United States
          Environmental Protection
          Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R10-92/036
December 1991
SEPA   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 found in this document have .been removed at the request of
the issuing agency. They contain material which supplement, but adds no further applicable information to
the content of the document. All supplemental material is. however. contained in the administrative record

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50272-1 01
REPORT DOCUMENTATION  1'. REPORT NO.      I~    3. Reclplenrs Accession No.    
 PAGE    EPA/ROD/R10-92/036              
4. Tille and Sublitle               5. Report Date      
SUPERFUND RECORD OF DECISION          . 12/05/91      
US DOE Idaho National Engineering Lab (OU5), ID    6.         
First Remedial Action - Interim                   
7. Author(a)               8. Performing Organization RepL No.  
9. Performing Orgainization Name and Address            10. ProjectfTask/Work Unit No.    
                  11. ContracI(C) or GranI(G) No.    
                  (C)         
                  (G)         
12. Sponsoring Organization Name and Address            13. Type 01 Report & Period Covered  
U.S. Environmental Protection Agency         800/000      
401 M Street, S.W.                       
Washington, D.C. 20460            14.         
15. Supplementary Notes                        
PB93-964603                        
16. Abstract (Umi1: 200 words)                        
The Idaho National Engineering Laboratory (INEL), located 32 miles west of Idaho  
Falls, Idaho, occupies 890 square miles of the Eastern Snake River Plain. Land use at
the INEL is industrial and mixed use, with a surrounding 500  square mile buffer zone
used for cattle and sheep grazing. The 7,700 INEL employees use the Snake River Plain
Aquifer that underlies the site, as a drinking water source.  The aquifer has been 
proposed as a sole-source aquifer pursuant to the SWDA. The TRA contains high neutron
flux nuclear test reactors. The Warm Waste Pond is located 200 feet east of the test
reactor area. The Warm Waste Pond is composed of three wastewater       
infiltration/evaporation ponds. Over the past 40 years, the Warm Waste Pond received
discharges of reactor cooling water, radioactive wastewater,  and regenerative   
solutions from ion exchange columns. As a result of an investigation conducted in 
1988, it was revealed that a release of radioactive and/or hazardous contaminants to
the Warm Waste Pond had resulted in contamination of the pond sediments and subsurface
water. The INEL is divided into 10 Waste Area Groups (WAGs), which are further  
subdivided into operable units to facilitate characterization and remedy selection for
similar or unique contamination issues. This ROD addresses the interim remedy for the
(See Attached Page)                       
17. Documen1 Analysla a. DescrIptors                       
Record of Decision - US DOE Idaho National Engineering Lab (OU5), ID      
First Remedial Action - Interim                  
Contaminated Media: sediment,                   
Key Contaminants: metals (chromium), radionuclides             
b. IdenlifiersiOpen-Ended T erma                       
c. COSATi FIeIdIGroup                        
18. AvailabiUty Statement           19. Security Class (This Report)    21. No. o' Pages  
               None     40    
              20. Security Class (This Page)    22. PrIce    
               f\1n,.,.,.          
                      OPTiONAL FORM 272 (4.77)
(See ANSl-Z39.18)
See Instructions on R-
(Formerfy NTtS-35)

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EPA/ROD/R10-92/036
US DOE Idaho National Engineering Lab (OU5), ID
First Remedial Action - Interim
Abstract (Continued)
Warm Waste Pond sediments that are part of the WAG 2 group that includes the TRA. Other
OUs are associated with this interim action and will address perched water below TRA.
Contamination of the Snake River Plain Aquifer and complete evaluation of risks
associated with the Warm Waste Pond will be addressed in separate investigations and
remedial actions, as necessary. The contaminants in the perched water, currently being
evaluated in an ongoing RI/FS, will be addressed in future remedial actions. The
primary contaminants of concern affecting the sediments are metals, including hexavalent
chromium; and radionuclides, including cesium-137 and cobalt-GO.
The selected remedial action for this site includes physical separation, then chemical
extraction, by treating onsite approximately 20,700 cubic yards of contaminated
sediment; hydraulic or mechanical excavation to load sediments into screening plant;
field screening to ensure all contaminated sediments are being excavated and input into
treatment plant; conducting classification to further separate very fine-grained
material from fine-grained material; chemical extraction of cesium-137, cobalt-GO, and
chromium using an acid solution; recovery of contaminants; testing residuals to
determine radioactive and chemical constituents; treating to meet applicable storage
and/or disposal criteria; and backfilling the pond to grade and revegetation. pilot
studies will be conducted to optimize the extraction process. capital costs for the
remedy, inclusive of treatment design, construction, treatability studies and storage of
residuals, are estimated at $7,195,000. An additional O&M cost for temporary storage
facilities and containers is estimated at $300,000 over the 18-month duration of the
remedial process.
PERFORMANCE STANDARDS OR GOALS: Federal and state clean-up standards for cesium-37,
cobalt-GO, and chromium have not been established at this time. Clean-up objectives for
cesium-37 are based on a 10-4 to 10-6 range for cancer risk to human health. Because
this action does not constitute a final remedy for this operable unit, subsequent
actions will fully address risks posed by the Warm Waste Pond sediments and associated

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/
FINAL
DECLARATION FOR THE WARM WASTE POND
AT mE TEST REACTOR AREA
AT THE IDAHO NATIONAL ENGINEERING LABORATORY
DECLARATION OF TIlE RECORD OF DECISION
Site Name and Location
Warm Waste Pond sediments
Test Reactor Area
Idaho National Engineering Laboratory
Statement of Basis and Purpose
This decision document presents the selected interim remedial action for the Warm
Waste Pond sediments, which was chosen in accordance with the Comprehensive Environmental
Response, Compensation, and Liability Act (CERCLA) as amended by the Superfund
Amendments and Reauthorization Act (SARA), and to the extent practicable, the National Oil
and Hazardous Substances Pollution Contingency Plan (NCP). This decision is based on the
administrative record for the site.
The State of Idaho concurs with, and the Environmental Protection Agency approves,
the selected remedy. .
Assessment of 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, may present an.
imminent and substantial endangerment to public health, welfare, or the environment, due to the
radioactively-contaminated sediments of the Warm Waste Pond.
Description of the Selected Remedy
This Record of Decision addresses the contamination of the sediments of the Warm
Waste Pond at the Test Reactor Area (TRA) at the Idaho National Engineering Laboratory
(INEL). TRA is one of ten Waste Area Groups at the INEL which are under investigation
pursuant to the Federal Facility Agreement/Consent Order (FFA/CO). The selected remedy is
a combination 6f physical separation and chemical extraction to recover contaminants from the
Warm Waste Pond sediments, followed by the backfilling of the Warm Waste Pond. The
remedy addresses the significant potential risks associated with the- site: external exposure to
radiation, and inhalation and ingestion of contaminated .sediment.

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F1 NAL
The major components of the remedy are:
.- 
or 
 .
 .
 .
 .
 .
 .
.
Treatability studies to optimize the extraction process,
Excavation of the sediments which are contaminated above the specified
criteria,
Physical screening of the excavated sediment to remove the large grained-size
particles, .
Classification to further separate the fine-grained particles,
Chemical extraction of cesium-13?, cobalt-60, and chromium using an acidic
solution,
Recovery of the contaminants from the acidic solution using ion exchange,
precipitation, or distillation, if the residuals cannot be processed by the Idaho
Chemical Processing Plant, .
Treatment of the waste residuals to be returned to the Warm Waste Pond, if
needed, to meet the specified criteria,
Backfilling the Pond to grade and vegetation, and
Storage until final disposal of the product residuals.
.
.
Statutory Determination
This interim action is protective of human health and the environment, complies with
Federal and State applicable or relevant and appropriate requirements for this limited-scope
action, and is cost-effective. Although this interim action is not intended to address fully the
statutory mandate for permanence and treatment to the maximum extent practicable, this interim
action does utilize treatment and is thus in furtherance of that statutory mandate, by utilizing
permanent solutions and alternative treatment technology, to the maximum extent practicable
given the limited scope of this action. Because this action may not constitute the final remedy
for the Warm Waste Pond, the statutory preference for remedies that employ treatment that
reduces toxicity, mobility, or volume as the principal element, although partially addressed in
this remedy, will be addressed at the time of the final response action. Subsequent actions may
be necessary to address fully the principal threats posed by the site. Because this remedy will
result in substances remaining on site, the effectiveness of the interim action as a final action
will be evaluated in the comprehensive Waste Area Group Remedial Investigation/Feasibility
Study and reviewed within five years of the initiation of the remedial action.
:,
The comprehensive Remedial Investigation! Feasibility Study for Waste Area Group 2
will su~ this interim action, which encompasses TRA in its entirety and will evaluate
additional actions for TRA, including the Warm Waste Pond.
. - .

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11I2J/91
Signature sheet for the. foregoing Warm Waste Pond at the Test Reactor Area at the Idaho
National Engineering Laboratory Record of Decision between the United States Department of
Energy and the United States Environmental Protection Agency, with concurrence by the Idaho
Department of Health and Welfare.
0rY~
/0n /

Date
AUGUSTINE A. PITROLO
Manager
Department of Energy Field Office, Idaho

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I /I~5,vl
SignatUre sheet for the foregoing Warm Waste Pond at the Test ReactOr Area at the Idaho
National Engineering LaboratOry Record of Decision between the United States Departmem of
Energy and the United States Environmental Protection Agency, with concurrence by the Idaho
Department of Health and Welfare. .
;[)/)2/tU<- a~
kl<.. .<2,-,! Z{.~ l/ ~'2Q-
/2/)/91
Date'
DANA RASMUSSEN
Regional AdministratOr, Region 10
Environmental Protection Agency
. - .

