PB97-964015
EPA/541/R-97/066
June 1998
EPA Superfund
Record of Decision:
Oak Ridge Reservation (USDOE)
(Sludge Removal from the Gunite &
Associated Tanks Operable Unit,
Waste Area Grouping 1)
Oak Ridge, TN
9/2/1997
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DOE/OR/02-1591&D2
Record of Decision for Interim Action:
Sludge Removal from the Gunite and Associated
Tanks Operable Unit, Waste Area Grouping 1,
Oak Ridge National Laboratory,
Oak Ridge, Tennessee
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DOE/OR/02-1591&D2
Record of Decision for Interim Action:
Sludge Removal from the Gunite and Associated
Tanks Operable Unit, Waste Area Grouping 1,
Oak Ridge National Laboratory,
Oak Ridge, Tennessee
Date Issued—August 1997
Prepared by
Jacobs EM Team
125 Broadway Avenue
Oak Ridge, Tennessee
under contract DE-AC05-93OR22028
Prepared for
U.S. Department of Energy
Office of Environmental Management
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PREFACE
This Record of Decision for Interim Action: Sludge Removal from
the Gunite and Associated Tanks Operable Unit, Waste Area
Grouping 1, Oak Ridge National Laboratory, Oak Ridge, Tennessee
(DOE/OR/02-1591&D2) was prepared in accordance with requirements
under the Comprehensive Environmental Response, Compensation, and
Liability Act of 1980 and documents selection of the interim action.
This work was performed under Work Breakdown Structure
1.4.12.6.1.01.41.19.18 (Activity Data Sheet 3300, "ORNL WAG 1
Treatability Studies"). This document identifies sludge removal as the
selected interim action for the Gunite and Associated Tanks Operable
Unit. This document summarizes information from the feasibility
study/proposed plan (DOE/OR/02-1509/V1&D2, and V2&D2).
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ACRONYMS AND ABBREVIATIONS
ARAR
bgs
BVEST
CERCLA
CFR
Ci
Cs
CY
DOE
EPA
ER
FFA
FS
ft
FY
GAAT
gal
kg
km
L
Ib
LLW
LSS
m
MVST
NCP
NTF
NTS
OHF
ORNL
ORR
OU
PP
Pu
RME
ROD
Sr
STF
STP
TDEC
Th
TRU
U
applicable or relevant and appropriate requirement
below ground surface
Bethel Valley Evaporator Service Tanks
Comprehensive Environmental Response, Compensation, and Liability
Act of 1980
Code of Federal Regulations
curie
cesium
calendar year
U.S. Department of Energy
U.S. Environmental Protection Agency
environmental restoration
Federal Facility Agreement
feasibility study
foot
fiscal year
Gunite and Associated Tanks
gallon
kilogram
kilometer
liter
pound
low-level (radioactive) waste
laboratory shift superintendent
meter
Melton Valley Storage Tanks
National Oil and Hazardous Substances Pollution Contingency Plan
North Tank Farm
Nevada Test Site
Old Hydrofracture Facility
Oak Ridge National Laboratory
Oak Ridge Reservation
operable unit
proposed plan
plutonium
reasonable maximum exposure
record of decision
strontium
South Tank Farm
site treatment plan
Tennessee Department of Environment and Conservation
thorium
transuranic
uranium
JT00589703.IWR/CJE
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August 25. 1997
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ACRONYMS AND ABBREVIATIONS (continued)
WAG waste area grouping
WIPP Waste Isolation Pilot Plant
nX»589703.IWR/aE IV Augua 25. 1997
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PARTI. DECLARATION
/T00589703.1WR/CJE Auguu 25, 1997
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STUDY AREA/OPERABLE UNIT NAME AND LOCATION
U.S. Department of Energy
Oak Ridge Reservation
Waste Area Grouping 1
Gunite and Associated Tanks Operable Unit at the Oak Ridge National Laboratory
Oak Ridge, Tennessee
STATEMENT OF BASIS AND PURPOSE
This record of decision (ROD) presents the selected interim remedial action for removing
mixed transuranic (TRU) waste sludge from eight tanks in the Gunite and Associated Tanks
(GAAT) Operable Unit (OU). The tanks are located in Oak Ridge National Laboratory (ORNL)
Waste Area Grouping (WAG) 1. The U.S. Department of Energy (DOE) has assigned a high
priority to the remediation of this OU because of its high contaminant inventory and the age of
the tanks. The objective of this interim action is to reduce the potential for on- and off-site risk
from the tank contents.
The interim action was chosen in accordance with the Comprehensive Environmental
Response, Compensation, and Liability Act of 1980 (CERCLA), as amended by the Superfund
Amendments and Reauthorization Act of 1986 (42 United States Code, Sect. 9601 et seq.) and,
to the extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan
(NCP) [40 Code of Federal Regulations (CFR) 300]. The ROD is based on the Administrative
Record for this site.
DOE issues this document as the lead agency for environmental restoration (ER) activities
on ORR. The U.S. Environmental Protection Agency (EPA) and the Tennessee Department of
Environment and Conservation (TDEC) are supportive agencies as parties to the Federal Facility
Agreement (FFA) for this response action. They concur with the selected remedy.
ASSESSMENT OF THE STUDY AREA/OU
A baseline risk assessment was conducted to determine whether remedial actions are
necessary to protect human health and the environment if current institutional controls are
removed. The scenarios considered include (1) dome failure resulting in direct exposure to
workers and on-site residents and (2) failure of the tank shell resulting in contamination of
JT00589703.IWR/CJE 1-2 August 25. 1997
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groundwater with the associated pathway to a resident of nearby White Oak Creek. The risk
assessment clearly demonstrates that without institutional controls the GAAT tanks pose an
unacceptable risk to human health and the environment now and in the future. Thus, a remedial
action is required to address the GAAT OU. The objective of this interim action is to reduce the
potential for on- and off-site risk from the tank contents.
Actual or threatened releases of hazardous substances from this OU, if not addressed by
implementing the response action selected in this ROD, may present an imminent and substantial
endangerment to public health, welfare, and the environment.
DESCRIPTION OF SELECTED REMEDY
The selected interim remedial action includes removal of the sludge and subsequent
transfer to the Melton Valley Storage Tanks (MVST). The plans for removing GAAT sludge will
be included in the remedial design and remedial action documentation. However, the basic
equipment and methodology are being demonstrated in an ongoing treatability study and have
been successfully demonstrated in a test facility. The most likely approach uses a remotely
controlled arm and vehicle combination to complete the sludge removal. High-pressure water
jet equipment attached to the arm or vehicle will remove sludge from the walls and floors and
pump it out of the tank. Where disposal options are available, equipment and debris will be
removed from the tanks, packaged, and disposed. Any remaining debris will be rinsed, sampled,
placed into retrievable containers, and positioned in the tanks for later retrieval and disposition.
The slurried waste from the tanks will be pumped to a consolidation tank and conditioned as
necessary (i.e., adjustment of water content or particle size) to facilitate pumping this material
through existing transfer lines to MVST. All MVST wastes will be prepared for eventual
disposal in another action.
