Summary

The Department of Energy (DOE) Savannah River site, which is located near Aiken, South Carolina, is responsible for managing DOE's inventory of aluminum spent nuclear fuel1 from foreign and domestic research reactors. During the next four decades, Savannah River will be responsible for receiving and storing approximately 42 MTHM2 of aluminum spent fuel at the site, processing it as necessary to put it into "road-ready" form3 for eventual shipment to a repository, and providing for interim storage of the road-ready product until a repository is ready to accept it.

In 1995, the Office of Spent Fuel Management of DOE established the Research Reactor Spent Nuclear Fuel Task Team, or "Task Team," to help develop a technical strategy for disposal of this aluminum spent fuel. The Task Team was asked to evaluate alternative treatment and packaging technologies that could be used in the place of conventional reprocessing4 to treat for disposal the aluminum spent fuel in a safe and cost-effective manner. The need to develop alternative treatment technologies for aluminum spent fuel was necessitated by

1  

Spent nuclear fuel is irradiated fuel that contains uranium-aluminum matrix fuel elements and (or) is clad in aluminum. DOE refers to this fuel as "aluminum-based" or "aluminum-clad" spent fuel, but in this report this fuel will be referred to as "aluminum spent fuel."

2  

Metric tons heavy metal, the amount of heavy metal (uranium, thorium, and plutonium) present in fresh (unirradiated) fuel.

3  

That is, the fuel will be treated and loaded into disposable canisters suitable for interim storage, shipping, and loading at the repository site into a final repository package.

4  

Conventional reprocessing involves the dissolution of aluminum spent fuel in acid followed by the chemical recovery of uranium and plutonium if present.



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--> Summary The Department of Energy (DOE) Savannah River site, which is located near Aiken, South Carolina, is responsible for managing DOE's inventory of aluminum spent nuclear fuel1 from foreign and domestic research reactors. During the next four decades, Savannah River will be responsible for receiving and storing approximately 42 MTHM2 of aluminum spent fuel at the site, processing it as necessary to put it into "road-ready" form3 for eventual shipment to a repository, and providing for interim storage of the road-ready product until a repository is ready to accept it. In 1995, the Office of Spent Fuel Management of DOE established the Research Reactor Spent Nuclear Fuel Task Team, or "Task Team," to help develop a technical strategy for disposal of this aluminum spent fuel. The Task Team was asked to evaluate alternative treatment and packaging technologies that could be used in the place of conventional reprocessing4 to treat for disposal the aluminum spent fuel in a safe and cost-effective manner. The need to develop alternative treatment technologies for aluminum spent fuel was necessitated by 1   Spent nuclear fuel is irradiated fuel that contains uranium-aluminum matrix fuel elements and (or) is clad in aluminum. DOE refers to this fuel as "aluminum-based" or "aluminum-clad" spent fuel, but in this report this fuel will be referred to as "aluminum spent fuel." 2   Metric tons heavy metal, the amount of heavy metal (uranium, thorium, and plutonium) present in fresh (unirradiated) fuel. 3   That is, the fuel will be treated and loaded into disposable canisters suitable for interim storage, shipping, and loading at the repository site into a final repository package. 4   Conventional reprocessing involves the dissolution of aluminum spent fuel in acid followed by the chemical recovery of uranium and plutonium if present.