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FINAL
Signature sheet for the foregoing Warm Waste Pond at the Test Reactor Area at the Idaho
National Engineering Laboratory Record of Decision between the United States Department of
Energy and the United States Environmental Protection Agency, with concurrence by the Idaho
Department of Health and Welfare.
2M~~

RICHARD DONDV A
Director
Idaho Department of Health and Welfare
5
/;2 - tJ'- 9/
Date

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FINAL
TABLE OF CONTENTS
  Page
 Acronyms 7
Decision Summary 8
I. Site Description 8
 -
II. Site History and Enforcement Activities 9
III. Highlights of Community Participation 11
IV. Scope and Role of Operable Unit and Response Action 12
V. Summary of Site Characteristics 12
VI. Summary of Site Risks 13
VII. Description of Alternatives 16
.'  
Vill. Summary of Comparative Analysis of Alternatives 19
IX. The Selected Remedy 28
X. Statutory Determination 31
XI. Explanation of Significant Differences 32
Responsiveness Summary 33

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AEA
ALARA
ARARs
CAA
CERCLA
COCA
CWA
DOE
EPA
FFAICO
HWMA
ICPP
IDHW
lNEL
LDR
nCilgm
NCP
NEPA
NESHAP
NPL
OSHA
OU
pCilgm
RCRA
RIlFS
ROD
SARA
TBCs
TCLP
TRA
WAG
FINAL
ACRONYMS
Atomic Energy Act
As low as reasonably achievable
Applicable or relevant and appropriate requirements
Clean Air Act
Comprehensive Environmental Response, Compensation, and Liability Act
Consent order and Compliance Agreement
Clean Water Act
Department of Energy
Environmental ~rotection Agency
Federal Facility Agreement/Consent Order
Hazardous Waste Management Act
Idaho Chemical Processing Plant -
Idaho Department of Health and Welfare
Idaho National Engineering Laboratory
Land Disposal Restrictions
nanocuries per gram
National Contingency Plan
National Environmental Policy Act
National Emission Standards for Hazardous Air Pollutants
National Priorities List
Occupational Health and Safety Administration
Operable Unit
picocuries per gram (lIlOOOth of nCilgm)
Resource Conservation and Recovery Act
Remedial Investigation/Feasibility Study
Record of Decision
Superfund Amendments and Reauthorization Act
to-be-considered
toxicity characteristic leaching procedure
Test Reactor Area
Waste Area Group
. -

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FINAL
DECISION SUMMARY
7
I. SITE DESCRIYfION
The Idaho National Engineering Laboratory (INEL) is located 32 miles west of Idaho
Falls, Idaho and occupies 890 square miles of the northeastern portion of the Eastern Snake
River Plain. The Test Reac;tor Area (TRA) is located in the southwestern portion of the INEL
(see map this page). The Warm Waste Pond is located approximately 200 feet east ofTRA and
consists of three wastewater infiltration/evaporation cells comprising approximately 4 acres (see
map next page).
The area around TRA is relatively flat. Elevations range from 4,907 to 4,945 feet
above sea level from the bottom of a pond to the top of a rubble pile. Generally, the land
surface slopes slightly from southwest to northeast. Elevation in the Warm Waste Pond ranges
from 4,908 to 4,913 feet.
Current land use at the INEL is classified as industrial and mixed use by the Bureau of
Land Management and has been designated as a National Environmental Research Park. The
developed area within the INEL is surrounded by a 500 square mile buffer zone used for cattle
and sheep grazing.
'.I
Approximately 7,700 people are employed at the INEL, with approximately 580
employed at TRA. The nearest off-site populations are in the cities of: Atomic City (13 miles
southeast ofTRA), Arco (17 miles
west), Howe (14 miles north),
Mud Lake (32 miles northeast),
and Terreton (34 miles northeast).
The lNEL property is
located on the northern edge of the
Eastern Snake River Plain, which
contains a substantial volume of
silicic and basaltic volcanic rocks
with relatively minor amounts of
sediment. Underlying TRA are a
series of basaltic lava flows
interbedded with sediments.. The
basalts immediately beneath the
site are relatively flat and covered
by 40 to 50 feet of alluvium. The
Snake River Plain Aquifer
underlies the INEL and has been
proposed as a sole source aquifer
pursuant to the Safe Drinking
Water Act.
-
T._-
" . - . .
I""'"
I I I I I
I I I
I . I ---
Figure 1: Test Reactor Area (TRA) at the Idaho
National Engineering Laboratory (INEL)

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FINAL
The lNEL has semi desert characteristics with hot summers and cold winters. Normal
annual precipitation is 9.1 inches per year, with estimated evapotranspiration of 6 to 9 inches
per year. Twenty distinctive vegetative cover types have been identified at the INEL, with big
sagebrush the dominant species, covering approximately 80 percent. The variety of habitats on
the lNEL supports numerous species of reptiles, birds, and mammals.
TRA covers approximately a 1,700 by 1,900 foot area and is surrounded by a double
security fence. Located inside of the fence are more than 73 buildings and 56 structures, such
as tanks, cooling towers, and roads. Located outside of the fences are parking areas, a
helicopter landing pad, a sewage treatment plant, a stack, a storage area, and four waste disposal
ponds. Also located around TRA are unpaved roads, groundwater monitoring wells, and rubble
piles. -
The Warm Waste Pond consists of three cells; one excavated in 1952 with bottom
dimensions 150 by 250 feet and a depth of 15 feet, one excavated in 1957 with bottom
dimensions of 125 by 230 feet and a depth of 15 feet, and one excavated in 1964 with bottom
dimensions of 250 by 400 feet and a depth of 6 feet.
n. SITE HISTORY AND ENFORCEMENT ACTIVITIES
TRA is located in the southwestern portion of the INEL north of the Big Lost River
(Figure 1). The facility houses high neutron flux nuclear test reactors. The TRA Warm Waste
Pond is located approximately 200 feet east of TRA, outside the security fence (Figure 2). I~
the past, the Warm Waste Pond has received discharges of reactor cooling water, radioactive
wastewater, and regenerative solutions from ion exchange columns.
The release of radioactive
and/or hazardous contaminants to the
Warm Waste 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 DOE-
ID/EP A Consent Orderl Compliance
Agreement (COCA).
l
Test Reactor
Area Facilities
The INEL was proposed for
listing on the National Priorities List
(NPL) on "July 14, 1989 [54 FR
29820]. The listing was proposed by
the EP A under the authorities granted
EP A by the Comprehensive
Environmental Response,
500.
Figure 2: Warm Waste Pond at Test Reactor Area

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FINAL
Compensation, and Liability Act of 1980. 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.
One of the reasons for the NPL listing was the release to groundwater of contaminants
from facilities at the TRA. These contaminants, mainly chromium and radionuclides, were
released to the environment at the Warm Waste Pond and other locations at TRA. Use of
chromium as a cooling tower corrosion inhibitor was discontinued in 1972.
Based on the characterization data available in the Administrative Record for the
sediments of the Warm Waste? Pond, a significant potential risk to human health and the
environment has been identified. The Warm Waste Pond was proposed for an interim action
under the Federal Facility Agreement/Consent Order (FFA/CQ). This Record of Decision
documents the decision to perform that interim "action and the remedy selected. The Warm
Waste Pond interim action will be evaluated for adequacy as a final remedial action in the Waste
Area Group 2 (WAG 2) Comprehensive Remedial Investigation/Feasibility Study (RIfFS)
scneduled to begin in 1996. WAG 2 encompasses TRA and the immediately surrounding area.
The Warm Waste Pond sediments have been sampled several times. In 1983, one
sample was collected for RCRA Appendix vm analysis~ In 1987, six sediment samples were
collected for RCRA Appendix vm analysis. In 1988, eighty eight samples were collected to
depths over 10 feet below the top of the sediments for the Preliminary Investigation conducted
under the COCA. In 1990, twenty six samples were collected from the upper' two feet of
sediment following CERCLA protocol. Evaluation of the data from these sampling efforts an~
the preliminary risk evaluation performed based on those data served as the basis for this interim
action. The contaminants which were mainly found in highest concentrations in the upper two
feet of the sediments are shown in the following table.
 Contaminant Average Concentration Half-life
  Radionuclides  
 Cesium-137 11,500 pCi/gm (11.5 nCi/gm) 30.2 years
 Cobalt-60 4620 pCi/gm (4.62 nCi/gm) 5.3 years
  Non-Radionuclides  
 Chromium 338 mg/kg  -
 Zinc 143 mg/kg  -
- Sulfide 28 mg/kg  -
 .'"..,

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FINAL
m. HIGHLIGHTS OF COMMUNITY PARTICIPATION
A series of five public informational meetings were held in late June 1991 in Idaho
Falls, Pocatello, Twin Falls, Boise, and Moscow to explain how the CERCLA process works
and to introduce the Warm Waste Pond cleanup project to the public. These informational
meetings were announced via the INEL Reporter newsletter distributed to 11,700 INEL
employees as well as 2100 of the general public, newspaper and radio advertisements, and an
INEL press release. Personal phone calls were made to key individuals, environmental groups,
and organizations by the INEL field offices in Pocatello, Twin Falls, and Boise. The
Community Relations Plan Coordinator made calls to Idaho Falls and Moscow. Each of the
meetings were videotaped.
The Notice of Availability for the Proposed Plan was published July 28, 1991 in the
Post Register (Idaho Falls), Idaho State Journal" (Pocatello), Times News (Twin Falls), Idaho
Statesman (Boise), and Idahoan (Moscow). A similar newspaper advertisement appeared in the
same newspapers the following week repeating the public meeting locations and times. Personal
phone calls, as noted above, were made to inform key individuals and groups about the comment
opportunity .
The Proposed Plan for the interim action of the TRA Warm Waste Pond sediments was
mailed to the public on July 26, 1991. The Proposed Plan was mailed to 2,100 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 Plan and to attend
public meetings. Copies of the Plan and the administrative record are available to the public in
six regional INEL information repositories: INEL Technical Library in Idaho Falls; and city
libraries in Idaho Falls, Pocatello, Twin Falls, Boise, and Moscow. Copies of the administrative
record file for the Warm Waste Pond Sediments Interim Action were placed in the information
repositories sections or at the reference desk in each of the libraries on July 26, 1991. .
The public comment period was held from July 29, 1991 to August 28, 1991. No
extension requests were made. Public meetings were held on August 7, 8, 13, 14, and 15, 1991
in Idaho Falls, Pocatello, Twin Falls, Boise, and Moscow respectively. At the meetings in
Idaho Falls and Pocatello, representatives from DOE, EP A and IDHW discussed the project,
answered questions, and received public comments. At the meetings in Twin Falls, Boise, and
Moscow, DOE and IDHW were represented. Verbatim transcripts were prepared by a court
reporter of each public meeting. Each was recorded on audio tape and the Twin Falls and Boise
meetings were videotaped as well. Written comment forms were distributed at each of the
meetings. .
A Responsiveness Summary has been prepared as part of the Record of Decision. All
verbal comments, as given at the public meetings, and all .written comments, as submitted, are
repeated verbatim in the Administrative Record "ror the Record of Becision. . Those comments
are annotated to indicate which response in the Responsiveness Summary addresses each
comment.

