The Energy Policy Act of 1992 (EPACT) called on the National Academy of Sciences to conduct a study and provide recommendations for reducing costs associated with the decontamination and decommissioning (D&D) of the nation's gaseous diffusion uranium enrichment facilities located at Oak Ridge, Tennessee; Paducah, Kentucky; and Portsmouth, Ohio. Following on this act and a request from the U.S. Department of Energy (DOE), the National Research Council (principal operating arm of the National Academy of Sciences) established the Committee on Decontamination and Decommissioning of Uranium Enrichment Facilities in November 1993. Beyond recommending general ways to reduce D&D costs, the committee was also charged with assessing options for the disposition of the large inventory of depleted uranium hexafluoride (DUF6) stored at the three sites. The committee was not asked to make a specific cost estimate for the D&D of the three gaseous diffusion plants (GDPs).
The committee determined the following:
- D&D of the GDPs is essentially a large deconstruction and demolition project that can effectively be undertaken in the near term.
- Based on the experience with other D&D projects, previously estimated costs to carry out the D&D of the three GDPs are high, and there are opportunities for major cost reductions.
- Proven technologies are available for cost-effective D&D of the GDPs. However, selection of the most effective process for some activities will benefit from a few focused demonstration projects (or programs). A large research and development program is not needed.
- Risks to public health and safety from the currently nonoperating GDP at Oak Ridge are small and do not require urgent action; the situation will be the same for the other two GDPs once they cease operations. However, until the D&D is complete, preventing the release or spread of the hazardous and radioactive materials inside the GDP buildings requires significant expenditures for surveillance, maintenance, and monitoring, and the risks will increase with time.
- D&D of the GDPs is a formidable task, but it can be completed successfully if able leaders on site are given sufficient freedom and authority. This will require
- some changes in current management practices applied to D&D and definition and implementation of a coordinated set of regulatory requirements.
- The use of an incremental, prioritized cost- and risk-reduction approach for the D&D program would permit D&D to begin soon, even though major uncertainties hamper planning and the complete D&D of the GDPs. For example, given the uncertainties and assumptions about the end states for the sites, a plan can be developed that entails a progressive D&D of the facilities in a stepwise fashion based on analysis of costs, risks, and social values. The most likely end states should be used in the first planning effort with the plan updated as the uncertainties become resolved and end states change.
- Consistent with the prioritized cost- and risk-reduction process, the DUF6 should be converted to a more stable chemical form for long-term storage.
- The scope of the committee charter was D&D of the facilities but did not include environmental restoration of the property under and around the buildings. However, the committee believes that the cleanup of the sites requires integrating the D&D of buildings and equipment, environmental restoration (such as for soil and groundwater contamination), and management of DUF6. The committee considered this integration in its deliberations and in this report.
The Oak Ridge GDP is a closed facility: some parts of the plant were closed in 1964; the remainder of the plant ceased operations in 1985, and permanent closure occurred in 1987. The Paducah and Portsmouth GDPs are operating plants, currently leased by the United States Enrichment Corporation (USEC) from DOE for the production of enriched uranium for the electric utility industry.
D&D requires the removal of radioactive and hazardous materials from buildings and equipment. The GDPs are complexes of large buildings, with hundreds of acres of floor area and thousands of large pieces of equipment. In addition to the process buildings that contain the enrichment cascades, there are auxiliary buildings, electrical switchyards, and connecting piping and electrical systems. The Oak Ridge and Portsmouth facilities were once used to produce highly enriched uranium (greater than 20 percent enrichment) for military purposes. The Portsmouth highly enriched uranium section was shut down in 1992.
