SUMMARY
On March 17, 1994, the U.S. Department of Energy (DOE) announced
in the Federal Register its intent to prepare an Environmental
Impact Statement (eis) to assess the Interim Management of
Nuclear Materials currently stored at the Savannah River Site
(SRS). On June 21, 1994, DOE announced in the Federal Register
its intent to prepare a Programmatic eis for Storage and
Disposition of Weapons-Usable Fissile Materials, which will
evaluate the long-term storage and disposition of such materials
nationwide at DOE sites. Proposed interim management activities
at the SRS would not affect long-term disposition decisions. The
purpose of these interim actions would be to stabilize materials
at the SRS that could pose environmental, health, and safety
risks to the public, workers, and the environment. The nuclear
materials inventory at the SRS includes weapons-usable fissile
materials. DOE has committed to prohibit the use of
plutonium-239 and weapons-usable highly enriched uranium
separated or stabilized during the phaseout, shutdown, and
cleanout of weapons complex facilities for nuclear explosive
purposes (Reis and Grumbly 1994).
Since the publication of the Notice of Intent for the eis on
Interim Management of Nuclear Materials, DOE has determined
that a potentially significant safety concern exists with
the continued storage of plutonium solutions in the F-Canyon
chemical separations facility. The condition of these plutonium
solutions warrants consideration of their stabilization before
DOE plans to make any decisions in relation to the Interim Management
of Nuclear Materials eis. On August 23, 1994, DOE published a
notice of an amendment to the Notice of Intent for the eis for the Interim
Management of Nuclear Materials at the SRS. The notice explained
the DOE decision to prepare this eis on F-Canyon Plutonium
Solutions to consider alternative ways to stabilize such
solutions. DOE has prepared this eis in accordance with the regulations
of the Council on Environmental Quality (40 CFR Parts 1500-1508) and
DOE NEPA Implementing Procedures (10 CFR Part 1021).
Purpose and Need
During the time the SRS was actively involved in nuclear material
production, DOE transferred irradiated fuels and targets from SRS reactors to
disassembly basins, which are water-filled pools, to allow
short-lived radioactive isotopes to decay. From the pools, DOE
transferred the fuel and targets to canyon facilities in F- and
H-Areas, which chemically dissolved them into liquid solutions.
The useful isotopes were recovered, converted to a solid form,
and either shipped to other DOE facilities or stored on the
Site.
In March 1992, DOE suspended chemical processing operations in
the F-Canyon to address a potential safety concern. That concern
was addressed; however, prior to the resumption of processing,
the Secretary of Energy directed that SRS phase out
defense-related chemical separations activities (i.e.,
reprocessing). Non-safety-related facility operations have
remained shut down since that time (March 1992). Approximately
303,000 liters (80,000 gallons) of solutions containing plutonium
have remained in tanks in F-Canyon since the suspension of
operations.
The plutonium solutions currently in storage in F-Canyon have
been held much longer than called
for in the original design and routine operation of the canyon.
As a result, the solutions are now in a condition not previously
envisioned. DOE has taken mitigating actions, such as the
addition of boron, to prevent an imminent hazard from occurring.
Continued deterioration in solution chemistry requires increasing
vigilance to ensure safe storage. However, this does not reduce
the inherent risk of storing plutonium in a liquid form.
The vulnerabilities associated with the continued storage of the
plutonium in solutions have been documented in environmental,
safety, and health studies conducted by DOE review teams and
outside
experts (see DNFSB 1994 and DOE 1994a). The Defense Nuclear
Facilities Safety Board
"concluded from observations and discussions with others that
imminent hazards could arise within 2 to 3 years unless certain
problems are corrected....The Board is especially concerned
about... (s)everal large tanks in the F-Canyon at the Savannah
River Site (that) contain tens of thousands of gallons of
solutions of plutonium and trans-plutonium isotopes. The
trans-plutonium solutions remain from californium-252 production;
they include highly radioactive isotopes of americium and curium.
