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Savannah River Site High-Level Waste Tank Closure
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
[Federal Register: August 19, 2002 (Volume 67, Number 160)]
[Notices]
[Page 53784-53787]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr19au02-50]
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DEPARTMENT OF ENERGY
Savannah River Site High-Level Waste Tank Closure
AGENCY: Department of Energy (DOE).
ACTION: Record of decision.
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SUMMARY: In the Savannah River Site (SRS) High-Level Waste Tank Closure
Environmental Impact Statement (Tank Closure EIS, DOE/EIS-0303) DOE
considered alternatives for closure of 49 high-level radioactive waste
(HLW) tanks and associated equipment such as evaporator systems,
transfer pipelines, diversion boxes, and pump pits. DOE needs to close
these tanks to reduce human health and safety risks at and near the HLW
tanks, and to reduce the eventual introduction of contaminants into the
environment. Moreover, DOE must comply with the provisions of the
Wastewater Systems Operating Permit issued by the South Carolina
Department of Health and Environmental Control (SCDHEC) for HLW tank
operations, and with the closure schedule and provisions contained in
the Industrial Wastewater Closure Plan for F- and H-Area High-Level
Waste Tank Systems (the General Closure Plan) approved by SCDHEC. DOE
evaluated three alternatives for closure of the tank systems: Stabilize
Tanks, Clean and Remove Tanks, and No Action. The Stabilize Tanks
alternative has three options--Fill with Grout (preferred alternative),
Fill with Sand, and Fill with Saltstone.
DOE has selected the preferred alternative identified in the Final
EIS, Stabilize Tanks--Fill with Grout, to guide development and
implementation of closure of the high-level waste tanks and associated
equipment at the SRS. Following bulk waste removal, DOE will clean the
tanks if associated equipment at the SRS. Following bulk waste removal,
DOE will clean the tanks if necessary to meet the performance
objectives contained in the General Closure Plan and the tank-specific
Closure Module, and then fill the tanks with grout.
In parallel with tank closures, DOE will evaluate and consult with
SCDHEC on closure methods and regulatory compliance revisions that will
allow accelerated closure and reduction of risk associated with the HLW
tanks. DOE remains committed to closure of the HLW tanks in accordance
with the approved General Closure Plan.
ADDRESSES: Copies of the Tank Closure EIS and this Record of Decision
may be obtained by calling a toll-free number (800-881-7292), by
sending an e-mail request to nepa@srs.gov, or by mailing a request to:
Andrew Grainger, National Environmental Policy Act (NEPA) Compliance
Officer, Savannah River Operations Office, Department of Energy,
Building 742A, Room 185, Aiken, SC 29808. This Record of Decision will
be available on the Department of Energy NEPA Web site, tis.eh.doe.gov/
nepa/whatsnew.htm.
FOR FURTHER INFORMATION CONTACT: Questions concerning the SRS tank
closure program can be submitted by calling 800-881-7292, mailing them
to Mr. Andrew Grainger at the above address, or sending them
electronically to the Savannah River Operations Office e-mail address,
nepa@srs.gov.
For general information on the DOE NEPA process, please contact:
Carol M. Borgstrom, Director, Office of NEPA Policy and Compliance,
U.S. Department of Energy, 1000 Independence Avenue, SW., Washington,
DC 20585, 202-586-4600 or leave a message at 800-472-2756.
SUPPLEMENTARY INFORMATION:
Background
Nuclear materials production at the SRS resulted in the generation
of large quantities of HLW that is stored onsite in large underground
tanks. The HLW resulted from the dissolution of spent reactor fuel and
nuclear targets to recover the valuable radioactive isotopes. DOE has
stored the HLW in 51 large underground storage tanks located in the F-
and H-Area Tank Farms at SRS. DOE has emptied and closed two of those
tanks. Approximately 37 million gallons of HLW is stored in the
remaining 49 HLW tanks.
The HLW tank systems at SRS are operated under the authority of the
Atomic Energy Act of 1954 (AEA) and DOE Orders issued pursuant to the
AEA. The HLW tank systems also are operated in accordance with a permit
issued by SCDHEC under the authority of the South Carolina Pollution
Control Act for industrial wastewater treatment facilities. DOE is
required to close the tank systems in accordance with AEA requirements
and South Carolina Regulation R.61-82, ``Proper Closeout of Wastewater
Treatment Facilities.'' This regulation requires that closures be
carried out according to site-specific guidelines established by SCDHEC
to prevent health hazards and to promote safety in and around the tank
systems.