The selected remedy was developed considering the TRU waste strategy [i.e., consolidate,
treat, and ship waste to the Waste Isolation Pilot Plant (WIPP) or the Nevada Test Site (NTS)]
and the strategy to evaluate residual contamination in the OU after waste removal as part of the
Bethel Valley Watershed remediation. After removal of sludge, samples of the tank shell will
be collected to provide contaminant levels for consideration during future closure evaluations, as
part of the Bethel Valley Watershed remediation.
rr
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STATUTORY DETERMINATIONS
This interim action protects human health and the environment, complies with federal
and state applicable or relevant and appropriate requirements (ARARs) directly associated with
this action, and is cost-effective. This action uses permanent solutions and alternative treatment
(or resource recovery) technologies to the maximum extent practicable, given the limited scope
of the action. This action does not constitute the final remedy for the OU; therefore, the
statutory preference for remedies that employ treatment for reduction of toxicity, mobility, or
volume as a principal element will not be satisfied by this interim action. Treatment of the
MVST waste, including the GAAT sludge, will be performed as part of another action. This
interim action addresses the principal threat posed by this OU and ensures that the liquid and
sludge will not increase future groundwater contamination. Removal of the wastes will permit
the remaining structures (i.e., tanks, piping, and associated equipment) to be included in a later
sitewide action. Because this is an interim action ROD, review of this site and of this remedy
will continue as DOE develops final remedial alternatives for this OU and the overall site.
JT00589TO3.IWR/CJE 1-4 Auguu 25. IW7
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APPROVALS
Rodney R. Nelson, Assistant Manager
U.S. Department of Energy
Oak Ridge Operations
/ "2. I
Date
Earl C. Leming, Director^—-
Date
U.S. Department of Energy Oversight Division
Tennessee Department of Environment and Conservation
Richard D. Green, Acting Director
Waste Management Division
U.S. Environmental Protection Agency, Region 4
Date
JTOOS89703.IWR/CJE
1-5
August 25. 1997
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PART 2. DECISION SUMMARY
JT00589703.IWR/CIE August 25. 1997
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DECISION OVERVIEW
This ROD describes the interim remedial action decision for the GAAT OU. The GAAT
OU comprises 16 tanks located in or near the North and South Tank Farms at ORNL WAG 1,
Oak Ridge Reservation (ORR), Oak Ridge, Tennessee. DOE assigned remediation of these tanks
a high priority because of the high contaminant inventory and the age of the tanks. The GAAT
OU includes the tanks, residual waste materials in the tanks, and the operating equipment
associated with the tanks. A baseline risk assessment was conducted to determine whether
current or future remedial actions are necessary to protect human health and the environment if
existing institutional controls are removed. The risk assessment clearly demonstrates that without
institutional controls the tanks pose an unacceptable risk to human health and the environment
both now and in the future. Therefore, a remedial action is required to address the GAAT OU.
The objective of this interim action is to reduce the potential for on- and off-site risk from the
tank contents.
The interim action proposed in this ROD is removal of liquid and sludge wastes from eight
tanks (W-3 through W-10) and transfer of the wastes to MVST. Seven other tanks (W-l, W-la,
W-2, W-l 1, W-13, W-14, and W-15) in the GAAT OU contain no recoverable sludge, have low
contaminant levels, and do not pose a significant threat to human health or the environment either
now or in the future. Tank TH-4 is also part of the GAAT OU and contains sludge; however,
its contents are very different from the contents of the other sludge-containing tanks and do not
pose a significant threat to human health and the environment. DOE is deferring action on the
contents of these eight tanks (seven nonsludge-bearing tanks plus Tank TH-4) and any residual
contamination left in Tanks W-3 through W-10 after waste removal. At that time, the need for
any further remedial action will be evaluated as part of the Bethel Valley Watershed remediation
decision process.
The Gunite tanks were originally constructed in the 1940s with a projected operational life
of 1 year. Although monitoring data have not indicated that any tanks are leaking, remote visual
inspections of the tanks have revealed some degradation on the interior surface of Tanks W-5 and
W-6. The results of these inspections and the age of the tanks have raised concerns about their
long-term integrity. Liquid and solid materials stored in the tanks include mixed wastes
containing radionuclides, organics in trace amounts, and heavy metals. Solids in some of the
tanks contain U, Pu, Th, and other long-lived (thousands of years) isotopes that meet the criteria
for TRU waste. These wastes also contain high concentrations of l37Cs and ^Sr, which have
relatively short half-lives (approximately 30 years), in addition to other radionuclides with half-
JT0058970J.IWR/CJE 2-2 AugusJ 25. 1997
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lives of a few days. The high radiation levels in the tanks will require "remote operation" to
control exposures to workers performing the waste removal operations.
Approximately 1.32 million L (350,000 gal) of liquid and 189,000 L (50,000 gal) of
sludge remain in the tanks. The estimated radionuclide inventory ranges from 40,000 Ci, based
on the most recent analytical results, to over 100,000 Ci, based on previous estimates for the
eight tanks addressed by this interim action.
DOE evaluations of cleanup options for the Gunite tanks indicate that the best current
action is to remove the tank liquid and sludge wastes, which could be released easily by a tank
failure, and transfer these wastes to a'permitted storage facility. Treatment will occur as part of
another action. The decision to remove these wastes from the Gunite tanks was made
concurrently with the need to manage similar wastes located in other tanks at ORNL. DOE
manages an inventory of more than 757,000 L (200,000 gal) of TRU waste at ORNL facilities,
including GAAT, MVST, the Bethel Valley Evaporator Service Tanks (BVEST), and the Old
Hydrofracture Facility (OHF). As part of a separate, nationwide effort, DOE is procuring
services to treat and dispose of this inventory at WIPP and NTS (DOE 1996a). The activities
at ORNL are also being conducted in compliance with the TDEC Commissioner's Order on the
site treatment plan (STP). Treatment and shipment of ORNL wastes are scheduled to coincide
with the window for receiving remote-handled TRU waste at WIPP, starting near the end of fiscal
year (FY) 2002. This limited window places a high priority on completing waste accumulation
and treatment activities at ORNL.
To support efficient treatment, DOE plans to accumulate all TRU tank waste, including
the Gunite tank wastes, at MVST. This will allow the treatment contractor sufficient time to
mobilize, build needed facilities, and begin treating and shipping the wastes to WIPP or NTS by
the end of FY 2002. MVST is comprised of eight, approximately 50,000 gal underground
storage tanks within a stainless-steel-lined concrete vault. These tanks meet FFA specified
secondary containment standards and are part of the permitted National Pollutant Discharge
Elimination System. These tanks are currently in use and contain TRU waste from previous
process and restoration activities.
MVST's capacity to receive wastes is limited until an ongoing project that will add six
new tanks to the MVST is completed in late calendar year (CY) 1998. DOE has developed a
strategy that allows all three of the waste removal projects (GAAT, BVEST, and OHF) to
proceed in parallel and meet the goal of accumulating the TRU tank waste at MVST by the end
of FY 2000. This strategy calls for the transfer of BVEST and OHF waste to MVST from late
CY 1997 to early CY 1999. During this period, DOE plans to use one or two of the existing
JTOOS89703.IWR/CIE 2-3 August 25, 1997
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Gunite tanks to temporarily hold, or "consolidate," the wastes that will be produced by the
GAAT interim action. This will allow several of the Gunite tanks to be cleaned while wastes
from BVEST and OHF are being transferred to MVST. The wastes are scheduled to be removed
from the consolidation tanks and transferred to MVST starting in early CY 1999. The
consolidation tanks will be emptied by March 2001.