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FINAL
In general, there were two predominant public opinions on the preferred alternative as
described in the Proposed Plan; the opinion that' it was too expensive, or agreement that it was
the best of the alternatives presented. Other issues raised were: adequacy of characterization
data; operations at TRA, e.g., the continued use of the Pond; adequacy of the risk assessment
process; remedial alternatives, including use of the Idaho Chemical Processing Plant (ICPP) for
treatment of residuals from the interim action; ability to implement the proposed action and
disposition of the residuals created; research of remedial technologies; degree of oversight of
DOE and its contractors in"performing the remedial action; community relations; and NEPA.
IV. SCOPE AND RO~E OF OPERABLE UNIT AND RESPONSE ACTION
Under the Federal Facility Agreement/<;onsent Order (FFA/CO) the INEL is divided
into ten Waste Area Groups (WAGs). The WAGs are further subdivided into operable units.
TRA has been designated WAG 2, and the Warm Waste Pond sediments have been designated
Operable Unit 2-10 (OU 2-10), one of the thirteen operable units at TRA. As is commonly done
on many Superfund sites, similar or unique problems at a site are grouped into operable units
to make characterization and remediation activities more efficient. In this case, existing
characterization data were available to identify the Warm Waste Pond sediments as a significant
threat to human health and the environment and select a remedial technology. Therefore, the
Warm Waste Pond sediments were designated as an operable unit to expedite an interim action.
:1
Two of the thirteen operable units at TRA are related to this interim action: OU 2-12
and OU 2-13. au 2-12 consists of the contaminated perched water below TRA. Some of the
, contaminants of concern in the perched water resulted from disposal of wastewater to the Warm
Waste pond. The perched water is currently being evaluated in an ongoing RI/FS. OU 2-13
is the final, overall evaluation of all characterization and remediation activities in WAG 2, which
encompasses all of TRA and the immediately surrounding area. All actions conducted at TRA
will be considered in the au 2-13 RI/FS, from the perspective of TRA as a whole to ensure that
all issues have been addressed adequately. Conducting this interim action is part of the overall
site strategy and is expected to be consistent with any planned future actions.
The interim action is, therefore, intended to reduce the risks associated with the Warm Waste
Pond sediments. Contaminants in the perched water and their effect on the Snake River Plain
Aquifer in the vicinity of TRA will be evaluated in the au 2-12 RI/FS, and remedial action
undertaken, as necessary. A complete evaluation of all risks associated with the Warm Waste
Pond will be conducted as part of the final comprehensive au 2-13 RI/FS.
V. SUMMARY OF SITE CHARACTERISTICS
The Warm Waste Pond consists of three wastewa~r,j~filtration cells, which have been
used for the disposal of reactor cooling water, radioactive "Wastewater; and regenerative solutions
from ion exchange. From 1952 until 1962, all liquid wastes from TRA, except sanitary sewage,
were discharged to the Warm Waste Pond. Wastewater from the demineralization plant went
to the Pond until 1962. Other non-radioactive wastewater, including water from the cooling

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FlNAL
towers, was disposed of in the Pond until 1964. Since 1964, the Warm Waste Pond has
received only radioactive wastewater. The volume of wastewater discharged to the Warm Waste
Pond has ranged from over 200 million gallons per year from 1958-1963 and 1969-1976 to. less
than 20 million gallons per year from 1987 to the present. Contaminant levels in the wastewater
discharged to the Pond have decreased significantly in the past 12 years. However, these past
disposal practices have resulted in contamination of the pond sediments.
The Warm Waste Pond was sampled several times between 1983 and 1990. Due to the
types of wastewater discharged to the Pond, the contaminants are mainly of two types:
inorganics and radionuclides. The inorganics, primarily metals, mainly resulted from the non-
radioactive wastewater sources. The contaminant in the highest concentration, and therefore the
largest total ~s, is chromium which was used (in hexavalent form) until 1972 as a corrosion
inhibitor in the cooling towers. The hexavalent chromium in the Pond sediments has undergone
chemical reduction to trivalent chromium, which is less toxic and less mobile than hexavalent
chromium. The total estimated volume of trivalent chromium in the Pond sediments is over.
26,000 pounds with an average concentration of 338 parts per million (ppm). In addition to
chromium, some of the other metals (with their corresponding average concentration in the upper
two feet of sediment and total weight in the Pond) are: zinc, 143 ppm, 4,085 pounds; lead, 18
ppm, 819 pounds; arsenic, 5 ppm, 631 pounds, and mercury, 3 ppm, 139 pounds. The Pond
sediments are not RCRA characteristic or listed hazardous waste.
Radionuclides have been discharged to the Warm Waste Pond for nearly 40 years.
Cumulatively, over 5 billion gallons of wastewater was discharged into the Pond. Peak volumes
of over 200 million gallons annually were discharged between 1958-1963 and 1969-1976. ¥1
recent years, the radionuc1ide content of the wastewater has dropped significantly. From 1979
to 1987, the total activity of the wastewater going to the Pond was reduced by over 90 percent.
Therefore, the radioactive contaminants which are now of greatest concern are those of greatest
quantity disposed or radionuclides that have not naturally decayed to levels resulting in
acceptably reduced risk. In addition, those radionuc1ides which were not trapped by the
sediments, for example tritium, will be addressed in a separate operable unit. Based upon the
combination of total quantity discharged, half-life, and ability of the Pond sediments to capture
the radionuclide, the predominant radionuclides at the present time are (with total curies
disposed, radioactive decay half-life, and average current concentration): cesium-137, 157
curies, 30.2 years, 11.5 nCilgm; cobalt-60, 471 curies, 5.3 years, 4.6 nCilgm; and strontium-
90, 99 curies, 29.1 years, 0.5 nCilgm. Nineteen radionuclides .have been identified in the Pond
sediments and most are present in very small amounts. The cesium-137 and cobalt-60 are
associated with the fine-grained sediments in the upper two feef of the Pond.
VI. SUMMARY OF SITE RISKS
Introduction ". - .
A preliminary risk evaluation was prepared to determine the risks to human health and
the environment posed by the Warm Waste Pond sediments. A future use scenario was

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F1NAL
evaluated in addition to the present case to ensure the consideration of the long-term adequacy
of the remedial alternatives. The preliminary evaluation consisted of two parts, human health
and ecological, and was utilized to determine if unacceptable risks are present. The final Record
of Decision (i.e., the comprehensive WAG 2 RIfFS) which addresses this operable unit will
evaluate the effectiveness of this interim action based upon a quantitative risk assessment.
Preliminary Human Health Risk Evaluation
Potential present and future risk(s) posed by the Warm Waste Pond sediments were
assessed in a preliminary risk evaluation using the standard procedures and default parameters
established in EPA guidance d9Cuments to determine if the risk justified a remedial action. In
addition, a future use scenario was evaluated so that remedial alternatives could also be
considered in terms of potential future risk(s).
Present Risk(s)
~.f
Since the Warm Waste Pond is currently under the institutional control of INEL site
security and is surrounded by a fence which approximates the boundary of the contaminated
area, the potential exposure scenarios, based on the present condition of the pond, were
occupational scenarios. The hypothetical receptor was assumed to be located at the boundary
of the operable unit as defined by the institutional controls (the fence). Two exposure pathways
were analyzed: inhalation of airborne, contaminated dust, and external exposure to radiation.
Several exposure conditions, ranging from 40 percent of the day, every day for 40 years to 5
hours per week for one year, were evaluated. A toxicity assessment was conducted to determine
the health effects associated with the identified contaminants. Noncarcinogenic and carcinogenic
toxicity values were identified or derived to perform the risk evaluation. Risks were quantified
for the selected contaminants of concern (individually), for multiple substances, and for multiple
pathways (for radionuclides). Noncarcinogenic effects were evaluated based on the hazard
quotient/index of toxicity. Carcinogenic risks were evalUated and compared to the accepted NCP
targe~ risk range of lQ4 to 1
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In addition to the present. occupational scenarios described above, ingestion of
contaminated soil was evaluated as a potential future risk. One potential scenario selected for
evaluation consisted of a residential receptor (a farming family with children) which is assumed
to reside at the operable unit starting in 100 yeats (2091), which is assumed for calculation
purposes to be the end of institutional controls. One hundred years is the DOE/NRC standard
for closure of low-level radioactive waste facilities, and for the preliminary evaluation was
assumed to be a reasonable time to expect institutional controls to be maintained. The
concentrations of contamini1J.1ts used in the evaluation were based on sampling data which was
then corrected for radioactive decay to establish contaminant concentrations after 100 years. The
exposure assessment followed EP A guidelines for default exposure parameters.
All hazard quotients for the evaluated chemicals were less than one, which indicate that
no adverse health effects (noncarcinogenic effects) are expected from the ingestion of soil for
the residential receptor. The noncarcinogenic hazard index (combined chemicals) is also below
the level of concern for noncarcinogenic effects. The carcinogenic risks for the chemicals was
3 x 10-5 and radionuclides was 4 x 10-5, which are within the NCP target risk range. However,
when combined with the inhalation pathway the risks do exceed the NCP target range. In each
case, cesium-137 is the primary risk driver.
Summary
The external exposure scenario based on an occupational receptor with the present
condition of the Warm Waste Pond is above the NCP target risk range and an interim action is
warranted. As mentioned, the Warm Waste Pond is currently under institutional controls, an~
DOE procedures are to reduce personal radiation exposure to as low as reasonably achievable
(ALARA). The inhalation scenario, based on the occupational receptor under the present
conditions, and the ingestion scenario, based on a future residential scenario of the Warm Waste
Pond beginning in 100 years, are both within the calculated target range. However,
cumulatively, the inhalation and ingestion scenarios are above the NCP target risk range and
should be reduced. This interim action will reduce the current risk posed by the radiation field
of the Warm Waste Pond and reduce potential future concerns. .
The calculated risk values carry some uncertainties inherent in the risk evaluation
process. The calculated risk values represent estimates of potential effects and do not represent
characterization of absolute risks. The risk measurements are conditional estimates dependent
on a number of assumptions about exposure and toxicity. However, the preliminary risk
evaluation is believed to be a reasonably protective estimate of risk and supports the need for
an interim action.
Ecological Concerns