Upon shutdown of an operating GDP, a significant amount of uranium deposits in the equipment can be removed by treatment with gaseous chlorine trifluoride (ClF3), which is heated by the compressors. The highly enriched uranium section of the Portsmouth plant has undergone such treatment to remove a significant part of the highly enriched uranium deposits representing a criticality concern. The USEC is obligated to remove uranium deposits representing a criticality risk before returning the facilities to DOE. It will likely subject the low enriched uranium sections of the Paducah and Portsmouth plants to such gaseous treatment to remove
deposits representing a nuclear criticality risk before returning the facilities to DOE.1 Quantities of highly enriched uranium remain in some of the process buildings at the Oak Ridge plant, the result of a cessation of operations without the benefit of a systematic removal of uranium deposits, such as with gaseous treatment. Because Oak Ridge is not a functioning plant, heated gaseous ClF3 cannot be passed, post facto, through the process equipment for uranium deposit removal. A deposit removal program is under way (using mechanical means, avoiding contact with water; and testing gaseous ClF3 at low [room] temperatures) to remove deposits from the Oak Ridge equipment that represent a nuclear criticality risk. Decontamination and removal of enriched uranium in the cascade equipment must occur in a carefully controlled manner to avoid nuclear criticality accidents and to conform to safeguards and security requirements for special nuclear materials. Preventing criticality is a distinguishing feature of the D&D of the GDPs, especially for the Oak Ridge site. Preventing criticality can be expensive, and a cost-effective D&D requires a clear understanding of where criticality will be a major concern, where it will be a relatively minor concern and easily handled, and where it is of no concern. In addition, large quantities of hazardous substances such as asbestos and polychlorinated biphenyls (PCBs) will have to be dealt with safely at all three sites.
Currently, there is no quantitative analysis of risk for a nonoperating plant, such as the Oak Ridge GDP. Although uranium is radioactive, its primary risk to human health is its chemical toxicity upon ingestion or inhalation. The uranium in the buildings is contained, for the most part, inside process equipment and does not present a hazard to human health. Other hazardous substances, such as asbestos and PCBs, are also contained within the buildings. Because potential exposure of the public to contaminants near a nonoperating plant is low to nonexistent, the committee believes that the near-term risk to the public from closed facilities is low. Although the risk is low, it will increase with time if the buildings and process equipment are allowed to deteriorate; for example, water could leak into the buildings and carry contaminants into the surrounding environment or, at the Oak Ridge GDP, possibly initiate small nuclear criticality events. The current program to remove uranium deposits at the Oak Ridge site is directed toward eliminating such a possibility; namely, removing the deposits that have the potential for a criticality incident.
The vast bulk of the uranium at the GDP sites is in the form of DUF 6 stored outdoors in steel cylinders. If DUF6 were to escape into the atmosphere, it would react with moisture in the air to form hydrogen fluoride (HF), a very toxic substance. Breaches that have occurred in some storage cylinders have been self-sealing, not allowing much DUF6 to escape. Although the committee has not conducted risk assessments or atmospheric dispersion modeling, it believes that if leaks are small, HF is unlikely to reach site boundaries in dangerous concentrations. For large releases, concentrations at the site boundaries would depend on atmospheric conditions. It seems to the committee that a major release of DUF6 from the large inventory contained in the steel cylinders in the storage yards is a very low probability event, provided that the cylinders are adequately maintained and monitored.
The committee believes that the primary risks will probably be to on-site workers performing surveillance, maintenance, and D&D activities. Potential risks will arise not only from possible chemical or radioactive contamination, but also from industrial accidents. Minimizing such risks will require strict adherence to applicable worker health and safety protection rules. To minimize risks during D&D operations, procedures will need to be designed to meet standards required for preventing criticality.
D&D Cost Estimates
Two D&D cost estimates were commissioned by DOE in 1991 to support the transition of the management of the enrichment facilities from the federal government to the USEC. Ebasco Environmental (Ebasco) assumed that the facilities would be cleaned of radioactive and hazardous materials and the sites restored to a condition such that a future occupant would not be exposed to harmful levels of substances. An initial estimate by Ebasco amounted to about $46 billion, but a successive set of reevaluations resulted in a final D&D cost estimate of $16.1 billion. The decrease in estimated cost from $46 billion to $16.1 billion reflected changes in scope and assumptions including reductions in overhead rates, fewer newly constructed facilities, greatly reduced program integration costs, and reductions in waste management costs. Disposal of the low-level radioactive waste generated was assumed to be at the sites. TLG Engineering (TLG) made an estimate for D&D of $13.9 billion, using different assumptions. For example, TLG assumed that the major cascade components would be removed, sealed, and transported to the Nevada Test Site for low-level radioactive waste disposal without prior decontamination. The committee believes that insufficient time was spent on the development of these cost estimates to conduct a thorough evaluation of alternative D&D technologies and waste disposal options or to optimize D&D operation sequence and schedule.