DOE has thoroughly investigated the integrity of the Gunite tanks and has selected Tank
W-9 to be the primary consolidation tank. DOE selected W-8 to be the backup consolidation
tank. Analysis of the structural integrity of these two tanks indicates they are sound, and analysis
of internal liquid level data from the tanks indicates that W-8 and W-9 are liquid tight within the
statistical uncertainties inherent in the analysis (ORNL 1997a). In addition to these analyses, the
electrical conductivity of the groundwater is being monitored in the dry wells associated with each
of the tanks. This method can easily detect releases from the Gunite tanks on the order of
0.5 gal/hour. The method has been thoroughly evaluated by conducting simulated (high
conductivity) liquid release tests on the Gunite tanks in the North Tank Farm (NTF) and South
Tank Farm (STF). Testing has been successfully completed in the NTF (ORNL 1997a), and
testing of the method for Tank W-9 in the STF was recently completed (ORNL 1997b). Testing
is in progress for Tank W-8 and other STF tanks. Results will be represented in subsequent
reports. The dry well conductivity monitoring method is being used to provide rapid real time
release detection for Tanks W-3 and W-4 in the NTF and will be used for real time release
detection for the consolidation tanks in the STF.
The overall responsibility for responding to emergencies at ORNL rests with the
laboratory shift superintendent (LSS). The office of the LSS is housed in the Laboratory
Emergency Response Center which has the responsibility, personnel, and equipment to respond
around-the-clock. The GAAT Spill/Leak Response Plan was developed in coordination and in
conjunction with the LSS and describes actions to be taken in the event of a release from the
tanks.
The GAAT Remediation Project has a trailer-mounted Moyno pump, hoses and fittings,
absorbent, and storm drain covers at its disposal. Covers will be placed over selected storm
drains and surrounded with absorbent, placed prior to transfers between tanks. Project and
selected support personnel will perform drills with the Spill/Leak Response Plan in coordination
with the LSS on an annual basis. Spills and leaks will be pumped into the active waste
management system or into a sound Gunite tank as conditions warrant. The LSS will assist the
GAAT Project in responding to any situations that require additional personnel and equipment.
JT00589703.1WR/CJE 2-4 Augusi 25. 1997
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DOE believes that any inefficiencies involved in double-handling the waste in the
consolidation process are outweighed by several important benefits.
The consolidation process provides the capability to even out the flow from the waste
removal equipment and accumulate large enough batches of waste for efficient transfer to MVST.
Excess water generated during the waste removal process can be extracted and sent to BVEST
for concentration, thereby minimizing the liquids generated during Gunite tank waste removal and
managing utilization of the limited space available at MVST. Most importantly, the consolidation
approach will facilitate the eventual transfer of the waste to MVST. Waste removed from the
Gunite tanks must be "conditioned" (particle size and water content adjusted) before it can be
transferred to MVST through the mile-long pipeline between Bethel Valley and Melton Valley.
DOE plans to install a conditioning system in the consolidation tanks similar to that used in the
1982 waste removal campaign that successfully avoided plugging the only route for transfer of
radioactive liquid waste from the main plant of ORNL to MVST (ORNL 1984).
A CERCLA treatability study was initiated to determine the effectiveness and cost of
technologies that could remove liquid and sludge wastes from the GAAT. A phased program was
developed to minimize risks to workers and the public during remediation. This program started
with "cold tests" that were designed to ensure the proper operation of waste removal equipment.
The cold tests, completed in May 1997, demonstrated that the equipment is able to remove
surrogate waste from a simulated tank as well as clean waste from the interior surface of a
simulated tank shell. "Hot tests" with the lower contaminant concentration wastes in Tanks W-3
and W-4 will be performed in the summer and fall of 1997; these tests are designed to confirm
that the waste removal equipment operates safely and effectively for actual radioactive tank waste.
This demonstration will increase confidence in the waste removal equipment's ability to safely
remove the much more radioactive wastes from Tanks W-5 through W-10 and will help define
how much waste can be removed from the tanks.
When waste removal operations in this interim action are complete, contamination
remaining in the tanks will be limited to small quantities of sludge, contaminants in the tank
shells, and contaminated debris (equipment, rocks, plastic, and Gunite pieces) collected during
the cleaning operation. Some residual liquid and sludge is likely to remain in pockets and low
points. A total of approximately 229 m (750 ft) of small diameter process piping with a
combined volume of approximately 1.3 m3 (45 ft3) will remain embedded in the concrete or
attached to walls of the tanks. The amount of contamination remaining in the tank shells after
waste removal will be determined through a combination of in situ measurements and sample
analysis. Solid debris collected to facilitate sludge removal will be packaged for subsequent
characterization and disposal in accordance with available disposal options.
JT00589703.1WR/CJE 2-5 Augusi 25. 1997
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Approximately 16.8 m3 (600 ft3) of wiring, piping, and other debris have been removed
from these tanks to provide access for waste removal equipment. Approximately 13,608 kg
(30,000 Ib) of surface equipment has been removed and recycled, and 33.6 m3 (1,200 ft3) of
contaminated LLW material was removed and shipped to an off-site contractor for disposal.
Disposal or remediation of any remaining equipment and debris collected during waste removal,
as well as potentially contaminated soils and tank appurtenances external to the tank shells, will
ultimately be evaluated as part of the Bethel Valley watershed remediation decision process.
Approximately 16.8 m3 (600 ft3) of mixed wastes are currently held in a process pit in the STF
and remain candidates for later waste consolidation. Moving this material as part of this interim
action is impractical because no better defined or permitted facilities are available locally for this
class of wastes.
SITE NAME, LOCATION, AND DESCRIPTION
The GAAT OU is located within ORNL on the DOE ORR, approximately 24 km
(15 miles) west of Knoxville, Tennessee, and 16 km (10 miles) southwest of the Oak Ridge,
Tennessee, business center (Fig. 2.1). The ORNL main plant area is located in Roane County
adjacent to Bethel Valley Road, approximately 2.5 km (1.5 miles) east of the intersection with
State Highway 95.
In the 1940s, DOE placed in service 12 Gunite tanks as part of the liquid waste treatment
system. Four smaller, steel tanks were constructed in the late 1940s and early 1950s. All 16
tanks are located underground in the main plant area. Eight of these tanks (W-3 through W-10)
are located at the intersection of Central Avenue and Third Street in the North and South Tank
Farms and are included in the scope of this interim action ROD.
SITE HISTORY AND ENFORCEMENT ACTIVITIES
ORNL, one of three major plants on ORR, opened in 1943 as the Clinton Laboratories
to support defense activities for the Manhattan Project. It evolved into a premier research facility
with a diverse range of programs. On November 21, 1989, EPA placed ORR on the National
Priorities List under CERCLA. On January 1, 1992, DOE, EPA, and TDEC entered into an
FFA to provide a procedural framework and schedule for evaluating, prioritizing, and managing
ER activities on ORR. The agreement also specifies that CERCLA procedures will be followed
to evaluate and remediate contamination problems.
mXK89703.IWR/aE 2-6 August 25, 1997
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ORNL Main Plant Area ,.,„.,..... „„.
NOT TO SCALE
JE
Fig. 2.1
Location of ORNL and the North and South Tank Farms
DOE - ORNl. WAG 1 Gunite and Assooaied Tanks • Oak Ridge. Tennessee
DOCUMENT 10 35M830
0058-05 / PS PP
96-1?928DWC
DRAWING DATE
16 Juni 97. WiM
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The Gunite tanks were originally constructed in the 1940s with a projected operational life
of 1 year. Mixed-TRU waste generated by operations of ORNL's processing and research
facilities was stored in a network of underground tanks as part of the Manhattan Project. The
tanks were removed from service beginning in the 1950s, with all tanks out of service by the
1970s. Most of the liquid and sludge waste was removed from the tanks between 1982 and 1984,
and staged temporarily in the MVST. Waste was mixed with grout and injected into a deep shale
formation.