These tanks, their appendages, and vital support systems are old,
subject to deterioration, prone to leakage, and are not seismically
qualified. If an earthquake or other accident were to breach the
tanks, F-Canyon would become so contaminated that cleanup would
be practically impossible. Containment of the radioactive
material under such circumstances would be highly uncertain....
Therefore, the Board recommends...(t)hat preparations be
expedited to process the dissolved plutonium and trans-plutonium
isotopes in tanks in the F-Canyon at the Savannah River Site into
forms safer for interim storage. The Board considers this
problem to be especially urgent" (DNFSB
1994). The DOE study concluded that there is an increasing risk
of criticality and abnormal transients due to the uncertainty of
solution chemistry.
Proposed Action and Alternatives
DOE is proposing to process F-Canyon plutonium solutions into
forms that it can store with less risk to the public, worker
health and safety, and the environment. This eis considers the
following alternatives for the stabilization of these solutions:
- No Action: DOE would continue to manage the existing
303,000-liter (80,000-gallon) inventory of solutions in
stainless-steel tanks in the F-Canyon. The solutions would
be monitored to minimize the potential for precipitation of
the plutonium and the possibility of an inadvertent
criticality. This action would continue for the 10-year time
period evaluated in this eis.
- Processing to Plutonium Metal (the preferred alternative):
DOE would process the plutonium solutions, using proven chemical
separations and conversion techniques, into plutonium metal that
could be stored with less risk to the public, worker health and safety,
and the environment in comparison to the No-Action Alternative. DOE
expects this stabilization alternative could be accomplished in 20 months
from the date of the Record of Decision of this eis, which
would be significantly faster than stabilization could be
accomplished under the other alternatives (described below).
The FB-Line is not currently configured to package plutonium
in accordance with the new DOE standard for long-term storage
of plutonium (DOE 1994b). After converting the plutonium
solutions to a metal and packaging and storing the resulting
metal discs, DOE would modify part of the FB-Line facility.
New equipment would provide the capability to repackage the
plutonium metal into a configuration that meets the new DOE
standard. DOE estimates that it could modify FB-Line and
repackage the material by late 1997 at a cost of
approximately $3 million.
Rather than modifying FB-Line, DOE could modify another
vault facility (Building 235-F) or construct a new
repackaging and vault facility in the F-Area. DOE estimates
this could cost between $70-150 million and that it could
complete this work by 2001.
Although repackaging of plutonium metal could occur in the
FB-Line at the completion of stabilization actions, the
environmental impacts are based on the assumption that the
repackaging would take place in a new vault facility.
- Processing to Plutonium Oxide: DOE would modify the FB-Line
to support conversion of the plutonium solutions to a
plutonium oxide and to package the material for storage. The
objective would be to produce a material form and packaging
configuration that met the new DOE standard for long-term
storage of plutonium. If the extent of the FB-Line
modifications necessary to meet this standard were
economically or physically impractical, DOE would perform the
stabilization in two phases. DOE would modify FB-Line to be
able to convert the material initially to an oxide form and
package it in FB-Line. At the same time, DOE would design and
construct a new facility (the Repackaging and Vault Facility;
see Appendix A) to process, package, and store the oxide in
accordance with the new standard. DOE estimates that the
minimum required modifications to FB-Line would cost $7 million
and take 3 years to complete. Following completion and
modification, DOE would operate the FB-Line for approximately
7 months to convert and package the oxide for storage.
- Vitrification (Defense Waste Processing Facility): DOE
would transfer the plutonium solutions to the SRS waste tank
farm. Before transfer, the solutions would be adjusted to
ensure the safety of the material in the tanks. DOE has
identified several concepts for adjusting the solutions:
diluting the solutions with water and chemicals to achieve
very low plutonium concentrations, diluting the solutions
with depleted uranium, or adding iron and manganese or other
neutron poisons such as gadolinium (DOE 1994a). In the waste
tanks, high-activity waste would settle to the bottom of the
tank in the form of sludge. DOE would transfer highly
radioactive sludge to the Defense Waste Processing Facility,
where it would be vitrified (converted to a glass-like
substance) and stored on the Site until DOE made final
disposition decisions.