The DOE's D&D program is incorporating the Ebasco $16.1 billion estimate in its D&D Program Life Cycle Baseline Summary. Both operating plants are assumed to close by 2005. The Ebasco estimate assumed a sequential cleanup—Oak Ridge, followed by Paducah, and then Portsmouth—extending over three decades to the year 2030.
A 1991 Martin Marietta Energy Systems (MMES) study estimated that converting the DUF6 into uranium oxide (U3O8) would cost between $1.3 billion and $4 billion (in 1992 dollars). These costs are in addition to the Ebasco and TLG cost estimates for the D&D of enrichment buildings, equipment, and materials.
The Uncertain Context
A number of uncertainties make D&D planning, cost estimation, and execution difficult. These are discussed briefly below.
Final State of the Sites
Although the scope of the study was limited to the D&D of the buildings and equipment, D&D must be considered within the context of the total site. The existing D&D cost estimates
assumed that the equipment and radioactive and hazardous materials would be removed from the buildings, which could subsequently be reused. Even if reuse of the buildings is not a desirable alternative, removal of the equipment and buildings may be the preferred approach, since the very long period of radioactive decay of uranium, as well as the large quantities of stable hazardous materials, makes entombment in place an unattractive alternative. However, a combination of end states could exist at each site: some buildings might be reused, some demolished, and some undergo continued surveillance and maintenance. End states should be determined with stakeholder involvement.
Disposal of Waste
The D&D of the facilities will generate low-level radioactive, mixed, and hazardous wastes. For low-level radioactive wastes rapidly rising disposal costs, closure of disposal sites, and potential public opposition to transport and licensing of new disposal sites make such waste management, siting, and transport uncertain and increasingly expensive. There are regulatory uncertainties about mixed wastes and, to a lesser degree, also about hazardous wastes.
Criteria for Release of Decontaminated Materials
Significant economic benefits may be realized if the large quantities of valuable metals in the plants can be decontaminated and reused. Surface-contaminated metals could be cleaned to whatever surface release criteria are established. Much of the nickel is in the diffusion barriers,2 for which it would be impractical to determine compliance with surface release criteria. Evaluation of such materials for release may be achieved with volumetric contamination standards, which do not exist at present in the United States. The U.S. Environmental Protection Agency and the U.S. Nuclear Regulatory Commission have begun preliminary work on criteria for release of radioactively contaminated materials. These criteria, which are uncertain at this time, will affect D&D costs. The availability of such standards is necessary for any recycling program.
The D&D Fund and Budgetary Uncertainties
The EPACT established a D&D Fund that would accumulate a total of $7.2 billion dollars over 15 years. However, the D&D Fund is being used for other than D&D activities. For example, in fiscal years 1993 and 1994, $165 million from this fund was spent on remedial actions, such as soil and groundwater cleanup. If the current profile of spending from the fund continues, there may not be sufficient funds to meet future GDP D&D needs. In addition, the federal government did not contribute as much as the 1992 act prescribed, and a recent court action makes the expected contributions from the electric utility industry uncertain.
The diffusion barriers, or membranes, are contained in the diffuser units in the cascade and accomplish the separation of 235UF6 by diffusion. Thousands of diffuser units are required to achieve significant separation (see Chapter 2).
Sequence of Plant Cleanup
The competitive economics of the U.S. enrichment plants in the world market for enriched uranium and the total demand for enrichment services are uncertain but could lead to early closure of either the Paducah or Portsmouth plant. If so, it might be preferable for a recently closed plant to undergo D&D first rather than, as currently planned, starting with the Oak Ridge plant. The sequence of plant cleanup should be reviewed for its cost implications.
Management of DUF6
It is uncertain what the plan will be for the management and funding for possible disposition of the DUF6. Possible options include refurbishment or replacement of the deteriorated cylinders with subsequent continued surveillance and maintenance; conversion of DUF6 to a useful product; or conversion of the DUF6 to the more stable oxide form for storage on site or at another location or for disposal. Each option has different implications for cost and future end states of the sites and can affect resources available for D&D.