[[Page 53785]]
DOE has adopted a general strategy for HLW tank system closure, set
forth in DOE's Industrial Wastewater Closure Plan for the F- and H-Area
High-Level Waste Tank Systems (March 2000), known as the General
Closure Plan.\1\ The General Closure Plan has been approved by SCDHEC
and DOE must gain SCDHEC's approval on any revisions to the General
Closure Plan. Also, DOE has entered into an agreement, the SRS Federal
Facility Agreement, with the U.S. Environmental Protection Agency (EPA)
and SCDHEC to remove from service and close 24 HLW tanks that do not
meet Resource Conservation and Recovery Act secondary containment
requirements. The remaining 27 tanks will also be closed when they are
no longer required for service. Closure of the HLW tanks will comply
with DOE's responsibilities under the AEA and the General Closure Plan,
and be carried out under a schedule agreed to by DOE, EPA, and SCDHEC.
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\1\ Although the Final Environmental Impact Statement reflected
the 2000 Closure Plan, the Statement incorrectly cited the 1996
Closure Plan.
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The General Closure Plan identifies the resources (e.g.,
groundwater, air) potentially affected by contaminants remaining in the
tanks after waste removal and closure; describes how the tanks will be
cleaned and how the tank systems and residual wastes will be
stabilized; and identifies Federal and State regulations and guidance
that apply to the closures. The Plan describes the use of fate and
transport models to calculate potential environmental exposure
concentrations or radiological dose rates from the residual waste left
in the tank systems. The General Closure Plan describes the method DOE
will use to make sure the impacts of closure of individual tank systems
do not exceed the environmental standards that apply to the entire F-
and H-Area Tank Farms.
Several issues related to the HLW tank closure program will be
resolved as DOE implements this Record of Decision. These issues will
be addressed during tank-by-tank closure and include: (1) Performance
objectives for each tank that allow the cumulative closure to meet the
overall performance standard; (2) the regulatory status of residual
waste in the tanks, through a determination whether they are ``waste
incidental to reprocessing;'' and (3) use of cleaning methods such as
spray water washing or oxalic acid cleaning, if needed to meet tank-
specific performance objectives.
Performance Objectives
In implementing this Record of Decision, DOE will establish
performance objectives for closure of each HLW tank. Each performance
objective will correspond to an overall performance standard identified
in the General Closure Plan and will ensure that the overall
performance standard can be met. For example, if the performance
standard for drinking water in the receiving stream is 4 millirem per
year, the combined contribution from contaminants from all tanks will
not exceed the 4 millirem-per-year limit. DOE will evaluate closure for
specific tanks to determine whether use of a specific closure option
will allow DOE to meet the overall performance standard. Based on this
analysis, DOE will develop a Closure Module (a tank-specific closure
plan) for each HLW tank such that the performance objectives for the
tank can be met. The Closure Module must be approved by SCDHEC before
tank closure can begin.
Waste Incidental to Reprocessing
Before bulk waste removal, the content of the tanks is HLW. The
goal of the bulk waste removal and, if needed, subsequent cleaning of
the tanks, is to meet DOE's criteria for Waste Incidental to
Reprocessing. DOE Manual 435.1-1, which implements DOE Order 435.1,
Radioactive Waste Management, describes two processes, citation and
evaluation, for determining that HLW can be considered ``waste
incidental to reprocessing'' and can therefore be managed under DOE's
regulatory authority in accordance with requirements for transuranic
waste or low-level waste. In implementing this Record of Decision, DOE
will perform a waste incidental to reprocessing determination by
evaluation on each HLW tank as part of the analysis used to prepare the
Closure Module.
HLW Tank Cleaning
Following bulk waste removal, DOE will clean the tanks, if
necessary, to meet the performance objectives contained in the General
Closure Plan and in the tank-specific Closure Module, which includes
DOE's criteria for Waste Incidental to Reprocessing. In accordance with
the General Closure Plan, the need for and the extent of any tank
cleaning will be determined based on the analysis presented in the
tank-specific Closure Module.
If necessary tank cleaning by spray water washing will initially be
performed. If performance objectives could not be met using spray water
washing, other cleaning techniques would be employed. These techniques
include mechanical methods, oxalic acid cleaning, or other chemical
cleaning methods. Potential criticality safety concerns and
interference with downstream waste processing activities such as
Defense Waste Processing Facility glass quality could arise with the
use of chemical cleaning methods and would have to be addressed.
Alternatives Considered
In the EIS DOE evaluated three alternatives for tank closure, each
of which begins when bulk waste removal from the tank has been
completed. Under each alternative except No Action, DOE would close 49
HLW tanks and associated waste handling equipment including
evaporators, pumps, diversion boxes, and transfer lines.
