentially pose a risk to human health and the environment.
WAG 5 consists of the PBF and the Auxiliary Reactor Area. The PBF Evaporation Pond sediments,
Corrosive Waste Sump, and connecting discharge pipe are identified as OU 5-13. The underlying
aquifer and unsaturated zone are not included in this OU but will be addressed in a subsequent
investigation.
Existing characterization data were available to identify OU 5-13 as a risk to human health
and the environment due to the presence of chromium and to support selection of a remedial -
technology. This interim action is intended to reduce immediate unacceptable risks associated with
the Evaporation Pond sediments and to remove and dispose of the contaminants contained in the
Corrosive Waste Sump to expedite overall INEL cleanup. On the basis of the characterization data
available in the Administrative Record for the sediments of the PBF Evaporation Pond, an immediate
unacceptable risk to human health has been identified due to potential receptor inhalation of
chromium. No exposure pathway exists that poses an unacceptable risk to human health and the
environment from contaminants contained within the Corrosive Waste Sump and discharge pipe.
However, the pipe and sump are being cleaned up under this action to eliminate a potential future
source of contamination to the pond sediments. The interim action will not be inconsistent with any
known future CERCLA actions.
As mandated by CERCLA, a review will be conducted within 5 yrs to reassess potential risk
from this OU. This review will only consider the effectiveness of the protective measures employed,
by an evaluation of actions and verification data to date. The interim action will be evaluated for
adequacy as a final remedial action as part of the WAG 5 Comprehensive RIfFS (OU 5-12),
scheduled to begin in 1996.
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5. SUMMARY OF SITE CHARACTERISTICS
To more definitively characterize materials contained within the PBF Evaporation Pond and
Corrosive Waste Sump, biased and random sediment samples were collected in 1989 and documented
in the Qosure Plan for the Power Burst Facility Corrosive Waste Sump and the Power Burst Facility
EvaporaJion Pond (COCA units PBF-08 and PBF-IO), EGG-WM-8996, May 1990. The regulatory
status was changed from RCRA to CERCLA in 1991 by the signing of the FFA/CO. Data from
samples collected in 1989 were used to support CERCLA site characterization. Analyses for the
presence of gamma-emitting radio nuclides and metals were performed on the samples collected from
the Evaporation Pond sediments (fable 1). Chromium (total) and cesium-137 were the contaminants
of concern identified in the toxicity screen performed on the Evaporation Pond sediments. Average
total chromium concentration of the random samples in the PBF Pond is 500 mglkg, with the
maximum concentration (3,439 mglkg) of total chromium occurring in a biased sample located near
the pond inlet. Because hexavalent chromium was chemically reduced prior to discharge, all the .
chromium in the sump and pond is assumed to be trivalent chromium. The highest concentration of
cesium-137 (325pCi/g) was from a biased sample near the pond inlet, with an average of 20.3 pCi/g
from all random samples collected throughout the pond. Figure 3 is a diagram of the PBF
Evaporation Pond, indicating sample locations and contaminant concentrations.
In addition to sampling the waste disposal areas, undisturbed areas upwind of the Corrosive
Waste Sump and the Evaporation Pond were sampled to characterize background metal levels. The
purpose of the background samples was to have a point of comparison for the samples collected in the
pond. Background samples indicated the surrounding soils have a mean total chromium concentration
of 21 mglkg, which is attributable to natural occurring chromium. These background samples were
well within the range of background chromium concentrations reported at other locations on the
JNEL. .
The results of the PBF Corrosive Waste Sump sampling indicated the presence of low-level
radioactivity (6.97 to 7.86 pCi/g of cesium-137). In addition, compounds found only in the sump
were the volatile organic compounds 4-methyl-2-pentanone (150.0 to 170.0 J.i.glkg), ethylbenzene (5.0
to 16.0 ILglkg), and xylene (32.0 to 100.0 ILglkg).
6. SUMMARY OF SITE RISKS
6.1 Human Health Risk
A preliminary risk evaluation was performed in accordance with EP A guidance to determine
the risks to human health posed by contaminants identified in the Evaporation Pond sediments, and is
.available in the Administrative Record. The contaminants identified in the sump (a closed concrete
vault) were not considered for this preliminary evaluation because it is unlikely these contaminants
have a pathway to receptors (since the contaminants are contained) and because of the small volume
of waste material in the sump. However, the sump and discharge pipe materials are to be removed to
eliminate future contamination of the pond sediments.