Ecological concerns will be addressed in the Remecii3I Inv~tigationl.Feasibility Study
for the WAG-wide Record of Decision. Since the major exposure routes are expected to be the
same as. human exposures, the risk reduction realized due to this interim action should achieve
a signific::ant reduction in adverse ecological effects.
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vu. DESCRIPTION OF ALTERNATIVES
Potential technologies which would achieve significant risk reduction while the final
remedy is developed were identified from the available literature. The technologies evaluated
for this interim action were temporary capping, stabilization, and a combination of physical
separation and chemical extraction. In addition, the no action alternative was evaluated.
Alternative 1: No Action
The no action alternative was evaluated in accordance with EPA guidance. Under the
no action alternative, the curre~t institutional controls which restrict access to the Warm Waste
Pond would be maintained. As is shown in the comparative analysis of alternatives, the no
action alternative was found to be unacceptable because it does not provide overall protection
of human health and the environment. .'
Alternative 2: Temporary Capping
Capping involves backfilling the Pond and covering the site with a barrier to prevent
biological (plant and animal) and precipitation intrusion. Cap design and construction would
consider: the need to attenuate the gamma radiation associated with the Pond sediments;
minimization of long-term water infiltration through the contaminated material; maintenance
minimization; and drainage and erosion. A typical cap design for the Warm Waste Pond would
include:
.
Backfilling the Pond to above grade with locally available materials (if withitl
design standards),
A three-foot layer of clay to prevent precipitation infiltration,
A one-half foot layer of sand to provide drainage,
A two-foot thick layer of cobbles acting as an anti-biointrusion layer, and
A three-foot thick layer of soil to allow vegetation.
.
.
.
.
Estimates of capital costs, including design and construction, for capping are
$2,786,000. Operational and maintenance costs would be approximately $50,000 annually which
includes monitoring and maintenance of institutional controls. A cap would take approximately
nine months to construct following five months of design and review.
Temporary capping has the advantages of ease of application, the fact that it is a well
known technology, and high reliability if maintained properly. Capping has relatively low
capital costs. Soil characteristics are not as critical for capping as other technologies and soil
is an excellent gamma radiation shield. The greatest disadvantage of capping is that it does
nothing to eliminate the contaminants, it simply impedes releases by shielding. All contaminants
remain in the Pond area. Plant roots, excavations for vario.~~ purposes, such as utilities repair,
and unwitting penetrations (e.g., post holes) cOuld resUlt-in significant breacheS in the cap.
Building construction is a clear threat to a cap. In addition, long-term maintenance costs for a
cap can be significantly higher than for a permanent remedy over time. However, as capping
is a temporary measure, significant additional costs may be realized at final remedy selection.
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Alternative 3: Stabilization
Solidification is a process which creates a monolithic block of immobilized waste with
high structural integrity in which the contaminants are mechanically, but not chemically, bonded
with the solidification agents and matrix. By adding chemical reagents, and thereby chemically
binding the contaminants, solidification becomes stabilization which further limits solubility and
mobility of the contaminants. Common reagents applicable to the Warm Waste Pond sediments
and proven to be effective in many cases include portland cement, pozzolanic fly ash, bitumen,
and lime. Stabilization is done one of two ways: the reagent is injected and mixed with the
sediments in place or the sediment is dug up and machine mixed with the stabilization agent
which is then re-deposited on or off site. A pilot-scale study would be required prior to
remedial design to optimize the- reagent concentration, mixing rate, and other process variables.
The estimated capital cost of stabilization, including the pilot-scale study, design, and
construction, is $5,296,000. Stabilization would take approximately' one year to implement
following seven months of design and review, some of which could be concurrent with the pilot-
scale study. The stabilized soil and contaminants would remain in the Pond and actually
increase the volume of contaminated sediment.
The advantages of stabilization are that the release and mobility of the contaminants are
reduced or eliminated. Stabilization can also facilitate transportation and off-site disposal,
especially where volume reduction or extraction techniques have been applied previously.
Stabilization may be effective in binding chemical contaminants in addition to the radionuclides.
Among the disadvantages of stabilization is the fact that its long-term effectiveness is unknown.
Also, stabilization traps the contaminants, but does not remove or eliminate them. Ap.
contaminants remain in the Pond and capping may be necessary to minimize exposure. Some
chemicals, particularly organics, may interfere with the stabilization process.
Alternative 4: Separation/Extraction
The separation/extraction alternative consists of a combination of two technologies:
physical separation and chemical extraction.
Physical Separation
Based on sampling of the Pond sediments, the radioactive and chemical contaminants
in soils are commonly as$OCiated with the fine-grained soil particles. Separation of the fine-
grained soil particles concentrates the contaminants and therefore reduces the volume of soil for
further treatment or disposal. Physical separation utilizes mechanical methods for separating
heterogeneous mixtures of solids to obtain a concentrated form of the contaminants. Chemical
agents may be added to enhance the separation process. The different types of physical
separation are typically most effective in dealing with a ~ific size range of soil particles and
a combination can be used to isolate the size fraction 9eSu-ed. . There are four major categories
of separation technology applicable to soil remediation: screening, classification, flotation, and
gravity concentration. Screening is the separation of particles on the basis of size by passing
the particles through a uniformly perforated surface. Classification is the separation of particles
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according to their settling rate in water. Flotation is concentration of the contaminants in the
froth which collects on a liquid. Gravity separation is separation of particles based on density,
shape, weight, and size.
Based on the results of the bench-scale treatability study of the Warm Waste Pond
sediments, the particles which are larger than 11 16th of an inch consist of more than 60 percent
of the volume. Therefore, screening would be the first part of any treatment system for the
Pond sediments. Further. isolation of finer grained materials would likely be done with
classification or gravity separation. The large and relatively uncontaminated particles would be
returned to the Pond.
The .advantages of physical separation are: it is an inexpensive method for separating
coarse and fine materials, high continuous processing capabilities are possible, and they are well
proven in the mining industry. The disadvantages are: screens are subject to plugging, soils with
large amounts of fine-grained materials are difficult to process, and to achieve a high level of
separation of a particular size particle requires longer processing times. .
Chemical Extraction
Chemical extraction uses chemicals to extract the cesium, cobalt, and chromium from
the sediment. The most common chemicals used for extraction are water, inorganic salts,
mineral acids, and complexing agents. Other chemical extraction methods include precipitation,
solvent extraction, and ion exchange. There are notable differences in the extractability rates
of each of the methods caused by the types of soil.
Bench-scale testing indicates that using acids as the extracting agents is effective in
extracting cesium, cobalt, and chromium from the Warm Waste Pond sediments. Chromium
removal will be maximized even though it was not shown to pose a risk in the preliminary risk
evaluation. The advantages of extraction with acids are: a high percentage of radionuclides can
be removed, a relatively smaliliquid-to-solids ratio is required, requiring less pumping power
and smaller tanks and equipment, and the acids can likely be recycled. 1Jle disadvantages of
using acids for the extracting agents are the possibility of increased costs due to the use of
relatively expensive reagents, higher operating temperatures, and stainless steel vessels and
pipes. It is possible that undesirable byproducts, such as characteristic mixed (radioactive and
hazardous) waste, could be produced which would be subject to RCRA regulatory requirements.
Separation/Extraction
For the contaminated sediments of the Warm Waste Pond, predominantly in the upper
two feet, a combination of physical separation followed by chemical ~xtraction is proposed. The
interim action will be preceded by a pilot scale treatab~~ study focusing on the chemical
extraction portion of the remedy. The purpose of the pilot treatability study will be to determine
if the extraction efficiencies which have been demonstrated in the bench scaIe treatability study
can be achieved on a larger scale. Specifically, the pilot study will evaluate whether an average
of 90 percent removal of cesium, cobalt, and chromium can be achieved with no
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RCRA-hazardous wastes generated which cannot be treated to be non-characteristic. The
estimated capital cost of the separation/extraction remedy, including the pilot study, design,
construction, and storage of the product residuals is $7,195,000. The separation/extraction unit
would be operated for approximately one year, followed by backfilling and grading. Design will
be completed following treatability study work, which will take nearly ten months to complete
following issuance of the Record of Decision.
Separation/extraction reduces the risks by removing much of the cesium-137 and cobalt-
60 from the Pond sediments. These radionuclides would be concentrated as the product of the
treatment process and would be further treated and stored on site such that it could be visually
monitored, either directly or .indirectly, until its final disposal can be determined in the
comprehensive WAG RI/FS. Following the separation/extraction process and return of the
residuals to the Pond, the Pond would be ba~kfilled. Backfilling will provide additional
reduction of potential external exposure from remaining contamination. The remaining risk of
the Pond sediments will be evaluated in the comprehensive WAG RI/FS. The selected remedy
is described in Section IX.
vm~ SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVFS
CERCLA guidance requires that each remedial alternative be evaluated according to
specific criteria. The purpose of the evaluation is to determine the advantages and disadvantages
of each alternative, and thereby guide selection of the remedial alternative offering the most
effective and 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 four remedial alternatives described in Section VII 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
. Short-term effectiveness
. Implementability
. Cost
Modifying criteria
. State acceptance
. Community acceptance.
. - . ,
.
.
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Threshold Criteria
!F
The remedial alternatives were evaluated .in relation to the threshold criteria: overall
protection of human health 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 Record of Decision. The threshold criteria must be met for a final remedial action, and
this interim action is intended to meet those criteria, if possible. The effectiveness of this
remedial action will be evaluated as a final remedy in the WAG-wide RIfFS.
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,. and 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,
short-term effectiveness, and compliance with ARARs. For an interim action, the present risk(s)
to 'human health and the environment must be reduced. If this interim action is successful,
potential risks will be reduced to acceptable levels, and further remedial action may be
unnecessary. The interim action will be followed by a final remedial action either.in the W AG-
wide RIfFS, or the perched water RIfFS, if necessary.
All of the remedial alternatives which were considered, except the no action. alternative,
provide short-term protection of human health and the environment by reducing the radiation
field and therefore the potential risk due to external exposure. All of the alternatives except the
no action are therefore acceptable as interim actions. .
Compliance with Applicable or Relevant and Appropriate Requirements (ARARs)
CERCLA, as amended by SARA, requires that remedial actions for Superfund sites
comply with Federal and State laws that are applicable to the action being taken. Remedial
actions must 'also comply with the requirements of laws and regulations that are not directly
applicable, but are relevant and appropriate; in other words, requirements that pertain to
situations sufficiently similar to those encountered at a Superfund site such that their use is well
suited to the site. Combined, these are referred to as applicable or relevant and appropriate
requirements (ARARs). State ARARs are limited to those requirements which are more
stringent than Federal requirements. Compliance with ARARs requires ev~uation of the
remedial alternatives for compliance with chemical-, location-, and action-specific ARARs or
justification for a waiver; and whether the remedial alternative considers other criteria,
advisories, and guidelines.
A waiver for interim measures may be applicable when a remedial action is only part
of a total set of measures as is the case for the Warm Waste Pond sedlments~. This waiver may
be granted if complete measures that will attain all ARARs will follow the interim action within
a reasonable period of time. In this case, all ARARs will be addressed by the WAG-wide
Record Of Decision, if not already attained in the interim action. An interim measure should
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not complicate nor delay the overall site cleanup and should be consistent with it. The granting
of ARARs waivers should not present an immediate threat to public health and the environment.
Chemical-Specific ARARs. Chemical- (and radionuclide-) specific ARARs are
standards for allowable levels of certain contaminants in the environment and are generally
issued pursuant to the Federal Safe Drinking Water Act (SDW A), the Clean Water Act (CW A),
the Clean Air Act (CAA), the- Resource Conservation and Recovery Act (RCRA; chemical, but
not radionuclides), the Atomic Energy Act (AEA; radionuclides, but not chemicals), and state
and local counterpart requirements.
When a chemical- or radionuclide-specific ARAR exists and is considered to be
protective of human health and environment, it becomes a specific cleanup goal. For the Warm
Waste Pond sediments, chemical-specific ARARs for cleanup standards are available for water
and air only. No specific cleanup levels for chemicals in soils are available. Guidance provided
under the authority of the AEA includes numerical criteria for air and water for radionuclides.
DOE has not established radionuclide-specific criteria for soil, but has established performance-
based standards for soil contamination at operating and decommissioned facilities. If a chemical-
or radionuclide-specific ARAR does not exist or is not adequately protective, the health-based
risk assessment performed under the RI would determine the appropriate cleanup goal .
The SDW A is generally used as the ARAR for appropriate cleanup standards for
contaminated groundwater that is or may be used as drinking water~ The CW A provides
guidelines to determine water quality standards of surface receiving waters. Since this interim
action addresses the external exposure concerns for the Warm Waste Pond sediments and does
not address groundwater or surface water, the SDW A and CW A are not ARARs, for this limited
action.
RCRA provides chemical-specific ARARs in the areas of groundwater monitoring,
cleanup standards, and treatment standards. The standards apply' if the waste is a listed or
characteristic'waste under RCRA, and either (1) the waste was treated, stored, or disposed after
the effective date of RCRA requirements under consideration, or (2) the CERCLA activity
constitutes treatment, storage, or disposal as defined by RCRA. The Hazardous Waste
Management Act (HWMA) establishes the State of Idaho's authorization to implement the RCRA
program.
In the case of the Warm Waste Pond, the sediments are not RCRA hazardous wastes
based on tests conducted in 1990. In addition, no RCRA wastes were disposed in the Pond after
1972, prior to the promulgation of RCRA. Therefore, RCRA is not applicable for establishing
cleanup or treatment standards for this action. If the remedy creates RCRA-hazardous waste,
that waste will be subject to the requirements of RCRA arid:Land Disposal Restrictions (LDRs)
requirements may be triggered. . - . -
Requirements under the - AEA are applicable to the procurement, use, and disposal of
all source, byproduct, and special nuclear material at the INEL. Regulations. governing
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operations of the DOE facility are contained in 10 CFR 200 et seq, and are implemented through
DOE Orders, Directives; and Notices that specify policy, standards, and guidance for all DOE
facilities. Although DOE Orders are not ARARs since they are not promulgated requirements,
all of the requirements of DOE Orders are to be considered (TBCs). DOE Orders which may
apply to CERCLA activities include DOE 5480.11 and DOE 5820.2A. DOE 5480.11,
"Radiation Protection for Occupational Workers," establishes radionuclide-specific criteria to
protect workers from hazard. of exposure to ionizing radiation and radioactive materials. DOE
5820.2A, "Radioactive Waste Management, " establishes standards for "external exposure to the
waste and concentration of radioactive material which may be released into surface water,
groundwater, soil, plants, and animals results in an effective dose equivalent that does not
exceed 25 mrem/year 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 years) will not exceed 100 mrer:nJyear for a continuous
exposure or 500 mrem/year for a single acute exposure." Capping, stabilization, and
separation/extraction as described all meet this standard.
~
The CAA establishes national standards and goals for air pollution control. For less
common air pollutants that can have acute effects on public health, such as radionuclides, EP A
establishes National Emission Standards for Hazardous Air Pollutants (NESHAP). Specific
NESHAP regulations apply to allowable off-site radionuclide doses to the public from emissions
at DOE facilities. Due to its location within the INEL, over fifteen miles from the nearest city,
the small scale of the processing plant, and the engineering controls used to limit air emissions,
the activities at the Warm Waste Pond should not result in additional off-site exposure to the
public.
Action-Specific ARARs. Certain design, performance, or action-specific ARARs could affect
this interim action.
If the requirements of RCRA LDRs apply to the residual waste, treatment technologies
meeting those restrictions will have to be employed or treatability variances sought.