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--> DOE's policy to phase out reprocessing at the Idaho National Engineering and Environmental Laboratory and Savannah River.5 The Task Team evaluated eleven treatment technologies and recommended a strategy for selecting, developing, and implementing one or more of these options by the year 2000. The treatment technologies evaluated by the Task Team fell into one of three categories: (1) direct disposal technologies, which involve no processing of the spent fuel except for drying; (2) highly enriched uranium (HEU)6 dilution technologies, in which the fuel is physically or metallurgically diluted with depleted uranium7 to reduce the amount of uranium-235 (235U) to 20 percent or less by mass;8 and (3) advanced treatment technologies, in which the fuel is processed to produce more acceptable waste forms for repository disposal than is possible for either the direct disposal or the HEU dilution technologies and to reduce the volume of waste for disposal. The Task Team used a combination of qualitative and quantitative methodologies to screen and rank the alternative treatment options, and it performed a sensitivity analysis of the results. The objective of this exercise was to eliminate from further consideration those options that were less likely to be implemented successfully because of technical, cost, or scheduling difficulties. The Task Team recommended direct co-disposal treatment, which involves the placement 5   The decision to phase-out reprocessing at these sites was announced by the Secretary of Energy in February 1992. This decision was based on recommendations from the Highly Enriched Uranium Task Force, which produced a predecisional draft report on spent fuel reprocessing in February 1992. A copy of this draft report was not made available to the P.I. until the present report was in the final stages of review. 6   Defined as a material that contains more than 20 percent uranium-235 (235U) by mass. In contrast, natural uranium contains about 0.7 percent 235U by mass. 7   Depleted uranium is depleted in 235U relative to natural abundances. 8   The diluted product is known as low-enriched uranium (LEU).

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--> of dried spent fuel into a canister for disposal in a larger package containing high-level waste glass logs (Chapter 2), as the primary treatment option, and melt and dilute treatment, in which the fuel is melted and diluted with depleted uranium, as a "parallel" option. The Task Team also recommended electrometallurgical treatment, which is essentially electrochemical reprocessing, as a backup option, because this technology is fundamentally different than the others and thus offers some protection against unforeseen technical or licensing problems. As part of its efforts to prepare an environmental impact statement (EIS) for disposing of the aluminum spent nuclear fuel under its management, the Savannah River Office of DOE asked the National Research Council (NRC) to review the alternative treatment options that it has identified to put this fuel into a form suitable for shipment to and emplacement in a repository (Appendix A). The statement of task for this study involved the examination of the following aspects of DOE's program for selecting and implementing a treatment option for aluminum spent fuel: examination of the set of technologies chosen by DOE and identification of other alternatives that DOE might consider; examination of the waste-package performance criteria developed by DOE to meet anticipated waste acceptance criteria for disposal of aluminum spent fuel and identification of other factors that DOE might consider; and to the extent possible given the schedule for this project, an assessment of the cost and timing aspects associated with implementation of each spent nuclear fuel treatment technology. This study is focused primarily on the treatment step of the disposal process, that is, the options for treating the aluminum spent fuel to make it acceptable for disposal in a repository. This report does not review the other components of the disposal program—for example, the

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--> shipment of aluminum spent fuel to Savannah River for storage and treatment, the shipment of treated fuel to a repository, or the emplacement of that treated fuel in the repository—but it does provide some analysis of the impacts of these other components on the selection and implementation of treatment options. Since the Task Team report was issued in 1996, DOE has undertaken a series of studies to assess the costs and technical viability of implementing one or more of these treatment options. These studies, which are cited in Appendix F of this report, formed the basis for this review. DOE intends to issue a final EIS-record of decision (ROD) in early 1999 that will select one or more of the treatment options for implementation. The findings of the present report will be used as an input to this decision. The following sections provide a summary of the findings on the three charges in the statement of task given above. Readers interested in a more detailed discussion of these findings should consult Chapters 2-5 of this report. Findings Related to the Selection of Aluminum Spent Fuel Treatment Options The first charge of the statement of task involves the examination of the set of technologies chosen by DOE for treatment of aluminum spent fuel and the identification of other alternatives that DOE might consider. The first charge of the statement of task is addressed in Chapter 2 through a discussion of four questions, as summarized below: 1.   Were a reasonably complete set of treatment alternatives identified by DOE? The answer to this question is a qualified "yes." Although the Task Team apparently made no effort to perform a systematic search for treatment technologies in use in other countries or industries that might be applied to aluminum spent fuel, it appears to have