DOE estimates it would take approximately 6 years to perform
the technical studies, training, and qualification efforts
necessary to ensure safe operation for transferring the
solutions and subsequent vitrification using this
stabilization alternative. DOE has estimated that
evaluations for transferring the solutions to the high-level
waste tanks could be completed in approximately 3 years (WSRC
1994a). However, the solutions would not be transferred to
these tanks until all studies for vitrification were final.
After these studies are complete, DOE estimates that it would
take an additional 3 years to complete the process of
transferring all the plutonium solutions to the high-level
waste tanks because of the availability of tank space and
criticality concerns. The plutonium solutions would remain
in the high-level waste tanks until DOE transferred the
contents to the Defense Waste Processing Facility for
vitrification.
- Vitrification (F-Canyon): Under this alternative, DOE would
vitrify the plutonium into a borosilicate glass matrix using
the F-Canyon Vitrification Facility. The modifications to the
F-Canyon would include the installation of a geometrically
favorable evaporator to concentrate plutonium solution and
equipment to convert the concentrated plutonium solution to a
glass matrix using technology similar to that to be used on a
larger scale in the Defense Waste Processing Facility. The
capital costs of these modifications would be about $27
million; the facility could be available by January 1999.
When the modifications to the F-Canyon Vitrification Facility
were complete, the plutonium solutions would be transferred
to the facility and evaporated. This concentrated plutonium
solution would be fed, along with finely ground glass (frit),
to a melter to produce a borosilicate glass containing the
plutonium. The molten glass would be poured into a
stainless-steel package and stored in an existing vault at
the F-Canyon.
Although the vitrification of this plutonium could begin as
early as January 1999, DOE analyzed the Vitrification in
F-Canyon Alternative as though it began during the first 6
months of 2000. Although DOE has not established the final
schedule for this alternative, this eis describes its
environmental consequences. Further changes to the schedule
would not cause changes to the environmental impacts.
Affected Environment
The SRS occupies an area of approximately 800 square kilometers
(300 square miles) adjacent to the Savannah River, primarily in
Aiken and Barnwell Counties in South Carolina. The Site is
approximately 40 kilometers (25 miles) southeast of Augusta,
Georgia, and 32 kilometers (20 miles) south of Aiken, South Carolina.
The alternatives (including no action) would all occur within an existing
industrial area (i.e., F-Area) at SRS.
Environmental Impacts
Table S-1 compares the environmental consequences for the five
alternatives based on the assessments contained in Chapter 4.
The table summarizes how each alternative compares to the
others.
Table S-1. Comparison of the potential environmental impacts of the alternatives
In addition to comparing alternatives against the environmental
criteria listed in Table S-1, DOE considered the following
factors related to the stabilization of nuclear materials:
- New facilities required
- Security and nonproliferation
- Implementation schedule
- Technology availability and technical feasibility
- Labor availability and core competency
- Aging facilities
- Minimum custodial care
These factors are representative of issues addressed by the
National Academy of Science in its study of the management and
disposition of plutonium (NAS 1994), the Office of Technology
Assessment plutonium study (OTA 1993), and comments received
during the eis scoping period. The Processing to Plutonium Metal
Alternative would be the most advantageous for all factors except
two:
- Security and nuclear nonproliferation concerns, because it
would result in a form that closely resembles materials used
in weapons production
- Aging facilities, because it would involve continued storage
of the metal in the FB-Line vault
In relation to security and nonproliferation concerns, the
Vitrification Alternative would be preferable because it would
produce a form of material least likely to be used in manufacturing
or producing a nuclear weapon. However, the technology
to accomplish the vitrification of plutonium (in other than trace
quantities) does not currently exist; DOE estimates it would take
6 years to develop the capability.
The Processing to Oxide and the Vitrification Alternatives could
involve minimal reliance on aging facilities. These alternatives
eventually could result in the use of new facilities for the
final step involved in stabilizing the plutonium and for storing
the plutonium after the completion of stabilization.
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