A more detailed discussion of the remaining tank contents and characteristics is presented
in the remedial investigation/baseline risk assessment for the GAAT OU (DOE 1994) and the
addendum to that report (DOE 1996b). These and other documents are available as part of the
Administrative Record. A treatability study associated with this action is currently underway.
The feasibility study (FS)/proposed plan (PP) evaluated potential interim actions in accordance
with the requirements of CERCLA and the NCP, presented DOE's determination that liquid and
sludge removal is necessary in eight of the tanks, and solicited public comment on the
determination (DOE 1997). Part 3 of this ROD documents public comments on the FS/PP and
DOE's response to those comments.
HIGHLIGHTS OF COMMUNITY PARTICIPATION
The FS/PP for the GAAT OU was released to the public May 2, 1997. This document
is part of the Administrative Record for the OU and is maintained at the DOE Information
Resource Center, 105 Broadway Avenue, Oak Ridge, Tennessee. The notice of availability for
this plan and other documents in the Administrative Record was published in The Knoxville News-
Sentinel May 2, 1997, The Oak Ridger May 1, 1997, and The Roane County News May 2, 1997.
A public meeting to discuss the FS/PP was held June 2, 1997. A public comment period
scheduled for May 2, 1997, through June 2, 1997, was extended to June 13, 1997. Oral and
written comments received from three members of the public are responded to in Part 3 of this
ROD.
SCOPE AND ROLE OF OU AND THE REMEDIAL ACTION
Under CERCLA, an OU is a discrete area that is part of a larger area or response action.
At ORNL, WAG 1 was divided into separate OUs. GAAT, an OU within WAG 1, comprises
16 tanks located in or near the North and South Tank Farms at ORNL. DOE assigned
remediation of these tanks a high priority because of the high contaminant inventory and the age
JT00589703.1WR/CJE 2-8 August IS. !W
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of the tanks. The GAAT OU includes the tanks, residual waste materials in the tanks, and the
operating equipment associated with the tanks. For purposes of this action, all the tanks and their
contents are being considered as one area of contamination.
To support efficient treatment, DOE plans to accumulate all TRU tank waste, including
the Gunite tank wastes, at MVST. This will allow the treatment contractor sufficient time to
mobilize, build needed facilities, and begin treating and shipping the wastes to WIPP or NTS by
the end of FY 2002. MVST's capacity to receive wastes is limited until an ongoing project that
will add six new tanks to MVST is completed in late CY 1998. DOE has developed a strategy
that allows all three of the waste removal projects (GAAT, BVEST, and OHF) to proceed in
parallel and meet the goal of accumulating the TRU tank waste at MVST. This strategy calls for
the transfer of BVEST and OHF waste to MVST from late CY 1997 to early CY 1999. During
this period, DOE plans to use one or two of the existing Gunite tanks to temporarily hold, or
"consolidate," the wastes that will be produced by the GAAT interim action. This will allow
several of the Gunite tanks to be cleaned while wastes from BVEST and OHF are being
transferred to MVST. The wastes are scheduled to be removed from the consolidation tanks and
transferred to MVST starting in early CY 1999. The consolidation tanks will be emptied by
March 2001.
The scope of this interim remedial action for the GAAT OU is limited to the contents of
Tanks W-3 through W-10. Discussions of groundwater and surface water were included in this
ROD only to identify potential sources of contamination and receptor pathways. Removal of the
liquid and sludge waste substantially reduces any future risk of release or exposure. The
remaining tank contamination (and the surrounding tank farm areas) will be evaluated as part of
the Bethel Valley Watershed remediation decision process. Appropriate follow-on actions will
be conducted at a later date if necessary. The selected interim remedy does not preclude any
future remedial actions at the site that may be implemented.
SUMMARY OF SITE CHARACTERISTICS
Liquid and solid materials stored in the tanks include mixed wastes containing
radionuclides, organics in trace amounts, and heavy metals. Solids in some of the tanks contain
U, Pu, Th, and other long-lived (thousands of years) isotopes that meet the criteria for TRU
waste. These wastes also contain high concentrations of l37Cs and ^Sr, which have relatively
short half-lives (approximately 30 years), in addition to other radionuclides with half-lives of a
few days. The high radiation levels in the tanks will require "remote operation" to control
exposures to workers performing the waste removal operations.
JTD0589703.IWR/CJE 2-9 August 15. 1997
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Approximately 1.32 million L (350,000 gal) of liquid and 189,000 L (50,000 gal) of
sludge remains in the tanks. The estimated radionuclide inventory ranges from 40,000 Ci, based
on the most recent analytical results, to over 100,000 Ci, based on previous estimates for the
eight tanks addressed by this interim action.
SUMMARY OF SITE RISKS
DOE enforces strict institutional controls at the GAAT OU to mitigate uncontrolled
exposures because of contaminants in the tanks. Institutional controls, along with administrative
controls, comply with regulatory limits for exposures to on-site workers and visitors, minimize
chances for direct contact with the tank contents, and ensure that off-site receptors are protected
if a tank leaks. An evaluation of tank level monitoring data indicates the tanks are not currently
leaking. The North and South Tank Farms each include a groundwater collection system that
lowers the ambient groundwater below the base of the tanks and directs the collected groundwater
to a pump station for transfer to the Process Waste Treatment Plant, where low concentrations
of radionuclides are reduced to a level that meets the requirements of DOE Order 5400.5,
"Radiation Protection of the Public and the Environment."
A baseline risk assessment (DOE 1994 and 1996b) was conducted to determine and
document the risk levels if institutional controls are removed. The evaluation was based on Tank
W-10 because this tank contains the highest radionuclide volume and concentrations for those
tanks that contain sludge. The pathways of concern are direct radiation exposure in the event of
a dome collapse and ingestion of contaminated drinking water by future residents. The source
release/groundwater transport model assumed that the tank shell immediately failed and
contaminants of concern in the liquid and sludge (primarily ^Sr and 137Cs) were released or
leached into groundwater. The contaminated groundwater was assumed to follow a
nondispersive, direct path into White Oak Creek at a point approximately 370 m (1,200 ft) south
of the NTF.
HUMAN HEALTH RISKS
The human health risks reported in the baseline risk assessment (DOE 1994) considered
current and future scenarios for potential impacts of a tank dome collapse and failure of a tank
shell. For the current use scenario, there is no evidence of contaminant release from the tanks
to a pathway for an off-site receptor. The existing institutional controls adequately protect
workers by limiting access to the site and monitoring exposure.
JT00589703.IWR/CJE 2-10 August 25, 1997
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For the future use scenario, risks to an on-site resident, an employee, a nearby resident,
and a child wading in White Oak Creek were considered. The EPA risk value of concern is
1 x 10^* or greater, which was exceeded for all but the last of the following:
• For an on-site resident, the greatest potential risk comes from direct radiation that
might be released if the tank dome collapsed. The total risk from all pathways is
6 x 10' for the reasonable maximum exposure (RME) and 9 x 102 for the mean
exposure.
• The potential risk to an employee from direct exposure associated with tank dome
collapse could reach 9 x 102 for the RME and 1 x 10"2 for the mean exposure.
• For a nearby resident, ingestion of contaminated drinking water from White Oak
Creek poses the greatest risk. The total risk is 1 x 103 for the RME and 3 x KT4
for the mean exposure.
• The calculated risk for a child wading in White Oak Creek (4 x 10 6 for the RME and
1 x 10"7 mean exposure) does not exceed the EPA target risk value of 1 x 10"*.