The following sections summarize the committee's principal recommendations.
Previous D&D Experience
The committee reviewed the Ebasco and TLG cost estimates, other cost analyses of the D&D of the GDPs, and experience from the D&D of nuclear power reactors, such as the Shippingport Atomic Power Station. It also had the benefit of actual reported data from the D&D of the British Nuclear Fuels Ltd. (BNFL) Capenhurst GDP in the United Kingdom, which was smaller but of design similar to that of the U.S. plants.
The cost of the Capenhurst D&D effort was about $160 million (in 1994 dollars). The operating plant, before completely ceasing of operations, was treated with gaseous ClF3 to remove significant amounts of the uranium deposited on the surface of the equipment in the plant cascades. The Capenhurst equipment was then removed, cut up into pieces, and dry mechanical removal of uranium was used to minimize criticality concerns. The metal pieces were then decontaminated using a series of aqueous (chemical) decontamination baths. British surface-release standards were achieved for most of the metal, allowing recycling to the commercial market. Concrete was surface decontaminated, and the clean material was used for road fill. Approximately 99 percent of the material in the plant, excluding the diffusion barrier material, had been recycled as of early 1995. Experience with melt refining in 1995 gives BNFL optimism that they can effectively decontaminate parts that are otherwise difficult to decontaminate. The Capenhurst D&D experience, as well as other D&D efforts, demonstrates that technology exists to accomplish the D&D of the GDPs in a cost-effective manner.
Although the Capenhurst plant was much smaller than the U.S. GDPs and used some different materials of construction, these differences are not sufficient to account for the hundredfold difference between the actual D&D cost of the Capenhurst facility and the estimates
for the U.S. GDPs. The review of previous D&D experiences and of the cost estimates leads the committee to believe that there are significant opportunities to reduce the costs for the D&D of the GDPs. While the potential cost savings are uncertain, they could exceed 50 percent of the current Ebasco estimate of $16.1 billion. Most of the cost reduction opportunities are not based on advances in technology but could come about from taking a different technical and management approach to the D&D than was assumed in the cost estimates.
Recommendation. The committee recommends that the technical and management approaches used successfully for the D&D of the Capenhurst gaseous diffusion plant and for recently completed D&D projects with U.S. nuclear power reactors be carefully considered by DOE to reduce costs for D&D of U.S. GDPs.
Major areas of potential cost reduction are identified below (see Chapter 6 for other detailed examples and approaches).
Contracting and Management
Large reductions in D&D project cost are unlikely to be achieved under the currently proposed project management approach using multiple prime contractors. Experience with other DOE projects demonstrates conclusively that this concept results in much higher costs than those of comparable projects managed by other government agencies and the private sector. DOE has traditionally managed its sites and the projects on its sites using a management and operations contractor, an approach assumed in the Ebasco cost estimate. This management approach uses multiple layers of management and results in a high ratio of the costs of management and professional services to the costs of actual D&D.
A more cost-effective approach would be a management structure employing a single prime contractor, as was done for the Shippingport D&D, who would assume total responsibility and accountability for all aspects of the D&D of the GDPs. This decommissioning operations contractor would be selected through an open, competitive bidding process based on demonstrated experience in successful management of D&D projects of comparable complexity. Improvements in the cost-effectiveness of projects could be achieved by incorporating financial incentives in the prime contract and all subcontracts. As part of the process of reducing costs, every aspect of the D&D effort needs to be examined closely to identify the most cost-effective alternatives and to eliminate redundant and excessive management oversight, while complying with health, safety, and environmental protection requirements.
Recommendation. Once adequate planning is in place to permit work to proceed, the committee recommends that a single contractor for carrying out D&D operations be selected through open competition and assigned total responsibility and accountability for all aspects of the assigned work.
Need for New Facilities
The Ebasco and TLG cost estimates assume the construction of two, new generalized multi-purpose facilities: a high-assay decontamination facility for equipment contaminated with highly enriched uranium; and a low-assay decontamination facility for equipment contaminated
with low-enriched uranium. This plan is quite different from the D&D experience at Capenhurst, where existing buildings were used to house a single, simple decontamination facility and limited-purpose shops were used to handle highly enriched uranium. The variety of technologies and capabilities and the large size of these decontamination facilities led to very high estimated capital and operating costs. The estimated direct capital and operating costs of the postulated low- and high-assay decontamination facilities, along with the certification facilities, is close to $3.5 billion.