In the preliminary risk evaluation, the potential for carcinogenic and noncarcinogenic tox.ic
effects was computed using EPA default parameters and methods found in the Risk Assessment
Guidance for Superfund, Volume I, "Human Health Evaluation Manual." The default model
parameters may be more conservative than site-specific parameters but are routinely applied.
.,
-------
Occupational and future residential scenarios were examined to assess the risks to humans
from exposure to the contaminants in the Evaporation Pond sediments. The pathways by which
workers or future residents could be potentially exposed to the contaminants within the pond were
identified as inhalation, ingestion, direct contact, and direct radiation. The risks from the
groundwater pathway were not included in this risk evaluation because OU 5-13 is confined to the
sediments overlying the Hypalon liner. The aquifer and unsaturated zone in this area will be
evaluated in another investigation within WAG 5.
Of the four exposure pathways identified, inhalation of fugitive dust and direct exposure to
. ionizing radiation were the greatest contributors to risk. The inhalation pathway of chromium
presented an excessive hazard quotient, and direct exposure to ionizing radiation contributed to an
excess in the incidence of cancer. For both of these pathways, future residential risk was the highest.
The future residential use scenario is based on an individual beginning future rt:Sidence at the pond
site 100 yrs in the future. One hundreds yes was agreed to by the three agencies involved for use in
evaluating future residential scenarios.
For present day workers (occupational) and future residents, the risk due to the inhalation of
existing levels of chrornium-contaminated dust were both calculated and found to exceed the EPA
hazard quotient of 1 (Table 2). This result implies sensitive sub-populations may exhibit adverse
health effects due to their exposure to fugitive dust emissions from the pond.
Additionally, exposure to direct ionizing radiation, due to the presence of cesium-137, was
found to be within the acceptable risk range defined in the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP) as lQ-4 to 1~ for occupational and residential populations. The
calculated value for present day workers is 8 additional cancer incidences in 100,000 exposed
workers, and for future residents the calculated value for excess cancer incidences is 4 additional
incidences of cancer per 10,000 exposed individuals residing near the pond 100 yrs in th~ future.
The NCP, 40 CFR 300.430, eSt2blishes the point of departUre for determining remedial goals as 1 in
1,000,000 (10~) for carcinogeriS. For cesium-137, a 1~ risk corresponds to a concentration of
0.66 pCi/g. .:
\(
Cleanup goals for the PBF Evaporation Pond sediments are based on a site-specific residential
use scenario for a population that begins residence at the site 100 yrs in the future. This scenario
results in the calculation of a conservative cleanup level protective of current occupational and future
residential populations at the PBF. The cleanup goal for chromium is 800 mg/kg. This level was
established using equations from'-the Risk Assessment Guidance for Superfund, Part A (EP A 1989),
and site-specific exposure parameters for the residential use scenario. An inhalation rate of 20 cnbic
meters/d, exposure time of 350 d/yr, and a PM-10 fraction (particles of less than 10 microns) of
12.5% of the total suspended particulates were used in these calculations (Rapid Assessment of the
Exposure to Paniculale Emissionsfrom Surface Contamination Sites, EPA/600/8-85/002, February
1985). The chromium cleanup level of 800 mglkg results in a hazard quotient below the EPA's
threshold hazard quotient and protects sensitive individuals and sub-populations from adverse health
effects .
The cesium-137 cleanup goal of 30 pCi/g will ensure the high concentrations of chromium
;!f.e also removed. Radioactive decay of the cesium-137, will result in a concentration of 3 pCilg at
t .~ site 100 yrs in the future. This corresponds to an excess cancer risk of 5 x 10"5 at the site 100
) ,in the future. These cleanup levels were calculated using EP A-approved methods (part B of the
Risk Assessment Guidance).
The presence of high concentrations of chromium is the primary risk driver for this interim
action. Although the risk of exposure to cesium-I37 is within the acceptable risk range, these risles
8
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-------
PBF0204
23
(534)
r
PBFOI09 PBFOllO
16.9 8.1
(309) (172)
PBF0111
8.6
(200)
PBF0202
325
(1. 664)
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M.tii;, 45 2
'M''"
-------
Table 1. Cesium-137 and chromium concentrations found in PBF Evaporation Pond samples.
