CHAPTER 2. PROPOSED ACTION AND ALTERNATIVES
This chapter describes alternatives for the stabilization of plutonium solutions currently stored in the F-Canyon (Figure 2-1). Sections 2.1 through 2.5 describe the following alternatives, which Chapter 4 evaluates in detail: - No Action - Processing to Plutonium Metal (preferred alternative) - Processing to Plutonium Oxide - Vitrification (Defense Waste Processing Facility) - Vitrification (F-Canyon) Figure 2-2 shows the schedules for these alternatives. Section 2.6 discusses other actions that would have the potential to reduce the risk associated with the plutonium solutions but that, standing alone, do not fulfill the identified purpose and need for agency action. Section 2.7 compares the environmental impacts associated with each alternative, including the storage of plutonium in vaults or tanks, as analyzed in Chapter 4. Section 2.8 discusses other factors which DOE considers relevant and compares these factors to the alternatives. Appendix A describes the facilities involved in the alternatives (i.e., F-Canyon, FB-Line, and associated support facilities). The appendix also describes the historic processing methods used in these facilities (including F-Canyon, FB-Line, and the PUREX process). These descriptions might be helpful in understanding the alternatives discussed below. Figure 2-3 shows the PUREX process in F-Canyon and indicates where DOE has stored plutonium solutions in various stages. Appendix B describes the potential accidents related to the continued storage of plutonium solutions and to facility operations that would be necessary to implement the alternatives. In relation to the stabilization alternatives described in this chapter, and in support of United States nonproliferation policy, DOE is exploring the possibility of making plutonium that is surplus to the Nation's defense requirements available for verification and inspection by the International Atomic Energy Agency (IAea). Figure 2-1. F-Canyon and surrounding area. Figure 2-2. Schedules for storage and stabilization alternatives. Figure 2-3. PUREX process in F-Canyon and location of plutonium solutions. With the shutdown of the Rocky Flats Plant near Denver, Colorado, DOE no longer has the capability to manufacture plutonium weapon components for the U.S. stockpile. DOE will address the plutonium manufacturing capability in the Programmatic eis on Stockpile Stewardship and Management, and will address plutonium disposition in the Programmatic eis for Disposition of Weapons-Usable Fissile Materials (see Section 1.3).
2.1 No Action
Under the No-Action Alternative, DOE would continue to manage the approximately 303,000 liters (80,000 gallons) of plutonium solutions stored in stainless-steel tanks in the F-Canyon as it has for approximately the past 2-1/2 years. DOE would continue to maintain the canyon facility in essentially a "warm standby" mode of operation in which no additional nuclear materials would be introduced into the canyons for chemical dissolution and subsequent processing. Existing plutonium solutions would not be processed to produce another form of nuclear material. DOE would continue to monitor the storage tanks and would sample plutonium solutions periodically to evaluate chemistry. As evaporation of a solution occurred or as chemical changes warranted, nitric acid or other chemicals would be added to minimize the potential for the precipitation of plutonium and the possibility of an inadvertent criticality. Solutions would be transferred within F-Canyon only as required for sampling or to alleviate problems with equipment (e.g., storage tanks). The implementation of the No-Action Alternative would neither reduce the risks associated with storage of the plutonium as a liquid nor stabilize the solutions. Further, the implementation of the No-Action Alternative would not fulfill the need for agency action.
2.2 Processing to Plutonium Metal
Under this alternative, DOE would use the existing PUREX process in F-Canyon (see Appendix A) and equipment in FB-Line to convert the plutonium solutions to metal (see Figure 2-4). The FB-Line would convert the solutions to a metal form, similar to that the facility produced historically. The metal would be a chemically stable form of plutonium that DOE could produce without modifying the existing equipment. Because there is no need for additional plutonium for weapons, DOE would not attempt to meet previous specifications or chemical purities that were applicable for weapons production (Reis 1994). The plutonium metal would be packaged and stored, similar to other plutonium metal already in the FB-Line vault. Figure 2-4. Plutonium to Metal Alternative After converting the plutonium solutions to a metal, and packaging and storing, 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 DOE standard for long-term storage of plutonium (DOE 1994b). DOE estimates that it could accomplish this activity by late 1997 at a cost of approximately $3 million. The DOE standard establishes criteria to ensure the safe storage of plutonium metal and oxide. The criteria are intended to reduce the generation of gas inside the storage containers. The generation of gas has the potential to pressurize and subsequently damage containers. 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 and 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. The alternative of Processing to Metal would produce a solid form of plutonium that would be safer and easier to store in the shortest amount of time. As a result, this is DOE's preferred alternative.
