Savannah River Operations Office; Interim Management of Nuclear Materials at the Savannah River Site

I. Background

The U.S. Department of Energy (DOE) prepared the final environmental impact statement (EIS), ``Interim Management of Nuclear Materials'' (DOE/EIS-0220, October 20, 1995), to assess the potential environmental impacts of actions necessary to manage nuclear materials at the Savannah River Site (SRS), Aiken, South Carolina, until decisions on their ultimate disposition are made and implemented. Some of the particular materials considered in the EIS could present environment, safety and health vulnerabilities in their current storage condition. The Final EIS identified processing to oxide using the H-Canyon and HB-Line facilities as the preferred alternative for the neptunium-237 solution and targets and the plutonium-239 solutions. On December 12, 1995, DOE issued a ROD and Notice of Preferred Alternatives (60 FR 65300) on the interim management of several categories of nuclear materials at the SRS. In addition, DOE indicated that neptunium-237 solution and targets would be stabilized either by processing to oxide or vitrification, and that plutonium-239 solutions in H-Canyon would be stabilized through processing to metal, processing to oxide, or vitrification. DOE stated that it would select and implement one stabilization method for each of these material categories, and that the stabilization method chosen would be dependent upon further reviews of costs, schedules, and facility utilization options. On February 8, 1996, DOE issued a Supplemental ROD (61 FR 6633) for the stabilization of two of the remaining categories of nuclear materials (Mark-16 and Mark-22 fuels, and other aluminum-clad targets) analyzed in the Final EIS. On February 29, 1996, Westinghouse Savannah River Company, the Department's management and operating contractor for the Savannah River Site, advised DOE that, while engaged in a scheduled upgrade of safety authorization basis documentation, it had discovered that seismic (earthquake) analyses performed in the early 1980s were based on assumptions that are inconsistent with the as-built condition of the canyon facilities. As a result of this discovery, the transfer of nuclear materials into the canyon facilities was suspended while detailed analyses and reviews were conducted to ensure the safety of the canyon facilities and to determine if the information contained in the Interim Management of Nuclear Materials Final EIS was sufficient. The F-Canyon analyses have been completed; the H-Canyon analyses are expected to be completed in September 1996. The completed F-Canyon analyses indicate that the ability of the F-Canyon facilities to withstand a severe earthquake is equal to or better than that predicted in existing Safety Analysis Reports and the EIS. Based on a Supplement Analysis, DOE determined that a Supplemental EIS for nuclear materials stabilization in F-Canyon is not required. After further consideration of the facility utilization strategy study, the Final EIS, budget and schedule projections, and comments from interested parties, DOE is now issuing its decisions for the stabilization of neptunium-237 solution and obsolete targets, and plutonium-239 solutions, the remaining two categories of nuclear materials at the SRS evaluated in the

Interim Management of Nuclear Materials EIS.

II. Alternatives Evaluated in the Final EIS

DOE evaluated the following alternatives for managing the neptunium-237 solution and obsolete reactor targets, and the plutonium- 239 solutions at the SRS: (A) Continuing Storage (i.e., ``No Action'' within the context of NEPA), (B) Processing to Oxide, (C) Processing and Storage for Vitrification in the Defense Waste Processing Facility (DWPF), and (D) Vitrification (F-Canyon). In addition, Processing to Metal was also evaluated for the plutonium-239 solutions. The following is a brief description of the alternatives evaluated.

A. Continuing Storage (No Action)

Under this alternative, DOE would continue to store the materials in their current physical and chemical form. DOE would relocate or repackage materials stored in vaults or tanks to consolidate the material or to respond to an immediate safety problem. Periodic sampling, destructive and non-destructive examination, weighing, visual inspection and similar activities would continue in order to monitor the physical and chemical condition of the nuclear material. Chemicals would be added to existing solutions in order to maintain concentration and chemistry within established parameters. Repackaging would include removing materials from damaged storage containers and placing them in new containers or placing the damaged containers in larger containers. A variety of activities could be required to maintain the materials in their current physical and chemical form. For example, DOE would maintain facilities in good working condition and would continue to provide utilities (water, electricity, steam, compressed gas, etc.) and services (security, maintenance, fire protection, etc.) for each facility. Training activities would ensure that personnel maintain the skills necessary to operate the facilities and equipment. DOE would continue with ongoing projects to alleviate facility-related vulnerabilities associated with storage of the materials and projects to upgrade or replace aging equipment (ventilation fans, etc.).