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-->      succeeded in identifying a reasonably complete set of alternatives. The affirmative answer to this question is qualified for two reasons. First, the Task Team may have incorrectly eliminated one of the treatment options (chloride volatility treatment) because it believed that no experimental work on this technology had been done. In fact, considerable experimental work on chloride volatility was completed between 1950 and 1965 at Argonne National Laboratory. The P.I. did not attempt to determine whether this treatment option would have ranked above the other advanced treatment alternatives had it been evaluated further by the Task Team. Second, the Task Team did not consider options for treating the depleted uranium spent fuel, which comprises about 40 percent of the inventory of aluminum spent fuel expected to be received at Savannah River. The Task Team identified this fuel as a candidate for reprocessing because the fuel is declad and is comprised of uranium metal that may not be suitable for disposal in the repository. If reprocessing is not possible for policy reasons, however, there is no obvious treatment and disposition pathway for this fuel. 2.   Was the methodology used to screen and rank the treatment alternatives technically sound, and did it lead to the selection of appropriate primary and backup treatment options? The answer to this question is a qualified "yes." The technical approach used by the Task Team to evaluate and rank the alternative treatment options was appropriate for the degree of technical maturity and the amount and quality of available data, and the ranking methodology was adequate for screening purposes. The output of the ranking methodology appears to be consistent with what one would expect. The affirmative answer to this question is qualified because neither the Task Team nor other parts of DOE have developed a complete set of process requirements, particularly waste form requirements and other waste acceptance criteria for repository disposal, that would allow a detailed assessment of the treatment options to be made. Most significantly, there appears to be some uncertainty about whether HEU

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-->      aluminum spent fuel will be acceptable for disposed in a repository because of criticality and nonproliferation concerns. Until such issues are resolved, implementation of appropriate treatment alternatives can not proceed without significant financial and schedule risks. A process that allows for some flexibility and phased decision-making in the selection and implementation of alternative treatment options seems warranted in light of this uncertainty. 3.   Are the primary and backup treatment options likely to work as described and produce acceptable waste forms? The direct co-disposal treatment is technically simple and straightforward to implement. The technologies for drying the fuel, placing it into a container, and sealing the container are readily available and can likely be adapted to this application with little additional development work. Melt and dilute treatment is more demanding technically than direct co-disposal treatment and will require a more significant infrastructure, including hot cell space, a melter, and an off-gas treatment system. The radioactive fuel must be melted at temperatures up to about 1000 °C, which will result in the release of some volatile fission products that must be recovered by an offgas system and recycled or otherwise disposed of. All of the technologies needed to make this system function successfully have been used in other applications, and it should be a relatively straightforward exercise to bring them together for aluminum spent fuel treatment. Melt and dilute treatment is worth pursuing despite the additional development and infrastructure requirements because it allows more control over waste form composition and performance characteristics than does direct co-disposal. Additionally, this option would reduce significantly the need for spent fuel characterization and the number of canisters to be interim-stored and eventually shipped to the repository, which would help offset the cost of treatment. There is not enough information at present about any of the advanced treatment technologies to select a backup option. In particular, not enough is known at present about electrometallurgical treatment,

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-->      which was selected as the backup option by the Task Team, to determine whether it will work as described, and additional development work will have to be done to determine the feasibility of applying this treatment technology to aluminum spent fuel. 4.   What other treatment options should DOE consider? DOE should have given more careful consideration to the conventional reprocessing option for treating aluminum spent fuel. There appear to be several technical advantages to this option over the others considered by the Task Team.9 This treatment option has been demonstrated to work for aluminum spent fuel from production reactors, the costs and risks are well known, the necessary facilities are currently in operation at Savannah River, and the waste form (borosilicate glass) will likely be acceptable for disposal at the repository. Reprocessing even a portion of the aluminum spent fuel could significantly reduce the overall costs of treating the total aluminum spent fuel inventory by alleviating the need for additional spent fuel storage space at Savannah River and eliminating the problems with odd-sized fuel elements that may be difficult to process by other methods. There is still some policy uncertainty about whether the F and H Canyons at Savannah River will be available after 2002 for reprocessing, and future developments in DOE proliferation policy may preclude the use of the reprocessing option except in special cases (e.g., disposing of damaged spent fuel elements). It is recommended that DOE-Savannah River undertake a common-basis cost and performance comparison of the two primary treatment alternatives (direct co-disposal and melt and dilute treatment) and conventional reprocessing as part of its process for evaluating and selecting a treatment option. 9   The Task Team was directed to consider alternatives to reprocessing, but the P.I. knows of no restrictions on DOE's ability to develop cost and schedule information on this option, if only for comparative purposes, in the EIS.