"a:.
Engineering controls will be used to the extent possible to eliminate or minimize air
emissions and will be described in the remedial design. The substaJ:ltive requirements of the
Idaho Rules and Regulations for the Control of Air Pollution will have to be met if the extraction
procedure would result in the release of gases, vapors and/or fugitive emissions. .
Location-Specific ARARs.Location-specific requirements include ordinances or rules and
regulations as well as restrictions or guidance contained in major Federal and State
environmental programs.
.
Idaho Water Quality Standards are issued on a basiit~by-basin basis and are therefore
location-specific,. but are only applicable to a remedial action if it involveS a point-source
discharge to surface or ground waters, and therefore is not applicable to any of the alternatives. .
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Although the National Historic Preservation Act would be applicable to CERCLA
actions, there are no places of historic significance which will be affected by remediation
activities at the Warm Waste Pond. Since no threatened or endangered species or habitat have
been identified at the Warm Waste Pond, the Endangered Species. Act is not an ARAR.
Balancing Criteria
Once an alternative satisfies the 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. .
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 remaining risks is evaluated by assessing the residual risk associated
with untreated 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 andlor
institutional controls to determine if they are sufficient to ensure that any exposure to residual
risks to human health and the environment is within protective levels. It includes consideration
of the potential need to replace technical components of the remedial action, such as a cap, and
the potential exposure pathway and risks which could be posed should the technical components
degrade over'time. .
For capping, the remaining risks are associated with the buried contaminants, all of
which remain in the Pond sediments. Capping reduces the potential risk due to external
exposure, inhalation, and ingestion to the extent that the integrity of the cap and backfilled
material can be assured until such time that the radioactive contaminants of. concern have
decayed to an acceptable level. It is estimated to be 400 years until the cesium-13? in the Warm
Waste Pond will decay to an acceptable level. Caps have a design life of 100 years and require
maintenance throughout the use of the cap. Therefore, capping cannot be considered as
permanent as separation/extraction. .
. - . .
Stabilization meets the criterion for long-terni effectiveness. by 'binding up the
contaminants in thecementlsediment matrix, thereby reducing residual risks. Unfortunately, the
permanence of stabilization technology is unproven for the length of time needed for the cesium-
137 to decay to acceptable levels and like capping is not as permanent as separation/extraction.
23
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Separation/extracti
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During implementation of any of the alternatives, protection of workers from radiation
exposure would be an important element of the remedial design. Since the Warm Waste Pond
is a radiologically controlled area, all personnel entering the area must have training for
hazardous substances, radioactive substances, and respirators. Health physics personnel will be
on site at all times when work is ongoing to monitor and control personnel radiation exposure.
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 ALARA (as low
as reasonably achievable) radiation dose goals for personnel which will be met.
By using engineering controls, such as a protective enclosure, and access restrictions,
the remedial action will not be- a risk to the community. Access to visitors and others not
working on the project will be strictly limited to those meeting the same training requirements
as the workers.
The remedial actions would begin in 1992. Stabilization and separation/extraction
would require a pilot-scale treatability study to refine design parameters during the remedial
design phase, which would be completed in the spring and summer of 1992. Upon completion
of the pilot-scale treatability study, final remedial design could be completed, with the remedial
action initiated. Capping could be implemented without testing.
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. The ability to coordinate actions with other agencies is the only
factor for evaluating administrative feasibility and is not a concern for this project. The
availability of services and materials requires evaluation of the following factors: availability of
treatment, storage capacity and disposal services; availability of necessary equipment. and
specialists; ami availability of prospective technologies.
The technical feasibility of capping is well established. Cap design and construction
is a readily available technology which has been in common use for a number of years. Capping
is reliable to the extent that the integrity of the cap can be maintained. In this ease, only a
temporary cap would be installed as this is not the final remedial action. The ~p is expected
to provide interim protection until the final remedial action was implemented. A cap is easily
removed, although additional material will become contaminated increasing the amount of
material which must be dealt with in any future remedial actions.
Stabilization is a rapidly emerging technology for treating ~ntaminated soils. Several
companies have developed equipment for mixing the stabilization agents with the soil in place,
and the equipment and personnel are available. Stabilization would require a pilot-scale
treatability study to determine the best stabilization agents, mixing rate, mixing speed, etc...
Two concerns with stabilization are the reliability of the technology and the ease of undertaking
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additional remedial actions should it be necessary in the future. . The technology is unproven for
the length of time required for the cesium-137 to decay to acceptable levels, therefore additional
remedial action may be required at a future time. The solid, stabilized mass could make it very
difficult to pursue additional remedial actions. The stabilized material would also require
backfilling to reduce the potential radiation exposure.
Physical separation .and chemical extraction are well developed technologies which have
been used in the mining industry for extraction of radionuclides from ores. Physical separation
is an easily implemented technology, in this case simply requiring separation of the sediment into
different grain size fractions using screens or sieves. Chemical extraction has not been used to
remediate a cesium-contaminated site, but bench-scale testing for this interim action on the
Warm Waste Pond sediments indicates that nearly 90 percent of the contaminants of concern can
be removed from the fined-grained material inthe.Warm Waste Pond after it has been separated
from the coarse material, which comprise over 60 percent of the total volume. A pilot scale
treatability study would be required to determine the best operating parameters, such as reagent
strength, holding times, and flow-through rates. The pilot treatability study would also be used
to ensure that no RCRA-hazardous wastes are generated. An additional treatment process within
the plant may be required for this purpose. All of the components of the pilot-plant and the final
remedial treatment plant are available. The separation/extraction process generates a
concentrated residual containing a large percentage of the contaminants of concern. In this case,
that residual is expected to be low-level radioactive waste. Although storage andlor disposal
facilities are available at the INEL, the State, as a condition of concurrence, requires that any
low-level waste residuals will be stored and visually monitored, either directly or indirectly, until.
final disposition. .
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, . administration, and periodic review. Actual costs are
expected to be no more than 50 percent over, or 30 percent under, the cost estimate.
Capital costs for capping are estimated at: design - $250,000; construction -
$2,113,000; 20 percent contingency - $423,000; total- $2,786,000. Maintenance and operation
are estimated to be an additional $50,000 annually.
Capital costs for stabilization are estimated at: design - $400,000; construction -
$3,480,000, 20 percent contingency - $696,000; pilot-scale treatability study - $720,000; total -
$5,296,000.- No operating and maintenance costs have been identified for the stabilization
option. . - . .
Capital costs for separation/extraction are estimated at: design - $500,000; construction
-$4,704,000; 20 percent contingency - $941,000; treatability studies - $750,000; storage of
product residuals - $300,000; total $7,195,000. The only operating and maintenance costs
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identified for the separation/extraction alternative is that associated with the storage of the
treatment process wastes not returned to the Pond. Those costs are estimated to be $300,000
for a temporary storage facility and storage containers.
All of the alternatives would be implemented and completed within the same time
frame, with a maximum difference of duration of 18 months. Therefore, all costs are in 1991
dollars.
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 which are considered include the elements of the . alternatives which are
supported, the elements of the alternatives which are not supported, and the elements of the
alternatives which have strong opposition.
State Acceptance
This assessment evaluates the technical and administrative issues and concerns the state
may have regarding each of the alternatives.
The State of Idaho prefers the separation/extraction alternative because it takes the
contaminants of concern from an uncontrolled situation to a controlled situation. If separation/,
extraction is implemented, the State prefers that the storage of the residuals be conducted sucH
that they can be visually monitored, either directly or indirectly, until their final disposition is
determined .
Community Acceptance
This assessment evaluates the issues and concerns the public may have with each of the
alternatives. -',
Capping was preferred by some citizens due to its lower cost and the possibility of
improved technologies which may be developed in the near future. Other citizens categorically
reject capping because it is not a cleanup and wanted the contaminants removed from the
sediments.
Stabilization received the least amount of public comment of the alternatives, although
some citizens did not consider it to be a cleanup. .
Separation/extraction was preferred by those citizeo.s.who felt that o~ly by removing
the co~taminants from the sediments could a cleanup be realized, although those same citizens
expressed concern that no final disposition for the residuals has been determined. Other citizens
felt that separation/extraction was too expensive.
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IX. TIlE SELECTED REMEDY
The selected remedy consists of physical separation followed by chemical extraction and
includes the following steps: excavation, screening, classification, chemical extraction, recovery,
residuals treatment, storage and/or disposal. The successful implementation of the selected
remedy depends upon the success of the pilot-scale treatability study, a demonstration project.
If the goals of the pilot-scale project are not met, the Wann Waste Pond sediments will be
addressed in an amendment to this Record of Decision or in a subsequent final action. The
pilot-scale demonstration will be a smaller-scale version of the proposed facilities which will be
used to fine-tune the design of the classification, chemical extraction, and recovery systems.
First, the sediments must be excavated to be input to the pilot plant. Two excavation