Sample Sample Cesium-137 Chromium Sediment
No. Location pCi/g (mg/kg) Depth em (ft)
PBFOIOIM Random 19.0 226 12.2 (0.40)
PBFOI02M Random 23.0 365 11.6 (0.38)
PBFOI03M Random 45.2 242 13.4 (0.44)
PBFOI04M Random 12.9 278 14.0 (0.46)
PBFOI05M Random 15.9 439 14.0 (0.46)
PBFO1 06M Random 14.7 534 13.1 (0.43)
PBFOI07M Random 51.3 2924 12.8 (0.42)
PBFOI08M Random 7.5 148 14.9 (0.49)
PBF0109M Random 16.9 309 9.5 (0.31)
PBFOII0M Random 8.1 172 12.8 (0.42)
\
PBF0111M Random 8.6 200 12.2 (0.33)
PBF0112M Random 14.7 260 11.9 (0.39)
PBFOI13M Random 17.5 710 15.2 (0.50)
PBF0114M Random 19.3 217 10.1 (0.33)
PBFO 115M Random 29.2 474 11.7 (0.39)
:\':"'~~d6¥~~pie"A~e~~g~/ ".." ....
..' H'"''
.. .....,.
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P' 0020.3 500 "., .. '. . ","~"P'"", ."
:12~?/ 9;~J)p':
PBF0201M Biased 282.0 3439 8.5 (0.28)
PBF0202M Biased 325.0 1664 9.8 (0.32)
PBF0203M Biased 48.1 481 20.1 (0.66)
PBF0204M Biased 23.0 534 20.4 (0.67)
PBF0205M Biased 10.0 639 16.2 (0.53)
Average of all Samples 50.0 713 13.2 (0.43)
-------
will also be reduced by removal of the contaminated sediments. The presence of cesium-137 will be
used as an indicator for the presence of chromium.
Based on 1989 sampling results, cesium-I37 and total chromium concentrations display a
strong spatial correlation. Figure 4 shows the spatial relationship of the two contaminants.
Removing areas of high concentrations of contaminants is predicated on the observed spatial
correlation between the cesium-137 and the chromium. Cleanup of higher radioactive areas, as
detected by field instrumentation, will indicate a reduction in the concentration of both contaminants
of concern. When the cleanup goal of 30 pCi/g for cesium-137 is attained, the cleanup goal of 800
mglkg for total chromium is assumed to be attained also. To confirm the effectiveness of the
. cleanup, sampling of the remaining sediments will be performed to verify residual concentrations of
cesium-137 and total chromium are at or below established cleanup levels.
6.2 Ecological Concerns
An ecological risle: assessment was not performed for this interim action. Because the interim
. risk evaluation methodology is conservative and the major ecological exposure routes are expected to
be the same as for human exposures, the risk reduction realized due to this interim action should also
achieve a significant reduction in adverse ecologiCal effects. An ecological assessment will be
performed as part of the INEL-wide Comprehensive RIIFS scheduled to begin in 1998.
6.3 Basis for Response
Actual or threatened releases of hazardous substances from this site, if not addressed by
implementing the response action selected in this ROD, may present an imminent and substantial
endangerment to human health or the environment due to the presence of chromium in the
Evaporation Pond sediments.
7. DESCRIPTION OF ALTERNATIVES
Consistent with NCP and EPA guidance, a limited nnmber of alternatives were evaluated for
this interim action. A summary of the alternatives and controls for each alternative is provided
below.
7.1 Alternative 1: No Action
If the No Action alternative is implemented, the au would remain in its current state. This
alternative does not further restrict access to the site or restrict the pathways through which the
contaminants may be transported. The No Action alternative was evaluated to determine if it is a
viable alternative as required by the NCP (40 CFR 300.430). No additional costs or implementation
time is involved with this alternative.
7.2 Alternative 2: Removal of Areas of High Contaminant Concentration
There is a strong correlation between areas of higher radioactivity (relative to the pond) and
elevated levels of chromium in the pond sediments as demonstrated by the 1989 sampling results
(Figure 4). Removing the areas of high contaminant concentration reduces potential risk to human
health. Removal options include but are not limited to, pneumatic lifting, manual extraction, or light
mechanical extraction. Removal of extracted material will be handled prior to treatment such that
exposure to direct ionizing radiation and emission of fugitive dust are minimized.
11
~ .. ... '"
-'",..--.,-.. .
-------
Table 2. Summary of risk from preliminary risk assessment for the PBF Evaporation Pond.