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--> Findings Related to Waste-Package Performance Criteria The second charge in the statement of task involves the examination of the waste-package performance criteria being developed by DOE-Savannah River for aluminum spent fuel and the identification of other criteria that should be considered. Most of the findings relate to the performance criteria that have been developed by DOE-Savannah River in response to the waste acceptance criteria (WAC) published by DOE-Yucca Mountain,10 but this report also includes comments on other criteria that could have a significant impact on the selection of a treatment option. The second charge of the statement of task in Chapter 3 was addressed through a discussion of three questions, summarized below: 1.   Have all of the important waste-package performance criteria been identified by DOE-Savannah River? The answer to this question is a qualified ''yes." DOE-Savannah River staff appear to be working closely with their counterparts at DOE-Yucca Mountain to ensure that the important waste acceptance criteria have been identified and that the right kind of work is being done to demonstrate conformance. DOE-Savannah River also appears to have access to the draft documents being prepared by DOE-Yucca Mountain that could affect the acceptability of aluminum spent fuel for disposal at the repository. The answer is qualified because many of the waste acceptance criteria are preliminary and could change significantly as waste package and repository designs are refined. Continuance of the ongoing dialogue between DOE-Savannah River and 10   The DOE-Office of Civilian Radioactive Waste Management and its management and operating contractor, which are responsible for characterizing the candidate repository at Yucca Mountain.

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-->      DOE-Yucca Mountain will be essential to track and respond effectively to any future changes. 2.   Are there other performance criteria that should be considered? The answer to this question has three parts, the first for the WAC, the second for the interim storage criteria, and the third for the transportation criteria. The answer to the first part of the second question is "no." The current WAC for the candidate repository at Yucca Mountain are very clearly laid out by DOE-Yucca Mountain documents, and the information received from DOE-Savannah River during the course of this study indicates that all of the potentially applicable WAC have been identified and are being addressed through ongoing work. However, many of the WAC are preliminary and could change significantly as DOE-Yucca Mountain refines the waste package and repository designs. These changes could have significant implications for the acceptability of any waste form for disposal. The answer to the second part of the second question—are there other criteria that should be considered for interim storage in addition to those that are required for repository acceptance?—is "no." Most of the criteria seem reasonable given the current plans that DOE-Savannah River has to store, retrieve, and process (as necessary) the fuel to put it into road-ready form. One of the criteria, however, appears to be unnecessary. Specifically, the criterion that sets limits for plastic deformation of the aluminum spent fuel in the disposable canister seems overly restrictive and potentially costly. The justification given for this requirement is that it will provide for ready removal of the fuel from the canister, but it is not clear why DOE-Savannah River would ever want to remove spent fuel from a disposable canister under normal operating conditions, and even under "abnormal" conditions such as a tipover accident the canister could be sectioned to remove the spent fuel. DOE-Savannah River is encouraged to reexamine the cost and potential benefit of this criterion in view of the unlikely need for future fuel removal.