ENVIRONMENTAL HEALTH RISKS
The GAAT OU is located in a highly developed industrial area with few ecological
receptors. Although the risk assessment for the GAAT OU did not calculate ecological effects
of this interim action, ecological issues will be addressed in a future sitewide study, as required
under the FFA.
DESCRIPTION OF ALTERNATIVES
Although several alternatives were initially considered for a full range of remedial actions,
an agreement among DOE, TDEC, and EPA for an interim action to remove only the tank
contents eliminated from consideration all but one action alternative. Thus, the only alternatives
considered in the FS/PP were:
• Alternative 1—No Action
• Alternative 2—Sludge Removal
JTOOS89703.IWR/CJE 2-11 • August 25. 1997
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ALTERNATIVE 1-NO ACTION
The NCP requires inclusion of a no action alternative for use as a baseline in comparing
and considering other remedial alternatives. The no action alternative assumes that existing
institutional controls—such as monitoring, removing water from the tanks, and restricting access
to the tank farms—would be maintained 30 years. No action would be taken to remediate the
tank shell.
Without removal of the liquid and sludge, eventual release of the waste following collapse
of the tank dome or failure of the tank shell could endanger human health and the environment.
As indicated in the "Summary of Site Risks" portion of this ROD, the risk of direct exposure
could be as high as 6 x 10"' for a future on-site resident and as high as 9 x 10"2 for a future
employee. The risk to a nearby resident from the ingestion of contaminated drinking water from
White Oak Creek could reach 1 x 103, but calculations indicate that the risk for a child wading
in the water would not exceed EPA's target value of 1 x 10"*.
ALTERNATIVE 2—REMOVAL/TRANSFER OF TANK CONTENTS TO MVST
This alternative includes removal of the liquid and sludge and subsequent transfer to
MVST. All MVST wastes will be prepared for eventual disposal in another action. Sludge from
the GAAT OU would be included in that effort.
The selected interim alternative will include removal of the liquid and sludge and
subsequent transfer to MVST. The approach for removing GAAT waste will be included in the
remedial design and remedial action documentation. However, the basic equipment and
methodology being evaluated in the treatability study have been successfully demonstrated in a
test facility. The most likely approach uses a remotely controlled arm and robotic vehicle
combination to complete the sludge removal. High-pressure water jet equipment attached to the
arm or vehicle will remove waste from the walls and floors and pump it out of the tank. Debris,
collected to facilitate sludge removal, will be rinsed, sampled, placed into retrievable containers,
and positioned in the tanks for later retrieval and disposition. Waste will be pumped to a
consolidation tank for conditioning (i.e., adjusting the water content, particle size) and transferred
by existing pipelines to MVST.
DOE plans to transfer GAAT wastes to MVST as part of the ORNL TRU waste strategy.
The treatability study will determine technical limits of the remediation technology and establish
an initial goal for waste removal. DOE will attempt to dislodge and remove all sludge materials
from the tanks and clean the walls and floor of each tank. The ability of the waste removal
JTOOS89703.IWR/CJE 2-12 Auguu 25, 1997
-------
system to accomplish this goal will not be completely known until the project is actually
underway. The FFA panics will determine when the waste removal system's practical limit has
been reached if the initial goal developed during the treatability study proves technically
impractical or cost-inefficient. Results will be documented in a project completion report.
DOE will maintain responsibility for treatment and final disposition of the GAAT wastes
after transfer to MVST, a permitted storage facility for mixed waste that contains wastes from
other OUs within the ER Program as well as non-ER wastes. Mixed wastes on ORR are being
managed under a modified STP as directed by the TDEC Commissioner's Order
(October 2, 1995) and as provided for in Section 105 of the Federal Facilities Compliance
Agreement (January 1992). The GAAT wastes, as pan of the MVST wastes, will be treated in
a permitted facility to meet all regulatory and DOE requirements as well as disposal facility waste
acceptance criteria. Final disposition of the wastes will be at WIPP, NTS, or another
appropriately permitted facility.
The GAAT OU is located in the ORNL historic district. DOE Oak Ridge Operations and
the State Historic Preservation Office signed a memorandum of agreement for the GAAT OU,
which the Advisory Council on Historic Preservation accepted January 31, 1995. This agreement
ensures that the site's aesthetics will be maintained to the extent practicable for the duration of
the action.
ARARs specific to Alternative 2 are listed in Table 2.1.
SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
Of seven action alternatives originally conceived, only one met the specifics of the
agreement among DOE, TDEC, and EPA to completely remove the sludge from the eight tanks.
This alternative and the mandated no action alternative were evaluated using the nine EPA criteria
(40 CFR 300.430). Table 2.2 summarizes this evaluation.
Alternative 2, removal and transfer of tank contents to MVST, removes and safely stores
the contaminant source to prevent exposure before final treatment and disposal, thus providing
both short- and long-term protection of human health and the environment.
/T00589703.IWR/CJE 2-13 A«g"* &. 1997
-------
Table 2.1. ARARs and TBC guidance for the preferred alternative for the GAAT Interim Remedial Action, WAG 1, ORNL,
Oak Ridge, Tennessee
i
m
Resource/Action
Requirement
Prerequisite
Citation
Location'Speciftc
Presence of federally
owned, administered,
or controlled historic
properties
Action(s) that will affect such resources must be
identified and alternatives to the action(s) examined and
considered
When alteration or destruction of the resource is
unavoidable, steps must be taken to minimize or
mitigate the impacts and to preserve records and data
of the resource
Steps must be taken to consider the historical,
architectural, or archaeological significance of sites,
structures, and objects and to consult with the SHPO
Action which will impact
such resources-
applicable
National Historic Preservation
Act Sections 106 and 110
(16 USC 470 et seq.);
36 CFR 800;
EO 11593 (TBC only)
Action-specific
Control of fugitive
dust
Control of
radionuclide
emissions
Take reasonable precautions to prevent paniculate
matter from becoming airborne; no visible emissions
are permitted beyond the property boundary lines for
more than 5 minute/hour or 20 minute/day
Exposures to members of the public from all radiation
sources released into the atmosphere shall not exceed
an EDE of 10 mrem (0.1 mSv)/year
Radiological emission measurements required at all
release points that have a potential to discharge
radionuclides in quantities which could cause an EDE
in excess of 1 % of the standard (0.1 mrem/year)
Nonpoint source air
emissions from
construction/remediation
activities—applicable
Release of radionuclide
emissions to the air from
DOE facilities-
applicable
Rules of the TDEC 1200-3-8-
.010
40 CFR 61.92;
Rules of the TDEC 1200-3-
11-.08
40CFR61.93(b)(4)(i);
Rules of the TDEC 1200-3-
-------
Table 2.1. (continued)
Resource/Action
Requirement
Prerequisite
Citation
Control of surface
water runoff
All radionuclides which could contribute greater than
10% of the standard (1 mrem/year) for a release point
shall be measured
Exposures to members of the public from all radiation
sources shall not cause an EDE to be > 100 mrem
(1 mSv)/year
DOE will carry out all DOE activities to ensure that
radiation doses to individuals will be ALARA
Implement good site planning and best management
practices to control stormwater discharges, including:
• document best management practices in a
stormwater control plan or equivalent document
• use minimal clearing for grading
• remove vegetation cover only within 20 days of
construction
• perform weekly erosion control inspections and
maintenance
• implement control measures to detain runoff