Carcinogenic Risk
(cesium-l 37)
Hazard Quotient
(chromium)
Occupational
8 in 100,000
(8 x l(t')
1.75
(1 ()() yr)
4 in 10,000
(4 x I~)
6.1
Future Residential
Two treatment and disposal options were proposed for the removed sediments. Option A
involves treatment (separation/extraction) and disposal using the sediment washing process proposed
for the Test Reactor Area (fRA) Warm Waste Pond Interim Action. Presently, treatability studies
are being conducted at TRA. The major applicable or relevant and appropriate requirements
(ARARs) pursuant to this option are discussed in the TRA ROD located in the Administrative Record.
Option B involves treatment (stabilization/solidification) followed by disposal at the
Radioactive Waste Management Complex (RWMC). The stabilized sediments would be used to fill
void spaces in existing certified low-level waste containers. Treatability studies will be conducted to
determine ~e optimum sediment/grout/additive mixture. Major ARARs pursuant to this option are
listed and discussed in Section 10.2.
During the sediment removal process, the materials located in the sump and discharge pipe
will also be removed, treated, and disposed. The sump and associated discharge pipe will be
decontaminated to ensure they will not be a continuing source of contamination.
8. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
CERCLA guidance requires each remedial alternative be evaluated according to specific
criteria. The purpose of the evaluation is to determine the advantages and disadvantages of each
alternative, thereby guiding selection of the remedial alternative offering the most effective ane-
feasible means of achieving the stated cleanup objectives. While all nine CERCLA criteria are
important, they are weighted differently in the decision making process depending on whether they
describe a required level of performance (threshold criteria), technical advantages and disadvantages
(balancing criteria), or review and evaluation by other entities (modifying criteria). The two remedial
alternatives described in Section 7 were evaluated according to the following CERCLA criteria:
. Threshold criteria
- Overall protection of human health and the environment
- Compliance with ARARs
. Balancing criteria
- Long-term effectiveness and permanence
- Reduction of toxicity, mobility, or volume through treatment
12
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- Short-term effectiveness
- Implementability
- Cost
. Modifying criteria
- State acceptance
- Community acceptance.
8.1 Threshold Criteria
The remedial alternatives were evaluated in relation to the two threshold criteria: overall
protection of human healdl and the environment and compliance with ARARs. The threshold criteria
must be met by the remedial alternatives for further consideration as potential remedies for the ROD.
The threshold criteria must be met for a final remedial action, and this interim action is intended to
meet those criteria to me maximum extent practicable. Th~ effectiveness of this remedial action as a
final remedy will be evaluated in the WAG 5 Comprehensive RI/FS.
8.1.1 Overall Protection of Human Health and the Environment
Overall protection of human health and the environment requires evaluation of how well the
remedial alternatives eliminate, reduce, or control the identified risks. This overall assessment of
protection of human health and the environment draws on the assessments conducted under other
evaluation criteria, especially long-term effectiveness and permanence, shott-term effectiveness, and
compliance with ARARs. For this interim action to be successful, present unacceptable risks will be
reduced and further remedial action may be unnecessary.
The No Action alternative provides no reduction in contaminant concentrations and, therefore, .
does not meet the protection of human health and the environment criterion. The alternative of
removing areas of high contaminant concentration from within the sediments provides protection of
human health and the environment by reducing the potential for exposure by inhalation of chromium
to below the threshold hazard quotient of 1. As described in Section 7.2, Option A involves
treatment and disposal using the sediment washing process proposed for the TRA Warm Waste Pond.
Option B involves treatment (stabilizationlsolidification) followed by disposal at the RWMC. Both of
these options, with the necessary facilities designed and constructed, would meet protective criteria.
8.1.2 Compliance with Applicable or Relevant and Appropriate Requirements
. CERCLA, as amended by SARA, requires remedial actions for Superfund sites comply with
federal and state substantive requirements that are applicable to the action being taken. Remedial
actions must also comply with the substantive requirements of laws and regulations that are not
directly applicable, but are relevant and appropriate unless waivers are granted. These are
requirements that pertain to situations sufficiently similar to those encountered at a Superfund site, so
their use is well suited. Combined, these are referred to as ARARs. State ARARs are limited to
those requirements that are more stringent than federal counterpart requirements. Compliance with
ARARs requires evaluation of the remedial alternatives for compliance with chemical-, location-, and
action-specific ARARs or justification for a waiver. Compliance also requires consideration of
whether the remedial alternative considers other criteria, advisories, and guidelines.
]4
. '. ~""". - . ..-. .