2.3 Processing to Plutonium Oxide
DOE would use the existing PUREX process, including the second plutonium cycle, in F-Canyon to prepare the solutions for introduction into FB-Line. Under this alternative, DOE would modify the FB-Line to support conversion of the plutonium solutions to a plutonium oxide and to package the material for storage (see Figure 2-5). DOE would produce a material form and packaging configuration that meets the new DOE standard for long-term storage of plutonium (DOE 1994b). If the extent of the FB-Line modifications necessary to meet this standard were economically or physically impractical (i.e., too expensive or not enough space for the equipment required), DOE would perform the stabilization in two phases. DOE would provide the capability to convert the material initially to an oxide form and package it in FB-Line. At the same time, DOE would either modify an existing vault facility (e.g., 235-F) or 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. The oxide initially produced in FB-Line would be stored in the existing FB-Line vault until the new or modified facility could be completed. The new facility would be in the existing F-Area industrial complex. Figure 2-5. Plutonium to Oxide Alternative DOE estimates that the minimum required modifications to FB-Line would cost $7 million and take 3 years to complete. DOE would operate the FB-Line for approximately 7 months to convert and package the oxide for storage. DOE estimates that modifications to an existing facility or a new facility would cost between $70 and $150 million and could be completed by 2001. Heating and repackaging the oxide would take approximately 3 months.
2.4 Vitrification (Defense Waste Processing Facility)
Under this alternative, DOE would transfer the plutonium solutions to the SRS waste tank farm (see Figure 2-6). Before transfer, the solutions would be adjusted to ensure the safety of the material in the high-level waste 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). DOE would operate portions of the PUREX process, as required, to make the necessary chemical adjustments. The addition of poisons or the dilution with depleted uranium would minimize the potential for inadvertent nuclear criticality in the waste tanks. This material would eventually be transferred to the Defense Waste Processing Facility for proposed vitrification. To demonstrate the feasibility of this alternative, DOE would have to address a number of issues: - The potential for criticality if plutonium precipitated during and following transfer to the high-level waste tanks. Detailed safety analysis would be required to address this concern and determine methods to reduce the potential for criticality. - The capability of the Defense Waste Processing Facility to process plutonium-bearing high-level waste (in other than trace quantities) has not been fully evaluated with respect to the effect that this material would have on the vitrification process. - Transfer of plutonium solutions to the high-level waste tanks has not been included in the High-Level Waste System Plan (WSRC 1994b). The availability of sufficient tank space, given plans to remove waste from and retire old waste tanks, must be addressed. Figure 2-6. Vitrification (Defense Waste Processing Facility) Alternative 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 were 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. Under this alternative, DOE would continue to store plutonium solutions in the F-Canyon, similar to the No- Action Alternative, during the 6 years required to complete the technical evaluations. As a precursor to stabilization, DOE would operate the second plutonium cycle. The vitrification of plutonium solutions would not begin within the 10-year period evaluated in this eis. As a result, this analysis does not inclu de the impacts of vitrification. However, if this alternative were implemented, solutions would eventually be vitrified and the environmental impacts associated with proposed Defense Waste Processing Facility operation would occur.
2.5 Vitrification (F-Canyon)
Under this alternative, DOE would modify an existing portion of F-Canyon, previously called the Multi-Purpose Processing Facility and now called the F-Canyon Vitrification Facility. The modifications would include removal of equipment no longer required and the installation of any new equipment required for the vitrification process. Appendix A contains a brief description of the F-Canyon Vitrification Facility and a summary of the modifications required. DOE would operate portions of the PUREX process in F-Canyon, as required, to prepare the solutions for vitrification. The vitrification process would involve concentrating the plutonium solution in a small geometrically favorable tank (i.e., the physical dimensions of the tank are such that a nuclear criticality could not occur). The solution would be mixed with finely ground glass (frit) and fed to a small melter. Molten borosilicate glass would be produced and poured into stainless-steel canisters. The canisters would be stored in existing vaults at the F-Canyon facility. Figure 2-7 shows this process. The process relies on similar, large-scale technology developed for proposed use in the Defense Waste Processing Facility. However, some process development work would be required due to the amount of fissile material that would be vitrified. DOE estimates that approximately $27 million in capital costs would be required to modify the F-Canyon to provide vitrification capability. In addition, DOE estimates that it could complete the necessary process development work and physical Figure 2-7. Vitrification (F-Canyon) Alternative modifications by early 1999 and that it would take approximately 6 months to vitrify the plutonium solutions.