B. Processing to Oxide

DOE would convert existing solutions of neptunium-237 and plutonium-239 to an oxide in HB-Line. Additional neptunium-237 solution would be generated in the processing of the obsolete reactor targets. After conversion of the plutonium and neptunium solutions to oxides, the oxides would be packaged and stored in accordance with applicable criteria in an existing vault until a new Actinide Packaging and Storage Facility is available.

C. Processing and Storage for Vitrification in the DWPF

DOE would perform research and development work to develop a method for chemically adjusting existing solutions and solutions that would result from the dissolution of the obsolete neptunium-237 targets in order to transfer them to the high level waste tanks in H-Area. The research and development work would be done to ensure nuclear criticality safety due to the amount of plutonium-239 in the existing solutions, and to evaluate the effects of the nuclear materials on the systems and facilities used to store and treat the liquid high level waste. Upon completion of the studies, existing solutions of neptunium-237 and plutonium-239 would be chemically adjusted and transferred to the high level waste tanks via underground pipelines. DOE would transport the obsolete targets from the K-Reactor area to F- or H-Canyon where they would be dissolved in nitric acid. The resulting solutions would be chemically adjusted and transferred to the high level waste tanks via underground pipelines. The solutions would be mixed with the existing volume of high level waste stored in the F- or H-Area tanks. The bulk of the radioactivity in the solutions would eventually be immobilized in borosilicate glass in the vitrification process at the DWPF. The glass would be contained within stainless steel canisters that would be stored in a facility adjacent to the DWPF pending geologic disposal by DOE. The bulk of the liquid would be immobilized by the Saltstone Facility into a grout containing very low levels of radioactivity. The grout would be poured into concrete vaults located at the Saltstone Facility.

D. Vitrification (F-Canyon)

For this alternative, DOE would utilize the vitrification capability that it decided in the December 12, 1995, ROD to install in F-Canyon for the stabilization of the americium and curium solution. The existing solutions of neptunium-237 and plutonium-239, currently stored in H-Canyon, would be transported to F-Canyon for vitrification upon development or procurement of a suitable shipping container. The obsolete neptunium-237 targets would be transported from K-Reactor area to F-Canyon, dissolved in nitric acid, and the neptunium chemically separated from other materials (principally aluminum). The resulting neptunium would be vitrified in conjunction with the existing neptunium solution. Neptunium separated from the processing of the Mark-16 and Mark-22 fuels pursuant to the February 8, 1996 ROD would be vitrified in conjunction with the existing neptunium materials. For the plutonium-239 this vitrified form would not meet the requirements of the storage standard (DOE Criteria for Safe Storage of Plutonium Metals and Oxides (DOE-STD-3013-94)), which prescribes stable oxide or metal. Furthermore, the vitrified form would require additional processing to prepare its disposition.

E. Processing to Metal

This alternative applies only to the plutonium-239 solutions. Under this alternative, DOE would transport the plutonium-239 solutions from H-Canyon to F-Canyon using the same container described above to transport the neptunium-237 solution. In F-Canyon, the plutonium solutions would be converted to plutonium metal using the FB-Line facility. After conversion, the metal would be packaged and stored in accordance with DOE's plutonium storage standard (DOE-STD-3013-94) in an existing vault until a new Actinide Packaging and Storage Facility is available. A new glove box is being installed in FB-Line to provide the equipment necessary to meet the storage standard criteria for the packaging of plutonium metal. The plutonium metal would be stored at the SRS until programmatic decisions are made and implemented by DOE on long-term storage or disposition.

III. Environmental Impacts of Alternatives

The Final EIS for the Interim Management of Nuclear Materials analyzed the potential environmental impacts that could result from implementation of the above management alternatives. DOE has concluded that there would be minimal environmental impact from implementation of any of these alternatives in the areas of geologic resources, ecological resources (including threatened or endangered species), cultural resources, aesthetic and scenic resources, noise, and land use. Impacts in these areas would be limited because facility modifications or construction of new facilities would occur within existing buildings or industrialized portions of the SRS. DOE