-------
8.2 Primary Balancing Criteria
After the proposed alternatives are evaluated using the two threshold criteria, five balancing
criteria are used to evaluate other aspects of the potential remedial alternatives. Each alternative is
evaluated using each of the balancing criteria. The balancing criteria are used in refining the selection
of the candidate alternatives for the site. The five balancing criteria are: long-term effectiveness and
permanence; reduction of toxicity, mobility, or volume through treatment; short-term effectiveness;
implementability; and cost. Each criterion is further explained in the following sections. The No
Action alternative did not meet the threshold criterion (protection of human health and the .
environment) and was not considered further.
8.2.1 Long-Term Effectiveness and Permanence
In evaluating long-term effectiveness and permanence, the magnitude of residual risks as well
as the adequacy and reliability of controls must be examined. The magnitude of the remaining risks
is evaluated by assessing the residual risk 3SSOciated with ~lntreated waste and the treated residual.
The characteristics of the residuals should be considered to the degree that they remain hazardous,
taking into account their volume, toxicity, mobility, and propensity to bioaccumulate. Adequacy and
reliability of controls is evaluated by assessing the containment and/or institutional controls to
determine if they are sufficient to ensure any exposure to residual risks is within protective levels.
Alternative 2, Option A (separation/extraction), reduces the risks associated with the
chromium and cesium-137 in the Evaporation Pond sediments by extracting the contaminants of
concern from the sediments and placing the treated residuals in a controlled environment, thereby
reducing the risks associated with the Evaporation Pond sediments. The contaminated sediment could
present a risk due to its radioactive content, but the material would be treated, containerized, and
stored in such Ci way as to be directly or indirectly monitored. Final disposal would be addressed in
the WAG 2 Comprehensive RI/FS.
Alternative 2, Option B (stabilization/solidification), meets the criterion for long-term
effectiveness because the contaminants in the sediment are physically bound in a grout mixture,
thereby reducing the residual risks associated with the Evaporation Pond sediments. The permanence
of stabilization technology is unproven for the length of time needed for the highest expected
concentration of cesium-137 to decay to acceptable levels consistent with the NCP. However,
regardless of the performance of the grout over time, the contaminated sediments will be placed in
certified low-l~vel waste containers and disposed of in the RWMC, which is a low-level waste
repository. Institutional and administrative controls are presently in place at the RWMC in -
accordance with the DOE Orders applicable to low-level waste storage. .
8.2.2 Reduction of Toxicity, Mobility, or Volume Through Treatment
This criterion addresses the statutory preference for selecting remedial actions employing
treatment technologies that permanently reduce toxicity, mobility, or volume of the hazardous
substances as their principal element. Evaluating alternatives based on the reduction of toxicity,
mobility, or volume through treatment requires analysis of the following factors: treatment process
used, toxicity and nature of the material treated, amount of hazardous material destroyed or treated,
irreversibility of the treatment, type and quantity of treatment byproducts, and statutory preference for
treatment as a principal element.
The separation/extraction process (Option A) would reduce the toxicity of the sediment
removed from the pond by removing the majority of the contaminants. Because the process is still in
development, the total reduction in toxicity and volume is not known at the present time. The
-------
concentrated sediment portions extracted should be more toxic than initial pond sediments because of
the concentrating of contaminants. However, the small volume of highly-contaminated material left
after extraction would be containerized, thereby reducing mobility of the contaminants while awaiting
final disposition.
Option B, stabilization/solidification, reduces the toxicity and mobility of the contaminants of
concern by dispersing the contaminants in an inert (grout/sediment) matrix. Stabilization increases the
volume of contaminated material due to the addition of grout, but this interim action utilizes existing
container void space to allow disposal with no net increase in the volume used in the RWMC.
Therefore, waste minimization principals have been considered.
8.2.3 Short-Term Effectiveness
lhe evaluation of alternatives based on the short-term effectiveness requires an evaluation of
the effectiveness of protection for the community and workers during remedial actions, environmental
impacts during implementation, and the amount of time required for remedial action objectives to be
achieved. Either option would achieve the remedial action objectives in about the same amount of
time. The time required to execute the action after design is completed is not anticipated to exceed
one field season. During implementation of either option of Alternative 2, protection of workers
from radiation exposure would be an important element of the remedial design. Because the
Evaporation Pond is currently a radioactively-controlled area, all personnel entering the area must
have training for working with hazardous substances, radioactive substances, and respirators. Health
physics personnel will be on site at all times when work is ongoing to monitor and control radiation
exposure to personnel. Every person entering the working area at the pond will wear appropriate
personal protective equipment, including a dosimeter to record the radiation received. DOE has as
low as reasonably achievable radiation dose goals for personnel; these goals will be met.