• prevent discharges from causing erosion
Release of radionuclides
into the environment—
TBC
Stormwater discharges
associated with
construction activities at
industrial sites that result
in a disturbance of 5 acres
or greater of total land
area—relevant and
appropriate
40CFR61.93(b)(4)(i);
Rules of the TDEC 1200-3-
DOE Order 5400.5(11. la);
10CFR834.101 (proposed)
DOE Order 5400.5(1.4);
10 CFR 834 (proposed)
Rules of the TDEC 1200-4-
10-.05;
40 CFR 122
-------
Table 2.1. (continued)
Resource/Action
Requirement
Prerequisite
Citation
I
m
Removal/transfer of
tank contents to
MVST system,
characterization and
disposal of treatment
residuals and
decontamination fluids
A person who generates solid waste must determine
whether that waste is hazardous using various methods,
including application of knowledge of the hazardous
characteristics of the waste based on information
regarding the materials or processes used
All tank systems, conveyance systems, or other
ancillary equipment (does not include containers) used
to transport RCRA-hazardous wastewater for treatment
are exempt from RCRA Subtitle C requirements if the
wastewater is sent to an on-site wastewater treatment
facility subject to regulation under Sections 402 or
307(b) of the CWA (i.e., NPDES-permitted)
Management of TRU waste shall be conducted in such
a manner as to provide reasonable assurance that the
combined annual dose equivalent to any member of the
public in the general environment resulting from
discharges of radioactive material and direct radiation
from such management shall not exceed 25 mrem/year
to the whole body and 75 mrem/year to any critical
organ
Must meet waste acceptance criteria of receiving
facility for storage/disposal of LLW/TRU waste at
ORR
Generator of solid
waste—applicable
Rules of the TDEC 1200-1-
Storage/transfer of any
RCRA-hazardous
wastewater including
decontamination water-
applicable
Handling/management of
TRU waste—relevant and
appropriate"*
40CFR262.il;
40 CFR 268.7
40CFR260.10;
40CFR264.1(g)(6);
40CFR270.1(c)(2)(v);
Rules of the TDEC 1200-1-
40 CFR 191.03(b)
Storage/disposal of any
LLW/TRU waste or
wastewater
generated-TBC
DOE Order 5820.2A
-------
Table 2.1. (continued)
Resource/Action
Requirement
iPrereqiciisltel
Citation
5
m
K)
Institutional controls
for contaminated
tanks left in place
Controls include, but are not limited to: periodic
monitoring, as appropriate; appropriate shielding;
physical barriers (i.e., fences, warning signs) to
prevent access; inspection and repair of coverings;
temporary dikes; drainage courses; appropriate
radiological safety measures to ensure protection during
activities at the site
Long-term management of
residual radioactive
material above guidelines
left in inaccessible
locations—TBC
DOE Order 5400.5 (IV.6c)
"10 CFR 834.109 (proposed mle) requires (hat management of radioactive waste not exceed an EDE of 25 mrem/year from all pathways. When promulgated, this rule will be legally
applicable.
'DOE Order 5400.5, Chapter Il.l(c)(l), requires thai TRU waste management and storage activities at facilities other than disposal facilities not cause members of the public to receive
in a year a dose equivalent > 25 mrem to the whole body or a committed dose equivalent > 75 mrem to any organ.
A LARA = as low as reasonably achievable
ARAR = applicable or relevant and appropriate requirement
CFR = Code of Federal Regulations
CWA = Clean Water Act of 1972
DOE = U.S. Department of Energy
EDE = effective dose equivalent
EO = Executive Order
FR = Federal Register
> = greater than
GAAT = Gunite and Associated Tanks
LLW = low-level (radioactive) waste
mrem = millirem
mSv = millisievert
MVST = Melton Valley Storage Tanks
NPDES = National Pollutant Discharge Elimination System
ORNL = Oak Ridge National Laboratory
ORR = Oak Ridge Reservation
% = percent
RCRA = Resource Conservation and Recovery Act of 1976
SHPO = Stale Historic Preservation Office
TBC = to be considered
TDEC = Tennessee Department of Environment and Conservation
TRU = transuranic
USC = United States Code
WAG = waste area grouping
.<*
1
-------
Table 2.2. Summary of alternative evaluation, GAAT OU, WAG 1, ORNL, Oak Ridge, Tennessee
CERCLA criteria
No action alternative
Removal and storage
I
m
to
>—•
00
Protection of human health and the
environment
Compliance with ARARs
Long-term effectiveness and
permanence
Short-term effectiveness
Reduction of toxicity. mobility, or
volume through treatment
Implementability
Cost
State acceptance
Community acceptance
Poor. Tanks will eventually fail and release contents
Not applicable
Poor. Tanks will eventually fail and release contents
Fair. Assuming tank failure is not imminent
Poor. Does not reduce toxicity, mobility, or volume
through treatment
Good. Alternative is already in place
Good. Removal and safe storage of sludge will remove major risk of
OU
Complies with all ARARs
Good. Removes principal threat from this OU
Moderate. Some risk associated with removal and transport of
radioactive sludges
Poor. Does not reduce toxicity, mobility, or volume through treatment
Good. Treatability study in progress will determine the most effective,
cost efficient design for removal devices
Water removal with treatment, maintenance: $4.2 million Total capital costs': $35.1 million
TDEC has expressed its desire that the waste be removed
from the tanks
No public support, through written comments or at the
public meeting June 2, 1997, was received regarding this
alternative.
Total postremoval operation and maintenance costs (5 years): $1.7 million
Total project present worth: $34.3 million
Regulators have reviewed and commented on documents during scheduled
review periods. Deadline for public comments on this document extended
from June 2, 1997, to June 13, 1997. Stakeholders also participated in the
review of documents
Public comments and DOE responses are summarized in Part 3 of this
document. At the June 2 meeting, the public strongly supported removal
of the waste from these tanks.
'Actual cost will vary depending on the results of the treatability study, subsequent waste transfer costs, and (he actual engineering options selected. Regardless, DOE believes that this
selected alternative will be a cost-effective remedy for removing GAAT sludge.
ARAR = applicable or relevant and appropriate
requirement
CERCLA = Comprehensive Environmental Response,
Compensation, and Liability Act of 1980
$ = dollar
DOE = U.S. Department of Energy
GAAT = Gunite and Associated Tanks
ORNL = Oak Ridge National Laboratory
OU = operable unit
WAG = waste area grouping
-------
THE SELECTED REMEDY
This selected interim remedy complies with all ARARs. Based on consideration of the
requirements of CERCLA, the detailed analysis of the alternatives using the nine criteria and
public comments, DOE, EPA, and TDEC have determined that the preferred alternative, removal
and transfer of tank contents to MVST, provides the most appropriate remedy for Tanks W-3
through W-10. As described in Alternative 2, the liquid and sludge will be removed, the tank
walls and floors cleaned, and the resulting waste pumped to MVST. Any remaining debris will
be sampled and containerized for future removal if necessary. The tank shells will be
characterized to support the Bethel Valley Watershed remediation decision process.
DOE believes that this selected alternative will be a cost-effective remedy for removing
the GAAT sludge. The unacceptable level of risk associated with tank failures will be reduced
or eliminated when the sludge in the tanks is removed.
STATUTORY DETERMINATIONS
Section 121 of CERCLA requires that remedial actions must (1) protect human health
and the environment, (2) comply with ARARs (or justify a waiver), (3) be cost effective, and
(4) use permanent solutions and alternative treatment (or resource recovery) technologies to the
maximum extent practicable. Additionally, CERCLA Section 121 establishes a preference for
remedial actions including, as a principal element of the remedy, treatment that permanently and
significantly reduces the volume, toxicity or mobility of hazardous substances, pollutants, and
contaminants. However, for interim remedial actions, these requirements apply only within the
limited scope of the action. For example, interim remedial actions are required to comply with
only those ARARs specific to the interim action itself.