Stabilize Tanks Alternative
Following bulk waste removal and any required cleaning, DOE would
fill the tanks with a material that would bind up remaining residual
waste and prevent future collapse of the tanks. In the EIS DOE
considered three options for tank stabilization under this alternative:
Fill with Grout (preferred alternative), Fill with Sand, and Fill with
Saltstone. Each tank system or group of tank systems would be evaluated
to determine the inventory of radiological and nonradiological
contaminants remaining after bulk waste removal. This information would
be used to conduct a performance evaluation as part of the preparation
of a Closure Module. In the evaluation DOE would consider (1) the types
of contamination in the tank and the configuration of the tank system,
and (2) the hydrogeologic conditions at and near the tank location,
such as distance from the water table and distance to nearby streams.
The performance evaluation would include modeling the projected
contamination pathways for selected closure methods, and comparing the
modeling results with the performance objectives developed in the
General Closure Plan. If the modeling shows that performance objectives
would be met, the Closure Module would be submitted to SCDHEC for
approval. If the modeling shows that the performance objectives would
not be met, then tank cleaning steps would be taken until sufficient
waste had been removed that the objectives could be met. Therefore the
closure configuration for each tank or group of tanks would be
determined on a case-by-case basis through development of the Closure
Module.
[[Page 53786]]
Following approval of a Closure Module by SCDHEC, the tank
stabilization process would begin. DOE's preferred option is to use
grout, a concrete-like material, as backfill. The fill material would
be high enough in pH to be compatible with the carbon steel walls of
the tank. The grout would be formulated with chemical properties that
would retard the movement of radionuclides in the residual waste in the
closed tank. The grout would be poured in three distinct layers. The
bottom-most layer would be specially formulated reducing grout to
retard the migration of important contaminants. The middle layer would
be a low-strength material designed to fill most of the volume of the
tank interior. The final layer would be a high-strength grout to deter
inadvertent intrusion from drilling. DOE is also considering an all-in-
one grout that would provide the same performance as the three separate
layers of grout. If this all-in-one grout would provide the same
performance and protection at a lesser cost, DOE would use it.
Other fill options that DOE considered in the EIS are sand and
saltstone. For these options, all other aspects of the closure process,
including the determination that performance objectives could be met
and approval of the Closure Module by SCDHEC, would be the same as
described for the Fill with Grout option. Sand is readily available and
inexpensive. However, it would be more difficult to completely fill
void spaces with sand than with grout, and sand could not be formulated
to retard the migration of radionuclides. Expected contamination levels
in groundwater and surface water resulting from migration of residual
contaminants would be higher than the levels for the preferred option.
Saltstone, which is the low-radioactivity fraction of HLW mixed with
cement, flyash, and slag, could also be used as fill material.
Saltstone is normally disposed of as low-level waste in the SRS
Saltstone Disposal Facility. This alternative would have the advantage
of reducing the amount of Saltstone Disposal Facility area that would
be required. Filling the tank with a grout mixture that is contaminated
with radionuclides, like saltstone, would considerably complicate the
project and increase worker radiation exposure. In addition, the
saltstone would contain large quantities of nitrate that would not be
present in the tank residual waste. Because nitrates are very mobile in
the environment, these large quantities of nitrate would adversely
impact the groundwater near the tank farms over the long term.
Following the use of any of the stabilization options, four tanks
in F-Area and four tanks in H-Area would require backfill soil to be
placed over the top of the tanks to bring the ground surface at these
tanks up to the surrounding surface elevation. The action would prevent
ponding conditions that could accelerate degradation of the tank
structure.
Clean and Remove Tanks Alternative
The Clean and Remove Tanks alternative would involve cleaning the
tanks, cutting them up in situ, removing them from the ground, and
transporting tank components for disposal in an engineered disposal
facility at another location on the SRS. For this alternative DOE would
have to clean the tanks until they were clean enough to be safely
removed and could meet waste acceptance criteria at SRS low-level waste
disposal facilities. Cleaning techniques such as oxalic acid cleaning,
mechanical cleaning and additional steps as yet undefined might be
required. Worker exposure would have to be As Low As Reasonably
Achievable to ensure protection of the individual workers required to
perform the tank removal operations.
Following bulk waste removal and tank cleaning, the steel
components of the tank would be cut up, removed, placed in radioactive
waste transport containers, (approximately 3,900 SRS low-level waste
disposal boxes per tank), and transported to SRS radioactive waste
disposal facilities for disposal. This alternative would require the
construction of approximately 16 new low-activity waste vaults at SRS
for disposal of the tank components. With removal of the tanks,
backfilling of the excavations left after the removal would be
required.
No Action Alternative
The No Action alternative would involve leaving the tank systems in
place after bulk waste removal has been accomplished. After bulk waste
removal, each tank would contain residual waste, and, in those tanks
that reside in the water table, ballast water. The tanks would not be
backfilled.
After some period of time (probably hundreds of years), the
reinforcing bar in the roof of the tank would rust and the roof would
fail, causing the structural integrity of the tank to degrade.
Similarly, the floor and walls of the tank would degrade over time.