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-->      The answer to the third part of the second question—are there other transportation criteria that should be considered?—cannot be answered at this time. It appears that relatively little work has been done to date on establishing criteria to meet transportation requirements. DOE-Savannah River should not encounter any significant problems meeting the requirements in 10 CFR 71, but DOE-Savannah River must review the shipping requirements before it finalizes the design of its disposable canisters. 3.   Is the work under way by DOE-Savannah River appropriate to demonstrate conformance with the various criteria and requirements? The answer to this question is a very qualified "yes." The development program under way to demonstrate conformance with the waste acceptance criteria appears to be properly focused and appropriate to the task. This answer is qualified because the short schedule for this project did not allow an in-depth review of all of the ongoing work in the aluminum spent fuel program. Several of the WAC are poorly defined at present and may be subject to significant future change.11 It may be quite some time before DOE-Savannah River knows with certainty whether direct co-disposal treatment is viable. This current state of uncertainty has significant implications for the "path forward" for selecting spent fuel treatment options. Three conclusions were identified based on these facts: (1) a single treatment option may not be suitable for all types of aluminum spent fuel; (2) the aluminum spent fuel program will have to maintain flexibility in selecting treatment options until there is more complete information on the WAC and other repository requirements; and (3) a path forward that involves phased decision-making in the selection and implementation of alternative treatment options is indicated. 11   Revised EPA standards, ongoing performance assessment (PA) work at Yucca Mountain, and other developments could result in changes to the WAC.

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--> Findings Related to Costs and Timing of Aluminum Spent Fuel Treatment Options The third and final charge of the statement of task requests that the National Research Council provide—to the extent possible given the accelerated schedule for this project—an assessment of the cost and timing aspects associated with implementation of each aluminum spent fuel treatment option. The four-month schedule for information gathering and report development did not permit a detailed review of the cost and schedule estimates for alternative treatment options. The study focused on a review of the methodologies used to estimate costs to see if they follow generally accepted practices, are applied consistently, and result in estimates that are useful for comparative and programmatic purposes. The third charge of the statement of task was addressed in Chapter 4 through a discussion of three questions, summarized below: 1.   Do the cost estimates account for all of the major cost factors in the aluminum spent fuel treatment program? The answer to this question is "yes." The major cost factors of the system for receiving, treating, handling, storing, and disposing of aluminum spent fuel for each of the treatment options were identified in the Task Team report, and systematic cost estimates for these major cost factors were developed in the alternative cost study report. Both reports provided reasonably complete cost breakdowns, a list of the programmatic assumptions used in the cost estimates, and an explanation of the methodologies used to estimate uncertainties in total system costs. 2.   Are the cost and schedule estimates suitable for comparison of the options and selection of one or more preferred alternatives? The answer to this question is a qualified "yes." The cost estimates appear to be sufficiently complete for comparative purposes and for selecting a small number of alternative treatment options for further consideration. However, the schedule estimates for implementing the treatment option

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-->      range from unrealistic to ambitious, and there is no provision in the cost estimates for additional program delays. Significant program delays will add substantially to the costs for this program. The answer to this question is qualified because costs did not turn out to be a particularly effective discriminator of the various treatment options, mainly because the treatment options themselves comprised a relatively small part (approximately 20 percent or less) of overall systems costs. There was not much consideration given to reducing overall systems costs by examining alternatives in the fuel receipt and handling schedule. The current schedule appears to be based on current handling and storage capabilities at Savannah River, and relatively little consideration has been given to how changes in this schedule could affect system costs or the selection of alternative treatment technologies. 3.   Are the cost and schedule estimates suitable for budget planning purposes? The answer to this question is "no." The schedule estimates are ambitious and depend to a great extent on the timely completion of work by other parts of DOE. The cost and schedule estimates also are limited by the lack of conceptual designs for some of the treatment facilities and because some of the process steps have not yet been demonstrated to work for aluminum spent fuel. Additionally, the cost estimates do not consider the impacts of program delays on costs and schedules. Some amount of delay seems inevitable even under the best of circumstances and could come from several quarters during the budgeting, contracting, construction, and health and safety review phases of the program. DOE-Savannah River has not provided contingencies for such delays in its current program plans. Concluding Observations The primary focus of this report is on options for treating aluminum spent fuel. However, spent fuel treatment is just one component of a much larger and complex aluminum spent fuel disposal