This interim action provides short- and long-term protection of human health and the
environment through removal of a contaminant source and limitation of the potential spread of
contamination. This action will comply with all ARARs. The action is cost-effective. DOE
believes the selected interim action represents the maximum extent to which an interim action can
be used and provides the best balance of trade-offs in terms of short-term effectiveness,
implementability, and cost. The action does not use treatment and is not permanent within the
scope of the action. The proposed action also reduces the potential contaminant release and is,
therefore, appropriate for an interim purpose.
/TOOS89703.IWR/CJE 2-19 Augusl 25. 1997
-------
EXPLANATION OF SIGNIFICANT CHANGES
A review of all comments resulted in no significant changes to the remedy as originally
identified in the FS/PP.
REFERENCES
DOE (U.S. Department of Energy). 1997. Feasibility Study/Proposed Plan for Sludge Removal
from the Gunite and Associated Tanks Operable Unit, Waste Area Grouping 1, Oak
Ridge National Laboratory, Oak Ridge, Tennessee, DOE/OR/02-1509/V1&D2, and
V2&D2. Oak Ridge, TN.
DOE. 1996a. Waste Isolation Pilot Plant Disposal Phase Draft Supplemental Environmental
Impact Statement, DOE/EIS-0026-S-2. DOE Carlsbad Area Office, Carlsbad, NM.
DOE. 1996b. Addendum to the Remedial Investigation/Baseline Risk Assessment for the
Gunite and Associated Tanks Operable Unit at Waste Area Grouping 1 at the Oak
Ridge National Laboratory, Oak Ridge, Tennessee, DOE/OR/02-1275&D2/A1. Oak
Ridge, TN.
DOE. 1994. Remedial Investigation/Baseline Risk Assessment for the Gunite and Associated
Tanks Operable Unit at Waste Area Grouping I, Oak Ridge, Tennessee, DOE/OR/02-
1275&D2. Oak Ridge, TN.
ORNL (Oak Ridge National Laboratory). 1997a. Evaluation and Monitoring Plan for
Consolidation Tanks: Gunite and Associated Tanks Operable Unit, Waste Area
Grouping, Oak Ridge National Laboratory, Oak Ridge, Tennessee, ORNL/ER-396.
Oak Ridge, TN.
ORNL. 1997b. Baseline Monitoring and Simulated Liquid Release Test Report for
Tank W-9, Oak Ridge National Laboratory, Oak Ridge, Tennessee, ORNL/ER-410.
Vista Research, Inc., Oak Ridge, TN.
ORNL. 1984. Sluicing Operations At Gunite Waste Storage Tanks, ORNL/NFW-84/72.
Oak Ridge, TN.
JT00589703.IWR/CJE 2-20 Augus 25, 1997
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PART 3. RESPONSIVENESS SUMMARY
JTOOS89TO3.IWR/CJE Augusi 25, 1997
-------
RESPONSIVENESS SUMMARY
The public comment period, originally scheduled for May 2, 1997, to June 2, 1997, was
extended to June 13, 1997. DOE received written comments from three individuals or groups.
A letter supporting the project from the Site Specific Advisory Board along with DOE's responses
to these comments are included at the end of Section 3. During the public meeting June 2, 1997,
DOE responded to questions from four individuals in the audience. For purposes of this
Responsiveness Summary, all public comments have been combined into four discrete comments
with DOE responses.
Comment 1. At the public meeting on June 2, 1997, several individuals indicated they felt
the FS/PP lacked a clear description of the overall strategy and details of this particular
action.
Response: In response to the request for a clearer description of the overall remediation
strategy, an additional section entitled "Decision Overview" has been added to the ROD. Also,
the descriptions of the approach to tank cleaning and overall waste treatment and disposal have
been expanded in the ROD.
Comment 2. Several individuals questioned pumping the waste from each Gunite tank to
a consolidation tank rather than directly to MVST.
Response: A consolidation tank is necessary to properly prepare the waste for batch
transfer to MVST and allow concurrent cleanup of the GAAT OU with other ORNL sites
containing TRU wastes. MVST volume considerations, aggravated by schedule constraints for
the waste's final disposal at WIPP, require that consolidation and waste volume reduction be
accomplished before transfer to MVST. Details of this approach have been added under the
"Decision Overview" section.
The consolidation process provides the capability to even out the flow from the waste
removal equipment and accumulate large enough batches of waste for efficient transfer to MVST.
Excess water generated during the waste removal process can be removed and sent to BVEST
for concentration, thereby maximizing the limited space available at MVST. Most importantly,
the consolidation approach will facilitate the eventual transfer of the waste to MVST. Waste
removed from the Gunite tanks must be "conditioned" (particle size and water content adjusted)
before it can be transferred to MVST through the mile-long pipeline between Bethel Valley and
Melton Valley. DOE plans to install a conditioning system in the consolidation tanks similar to
JTOOS89703.IWR/CIE 3-2 August 25. 1997
-------
that used in the 1982 waste removal campaign which successfully avoided plugging the only route
for transfer of radioactive liquid waste from the main plant of ORNL to MVST (ORNL 1984).
DOE has thoroughly investigated the integrity of the Gunite tanks and has selected Tanks W-8
and W-9 as the best candidates for use as consolidation tanks. Additional tests of these tanks are
underway to confirm their integrity and demonstrate the effectiveness of a new leak monitoring
system that has been installed for the tanks.
Comment 3. Several individuals expressed interest in specific details concerning conditioning
of the waste before transfer to MVST and the transfer of the wastes through an
underground pipeline.
Response: Available information on waste conditioning and transfer was discussed at the
public meeting on June 2, 1997. However, final details of this process will be developed during
the ongoing treatability study. When these details are developed they will be made available to
the public through the Information Resource Center.
Comment 4. One individual expressed concern that the total activity of the radioactive
material remaining in the tanks might be higher than the estimate used in the risk
assessment.
Response: The risk assessment narrative's figure of 40,000 Ci was based on the most
recent sampling event at the time the estimate was prepared. Previously, estimates in excess of
100,000 Ci have been advanced by parties with substantial experience and knowledge of the
tank's contents. However, because the waste inventory is being removed, differences in this
range will not exclude the selection of this remedy.
JT00589703.IWR/CJE 3-3 August 25. 1997
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AK RIDGE RESERVATION
Environmental Management
June 17. 1997
Mr. Rod Nelson
Assistant Manager for Environmental Management
DOE/ORO
P.O. Box 2001
OakRidce. TN 37831
Dear Mr. Nelson:
At our June 11, 1997 meeting, the Oak Ridge Reservation Environmental
Management Site Specific' Advison.- Board (ORREMSSAB) reviewed and
approved the enclosed recommendations for the Feasibility Study Proposed
Plan (FS/PP) for Sludge Removal from the Gunite and Associated Tanks
Operable Unit Waste Area Group 1, Oak Ridge National Laboratory. Oak
Ridge. Tennessee.
We look forward to receiving your written responses to our
recommendations. Thank you for your continued support of the
ORREMSS.AB.