2.6 Other Activities for Reduction of Risk
DOE identified the following activities that would have the potential to reduce the risks associated with the plutonium solutions in F-Canyon: the transportation of the solutions to H-Canyon for stabilization, purification of the solutions by processing those that had the greatest criticality risk through the second plutonium cycle in F-Canyon, those risk reduction activities identified in the DOE Assessment of Interim Storage of Plutonium Solutions in F-Canyon and Mark-31 Targets in L-Basin at the Savannah River Site (DOE 1994a), and shipment of the solutions off the Site for stabilization. These risk reduction activities would be in addition to those encompassed by the No-Action Alternative and already taken to reduce the risk, such as the addition of boron to selected tanks and the periodic adjustments of tank chemistry and concentrations to minimize the potential for precipitation of plutonium. DOE evaluated the potential alternative of operating portions of the PUREX process (e.g., the second plutonium cycle) in F-Canyon. Figure 2-3 shows the current storage locations of the solutions in the various portions of the PUREX process. As Figure 2-3 demonstrates, only a small amount of the solutions [approximately 15,100 liters (4,000 gallons)] have been through all the PUREX stages. The initial stages of the PUREX process, head-end and first cycle, remove fission products and some impurities. In addition, first cycle separates uranium and plutonium solutions from each other. The second cycle concentrates plutonium for introduction to the FB-Line for conversion into a metal. Before the preparation of this eis, DOE discussed the possibility of operating only second cycle to process all the plutonium solutions currently in F-Canyon to reduce the risk of continued storage of plutonium (Fiori 1994). Operational upgrades for that portion of the F-Canyon were nearing completion, and the performance operational readiness review was under way. DOE believed that the operation of second cycle as a purification activity would reduce the risk of inadvertent criticality, which could occur as a result of the current abnormal solution chemistry. Operation of the second cycle could also reduce the chance of leakage by consolidating the solutions in fewer tanks. However, releases could still occur from accidents due to leaks, spills, transfer errors, and other accidents associated with storing plutonium in a liquid form. These accident risks could be eliminated only by converting the liquid form to a solid form. The use of the second cycle only would require changes to the process historically used to process plutonium solutions. Rather than moving the solutions sequentially through each stage of the PUREX process, the revised process would transfer the solutions directly to the second cycle for the removal of fission products and the separation and concentration of plutonium and uranium. The PUREX process has never been operated in this manner. To do so would require process development work and establishment of operating parameters, which would take several months. Nevertheless, even if DOE could resolve the technical issues, there would be several important issues associated with implementation of this potential alternative. For example, the operation of the second plutonium cycle would result in unprecedented high levels of radiation in the second cycle portion of the facility due to the presence of fission products. These fission products normally would have been removed in the head end and first cycle portion of the facility, which has shielding to reduce potential radiation exposure to workers. The portion of the facility housing the second plutonium cycle is not as heavily shielded. The chemistry of the solutions produced would be within known technical experience. The risk associated with plutonium in solution (e.g., inadvertent criticality) would remain until the plutonium solutions were converted to a stabilized form. Further, because the second plutonium cycle functions to increase the concentration of the plutonium, an inadvertent criticality would result in a greater release of radioactivity. Purification, like the other risk reduction activities described in DOE (1994a), would not fully mitigate the inherent risks of plutonium being stored in liquid form. As evaluated in this eis, however, purification of the solutions utilizing the second plutonium cycle would be part of the alternatives that would stabilize to a metal or an oxide. DOE estimates that the impacts for normal operations and accidents associated with PUREX-related operations are within the impacts discussed in Chapters 4 and 5 of this eis. PUREX operations would be likely to generate slightly greater impacts than the No-Action Alternative because operating the process would involve transferring the material through equipment not used for No Action. However, the impacts would be well below those estimated for the Processing to Metal or Processing to Oxide Alternative because the operation of the PUREX process would be part of the activities necessary to complete those stabilization alternatives. The increase in impacts above No Action would be likely to occur primarily in the generation of high-level waste and F-Canyon worker radiation exposure. Finally, regarding the transportation of the plutonium solutions in F-Canyon to H-Canyon for stabilization, the shipment, while theoretically feasible, would involve all the risks associated with the alternatives for stabilization plus the risks that would be associated with the transport of radioactive liquids between two facilities. Further, the time required to accomplish this alternative would be longer than that for any other alternative. The shipment of the plutonium solutions to another site for stabilization would involve the additional risk and questionable feasibility of shipping plutonium solutions over public thoroughfares.