By using administrative and institutional controis, either option for Alternative 2 proposed for
the Evaporation Pend minimizes any short-term risk to the community from this interim action. The
large distances from population centers and the strict security at the PBF prevent risks to communities
during implementation of this interim -action. Access by visitors and site personnel not working on
the project will be restricted to those meeting lNEL requirements.
8.2.4 Implementability
The implementability criterion has three factors requiring evaluation: technical feasibility,
administrative feasibility, and the availability of services and materials. Technical feasibility requires
an evaluation of the ability to construct and operate the technology, the reliability of the technology,
the ease of undertaking additional remedial action (if necessary), and monitoring considerations.
Removal of contaminated sediments as proposed by Alternative 2, is a common approach to
risk reduction. Because a small volume of material is to be removed (approximately 100 cubic
yards), this approach is easily implemented. The ability to coordinate actions with other agencies is a
factor for evaluating administrative feasibility and is not anticipated to be a major issue for this
project. The availability of services and materials requires evaluation of treatment, storage capacity,
disposal services, necessary equipment and specialists, and prospective technologies.
Implementation of the treatment and disposal options at the TRA Treatment Facility
(Option A) and the RWMC (Option B) varies considerably. Implementation of treatment and disposal
at TRA is dependent on developing a new application of an existing technology. If the timing of the
projects does not correspond, implementing the proposed TRA treatment and disposal option will be
problematic. The RWMC is an existing facility, and the equipment for grouting can be acquired and
-------
assembled in a timely manner. The disposal of the stabilized waste will be in an existing facility.
For these reasons, grouting (Option B) followed by disposal of the waste at the RWMC is the option
most implementable.
8.2.5 Cost
In evaluating project costs, an estimation of capital costs, operation and maintenance costs,
and present worth costs are required. Capital costs include design, construction, equipment,
buildings, startup, and contingency costs. Operating and maintenance costs include labor, power,
disposal of residuals, administrative, and periodic review. Actual costs are expected to be no more
than 50 percent over, or 30 percent under, the cost estimate. Costs for each alternative are
summarized in Table 3. Alternative 1, No Action, has no cost. The total cost for Alternative 2,
Option A. including sediment removal and treatment would be $557,000, while Option B total cost
would be $480,000 (see Table 3).
8.3 Modifying Criteria
The modifying criteria are used in the final evaluation of remedial alternatives. The two
modifying criteria are state acceptance and community acceptance. For both of these criteria, the
factors considered include the elements of the altemativese supported, the elements of the alternatives
not supported, and the elements of the alternatives having strong opposition.
8.3.1 State Acceptance
This assessment evaluates the technical and administrative issues and concerns the state may.
have regarding each of the alternatives. The IDHW concurs with the interim action because it takes
the contaminants of concern from an uncontrolled environment to a controlled situation. The IDHW
participated in the development of this project, including preparation of the Proposed Plan and L~is
decision document. Comments received from the state were incorporated into these documents,
which have been issued with concurrence from the IDHW.
8.3.2 Community Acceptance
The public comment period, which was held from March 25 to May 24, 1992, provided the
opportunity for the public to express their opinions regarding each of the remedial alternatives. Many
citizens comme~ted on the efficacy of the preferred alternative. Some suggested the agencies should
remove all the pond sediments, liner, and any potential contamination present beneath the pOI'ia liner.
Other members of the public believed the risk to human health and the environment to be minimal
and supported the No Action alternative. Public comments on the plan were considered during the
preparation of this ROD and are responded to in the attached Responsiveness Summary.
9. SELECTED REMEDY
The DOE, EP A, and IDHW selected Alternative 2, Option B (removal of areas of high
contaminant concentration and grouting of the sediments for disposal at the RWMC), as the interim
action for the PBF Evaporation Pond, Corrosive Waste Sump, and discharge pipe. This alternative is
preferred because it is a standard, available technology that can be readily implemented at reasonable
cost. The contaminated sediments will be characterized, treated by stabilization/solidification, and
disposed of at the RWMC. A treatability study will be performed to determine the optimum sediment
grout additive mixture. Voids in certified low-level waste containers, which are to be disposed of in
the RWMC, will be filled with the grout mixture containing the contaminated sedimentS. The
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Table 3. Cost Estimation for Alternatives.
Alternative
Cost
Alternative 1 No Action
.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..
Alternative 2 Option A
Contaminated Sediment Removal
.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..
Emergency Discharge Tank ..........................
Sump Decontamination. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Technical Support. . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . .
Treatment and Disposal at the TRA Warm Waste Pond. . . . . . . . .
Total Option A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Option B
Contaminated Sediment Removal
.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..
Emergency Discharge Tank ..........................
Sump Decontamination. . . . . . . . .. . . . . . . . . . . . . . . . . . . .
Technicai Support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Treatment and Disposal at the RWMC . . . . . . . . . . . . . . . . . . . .
Total Option B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
$
o
$
213,000
37,000
22,000
95,000
190,000
557,000
$
$
213,000
37,000
22,000
95,000
113,000
$
480,000
estimated amount of contaminated sediments to be removed is approximately 100 cubic yards. The
interim action of,OU 5-13 will cost an estimated $480,000.
Removing the areas of high contaminant concentration will reduce the risk to human health by
reducing the potential for exposure to chromium from inhalation and cesium-137 from direct ionizing
radiation. The effectiveness of the interim action as a final action will be evaluated in the WAG 5
Comprehensive RIIFS, OU 5-12, scheduled to begin in 1996.
9.1 Sump Decontamination
Sludge and sediments will be removed from the sump to eliminate future contamination to the
pond sediments during future discharge events. The sump will be pumped and the sludge and
sediments will be collected and sampled. The interior of the sump will be decontaminated. The
interior of the sump will be analyzed for radioactivity to ensure decontamination is complete. The
discharge pipe will also be decontaminated and analyzed for residual radioactivity. Treatment of
materials and sediments removed from the sump will be by grouting, if feasible based on treatability
studies, and disposal at the RWMC.
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9.2 Contaminated Sediment Remo\'al
Approximately 100 cubic yards of the sediments in the PBF Evaporation Pond will be
removed, incorporated into a grout mixture, and injected in void spaces of existing certified low-level
waste containers for disposal at the RWMC. Field screening using portable radiation detectors will
be used to identify sediments to be removed. The chromium and cesium-:137 concentrations correlate
well in the" pond sediments as demonstrated by previous sampling efforts. By using field screening,
elevated concentrations of cesium-137 and corresponding areas of elevated concentrations of
chromium can be identified. Verification samples will be collected to ensure the concentration of
remaining chromium does not pose an unacceptable risk. Sediment samples will be taken under the
liner, and any sediments contaminated above cleanup levels will be removed and disposed of as part
of this action. However, since no contamination has been identified beneath the liner, none of that
material was included in the estimated volume of sediments to be removed. The cleanup levels for
this interim a(:tion are 800 mglkg for chromium and 30 pCi/g for cesium-137.
A doubled lined evaporation tank will be placed on the site to receive discharges that may
occur during the interim action due to an emergency situation. This tank: may be used for future
discharges in lieu of relining the pond.
9.3 Estimated Waste Generation and Disposal Option
Any wastes generated by removing areas of high contaminant concentration will be disposed
of in accordance with laws regulating their characteristics (hazardous, radioactive). Low-level
radioactive wastes will be disposed of at the RWMC on the INEL. Minimal quantities of other
hazardous wastes, such as laboratory wastes, may be disposed of offsite in accordance with EPA's .
Revised Procedures for Planning and Implementing Off-Site &sponse Actions. Solid waste will be
disposed at off site and onsite facilities, depending on availabiIit"J.
If these existing treatdi~t, storage, and disposal facilities are inadequate or unavailabie, the
following option will be implemented: .
.
The waste would be stored on the INEL until additional disposal facilities are available
If this conditions occurs, it would be resolved as soon as possible, but no later than the WAG 5 ROD
(OU 5-12).
"'0;>"':':0:..
10. STATUTORY DETERMINATIONS
Under CERCLA, the DOE and EPA have primary responsibility to ensure interim actions
taken at the site reduce the immediate, identified risks to human health and the environment.
Additionally, CERCLA, section 121, as amended by SARA, establishes several other statutory
requirements and preferences. These specify that, when complete, the final selected remedy at each
OU must implement applicable or relevant and appropriate environmental standards established under
federal and state environmental laws unless a statutory waiver is justified.
The selected remedy must also be cost-effective and use permanent solutions and alternative
treatment technologies or resource recovery technologies to the maximum extent practicable. The
remedy should represent the best balance of tradeoffs among alternatives with respect to pertinent
criteria. Finally, the statute includes a preference for remedies employing treatments that permanently
and significantly reduce the volume, toxicity, or mobility of hazardous wastes as their principal
element. The selected remedy (removal of areas of high contaminant concentration and grouting of
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i
the sediments for disposal at the RWMC) for the interim remedial action for OU 5-13 at the INEL
meets these statutory requirements.