techniques are being considered: hydraulic and heavy machinery. Hydraulic excavation consists
of the use of a water-jetting and suction system. The sediments are excavated using a water
stream which is sucked into the input side of the screening system. The advantages of hydraulic
excavation are the lack of dust produced and the fact that the large-grained materials can be left .
in the Pond if the system is adjusted properly. Hydraulic excavation will be considered in the
pilot-scale demonstration project. Heavy machinery excavation is the use of bulldozers,
backhoes, front-end loaders and other similar equipment to remove the sediments and load them.
into the input side of the screening plant. Either excavation technique, or a combination of the
two, will be used.
An average of two feet of sediment will be excavated from the Pond. Field screening
with portable gamma detecting instruments and/or sampling will be conducted during the
excavation to ensure that all of the contaminated sediments above the removal criteria are being
excavated and input to the treatment plant. The removal criteria is based upon risk reduction
to within the NCP target range. Based upon the preliminary risk evaluation, it is estimated that
a level of cesium averaging below 690 pCilgm.in the Pond sediments wil~ adequately reduce the
potential risks. Therefore, that has been established as the removal criteria. The total volume
of excavated material will be approximately 20,700 yd3 based on a surface area (including banks)
of 280,000 ff-.and an average depth of 2 feet. The estimated weight of the material, assuming
all grain sizes are excavated, that will be input to the screening plant is 44,000 tons with an
assumed feed rate of 5 tons per hour.
Screening is the first portion of the treatment plant. The screen plant will separate the
large-grained material from the fine-grained material. Based upon the bench-SGaie treatability
study, at least a 6O-percent volume reduction in contaminated material is expected following
screening. Water is likely to be used during screening to wash the large-gt;ained materials, as
well as keep dust to a minimum. The larger material will be returned to the Pond. It is
estimated that wet screening will separate 29;000 tons of large-grained material to be returned
to the Pond. . - . .
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It is likely that c1assi.fication will follow screening to further separate very fine-grained
material from fine-grained material. Hydrocylones or similar equipment will be used to further
reduce the volume of material input to the chemical extraction unit. The larger material will be
returned to the Pond. An additional 20-percent reduction in volume of contaminated material
is expected following classification, resulting in 12,000 tons of very fine-grained material to be
input to the chemical extraction system, assumed to be fed at the rate of 1.5 tons per hour.
The very fine-grained material resulting from the physical separation processes is input
to the chemical extraction unit. The fine-grained material is mixed with acid and held in a tank
to allow maximum leaching of the contaminants. The strength and type of acid as well as the
holding time will be evaluated in the treatability studies, but hydrochloric acid or aqua regia (a
mixture of nitric acid and hydrochloric acid) appear to work most effectively. The extraction
system is expected to be a two stage system.. The chemical extraction process results in two
products: the waste residuals which are removed from the liquid and an acidic liquid which
contains the contaminants of concern. The waste residuals will be combined with backfill
materials and returned to the Pond. The mixture of residuals and backfill materials will meet
the removal criteria. The Pond will be backfilled to above grade following completion of
processing of the sediments.
The acidic liquid is input to the recovery system which removes the contaminants of
concern. The preferred recovery system is ion exchange, although chemical precipitation or
filtration may prove more cost effective. Ion exchange produces less sludge than chemical
precipitation or filtration, but has not proven as efficient in bench-scale tests. The liquid can
then be recycled and reused in the chemical extraction system. It is likely that the cesium':
cobalt, and chromium can be removed individually from the acidic liquid. It may be possible
to treat the cesium and cobalt liquid waste stream at the Idaho Chemical Processing Plant (ICPP)
at the INEL. The residual would be processed in the residual treatment portion of the treatment
plant.
. The residuals will be tested to determine the radioactive and chemical constituents and
treated, if necessary, to meet all applicable storage and/or disposal criteria. For example, if the
residuals are RCRA-hazardous due to leaching using the TCLP test, they will be treated to
reduce the leachability to ensure that all storage and disposal criteria are met. If the residuals
contain any liquids they will have to be dried. If separate residuals are created by separating
the cesium, cobalt, and chromium individually, each will be tested and treated as Recessary.
.
The residuals will then be stored in containers such that they can be visually monitored,
either directly or indirectly, to verify the integrity of the storage containers until the final
disposition of the residuals is determined. The disposition of the residuals will be determined
no later than. the WAG-wide Record of Decision scheduled to begin in 1996. The storage
criteria will be finalized following the pilot-scale treatability stUdy fr01!1 which the characteristics
of the waste will be determined. The waste is expected to be low-level radioa:ctive, non-RCRA
hazardous waste, and if so, the residuals will be stored within a radioactive storage area. The
expected criteria for selection of storage containers and controls is the radioactive field due to
the residuals and the associated restrictions and requirements. The storage containers likely.to
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be used are concrete boxes, which provide radiological protection and can be stored such that
the integrity of the containers can be monitored. One of the goals of the pilot study is to
minimize the amount of waste created.
Pilot-Scale Treatability Study
As the proposed reQIedial alternative is an innovative technology and has not been used
for the remediation of radiologically-contaminated soils, testing of the processes involved will
be required. . Bench-scale testing has indicated that the required removal efficiency of the
contaminants of concern can be achieved using a combination of separation and extraction.
Additional bench-scale testing will be conducted to optimize the extraction efficiency. The pilot
study is to demonstrate- that the processes which have been proven in the laboratory can be
replicated in a Scaled-liP processing plant.
The goals of the pilot study are:
. -
.
.
.
.
.
.
Verify the 60+ percent reduction in volume by screening,
Evaluate whether an average of 90 percent removal of cesium, cobalt, and
chromium can be achieved, .
Maximize the efficiency of the classification process to minimize the amount
of materials input to the chemical extraction unit,
Determine the parameters in the chemical extraction unit which will achieve
the required removal efficiency while at the same time produce the smallest
amount of residuals, ;
Minimize the waste produced by the recovery system,
Minimize or eliminate any characteristic which makes the waste RCRA
hazardous, including treatment if necessary, and
Provide design information for the remedial action, particularly in the area of
geometry of components to minimize potential exposure to workers.
The primary goal of the pilot plant is to demonstrate the removal efficiency of cesium-
137, cobalt-60, and chromium. Although cobalt-60 presents a potential risk due to the radiation
field associated with it, its relatively short half-life of 5.3 years effectively eliminates it in the
future use scenarios beginning in 100 years. A design goal for the cesium-137 removal was
established based upon reduction of potential risks to within the NCP target range. . Backfilling
of the Pond following the separation/extraction reduces the risk due to external exposure and will
reduce or eliminate the present potential risk due to inhalation. Based upon these assumptions,
a preliminary estimate of the cleanup level for cesium-137 of 1385 pCilgm would achieve a
calculated risk of one in 10,000 increased incidence of cancer. Therefore, the pilot study will
maximize the cesium-i37 removal efficiency. The removallbackfill criteria established at an
average concentration of 690 pCiI gm would put the estimated .Calculated risk in the range of one
in 100,000. Higher removal efficiency will be utilized "if possible- and the -adequacy of the
interim action as a final action will be assessed in the comprehensive WAG RIfFS. .
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x. STATUTORY DETERMINATION
CERCLA remedy selection is based on the Superfund Amendments and Reauthorization
Act of 1986 (SARA) and the regulations contained in the National Contingency Plan (NCP).
SARA requires that the EP A utilize permanent solutions and alternative treatment technologies
to the maximum extent practicable. All remedies must meet the threshold criteria established
in the NCP: protection of human health and the environment and attainment of ARARs.
Protection of Human Health and the Environment
As described in SectionJX, the selected remedy will eliminate or reduce identified risks
at the Warm Waste Pond by treating the Pond sediments to the extent necessary. The remedy
will reduce the cumulative carcinogenic risk due primarily to external exposure to within the lQ4
to 1045 range as required by the NCP. Storage and/or disposal of the concentrated residuals will
meet all applicable acceptance standards. .
Compliance with ARARs
The selected. remedy will comply with the substantive requirements of all ARARs.
ARARs are discussed in Section VllI.
Cost Effectiveness
Although the estimated cost for the selected remedy is higher than that for the other:
alternatives, separation/extraction provides a long-term solution that compensates for the
additional costs by removing the majority of the contaminants of concern and thereby providing
potentially permanent protection of human health and the environment. It also removes these
contaminants from the Pond making them unavailable for potential leaching into the underlying
soils and groundwater.
-.,Utilization of Permanent Solutions and Alternative Treatment
Technologies to the Maximum Extent Possible
The selected remedy meets the statutory requirements to utilize permanent solutions and
treatment technologies to the maximum extent possible, for this interim action. The Agencies
prefer a potential permanent solution whenever possible and in the case of ther Warm Waste
Pond, it is possible to meet the objectives of an interim action and provide a potentially
permanent treatment solution. The selected remedy significantly reduces the volume of
contaminated material. In addition, it will reduce the volume of contaminants in the Pond
sediments. Based on the evaluation of the CERCLA remedial alternative criteria, and in
particular the five balancing criteria, separation/extractionjs~the clear choice if seeking a long-
term solution which reduces the toxicity, J1.1obility or volume of the cOntaminants. The criteria
which was the determining factor was long-term effectiveness. Utilizing separation/extraction
will increase the likelihood that no future remedial actions will be required for the Warm Waste
Pond. .
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Preference for Treatment as a Principal Element
The statutory preference for treatment that permanently and significantly reduces the
toxicity, mobility, or volume of hazardous substances as a principal element is met by the use
of separation/extraction, which provides a permanent reduction in toxicity, mobility, and volume