Rainwater would enter the exposed tank, flushing contaminants from the
residual waste in the tanks and eventually carrying these contaminants
into the groundwater. Contamination of the groundwater would be much
greater and occur much more quickly than it would if the tank were
backfilled and the residual waste bound with the backfill material.
Environmentally Preferable Alternative
Overall, the Stabilize Tanks--Fill with Grout alternative is the
environmentally preferable alternative. Review of the data presented in
the Tank Closure EIS shows that in the near term the impacts of the
Stabilize Tanks--Fill with Grout alternative are similar to or less
than those of the Stabilize Tanks--Fill with Sand and the Stabilize
Tanks--Fill with Saltstone alternatives.
Waste removal and, if necessary, cleaning activities would be
similar for each of these alternatives, although worker exposures and
resultant latent cancer fatalities would be slightly higher for the
Stabilize Tanks--Fill with Saltstone alternative due to the
radionuclide content of the saltstone. In the short term the Clean and
Remove Tanks alternative would have substantially greater impacts than
any of the Stabilize Tanks options, as a result of the worker exposures
that would be required to clean and remove the tanks and tank systems.
The No Action alternative has the least short-term impacts.
In the long term, the impacts of the Clean and Remove Tanks
alternative would be the least of all the alternatives, because the
groundwater contaminant source term would have been removed. Some small
long-term impacts would result from release of contaminants from the
disposal facility that would receive the tank systems after removal.
Long-term impacts of the preferred alternative, Stabilize Tanks--Fill
with Grout, would be greater than those of the Clean and Remove Tanks
Alternative, although very small; no latent cancer fatalities would
result from implementation of the Stabilize Tanks--Fill with Grout
alternative. The No Action alternative has the greatest long-term
impacts.
Decision
DOE has selected the preferred alternative identified in the Final
EIS, Stabilize Tanks--Fill with Grout, to guide development and
implementation of closure of the high-level waste tanks and associated
equipment at SRS. Following bulk waste removal, DOE will clean the
tanks if necessary to meet the performance objectives contained in the
General Closure Plan and the tank-
[[Page 53787]]
specific Closure Module and then fill the tanks with grout.
In parallel with tank closures, DOE will evaluate and consult with
SCDHEC on closure methods and regulatory revisions that will allow
accelerated closure and reduction of risk associated with the HLW
tanks. DOE remains committed to closure of the HLW tanks in accordance
with the approved General Closure Plan.
DOE has selected the Stabilize Tanks--Fill with Grout alternative
for several reasons. First, DOE has confidence in the method due to the
demonstrated performance of the reducing grout and the successful waste
removal and closure process employed for Tanks 17 and 20. On the basis
of the analysis in the EIS, the selected alternative is superior to the
Fill with Sand and Fill with Saltstone options in terms of binding
residual waste in the tanks and thereby preventing future environmental
contamination. This alternative would likely require the least tank
cleaning of any alternative and would therefore minimize worker
exposures and waste management concerns while meeting the performance
objectives. In addition, this alternative was found to be the
environmentally preferable alternative.
As described in the EIS, bulk waste removal has been demonstrated
to remove about 97 percent of the radioactive material content,
measured in curies, from a HLW tank. Spray water washing has been shown
to remove slightly less than an additional one percent and generates
additional wastewater that requires processing. DOE will employ spray
water washing or an enhanced cleaning method only if it is necessary to
meet the performance objectives.
In accordance with the General Closure Plan, DOE must demonstrate
whether residual waste (that is, waste that will remain in the tank
following any necessary cleaning, and that will be immobilized in the
grout used to stabilize the tank) is low-level or transuranic waste in
accordance with the Waste Incidental to Reprocessing provision in DOE
Order 435.1. However, because DOE must meet overall performance
standards in any case, the regulatory status of the residual waste does
not affect the assessment of environmental impacts.
Mitigation
DOE is committed to environmental stewardship and to operating the
SRS in compliance with all applicable laws, regulations, DOE Orders,
permits, and compliance agreements. In addition to good engineering
practice, closure of the HLW tanks will follow the approved Industrial
Wastewater Closure Plan for the F- and H-Area High-Level Waste Tank
Systems, known as the General Closure Plan, and the individual Tank
Closure Modules required by the General Closure Plan. This process will
serve to ensure that risks are minimized and the environmental and
health and safety impacts of tank closure are within the bounds
described in the Final EIS. DOE considers this process to be standard
operating procedures that do not require a mitigation action plan under
10 CFR 1021.331(a).
Issued at Washington, DC, August 9th, 2002.
Paul M. Golan,
Acting Assistant Secretary for Environmental Management.
[FR Doc. 02-20968 Filed 8-16-02; 8:45 am]
BILLING CODE 6450-01-P