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1 introduction "The Department fof Energy] has about 1 00 mi 11 ion gal ions of I iquid HLW thigh-level waster stored in underground tanks at its Savannah River and Hanford Sites and about 4,000 cubic meters of solid HLW stored in bins at the Idaho Site. The Department estimates that it will spend on the order of $50 billion over the next 50 years or so to put this waste into a more stable form for shipment to a geological reposito- ry. f...] The Department believes that it must invest in long-term basic research to address effectively its HLW t...l responsibilities and would like to have the National Research Council's advice on what research investments shou Id be made" (Huntoon, 1 999~. In response to this request, the present study was undertaken to assist the U.S. Department of Energy's (DOE's) Office of Environmental Management (EM) in the development of a long-term basic research agenda (see Sidebar 1.1 ) addressing the HLW problems at DOE sites set out above. H LW is defi ned by DOE as the h igh Iy red inactive waste from the chemical reprocessing of spent fuel and target materials to recover plutonium and uranium for the production of nuclear weapons (Sidebar 1.2~. The EM Science Program (EMSP) provides the basic research support for environmental cleanup activities across DOE's HLW sites. The EMSP mission and other details on the program are given in Sidebar 1.3 and in Appendix D. Ob jectives of This Study As mentioned in the statement of task (Sidebar P.1 of the Preface), the objective of this study is twofold: 1. identify significant HLW problems that cannot be addressed effectively with current technologies, and n t r o d u c t i o n
SIDEBAR 1.1 COMMITTEE'S DEFINITION OF LONG-TERM BASIC RESEARCH FOR THE EMSP For the purpose of this study, the committee interpreted the expression "long-term basic research," mentioned in the statement of task, as research that creates new generic knowledge underlying funda- mental processes and phenomena and is focused on long-term, rather than short-term, problems. Moreover, in alignment with the EMSP mission, this research should be "needs-driven" or "mission- directed,"with potential high-impact results on the EM-HLW management program. A similar defini- tion of basic research was provided in other NRC reports relevant to the EMSP (NRC, 1997, 2000a, 2000c).This definition differs from that used by academia and by government agencies, such as the National Science Foundation,where basic research is"research whose objective is to gain knowledge or understanding of phenomena without specific applications in mind" (AAAS, 2001). 2. recommend areas of research where the EMSP can make signifi- cant contributions to solve these problems and increase scientific knowledge generally. The ultimate objective of the committee's recommendations is to help EMSP build a long-term science program that will contribute to the EM cleanup mission of reducing risks to the environment, workers and public, and reducing cleanup time and costs. Strategy To Address the Task The recommended long-term research agenda is organized accord- ~ng to DOE's current approach for HEW managements as follows: . · Characterization Retrieval and pretreatment · I mmobi I ization · Tank closure The motivation for selecting the long-term research activities in this report is to provide contingency approaches for DOE's HEW manage- ment programs and to improve process effectiveness. The committee recommends research topics that wou Id provide conti ngency approach- es as the basis for program support in case of interferences or disrup- This approach is discussed in more detai I in Chapter 2. H ~ G H - L E V E E W A S T E
tions to current waste management plans. Results from these research activities would contribute to reducing technological risk over the next decades. The committee also recommends research topics that would improve process effectiveness or lead to a decrease in the volume of immobi I ized H LW and secondary waste streams. The long-term research activities recommended in this report address both identified problems that are already affecting the HLW sites cleanup and future potential problems. In addressing the task of developing a long-term basic research agenda, the committee identified problem areas and research objectives, rather than specific research projects. It is not possible, with today's knowledge, to clearly define specific research activities addressing many of DOE's HLW problems. It is the role of EMSP investigators to determine the pathway to achieve these research objectives as more information becomes available. The results of the EMSP research could potentially find application at any