of the contaminated material at the Warm Waste Pond.
XI. EXPLANATION OF SIGNIFICANT DIFFERENCES
A significant change from the Proposed Plan set forth in the Record of Decision is the
elimination of the contingency remedy. In the Proposed Plan, it was stated that if the pilot study
of the physical separation/chemical extraction was unsuccessful, a contingency remedy, cappi....tg,
would be implemented.' Upon reevaluation, it was determined that since the primary purpose
of a cap is to prevent infiltration of precipitation and that th~ need for such infiltration
prevention has not been determined, the need for a cap has not been established. If the need to
prevent infiltration of precipitation is identified in the perched water RIfFS or the comprehensive
WAG 'RlfFS, a cap would be evaluated as an option at that point. As part of the interim action,
. the Pond would be backfilled to above grade, which would reduce the radiation field and
mitigate the potential for blowi~g dust. In the event the g~s of the pilot-scale project are not
met, a soil cover will be placed over the Warm Waste Pond to reduce the radiation field and
mitigate the potential for blowing dust.
Another change from the Proposed Plan is the possibility of shipping the cesium and
cobalt residual for treatment at the ICPP which is located at the INEL.. This option had not
been considered in the Proposed Plan, but was suggested by a commentor at a public meeting.
The treatability studies will determine if the .use of ICPP for treatment is possible and cost
effective.
".,
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RESPONSIVENESS SUMMARY
Overview
The sediments of the Warm Waste Pond at the Test Reactor Area (fRA) are the first
operable unit to be addressed through a Record of Decision at the Idaho National Engineering
Laboratory (INEL). A Proposed Plan was released on July 25, 1991 with a public comment
period from July 29 to August 28, 1991. The Proposed Plan recommended a combination of
physical separation and chemical extraction to remove cesium-137 and cobalt-60 from the Pond
sediments.
Nearly all of the comments were verbal comments received at the public meetings held
at five locations around the State of Idaho. Only fifteen sets of written comments were received
from 10 individuals.
In general, there were two predominant public opinions on the preferred alternative as
described in the Proposed Plan; it was too expensive or. it was the best alternative of the
alternatives presented. Those who felt the preferred alternative was too expensive usually
expressed concern that a large sum of money was being spent to reduce potential risks which
did not reflect the actual risks posed by the Pond. Many felt capping, the least expensive
alternative, should be the implemented action. The other predominant reasoning was that of the
alternatives evaluated in the Proposed Plan, only the preferred alternative was actually a
"cleanup," given that each of the other alternatives leaves the contaminants in the ground.
Other issues raised were: adequacy of characterization data; operations at TRA, the
continued use of the Pond; adequacy of the risk assessment process; remedial alternatives; ability
to implement the proposed action and disposition of the residual created; research of remedial
of technologies; degree of oversight of DOE and its contractors in performing the. remedial
action; community relations; and NEPA.
",
Background on Community Involvement
A series of five public informational meetings were held in late June 1991 to explain
how the CERCLA process works and to introduce the Warm Waste Pond cleanup project to the
public. These informational meetings were announced via the INEL Reporter. newsletter,
newspaper and radio advertisements, and an INEL press release. Phone calls wele made to key
individuals, environmental groups, and organizations by the INEL field offices in Pocatello,
Twin Falls, and Boise. The Community Relations Plan Coordinator ~ade calls to key
individuals in Idaho Falls and Moscow. Each of the meetings were videotaped.
The Notice of Availability for the Proposed Plan was published July 28, 1991 in the
Post Register (Idaho Falls), Idaho State Journal (pocatello), Times News (Twin Falls), Idaho
Statesman (Boise), and Idahoan (Moscow). A similar newspaper advertisement appeared in the
same newspapers the following week repeating the public meeting locations and times. Personal
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phone calls as noted above were made to inform key individuals and groups about the comment
opportunity. .
The Proposed Plan for the interim action of the TRA Warm Waste Pond sediments was
mailed to the public on July 26, 1991. The Proposed Plan was mailed to 2,100 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 Plan and to attend
publ~c meetings. Copies of the Plan and the administrative record are available to the public in
six regional INEL information repositories: INEL Technical Library in Idaho Falls; and city
libraries in Idaho Falls, Pocatello, Twin Falls, Boise, and Moscow. The Administrative Record
file for the Warm Waste Pond Sediments Interim Action was placed in the information
repositories sections or at the reference desk in each of the libraries on July 26, 1991.
~J
The public comment period was held from July 29, 1991 to August 28, 1991. No
extension requests were made. Public meetings were held on August 7, 8, 13, 14, and 15, 1991
in Idaho Falls, Pocatello, Twin Falls, Boise, and Moscow respectively. At the meetings in
Idaho Falls and Pocatello, representatives from DOE, EPA and IDHW discussed the project,
answered questions, and received public comments. At the meetings in Twin Falls, Boise, and
Moscow, DOE and IDHW were represented. Verbatim transcripts were prepared by a court
reporter of each public meeting. Each was recorded on audio tape and the Twin Falls and Boise
meetings were videotaped as well. Written comment forms were distributed at each of the
meetings.
Summary of Comments Received During Public Comment Period
Comments and questions raised during the Warm Waste Pond interim action public
comment period on the Proposed Plan are summarized briefly below. The comment period was
held from July 29 to August 28, 1991. Many questions were answered at the public meeting
as reflected in the transcripts in Appendix A. Comments and questions on a variety of subjects
not specific to the Warm Waste Pond were recorded. Those subjects included nuclear arms
production, dose reconstruction, diversion of cleanup funds, references to unrelated documents,
etc., and are not responded to in this Responsiveness Summary. Additional information on these
unrelated subjects can be obtained from the INEL Public Affairs Office in Idaho Falls or at the
local INEL offices in Pocatello, Twin Falls, and Boise. The questions on the Warm Waste Pond
not addressed at the meetings, and comments, are categorized below.
Characterization Data
Many questions at the public meetings concerned the characterization data, including
monitoring, geological and hydrogeological infonnation used as the basis for the proposed
action. Unless specifically addressed below, that infonnatien'is available in the administrative
~~repo~ ~ ,
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1.
Two commentors expressed concern that the analyses for radionuclides was incomplete.
Response: A standard set of radiological analyses were conducted on the Pond
sediments, including 1-129, Pu-238, Pu-239, and Pu-240. The 1-129 analysis was not
discussed in the Proposed Plan, but averages approximately 0.3 pCi/gm, and does not
pose an unacceptable risk.
One commentor felt that the Warm Waste Pond as an operable unit allowed for
inadequate characterization or confused the public concerning the number of sites at
TRA.
There are thirteen operable units at TRA encompassing 49 sites. All of the operable
units will be, or are being, evaluated as d~ribed in the FFAlCO, which also includes
a description of the breakout of the Warm Waste Pond as an operable unit. Other
operable units include the MTR canal, the Retention Basin and associated piping, and
the perched water.
Operations at Test Reactor Area
3.
Many com mentors felt the current use of the Pond is inappropriate, if not illegal, and
were concerned with the effects of leaching contaminants, perched water, and fugitive
dust.
Response: The use of the Warm Waste Pond has always met the laws and regulation~
in effect at the time, including its use at the present time. Most of the contaminants in
the Pond sediments are the result of past disposal practices, not current discharges.
The volume and levels of contaminants in the wastewater have decreased over 90
percent in the last 10-15 years. The wastewater discharged to the Pond, as well as the
sediments in the Pond, are not hazardous as defined by RCRA. The contaminants
present in the sediments are largely insoluble and are not easily leached. Information
from..investigations show that the more soluble contaminants have migrated to layers
below the ponds into the perched water and the aquifer. The water discharged to the
Pond contributes to the perched water system. The impact of the perched water system
on the Snake River Plain Aquifer, is currently being evaluated in an RIfFS. The Warm
Waste Pond is scheduled to be replaced by a lined evaporation pond in 1992, and
therefore for all of the alternatives the potential leaching of contaminants would be
reduced. An acrylic-copolymer dust suppressant has been sprayed on the Pond to
reduce fugitive dust and will be reapplied as necessary.
4.
Thre.e commentors expressed concern that the lined evaporation pond which will replace
the Warm Waste Pond could leak or asked about the. cost and/or schedule for the new
pond.
Response: The proposed action addresses cleanup of the sediments which may pose a
threat to workers/visitors due to the radiological hazard primarily from cesium and
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cobalt. The elimination of future discharges to the Pond is being evaluated in the
perched water RIfFS. The new lined evaporation pond is subject to operating and
regulatory requirements which are beyond the scope of this document. Information on
. subjects like the new evaporation pond can be directed to the lNEL Public Affairs
Office.
Risk Assessment
Many com mentors had questions or concerns regarding risk assessments.
5.
Many com mentors felt that the preliminary risk assessment process is flawed and the
scenarios evaluated were inappropriate, in that institutional controls were adequate to
prevent the calculated estimated risk. .
Response: National risk assessment guidance was used for the evaluation of risks to
human health and the environment. This guidance applies to all publicly or privately
owned facilities. As is often the case, there are a wide variety of opinions on the
degree of risk which is acceptable and the scenarios which should be evaluated to
determine that risk. Institutional controls are not included in the evaluation as they may
not continue indefinitely. The preliminary risk evaluation considered several scenarios
to assess the potential threat to human health and the environment.
6.
Several comments concerned the interpretation of the risk assessment of the interim
action.
Response: The results of the preliminary risk evaluation for the interim action, which
is in the administrative record, are summarized in Section VI of the Decision Summary
of this Record of Decision. The risks associated with external exposure to radiation,
and inhalation and ingestion of contaminated soil were evaluated. The risks due to
ingestion of contaminated water below the Pond will be evaluated in the perched water
RIfFS. The uncertainties associated with the risk evaluation process are addressed in
the preliminary risk evaluation report. The target treatment level established for the
pilot study, when implemented in the remedial action, will reduce all of the identified
risks to within the target risk range.
Remedial Alternatives
7.
Concerns were raised that not all appropriate technologies were considered, particularly