anticipates that the existing SRS workforce would support any construction projects and other activities required to implement any of the alternatives. As a result, DOE expects negligible socioeconomic impacts from implementing any of the alternatives. Management alternatives requiring the use of the large chemical separations facilities would have greater environmental impacts (e.g., radiological, waste generation) during the actual dissolving, processing or conversion activities than simply storing these materials in the F- and H-Canyon facilities. After dissolving, processing and conversion activities have stabilized these materials, however, impacts of normal facility operations related to management of these materials would decline, and potential impacts of accidents associated with these materials would be reduced, with certain kinds of accidents eliminated (e.g., solution spills or releases). Potential health effects from normal operations from any of the alternatives, including those involving the operation of the canyon facilities, would be low and well within regulatory limits. All of the alternatives require some use of the canyon facilities. Annual impacts from normal operations and potential accidents associated with nuclear material storage would be reduced after material stabilization alternatives are implemented. Since actively operating facilities have potentially larger environmental impacts, stabilization alternatives requiring longer periods of time to complete are estimated to have relatively higher impacts than alternatives requiring less time to complete. Continuing Storage (or ``No Action'') alternatives would result in low annual environmental impacts, but the impacts would continue for an indefinite period of time. Stabilization alternatives would be expected to result in slightly higher annual environmental impacts than ``No Action'' in the near-term, but would result in lower environmental impacts upon completion of the stabilization action. Under Continuing Storage alternatives, although chemicals would be added to existing solutions in order to maintain concentrations and chemistry within established parameters, no actions would be taken to chemically or physically stabilize the storage conditions. All of the stabilization alternatives, upon completion of the actions required, would reduce the potential for accidents and associated consequences. Several of the stabilization alternatives would involve a short-term increase in the risks from accidents until the required actions are completed. Emissions of hazardous air pollutants and releases of hazardous liquid effluents for any of the alternatives would be within applicable federal standards and existing regulatory permits for the SRS facilities. Similarly, high level liquid waste, transuranic waste, mixed hazardous waste and low level solid waste generated by implementation of any of the alternatives would be handled by existing waste management facilities. All of the waste types and volumes are within the capability of the existing SRS waste management facilities for storage, treatment or disposal. SRS facilities that will be used to stabilize and store the nuclear materials incorporate engineered features to limit the potential impacts of facility operations to workers, the public and the environment. All of the engineered systems and administrative controls are subject to DOE Order requirements to ensure safe operation of the facilities. No other mitigation measures have been identified; therefore DOE need not prepare a Mitigation Action Plan.

IV. Other Factors

In addition to comparing the environmental impacts of implementing the various alternatives, DOE considered other factors in making the decisions announced in this supplemental ROD. These other factors included: (1) The need to construct and operate modified or new facilities (e.g., a vitrification facility) and the reliability of older facilities, (2) nonproliferation concerns, involving potential impacts to United States nonproliferation policy as affected by both the operation of certain facilities and the attractiveness of the managed nuclear materials for potential weapons use, (3) implementation schedules, (4) technology availability, (5) labor availability and core competency, (6) level of custodial care for the continued safe management of the nuclear materials, (7) cost and budget considerations, (8) technical uncertainty (e.g., radiation and chemically induced changes to solution chemistry, criticality concerns for undeveloped processes), and (9) comments received during the scoping period for the EIS on the Interim Management of Nuclear Materials, and comments received on the Draft and Final EISs.

V. Environmentally Preferable Alternatives

As described in the Final EIS for Interim Management of Nuclear Materials, certain management alternatives are expected to result in lower environmental impacts than others. However, a single alternative was rarely estimated to have lower impacts for all environmental factors evaluated by DOE. For example, an alternative might be expected to result in lower releases of hazardous pollutants to air or water than other alternatives, but might generate slightly higher amounts of radioactive waste. DOE reviewed the environmental impacts estimated for the alternatives evaluated for the neptunium-237 solution and targets, and plutonium-239 solutions, and identified the following as the environmentally preferable alternative for each material. The health and environmental effects from any of the alternatives are all low and well within regulatory limits.

Neptunium-237--Vitrification (F-Canyon)

Vitrification in F-Canyon is the environmentally preferable alternative for stabilizing solutions and targets containing neptunium. Although vitrification in F-Canyon is estimated to result in slightly higher radiological doses to the SRS workers, it is estimated to result in the lowest potential radiological doses to the offsite public. Similarly, although it could result in higher airborne emissions of hazardous pollutants than the other alternatives, the levels of liquid effluent emissions would be comparable to the other alternatives. Vitrification (F-Canyon) would generate the least amount of high level, transuranic and mixed waste, and would generate comparable amounts of low level waste to the other alternatives.

Plutonium-239--Vitrification (F-Canyon)

Vitrification in F-Canyon is the environmentally preferable alternative for stabilizing the plutonium-239 solutions stored in H- Canyon. Of the stabilization alternatives, vitrification in F-Canyon is estimated to result in the lowest radiological doses to the offsite public and the SRS workers; result in comparable levels of hazardous pollutant emissions to the air and water; and result in the least amount of transuranic, mixed, and low level waste with comparable amounts of high level waste. However, as indicated above, this alternative would require additional processing of the vitrified plutonium to prepare it for disposition.