Recommendation. The committee recommends that the high-assay decontamination facility be eliminated and the low-assay decontamination facility be simplified to focus primarily on aqueous decontamination and be housed in existing buildings.
The cost estimates also assumed construction of a new administration building at the Oak Ridge GDP site for several thousand people, the large staff resulting from the assumed management and contracting approach. Such construction is not warranted, especially if the committee's recommended management and contracting approaches are implemented, which should reduce the size of the management and professional staff to levels that can adequately be housed in existing administrative buildings.
Recommendation. The committee recommends that existing facilities be used to house the management and professional D&D staff rather than constructing a new administration building.
Management of hazardous, radioactive, and mixed wastes presents significant opportunities for cost reduction. The quantity of waste from D&D will be substantial and its disposal expensive. This quantity could be reduced by reusing decontaminated materials. The value of decontaminating materials for reuse will be strongly affected by the cost of decontamination, the market value of the material, and the savings from reducing the amount of waste requiring disposal. The uncertainties associated with low-level radioactive and mixed waste disposal and the potential large cost favor a strategy of waste minimization. Waste minimization strategies should incorporate several general rules:
- Materials should be cleaned and reused, if economically feasible.
- Generation of mixed waste, which contain both hazardous and radioactive wastes, should be avoided, because its processing and disposal entails a costly and complex regulatory regime.
- Approaches, such as reuse, should be taken that minimize the creation of secondary waste streams, such as contaminated water from cleaning operations.
The committee is also concerned about the practice of temporarily storing radioactive, hazardous, and mixed wastes from other activities on the Oak Ridge Reservation within the GDP
process buildings. This will complicate and could delay D&D efforts and will engender costs during D&D that should not be ascribed to the D&D program.
Recommendation. The committee recommends that an integrated, optimized waste management plan be developed that encompasses material reuse, recycling, packaging, transport, and waste disposal. Consistent with cost reduction and public health and environmental protection, materials should be cleaned to free-release standards and released to the commercial sector for recycling. Material that cannot be cleaned to free-release standards should be considered for recycling within the DOE or Department of Defense complexes in applications where slightly contaminated materials are acceptable, such as for shield blocks or waste containers.
There are numerous laws, regulations, and regulatory bodies at federal, state, and local levels, that will affect D&D. The large number of regulators with jurisdiction over the enrichment plants and their decontamination, and the large number of applicable laws and regulations, virtually ensure an overlapping and conflicting regulatory regime. This very complex regulatory environment can result in costly and labor-intensive site practices and may be counterproductive to protecting public health and safety. The regulatory environment could also result in delays, extending annual surveillance and maintenance expenditures.
Guidelines for decommissioning have been published by the Nuclear Regulatory Commission and by DOE. Cooperative efforts are under way by DOE, the Environmental Protection Agency, and the Nuclear Regulatory Commission to develop release standards based on current radiation protection concepts. The draft guidelines include a proposed annual dose equivalent of 15 mrem/yr, based on generic exposure scenarios, for the release of sites and materials. The agencies recommend that each exposure scenario be evaluated for a specific site.
The committee believes that regulatory coordination should proceed expeditiously; avoiding conflicting, redundant, or unnecessary regulations is essential to reduce costs and streamline site practices. DOE should capitalize upon recent congressional interest in regulatory coordination, particularly in the area of radiation standards.
Recommendation. The committee recommends that DOE seek coordination of all regulatory aspects of D&D with the appropriate state and federal agencies early in planning to provide consistency during D&D planning and execution.
Coordinated planning—at the DOE headquarters level, across the complex of the three GDPs, and at each site—will be required to ensure that D&D is integrated effectively with other operating or cleanup activities at the sites and that resources, including disbursements from the D&D Fund, are used effectively. DOE-level planning would outline decisions on D&D financing, on integration of D&D with other DOE programs, and on the broad contracting, regulatory, and stakeholder involvement approaches for D&D.