vitrification.
Response: For an interim action, it is sufficient to Select a remedial technology which
reduces the present potential risk and therefore, .the evaluation of orily one remedial
alternative may be adequate. In this case, EPA guidance documents (which are in the
administrative record) were consulted to determine the technologies most appropriate
for the cleanup of radiologically contaminated soils. Only two technologies had been
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used to "cleanup" radiologically-contaminated soils, capping and land encapsulation..
Capping was further evaluated; land encapsulation was not, due to the large volume of
material which would have to be removed, transported, stored, andlor disposed.
Technologies which had been field demonstrated with radioactive material, but have not
been used to remediate radiologically-contaminated soils, are stabilization or
solidification, vitrification, chemical extraction and physical separation. All of these
were further considered for the Warm Waste pond except vitrification, which has only
been demonstrated on much smaller-scale projects and would be much more expensive
than the other alternatives evaluated. The no action alternative was also evaluated.
Several commentors felt capping was oot "cleanup"; others felt it was the most cost
effective alternative.
Response: Capping is described in Section vn of the Decision Summary. Based upon
the potential risks which must be reduced, capping is appropriate as an interim action
because it reduces the risk due to external exposure and reduces the mobility of the
contaminants. However, since the contaminants are left in place and therefore oot
"cleaned up", the potential for future problems exists. In some cases, that potential risk
would be low enough such that capping would be an adequate remedy. For example,
if only cobalt-60 were in the Pond sediments, with a 5.3 year half life, it would decay
significantly in 100 y~ and would therefore not be a problem in that future use
scenario. Cesium-137 has a half life of 30.2 years and would not decay quickly enough
to be eliminated as a long-term future risk. Therefore, the Pond sediments would have.
to be addressed in another remedial action at a later date if capping is implemented in.
this interim action. Regardless of the alternative selected, the need for monitoring the
groundwater will be evaluated in the perched water RIIFS.
Many com mentors felt stabilization was inappropriate to the cleanup of the Warm
Waste Pond or questioned whether it provided less exposure to workers during
implementation. .
.,.
Response: Stabilization is described in Section VII of the Decision Summary.
Stabilization immobilizes the contaminants and, when backfilled, reduces all of the
identified potential risks. Two problems identified by com mentors were the long-tenn
effectiveness and interference with future remedies. Both are legitimate concerns. As
pointed out in the above response, if only short-lived radionuclides werp involved, the
expected permanence of the stabilized mass would be adequate. With the longer-lived
radionuclides, this becomes more of a concern. Of course, the stabilized. mass could
make future remedial efforts difficult and more expensive. Stabilizing, then removing
the sediment would involve an excessive volume of material. It is for those reasons
that the Agencies did not select stabilization as '. die. preferred or contingent remedy.
Whichever alternative was selected, the same degree of worker proteCtion and radiation
exposure minimization would be incorporated into the design.
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Selected Remedy
10.
Several questions and comments focused on the implementability and cost. of
separation/extraction, the treatability study, and the contingency remedy.
.t
Response: As described in Response 7 above, capping and land encapsulation are the
only remedies which have been used to remediate radiologica1ly-contaminated soils.
The Agencies preferred a remedy which removed the contaminants and thereby
permanently reduce the risks associated with the Warm Waste Pond. Physical
separation and chemical extraction provide that removal. While the initial capital costs
of separation/extraction- are higher than the other alternatives (as described in Sections
VII and VIII of the Decision Summary, the long term costs are likely to be lower due
to lack of maintenance costs or cost associated with another remedial action. Although
the Warm Waste Pond remediation would be the first use of separation/extraction
technologies in remediating a radiologically-contaminated Superfund site, the
technologies are both commonly used in the mining industry. The main difference
between this application and in mining are the target radionuclides. Cesium is not
mined and therefore has not been evaluated for this technology. A bench-scale
treatability study (in administrative record) indicates that the desirable cleanup levels
can be achieved. A pilot study is required to ensure that the range of contaminants and
sediment types found in the Warm Waste Pond can be successfully remediated and is
included in the cost estimate. Following the Record of Decision, further treatability
studies will begin and will be performed by DOE contractors. The treatability studies
are described in Section IX of the Decision Summary. The material returned to the
Pond and the residuals will be tested to ensure the cleanup. standards are being met.
If successful, the technology developed for the remediation of the Warm Waste Pond
will be applicable to many sites at the INEL and across the nation. The equipment will
be designed to be modular so that it can be dismantled and reused at other DOE sites.
The remedial design will be included in the administrative record upon completion.
The contingency remedy was omitted as described in the Explanation of Significant
Differences on Page 32. .
11.
Many concerns were raised on the storage of the residuals created by the
separation/extraction process. One commentor asked if the ICPP could process the
residuals. . .
Response: U nill the treatability studies described in Section IX of the Decision
Summary are completed, the type and quantity of waste gene~ted can only be
estimated. However, it is expected that less than 200 cubic yards of low-level
radioactive waste will be generated. The sediment in the Pond is not RCRA hazardous.
If the metals are concentrated enough by the separation/extraction process so that they
leach using the Toxicity Leaching Characteristic Procedure (TCLP) in amounts
sufficient to be above the RCRA limits, the residual will be treated to reduce the
leachability to acceptable levels. Therefore, no RCRA hazardous or mixed waste is
likely to be generated. The State has stipulated that the residuals be stored such that
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they can be visually monitored until the final disposition of the waste has been
determined. The final disposition of the residuals must be determined prior tQ or in the
WAG-wide Record of Decision. Therefore, at this time the residuals will be stored in
containers in a controlled manner at or near the site of the Warm Waste Pond. Final
disposition of the residuals will be determined at a later date with State concurrence.
If necessary, transportation of the residuals will be in compliance with all INEL and
DOT requirements, .which base the packaging, labelling, etc... on the type and degree
of hazard posed by the shipment.' The ability and cost effectiveness of the ICPP to
process the product residual will be evaluated in the pilot study.
Research Applications
12.
Concerns and questions arose about research in waste management and remedial
technologies and their appJicability to INEL.
Response: Research has always been a major part of the INEL's mission, and in recent
years research in waste management and remedial technologies has expanded.
Technologies which involve treatment are preferred under CERCLA, although cleanup
is not delayed until new technologies are developed. Testing of a technology may be
part of the remedial design or remedial action, as is the case in this Record of Decision.
Although not a consideration in the selection of the remedial alternative for the Warm
Waste Pond, proving the use of separation/extraction as a remedial alternative for
radiologically contaminated soils will make it a more viable option for future remedial
actions nationwide. Remote cleanup methods may be utilized where the hazards posed:
by the site make it more efficient.
Agency Involvement
13'.
Several commentors felt the identification of sites, prioritization of cleanups,
. coordination of activities, and the standards set for cleanups were unclear.
"..
Response: Environmental restoration at the INEL and most other DOE facilities is
conducted under agreements with state and federal agencies. At the INEL, this
agreement was the Consent Order/Compliance Agreement (COCA) with the EPA.
Following public comment, the FFAICO will supersede the COCA, thereby giving the
State of Idaho and EP A equal say in establishing envirQnmental restoration priorities
at the INEL. Coordination among DOE facilities is managed by DOE Headquarters.
As new sites are identified, through process knowledge, employee interviews, or field
detection, they are prioritized by the Agencies. All cleanups must meet federal and
state. requirements, which require sites which present an. unacceptable risk to be
evaluated using the nine CERCLA criteria a,nc!":cleaned up. Other CERCLA
requirements include a timetable for remedial activitieg following a ROD and
community relations activities.
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14.
Several com mentors felt that DOE and/or EG&G should not be responsible for cleaning
up sites which it had contaminated. .
Response: As a result of inclusion on the National Priorities List (NPL), the lNEL
must follow the requirements of CERCLA, the Superfund law. CERCLA has clear
requirements for characterization, risk assessment, remedial technology selection, and
community involvement. DOE, with the State of Idaho and EP A oversight, will
proceed with characterization and cleanup of the INEL following the requirements of
CERCLA.
Community Relations .
15.
Several com mentors felt that the meetings were poorly attended because of inadequate
media coverage or notice, the Proposed Plan was inadequate, or that comments may not
impact the decision process anyway.
Response: Community relations activities, including newspaper, radio, and television
advertisements and stories are described in Section ill of the Decision Summary and
Section 2 of this Responsiveness Summary. Since no extension of the public comment
period was requested, it appears adequate time was allowed for comme~ts. Local
television and radio stations were notified of each meeting in advance. Written
comment forms were available at each public meeting and written comments were
encouraged at the meetings, in the Proposed Plan, and in the cover letter. All
comments, verbal or written, and all unanswered questions pertaining to the Warm
Waste Pond are addressed in this Responsiveness Summary. The transcripts of each
meeting and copies of each written comment are in the Information Repositories.
Comments are indexed to the number of the response which addresses them in the
Responsiveness Summary. An example of the positive impact of public comment in the
decision process for this Record of Decision was the incorporation of the suggestion
that the ICPP be evaluated for treatment of the extracted contaminants. The Proposed
Plan is not meant to be an all-encompassing document, but rather a concise summary
of the preferred alternative and the information leading to its recommendation.
NEPA
16.
Several com mentors questioned whether NEP A requirements were being met by the
.interim action. .
ResPonse: This Record of Decision addres~....CERCLA requirements.
requirements of NEPA for this action are being evaluated separately...
The
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