2.7 Comparison of Alternatives
Table 2-1 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.
2.8 Other Factors
The selection of an alternative for stabilizing the F-Canyon plutonium solutions depends in part on existing technology (or on technology that DOE could develop quickly), the capabilities of existing SRS facilities, and the extent to which the actions would support long-term storage objectives. Consistent with a comprehensive review of long-term options for plutonium disposition, DOE will consider the technical, nonproliferation, environmental, budgetary, and economic aspects of each alternative before it selects one alternative for implementation. In addition to comparing alternatives against the environmental criteria listed in Table 2-1, DOE considered other factors related to the Table 2-1. Comparison of the potential environmental impacts of the alternatives. stabilization of nuclear materials. 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 following sections describe these factors.
2.8.1 NEW FACILITIES REQUIRED
This factor considers qualitative impacts on the number and size of new facilities required, and the probable long-term restoration requirements after their use. The No-Action and Vitrification Alternative using the Defense Waste Processing Facility would rely totally on existing facilities and, therefore, would be the most advantageous because they could be implemented immediately with no additional capital or environmental impact due to construction. The Processing to Metal Alternative would require minor modifications to FB-Line to provide new repackaging capabilities for the metal produced. The Processing to Oxide Alternative would involve more extensive modifications to FB-Line and potentially a new facility. Similarly, the Vitrification Alternative using F-Canyon would require extensive modifications to the facility.
2.8.2 SECURITY AND NONPROLIFERATION
This factor relates to how well each alternative supports national security objectives and nonproliferation. This issue is being debated on the national and international level, and consensus has yet to be reached. However, DOE has qualitatively evaluated the alternatives and rated them in comparison to one another. All the alternatives involve the use of facilities within controlled industrial areas of the SRS, which are supported and protected by an armed guard force. However, the solutions or stabilized forms of plutonium would have varying degrees of use in potentially supporting or leading to the manufacture of a nuclear weapon. Methods could be used to further reduce this potential. For example, DOE considered the addition of fission products to increase the radioactivity of the stabilized form of material (e.g., metal). The addition of fission products would make the material essentially "self-protecting" from theft or potential use in weapons because of high radiation levels. However, this method would result in increased exposures to personnel performing processing and handling operations (e.g., at FB-Line). DOE does not consider such increased exposures to personnel to be warranted based on the relatively small amount of plutonium that these solutions represent in comparison to the U.S. stockpile. 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). Further, in support of United States nonproliferation policy, DOE is exploring the possibility of making plutonium that is surplus to the Nation's defense requirements available for verification and inspection by the International Atomic Energy Agency (IAea). The Vitrification Alternatives would produce a material form that would be least attractive for use in manufacturing or producing a nuclear weapon. Therefore, they represent the most advantageous alternatives in this regard. The Processing to Plutonium Metal Alternative would result in a form that closely resembled that used in weapons production. The No-Action and Processing to Plutonium Oxide Alternatives would maintain or convert plutonium to forms that would require increasing degrees of processing to produce a form suitable for weapons use. In either the Metal or Oxide alternative, large quantities of plutonium already exist in these forms; therefore, processing this small increment of plutonium to either of these forms would not impact decisions and alternatives for ultimate disposition.
2.8.3 IMPLEMENTATION SCHEDULE
Of the stabilization alternatives, the Processing to Metal Alternative could be implemented in the shortest period of time. The Processing to Oxide Alternative could begin within approximately 3 years. The Vitrification Alternative using F- Canyon could begin within approximately 5 years. Vitrification in the Defense Waste Processing Facility could not be completed within 10 years, but initial actions to implement that alternative could begin in approximately 6 years. The No-Action Alternative could be implemented immediately, but would not satisfy the DOE purpose and need.