A complex-level master plan would coordinate such decisions as the sequence of plant cleanup, the priority actions to be taken, allocation of funds among the sites, and cleanup strategies, including approaches to waste management and recycling. Setting priorities would be based on analysis of risks, costs, and social values.
Site-specific plans are also needed to coordinate D&D, environmental remediation efforts, and management of the DUF6 inventory at each of the three sites. For example, it would be costly if previously cleaned areas of soil and the groundwater were recontaminated during D&D operations. For Oak Ridge, the site plan should be coordinated with the plan for the whole Oak Ridge Reservation. It was not clear to the committee that the idea of cleaning the areas that the buildings occupy to greenfield status is reasonable, especially if other parts of the sites remain contaminated or if DUF6 continues to be stored on site.
Detailed site-level D&D plans, which the committee believes should not take more than 18 to 24 months to prepare, should be developed, delineating the sequence of activities necessary to incrementally achieve the D&D of the facilities. The sequence of tasks should be based on considerations of cost and risk. Uncertainty regarding the final end states should not delay the development of this D&D plan, which would be expected to change as the situation evolves. The D&D plan should incorporate all major assumptions (technical, cost, and institutional), a proposed management organizational structure for both DOE and the decommissioning operations contractor, tradeoff studies for determining an optimized decommissioning sequence, a detailed work breakdown structure, and a detailed cost estimate and schedule. The detailed sequence document with a work breakdown structure would specify, for example, the sequence of steps required to dismantle and remove the equipment, decontaminate the equipment and buildings, tear down any indicated buildings, recycle material, and dispose of wastes. These plans would be used by the decommissioning contractor for soliciting competitive bids for execution of the work.
Recommendation. The committee recommends that DOE develop three plans, namely, headquarters-level, GDP complex-level, and GDP site-level, that address and integrate the D&D of the facilities, environmental remediation activities, and management of the DUF6.
Site planning and the associated planning for D&D of the GDPs should be undertaken in consultation with the stakeholders, such as public groups, regulators, workers, DOE, and any future potential users of the sites. This process of communication among various interested parties should start at the beginning of planning. For example, a consensus-building process would elicit public advice on the incremental cost- and risk-reduction approach and on the desired end states of the sites, taking into account costs, risks, and social values. It is essential that a credible and meaningful stakeholder and public involvement process be implemented that ensures smooth planning and implementation of D&D. Increased attention to stakeholders and the public concerning D&D at the three GDP sites can contribute to decisions that enjoy wide public acceptance and could avoid lengthy delays and additional costs arising from court challenges to the planned actions. Effective efforts to integrate the multiplicity of citizen and
stakeholder interests are needed to provide meaningful inputs to decision making on such issues as health and safety, budgets, employment, and end states.
Recommendation. The committee recommends that a stakeholder involvement program be pursued to obtain timely and substantive public participation and input to ensure that social values are reflected in policy decisions.
Prioritized Cost and Risk Reduction
Proceeding expeditiously with D&D planning and execution is important because delays will lead to substantial expenditures for surveillance and maintenance, deterioration of the facilities will exacerbate these costs, risks to individuals will increase, and the costs for an expensive safeguards and security regime for highly enriched uranium will continue. Because the D&D of the three sites could very well occur over a period of several decades, political priorities, budget commitments, and regulatory standards could change. The uncertain context within which D&D will be planned and executed could also result in serious delays.
A prioritized, incremental cost- and risk-reduction approach would identify conditions at the sites that, if not quickly remediated, could lead to increased risks or costs as a result of delay. This approach would allow initiating D&D operations during the planning process. For example, regardless of the end states of the sites, removal of highly enriched uranium deposits from the Oak Ridge process equipment should be a first priority because this would reduce safeguards and security costs, reduce the risk of criticality accidents, and reduce costs of subsequent D&D efforts because nuclear criticality would be of much less concern. A prioritized cost- and risk-reduction approach would identify the best sequence of D&D actions to be included in a detailed D&D plan and cost estimate. This approach would schedule projects within the detailed D&D work plan to minimize risks to workers and the public, minimize total costs of surveillance and maintenance and D&D activities, be flexible, and not preclude alternative end states.