Sincerely,
Randy Cordon, Chair
ORREMSSAB
ER/RG/sb
Enclosure
cc: Mr. John Hankinson, USEPA Region IV
Mr. Earl Leming, TDEC/DOE/ORO
P.O. Box 2001 • Mail Slop EW-91 • Oak Ridge, TN 37B31 • K23) 241-3665
-------
Comments on the Feasibility Study/Proposed Plan (FS/PP) for
Sludge Removal from the Gunite and Associated Tanks Operable Unit
Waste Area Group 1, Oak Ridge National Laboratory
Oak Ridge, Tennessee
The Oak Ridge Reservation Environmental Management Site Specific Advisory Board
(ORREMSSAB) is in general accord with the second alternative described in the FS/PP to
remove the bulk of the liquid and sludge from the gunite and associated tanks. The no
action alternative would be entirely unsatisfactory and quite problematic. Piping the
activity to the more modern Melton Valley Storage Tanks to mix with similar wastes
seems the correct course.
The document describes the removal of sludges as an interim action and states that it is
expected that the removed sludges will be sent to the Waste Isolation Pilot Plant (W1PP).
Since the WIPP facility is not yet an operational facility, there should be discussion about
the safety of storing the gunite tank waste in the Melton Valley Storage Tanks for an
unknown interim period. Either in this document or elsewhere, there should be
contingency plans in case postponement of the WIPP continues indefinitely or WIPP does
not open at all.
The document also discusses that remedial action on the contents of TH-4 is being
deferred until a later date. However, the program under which TH-4 will be addressed is
not identified. Similarly, the remedial actions to address the tank shells, appurtenances,
surrounding soils, and groundwater have not been identified, although it is our
understanding that these actions will be addressed in the Bethel Valley Record of
Decision. The public needs to be informed as to when and how deferred actions will be
addressed.
We assume that the most efficient time to determine the post-transfer residual
contamination of each tank is just after the sludge and liquids have been removed from
that tank. The initial sampling plan outlined in the section describing alternatives (p. 11)
will likely be too sparse unless video observations suggest that tank inner surfaces appear
to be uniform and clean. The ORREMSSAB recommends that the Record of Decision
explicitly outline a more comprehensive minimum sampling plan which will determine the
nature of irregular features. This information will allow for dependable plans to be
developed for the future tank closures.
Recommendation 97.10 1 Approved June 11, 1997
-------
Department of Energy
Oak Ridge Operations Office
P.O. Box 2001
Oak Ridge, Tennessee 37831—
August 6, 1997
Mr. Randall R. Gordon
3602 River Road
Ten Mile, Tennessee 37880
Dear Mr. Gordon:
RESPONSES TO SITE SPECIFIC ADVISORY BOARD COMMENTS ON GUNITE
TANKS REMEDIATION FEASIBILITY STUDY/PROPOSED PLAN D2
Thank you for your comments on the subject document. Our response to your comments are
enclosed. We appreciate your input on this important Comprehensive Environmental Response,
Compensation, and Liability Act document to help ensure that the basis for our decisions is
explained and understood. Many of the comments you raised will be addressed in the Record of
Decision which is currently being prepared and in the Remedial Design Report/Remedial Action
work plan which will be prepared later this Fiscal Year.
If you have any questions, please call Sandy Perkins at (423) 576-1590.
Sincerely,
Rodney R. Nelson
Assistant Manager for
Environmental Management
Enclosure
' PRINTED OK RECYCLED »A°cH
-------
Responses to Site Specific Advisory Board Comments
On Gunite Tanks Remediation Feasibility Study/Proposed Plan D2
Comment 1. The document describes the removal of sludges as an interim action and states that
it is expected that the removed sludges will be sent to the Waste Isolation Pilot Plant (WIPP).
Since the WIPP facility is not yet an operational facility, there should be discussion about the
safety of storing the Gunite tank waste in the Melton Valley Storage Tanks (MVST) for an
unknown interim period. Either in this document or elsewhere, there should be contingency plans
in case postponement of the WIPP continues indefinitely or WIPP does not open at all.
Response The consolidation of all Oak Ridge National Laboratory (ORNL) Transuranic sludges
in the MVST for treatment and shipment to WIPP is a central component of the Site Treatment
Plan submitted under the provisions of the Federal Facilities Compliance Agreement. The Plan
calls for sludge transfers of 50,000 gallons from Gunite Tanks, 20,000 gallons from the Old
Hydrofracture Facility, and 30,000 gallons from the Bethel Valley Evaporator Service Tanks to be
consolidated with the 100,000 gallons of sludge currently located in the MVST. Specific
contingency plans have not been developed for the possibility that WIPP may not open and that
longer storage of the sludges in MVST might be required. The MVST are fully permitted, "state
of the art," tanks which are expected to have continued service lives in excess of twenty five
years. This would provide sufficient time for the development and implementation of an
alternative approach to the long-term management of the sludges in the MVST should the need
arise.
Comment 2. The document also discusses that remedial action on the contents of TH-4 is being
deferred until a later date. However, the program under which TH-4 will be addressed is not
identified. Similarly, the remedial actions to address the tank shells, appurtenances, surrounding
soils, and groundwater have not been identified, although it is our understanding that these actions
will be addressed in the Bethel Valley Record of Decision. The public needs to be informed as to
when and how deferred actions will be addressed.
Response The Bethel Valley Watershed Record of Decision will include remedial action plans for
TH-4, several other smaller Gunite tanks, the eight large tank shells, appurtenances, surrounding
soils, and groundwater, in addition to the remainder of the Bethel Valley area. The current plans
call for the Dl Remedial Investigation/Feasibility Study to be issued June, 1998, the Dl Proposed
Plan to be issued November, 1998, and the Dl Record of Decision to be issued April, 1999.
Comment 3. We assume that the most efficient time to determine the post-transfer residual
contamination of each tank is just after the sludge and liquids have been removed from the tank.
The initial sampling plan outlined in the section describing alternatives (p. 11) will likely be too
sparse unless video observations suggest that the tank inner surfaces appear to be uniform and
clean. The Oak Ridge Reservation Environmental Management Sites Specific Advisory Board
recommends that the Record of Decision explicitly outline a more comprehensive minimum
sampling plan which will determine the nature of irregular features. This information will allow
for dependable plans to be developed for the future tank closures.
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Response The Department of Energy (DOE) plans to obtain the data to characterize the residual
contamination in the tanks shells at the completion of the waste removal and wall cleaning
activities. The details of the shell characterization are being developed as part of the on-going
Treatability Study, and are planned to be reflected in the Remedial Design Report/Remedial
Action Work Plan.
Based on information currently in hand, DOE expects that the sampling and analysis required for
the tank shells will be generally as described in the Feasibility Study/Proposed Plan. Based on
analyses performed in the "Risk Assessment Pathway/Transport Modeling for the Gunite and
Associated Tanks (GAAT), ORNL" (DOE/OR/02-1454&D1, March 1996) there is no reasonable
scenario that would result in the GAAT shells being a risk after sludge removal, a "washing" of
the wall, and then filling the tank with grout/concrete. The controlling mechanism for any
radionuclides to contact groundwater around the exterior of the tanks is by diffusion. The rate of
diffusion for ^Sr, coupled with the relatively short half-life of 90Sr, is such that a remaining shell
inventory after tank cleaning of billions of curies would be required for the 90Sr levels at the
exterior of the tank to approach any risk level for ^Sr. The diffusion rates for other radionuclides
are slower than for ^Sr and these radionculides are not mobile in the environment. Even if the
GAAT shell disintegrates in 300 years, these non-mobile radionuclides will be immediately
captured by surrounding soil, 20 plus feet underground. The small '"Sr inventory remaining after
clean out would have decayed through ten half-lives during this 300 period. There is nothing in
our experience or the literature to refute this logic. During the Treatability Study we will
investigate the logic and provide data to confirm this conclusion.
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