2.8.4 TECHNOLOGY AVAILABILITY AND TECHNICAL FEASIBILITY
This factor relates to the extent that technology development is required and the likelihood of success. Of the stabilization alternatives, Processing to Plutonium Metal represents the most technically proven; it would use existing technology and equipment. The Processing to Plutonium Oxide Alternative is also technically feasible, but would require technology development and new equipment to accomplish stabilization. Similarly, the Vitrification Alternatives appear to be technically feasible, but would require the most technology development. The technical uncertainty would increase as the stabilized form differed from that historically produced. There would also be technical uncertainty associated with the continued storage of the plutonium solutions under the No-Action Alternative as a result of radiation and chemically induced changes in the solution chemistry and form.
2.8.5 LABOR AVAILABILITY AND CORE COMPETENCY
There are differences between the level of personnel knowledge and training required for each alternative. In addition, there would be impacts from providing the needed level of training. All the alternatives would require approximately the same amount of labor to implement. The No-Action and Processing to Plutonium Metal Alternatives would involve activities similar to those performed in the past; as a result, facility personnel would have existing training and qualification programs to maintain core competency. The Processing to Plutonium Oxide and Vitrification Alternatives would require additional levels of training; the only impact anticipated from such additional training would be the incremental funding required.
2.8.6 AGING FACILITIES
All the alternatives involve the use of existing facilities, some of which have been in operation for more than 40 years (e.g., F-Canyon). The No-Action Alternative would require continued storage of the material in the F-Canyon and is, therefore, the least desirable or advantageous in this regard. The Vitrification (Defense Waste Processing Facility) Alternative would require maintenance of the solutions in F-Canyon for approximately 6 to 9 years. In addition, it would involve the transfer of the plutonium solutions to the high-level waste tanks, some of which have been in use since the 1950s. Therefore, this alternative has only a slight advantage over the No-Action Alternative. The Vitrification (F-Canyon) Alternative would require maintenance of the solutions in the canyon for approximately 5 years. Even though this alternative would use a substantial amount of new equipment, the area that would be modified is in the F-Canyon, which is more than 40 years old. The vitrified material would be stored in an existing vault or the F-Canyon. As with the Vitrification (DWPF) Alternative, this alternative has only a slight advantage over the No-Action Alternative. The Processing to Plutonium Oxide Alternative could involve limited use of the F-Canyon and FB-Line facilities. It could use a new or modified facility for conversion or repackaging of the oxide and eventual storage. If a new facility were required, it would represent the minimum reliance on existing facilities. While the Processing to Plutonium Metal Alternative would involve limited use of the F-Canyon and FB-Line for stabilization, it would involve continued storage of the metal in the FB-Line vault. Therefore, it represents some reliance on aging facilities, but also represents an advantage over the No-Action and Vitrification Alternatives.
2.8.7 MINIMUM CUSTODIAL CARE
The Vitrification Alternative would eventually result in a stabilized form of material that would require a minimum of custodial care. However, continued custodial care of the solutions would be required in F-Canyon or the high-level waste tanks until vitrification was accomplished. Continued storage would involve maintaining a dispersible form of material for at least 5 years in facilities with limited passive safety features, such as tanks that do not have a physical geometry that prevents the possibility of a criticality. Therefore, this alternative is undesirable. The No-Action Alternative would involve a similar level of custodial care and, therefore, is also undesirable. The Processing to Plutonium Oxide Alternative would require continued storage of the solutions for approximately 3 years. This material form would require continued surveillance on a frequent basis. The alternative could use existing facilities that have limited passive safety features. The new or modified facility and eventual storage configuration could incorporate the increased use of passive safety systems such as specially designed and built racks that would prevent movement of material during earthquakes. (A passive safety system is one that requires no action to function, such as a reinforced door panel for a vehicle. An active safety system is one that requires an action, such as buckling a vehicle seatbelt.) The Processing to Plutonium Metal Alternative would result in a reduced level of custodial care after stabilization of the solutions. Although the passive safety systems of the storage facility (FB-Line vault) are limited, plutonium metal is a significantly less dispersible form than solutions or oxide. As a result, this alternative is the most advantageous in minimizing custodial care.
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