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--> program, a program that is slated to last for about 40 years and cost in excess of $2 billion. The aluminum spent fuel disposal program is a complex web of activities at multiple sites around the world, ranging from operations at foreign and domestic research reactors that generate aluminum spent fuel to the repository development program at the candidate site at Yucca Mountain. Several parties have responsibilities for activities that take place in this program, and the decisions made by one party can have significant impacts on costs, schedules, and current or planned operations elsewhere in the program. DOE-Savannah River must select one or more treatment options for aluminum spent fuel that will meet repository waste acceptance criteria, which have yet to be finalized; design treatment and storage facilities that are sized appropriately to waste streams, which are subject to future change; and provide for interim storage of the processed waste until the repository, which is yet to be designed, licensed, or constructed, is able to accept it. The spent fuel disposal program is a systems problem in the classic sense. It involves several interacting components, each associated with different programmatic factors (e.g., cost, time, safety, policy constraints), multiple responsible parties, and different levels of uncertainty. The selection of aluminum spent fuel treatment options in the face of such uncertainties calls for a phased strategy in which critical programmatic decisions—that is, decisions that involve major program directions and commitments of funds—are made and implemented when the information needed to base sound choices becomes available. The acquisition of information for decision making also is an important part of the phased-strategy approach, both the acquisition of existing data from third-party sources and the generation of new data to fill information gaps. Of course, the phased strategy recognizes that there may be trade-offs between information acquisition and costs of delayed decisions and seeks to maximize the former and minimize the latter. In the context of the aluminum spent fuel treatment activities at DOE-Savannah River, the primary objectives of the phased strategy

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--> should be to maximize the probability of program success, minimize overall costs, and protect the program against the down-side risks from changes over which it has little or no control. The major programmatic decisions that must be made by DOE-Savannah River include the selection of one or more options for treating aluminum spent fuel and also the selection of a design for the treatment, storage, and shipping (TSS) facilities. The criteria for the decision process include the effectiveness of the treatment process, cost, schedule, compliance with applicable environmental health and safety standards, and consistency with other applicable policies. The options selected and facilities constructed also must be matched appropriately to the front (spent fuel generation) and back (disposal and D&D) ends of the overall disposal program. DOE-Savannah River appears to recognize the importance of a phased decision-making strategy and is already applying it to individual parts of its program. However, a systems-oriented strategy is needed in the treatment program to ensure that technically sound and cost-effective decisions are made and implemented in a timely manner. Three illustrative examples of such strategies are provided below, and a more detailed discussion is given in Chapter 5. 1.   Spent Fuel Receipt and Storage. As part of the phased decision strategy on the treatment option for aluminum spent fuel, the fuel receipt and storage schedule will have to be considered, and one of the important programmatic factors on this schedule is the high cost of time.12 The prompt shipment of all aluminum spent fuel to Savannah River for 12   The cost of time can be thought of as the operational costs that are unrelated to actual production activities. These would include management and administrative costs, costs of supporting workers in a stand-by mode, and other operational costs that are time related rather than production or throughput related, for example, certain types of maintenance costs. To the first order, these operational costs are fixed per unit of time, consequently, cost is approximately proportional to time.