VI. Decision

After careful consideration of the issues and public comments received concerning the stabilization and management of SRS nuclear materials, the analyses of environmental impacts (including the ability of the F-Canyon facilities to withstand severe seismic events) and other factors, DOE has made the following decisions for the interim management of neptunium-237 and plutonium-239:

Neptunium-237--Vitrification (F-Canyon)

DOE has decided to stabilize the neptunium-237 solution and obsolete reactor targets by vitrification in F-Canyon (the environmentally preferable alternative). The neptunium solution will be transported from H-Canyon to F-Canyon in a container meeting DOE Order 0460.1, PACKAGING AND TRANSPORTATION SAFETY requirements. Transport of the package will be subjected to management controls, such as restrictions on vehicle speed, route specifications, and escort requirements. The nine obsolete reactor targets will be transported from K-Reactor to F-Canyon. At F-Canyon, the targets will be dissolved and processed to separate the neptunium from other materials (principally aluminum). These other materials will be sent to the high level waste tanks for eventual treatment through the Saltstone and DWPF facilities. The existing neptunium solution and those generated from the obsolete reactor targets will be placed in a glass matrix, using vitrification equipment to be installed in F-Canyon (as announced in the December 12, 1995 ROD and Notice for the vitrification of the americium and curium solution). In addition, neptunium separated from the stabilization of the Mark-16 and Mark-22 fuels (as announced in the February 8, 1996 supplemental ROD) will be stabilized in conjunction with these other solutions. The resulting stainless steel canisters containing the neptunium glass will be stored in the F-Canyon or a new Actinide Packaging and Storage Facility, when constructed, until DOE implements programmatic decisions on the future use or disposition of the neptunium. DOE selected vitrification in F-Canyon for several reasons. Although the SRS has an existing facility (HB-Line, Phase II) designed to purify and convert neptunium (and plutonium-239) to an oxide, it has never been operated. DOE can avoid both the costs to start up this portion of the HB-Line facility and the future decontamination of the facility by vitrifying the solution in F-Canyon. DOE could transfer the neptunium solution in H-Canyon to the adjacent high level waste tanks and eventually vitrify them in the DWPF. However, the physical form of glass produced by the DWPF would render any future recovery and use of the neptunium impractical due to cost and technical complexity. To maintain the neptunium in a concentrated physical form, thus preserving the potential for future use (for the potential production of plutonium-238), DOE evaluated alternatives for converting the neptunium to either an oxide or glass. Either form could support future use of the material, if required. DOE has found that the glass form offers significant advantages over the oxide form for future storage and handling. The glass matrix produced by the vitrification process provides some ``self-shielding'' compared to oxide. This reduces the radiation levels associated with the neptunium, thereby reducing exposure to workers. The glass matrix is also a much less dispersible form of radioactive material compared to the oxide in the event of a severe facility- related accident, such as a major fire. DOE has decided to dissolve and process the nine obsolete reactor targets because it would be advantageous to recover and consolidate the neptunium-237 into a single physical form for continued safe storage. The amount of material to be dissolved and processed is very small and can be done at minimal cost. Potential waste generation impacts are lower for the selected vitrification alternative than for the processing to oxide alternative. Potential safety and health impacts to workers and the public, and potential impacts to air and water resources are comparable between the two alternatives. Potential safety, health and environmental impacts are low and well within regulatory and management control limits.