Recommendation. The committee recommends that a prioritized costand risk-reduction approach be used as a basis for developing the D&D plan. This approach should be used to accomplish D&D activities prior to completion of the entire plan.
D&D Technology Issues
Proven technologies are available for the D&D of the GDPs. These include technologies for characterization, disassembly, removal of uranium deposits from the process equipment, decontamination of the process equipment and buildings, melt refining and recycling of metals, and treatment of wastes. A major research and development program is not needed. However, there are some uncertainties about technical effectiveness, such as the degree to which certain technologies can remove technetium-99 (99Tc, which is present from using recycled reactor feed) or decontaminate to the required levels, and about what degree of cost savings can be achieved. The large areas in the plants that need to be characterized and the repetitive nature of the equipment design encourage the use of robotics and automation. Determining answers to performance and cost-effectiveness questions would require a few focused demonstrations, not
major research and development programs. With regard to decontamination technologies, the committee believes that while gaseous decontamination using ClF3 is appropriate for removing bulk uranium deposits representing a criticality risk, for example, in the high-assay section at Portsmouth, subsequent decontamination should use aqueous techniques rather than gaseous ClF3. Aqueous technology has proven to be very effective, and the committee envisions laboratory-scale efforts of a sufficient size to ascertain performance at full-scale operation. Automation and robotics demonstrations may have to occur in the plants. Such focused demonstration efforts on currently available technologies would help D&D planners select the most appropriate technologies based on considerations of cost, environmental protection, performance, and safety.
Recommendation. The committee recommends that a few highly focused D&D demonstrations be undertaken to verify the cost and effectiveness of specific technologies, including the following two:
- Optimization of aqueous decontamination to remove radioactive surface contamination from materials and process equipment, with special attention to 99Tc.
- Support of current DOE robotics programs, with highly focused demonstrations to verify potential cost savings and safety benefits.
The committee recommends that a modest research program be established to develop methods to effectively decontaminate the diffusion barrier material.
Safeguards and Security
The assumption was made in the Ebasco cost estimate that the diffusion barrier, or membrane, and compressor seals would be declassified prior to D&D. Costs will be higher if these components remain classified and the D&D has to be carried out in a “secure" environment. Furthermore, the D&D of the GDPs will require the handling of special nuclear materials. The regulatory requirements to safeguard these materials entail significant costs that could be reduced if less stringent requirements could be applied. For example, special nuclear material should be removed from the high-enrichment sections of the cascade prior to the start of large-scale D&D operations so that safeguards and security requirements can be relaxed.
Recommendation. The committee recommends that to reduce costs without compromising information security for the gaseous diffusion technology DOE should try to define physical security requirements that allow uncleared workers under adequate supervision to conduct D&D operations. In addition, DOE should conduct an in-depth evaluation of the safeguards and security requirements during D&D to determine how their impact on D&D cost could be reduced.
A DOE study has found that past practices for storage of DUF6 have been inadequate in several respects. There have been no serious consequences, however, and there is a vigorous program to correct past deficiencies.
There is general agreement, however, that DUF6 is an unsuitable chemical form for long-term storage; it is too reactive and too volatile. Eventually it needs to be converted to the more suitable form uranium oxide (U3O8). No large-scale uses for the DUF6 have been identified, and the most promising potential uses do not preclude conversion to oxide.
Estimates prepared for DOE indicate that costs for the conversion of DUF6 to U3O8 will be high, over $2 billion. It should be possible to realize cost savings by optimizing a number of factors, such as plant size and the conversion schedule. Conversion processes are conventionally used in the nuclear fuel industry, and several alternatives are known. The processes are rather simple, so that large cost reductions through new technology do not appear likely. Considering cost, risk, and social values, the most attractive of the known processes can be chosen.
Significant savings in the cost of long-term storage should be possible by improving the physical properties of the U3O8; in particular, increased particle size and much higher packing density should be possible, which would reduce storage costs based on volumetric fees. This area promises benefits from a limited research and development program.
Recommendation. The committee recommends that, if consistent with the prioritized cost- and risk-reduction process, the DUF6 should be converted to the more stable chemical form, U3O8, for storage or disposal.
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