10.1 Protection of Human Health and the Environment
As described in Section 9, the selected remedy will alleviate the potential risk to human health
by reducing the potential for exposure to chromium by inhalation and cesium-137 by direct ionizing
radiation. This action may not constitute the final remedy for the PBF Evaporation Pond, Corrosive
Waste Sump, and the discharge pipe. However, the statutory preference for remedies employing
treatment that reduces toxicity, mobility, or volume as the principal element, although partial I y
addressed in this remedy, will be fully addressed at the time of the final response action.
.10.2 Compliance with ARARS
The selected remedy will comply with the substantive requirements of all ARARs. A
summary of the ARARs for this interim actio%!. is given in the following sections.
10.2.1 Chemical-Specific ARARS
The Clean Air Act establishes national standards and goals for air pollution control. The
chemical-specific ARAR applicable to this interim action is 4{) CFR 61.92, "National Emission
Standards for Hazardous Air Pollutants [NESHAP], National Emission Standards for Radionudide
Emission from DOE facilities." This applicable requirement specifies a limit of 10 mremlyr for
radiation exposures for the general public from ambient air concentrations of radionuclides.
Air emissions from the interim action facility will meet these standards. Based on current
. knowledge, there are no oth~r chemical- or radionuclide-specific ARARs governing cleanup levels for
the Evapoq.tion Pond sediments, Corrosive Waste Sump, or discharge pipe.
10.2.2 Action Specific ARARs
.
Applicable requirements of the rules for the "Control of Fugitive. Dust," IDAP A
16.01.01251 and .01252 which specify that all reasonable precautions be taken to prevent
the generation of fugitive dusts.
.
AppFcable requirements of 4{) CFR 61.93, NESHAP, "Emission Monitoring and Testing
Procedures," which contains monitoring requirements.
10.2.3 Location-Specific ARARs
There are no location-specific ARARs identified for this interim action.
10.2.4 Other Criteria, Advisories, or Guidance To-Be-Considered
Requirements under the Atomic Energy Act are applicable to the procurement, use, and
disposal of all source, byproduct, and special nuclear material at the INEL. Although DOE Orders
are not ARARs, since they are not promulgated requirements, all of the requirements of DOE Orders
are to be considered. DOE Orders that may apply to this CERCLA activity include:
.
DOE 5480.11, "Radiation Protection for Occupational Workers," esublishes radionuclide-
specific criteria to protect workers from hazard of exposure to ionizing radiation and
radioactive materials.
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.
.
DOE 5820.2A, "Radioactive Waste Management, W establishes standards for radiation
exposure as follows:
. . . external exposure to the waste and concentration of radioactive material
which may be released into surface water, groundwater, soil, plants, and
animals which results in an effective dose equivalent that does not exceed
25 mremlyr to any member of the public. . . and assures that the committed
effective dose equivalents received by individuals who inadvertently may
intrude into the facility after the loss of active institutional control (100 yrs)
will not exceed 100 mremlyr for a continuous exposure or 500 mremlyr for a
single-:icute exposure.
Removal of pond sediments and stabilization/solidification, as described, meets this standard for both
the removed contaminants and the residual pond sediments.
11. DOCUMENTATION OF SIGNIFICANT CHANGES
The Proposed Plan for OU 5-13, interim action of the PBF Evaporation Pond and Corrosive
Waste Sump was released for public comment in March 1992. The PBF Proposed Plan identified
Alternative 2, removal of areas of high contaminant concentration, as the preferred alternative. Upon
review of the cost estimates presented for the two disposal options in the Proposed Plan, the cost
estimates were found to be low. The revised total cost for this interim action, Alternative 2,
Option B, is $480,000. This change reflects the addition of the costs for: technical support,
decontamination of the sump and discharge pipe, and assembling a tank to receive any emergency
discharge that may be necessary during the interim action.. The increase in the cost estimates, which
have changed from Table 2 of the Proposed Plan to the updat~ in Table 3 of this ROD (Section
8.2.5), resulted from a review and revision of the assumptions used in developing the estimates. The
adjustment is the same for both options presented for Alternative 2, and therefore, has no effect on
the selected remedy.
The DOE, EP A, and IDHW have reviewed all written and verbal comments submitted during
the public comment period. Upon review of these comments, it was determined no further significant
changes to the remedy, as it was originally identified in the Proposed Plan, were necessary.
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