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-->      treatment might require the purchase of additional shipping casks but could significantly reduce overall costs. However, shipment and treatment must be phased to minimize the need for new facilities. 2.   Treatment and Interim Storage. Based on information received by the P.I. during the course of this study, there does not appear to be a technical basis for rejecting conventional reprocessing as an option for treating aluminum spent fuel from foreign and domestic research reactors. Conventional reprocessing is a proven and reliable spent fuel treatment technology based on over 300 plant-years of operation worldwide, and the necessary treatment facilities (the F and H Canyons and the Defense Waste Processing Facility [DWPF]) are operating at Savannah River and are being used to treat aluminum spent fuel from research and production reactors. The alternative cost study prepared by Westinghouse Savannah River Company suggested that conventional reprocessing was a cost-effective treatment option when compared with direct co-disposal and melt and dilute treatment, the two primary treatment alternatives considered by the Task Team. However, the cost estimates for these three treatment alternatives have not been independently validated in this or any other study. Although it is difficult to make quantitative comparisons between a proven treatment technology such as conventional reprocessing and some of the other unproven treatment technologies considered by the Task Team, it is clear that the cost, performance, and safety of unproven technologies have much greater uncertainties than those of a demonstrated technology such as reprocessing. The common-basis cost and performance comparison of the two primary treatment alternatives (direct co-disposal and melt and dilute treatment) and conventional reprocessing, which was recommended elsewhere in this report, will enable DOE-Savannah River to determine whether conventional reprocessing is an appropriate treatment option for this fuel. The concern with conventional processing appears to be mainly one of policy and is related to the use of reprocessing for waste

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--> management generally rather than any specific concern about reprocessing this particular fuel type. Current U.S. nonproliferation policy does not encourage the civil use of plutonium. Accordingly, the United States "does not itself engage in plutonium reprocessing for either nuclear power or nuclear explosive purposes."13 The P.I. notes that plutonium separation is not a significant problem with conventional reprocessing of enriched aluminum spent fuel from research reactors. There is less plutonium in this fuel in comparison to commercial spent fuel owing to its high 235U enrichment, and separation of plutonium is not a required part of reprocessing treatment. The plutonium can be left in the liquid waste stream along with the fission products for later vitrification in glass. For aluminum spent fuel, the 235U separated during conventional processing represents a potential proliferation hazard, but it can be diluted with 238U within the reprocessing facility to make LEU. Moreover, Savannah River is a weapons material secure site and will remain so for the duration of this program. Finally, the reprocessing of aluminum spent fuel does not appear to be in conflict with the DOE decision to phase out reprocessing at Savannah River. The Highly Enriched Uranium Task Force noted in its predecisional draft report that the need for reprocessing for long-term DOE spent fuel management was unclear at present and that DOE should evaluate the near-term operational requirements to bring its facilities to a condition for transfer to the Office of Environmental Management for potential future operations. Indeed, as noted elsewhere in this report, DOE has or plans to reprocess some of its aluminum spent fuel in the Canyons at Savannah River because of safety concerns. It is the P.I.'s opinion that the acceptability of conventional reprocessing might be increased if it were redesigned as a reprocess-and- 13   The quote is taken from the White House Fact Sheet entitled "Nonproliferation and Export Control Policy" dated September 27, 1993. The fact sheet is based on Presidential Decision Directive 13, which is classified and was not reviewed in this study.

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-->      dilute operation, in which spent fuel is conventionally reprocessed and the separated 235U is diluted with 238U to produce low-enriched uranium before it leaves the reprocessing facility.14 3.   Post-2015 Aluminum Spent Fuel Inventory. There does not appear to be any reason at this time to make a decision about the disposition of the post-2015 inventory of aluminum spent fuel. This inventory could well be different in size (most likely smaller) and composition than currently anticipated, therefore, treatment options that do not appear to be available today may in fact be available when the time comes to treat this fuel. DOE-Savannah River is doing a commendable job of collecting data for decision making on many of the individual components of its treatment option selection program. In addition, DOE-Savannah River is in the process of defining a decision strategy for selecting and implementing a treatment option for aluminum spent fuel. As part of this decision strategy, it is recommended that DOE-Savannah River conduct a complete systems review to identify and understand the relationships among the various components of the aluminum spent fuel disposal program. DOE-Savannah River also is encouraged to apply a phased strategy for selecting and implementing a treatment option for aluminum spent fuel that takes into account the considerations discussed above. This phased approach will support the analysis required in the environmental impact statement and will lead to a more credible EIS-ROD and a more successful and cost-effective path forward for the aluminum spent fuel treatment program. 14   This dilution could in fact be done at almost any step of the process.