Plutonium-239--Processing to Metal

DOE has decided to stabilize the plutonium-239 solutions by processing them to metal in the currently operating F-Canyon and FB- Line facilities. Plutonium-239 solutions will be transported from H- Canyon to F-Canyon in a container meeting DOE Order 0460.1, PACKAGING AND TRANSPORTATION SAFETY requirements. Transport of the package will be subjected to management controls, such as restrictions on vehicle speed, route specifications, and escort requirements. The plutonium-239 solutions will undergo processing as necessary to remove impurities that would interfere with the conversion to metal process in FB-Line. The resulting stabilized plutonium metal will be packaged in accordance with DOE's storage standard (DOE-STD-3013-94) and stored in an existing vault at the SRS until a new Actinide Packaging and Storage Facility is available. The plutonium will be stored until DOE implements long-term storage and disposition decisions on weapons useable forms of plutonium. As indicated above, the SRS could use a never-before operated portion of the HB-Line to stabilize the plutonium-239 to an oxide. Startup and future decontamination costs associated with this facility will be avoided by processing the plutonium to metal in the F-Canyon and FB-Line facilities. DOE evaluated transferring the plutonium-239 solutions to the adjacent high level waste tanks for storage and subsequent vitrification in DWPF. This alternative would be more technically complex and potentially more expensive, and added criticality controls would be needed for tanks and facilities used for storage and treatment of the high level liquid waste. DOE also considered vitrifying the plutonium in F-Canyon (the environmentally preferable alternative) using the same equipment in F- Canyon as planned for the vitrification of the americium/curium and neptunium solutions. This would produce a glass matrix with similar safe storage characteristics as described above for the vitrified neptunium. Demonstration and research activities are currently ongoing concerning vitrification of surplus plutonium pursuant to the Department's Materials Disposition program, but those activities focus primarily on stable forms of plutonium that are not in solution. Additional research and analytical work would be required for vitrification of plutonium solutions which may pose a health, safety or environmental concern in the next 10 years to ensure adequate criticality controls for the conversion process and for the safe storage of the product. It is expected that vitrification equipment modifications would be required to ensure adequate criticality control. Thus, while vitrification is not as viable as processing to metal in the near term, the decision to stabilize the plutonium to metal is compatible with all alternatives being considered for disposition of surplus weapons-useable plutonium. Potential waste generation impacts from processing to metal are comparable to the vitrification (environmentally preferable) alternative for high level waste, but greater for transuranic and

low level wastes. Potential safety and health impacts to workers and the public, and potential impacts to air and water resources for the conversion activity are comparable for the processing to metal, oxide, or vitrification alternatives. Potential safety, health and environmental impacts are low and well within regulatory and management control limits. The selected stabilization action will result in plutonium metal, a weapons-usable product. However, the quantity produced (including the metal to be produced as a result of decisions made in the December 12, 1995 ROD and Notice) will be a small fraction of DOE's existing inventory of plutonium metal, and DOE believes this small amount does not present nuclear proliferation concerns. None of the stabilization alternatives would denature the plutonium in a way that would preclude its recovery and use in nuclear weapons manufacture. The stabilized plutonium will not be used for nuclear explosive purposes. In addition, DOE is pursuing options for placing surplus plutonium-239 under international (e.g., IAEA) safeguards. Finally, as noted above, the H-Canyon seismic analyses are expected to be completed in September 1996. A decision now to move neptunium and plutonium solutions from H-Canyon to F-Canyon is permissible and appropriate prior to the completion of the H-Canyon analyses because removal of the materials from H-Canyon would not involve operation of the HB-Line, but would result in reducing the amount of nuclear materials present in H-Canyon. No additional nuclear materials will be introduced into H-Canyon until the on-going seismic analyses are complete.

VII. Conclusion

The Final EIS analyzes interim management alternatives for nuclear materials at the SRS. Those alternatives and the decisions associated with the safe management of these materials directly affect the operational status of the nuclear material processing facilities at the Site. The decisions in this supplemental ROD, as in the December 12, 1995 ROD and Notice and February 8, 1996 Supplemental ROD, are structured to effect the completion of actions necessary to stabilize or convert nuclear materials into forms suitable for safe storage and prepare the facilities for potential subsequent shutdown and deactivation. The actions being implemented will support efficient, cost-effective consolidation of the storage of nuclear materials and will result in stabilization of the nuclear materials and alleviation of associated vulnerabilities within the time frame recommended by the DNFSB. The stabilization decisions utilize existing facilities and processes to the extent practical; can be implemented within expected budget constraints and with minimal additional training for involved personnel; rely upon proven technology; use an integrated approach considering a multiplicity of factors; and represent the optimum use of facilities to stabilize the materials in the shortest amount of time. Only minor modifications of the canyon facilities will be required (loading and unloading stations, and modification to the vitrification equipment to be installed for the americium/curium solution stabilization as announced in the December 12, 1995 ROD and Notice). Several years will be required to achieve stabilization of the nuclear materials within the scope of this and the previous RODs. Stabilization of the candidate nuclear materials will entail the operation of many portions of the chemical processing facilities and, consistent with DNFSB Recommendation 94-1, will preserve DOE's capabilities for the management and stabilization of other nuclear materials until programmatic decisions are made.

Issued at Washington, DC, September 6, 1996. Alvin L. Alm, Assistant Secretary for Environmental Management. [FR Doc. 96-23352 Filed 9-12-96; 8:45 am] BILLING CODE 6450-01-P