time during the multi-decade EM cleanup program. Because the EMSP research program should be needs-driven (see Sidebar 1.1), the committee identified broad problem areas throughout the HLW management process. It is not the purpose of this report to cir- cumscribe investigators' creativity by giving a detailed listof research projects; rather, the committee leaves to the investigators the charge of addressing the scientific basis underlying the problem areas described SIDEBAR 1.2 DEFINITION OF HIGH-LEVEL WASTE High-level waste was defined in the Nuclear Waste Policy Act (1982) as (A) the highly radioactive material resulting from the reprocessing of spent nuclear fuel, including liquid waste produced directly in reprocessing and any solid material derived from such liquid waste that contains fission products in sufficient concentrations; and (B) other highly radioactive material that the U. S. Nuclear Regulatory Commission (USNRC), consis- tent with existing law, determines by rule requires permanent isolation. The definition from the 1982 Nuclear Waste Policy Act has been amplified (Congress, 1 982).The USNRC has defined, in Title 10 Code of Federal Regulations (CFR) Part 60.2, that HLW"means: (1 ) Irradiated reactor fuel, (2) liquid wastes resulting from the operation of the first cycle solvent extraction system, or equivalent, and the concentrated wastes from subsequent extraction cycles, or equivalent, in a facili- ty for reprocessing irradiated reactor fuel, and (3) solids into which such liquid wastes have been con- verted." Commercial spent fuel is stored for direct disposal and is classified as HLW according to the USNRC definition. However, according to DOE's definition, irradiated reactor fuel is not classified as HLW but as "spent fuel," pending a decision to dispose of it, as explained in DOE's Order 435.1 on radioactive waste management, and its implementation guide G.435.1-1 (DOE, 1999, pages 11-1 to 11-6). n t r o d u c t i o n
SIDEBAR 1.3 THE EMSP AND ITS MISSION The EMSP, created in 1996, is a partnership between DOE's EM and SC.The mission of the EMSP is the following (DOE-EMSP, 2000): · Develop a targeted, long-term basic research agenda to reduce cleanup costs and risks to work- ers and public; Bridge the gap between broad fundamental research and needs-driven applied technology; and Serve as a stimulus for focusing the nation's science infrastructure on critical environmental problems. The EMSP directs research in seven EM "problem areas": HLW, deactivation and decommissioning, spent nuclear fuel, nuclear materials, subsurface contamination, mixed and transuranic waste, and health/ecology/risk.The EMSP develops its research program through complex-wide surveys, site workshops, system analysis, and recently, through the advice of the National Research Council (NRC, 2000a, 2000c). EMSP grants are awarded to research projects responding to requests for proposals (RFPs), published in the Federal Register, issued by the EM and the SC.The proposals are screened through a two-step peer review process, described in Appendix D. in this report. Therefore, the recommendations are provided under the form of research objectives warranting further basic research invest- ment, rather than research activities. Throughout the report, examples of research topics are provided to illustrate how the committee would address the identified HLW problems. These examples are not to be considered as recommendations or research priorities. Some of the issues discussed in this report were not considered as "high priority" for basic research as others because different programs within DOE are already addressing them. Moreover, the committee did not want to "drown" high-priority research in an excessively long list of needs. Boundaries of the Statement of Task The committee has elected to focus its attention and information- gathering activities on HLW problems involving only wastes stored in tanks and binsat the principalDOEHLWsites.2 Consistent with the statement of task, this study does not address issues related to spent 'This decision has been made in agreement with the sponsor during the first committee meeting. H ~ G H - L E V E E W A S T E
nuclear fuel, transuranic waste (in particular plutonium), or other sec- ondary waste streams from the process) ng and hand I i ng of H LW. Appendix C gives a brief perspective on DOE's spent nuclear fuel issues. There are several other problems related to HLW at DOE sites. These problems have been or are being discussed by other NRC (National Research Council) committees. For instance, three NRC committees accomplished or are currently accomplishing the task of identifying research neeas for fine EMUS In fine subsurface contamination (NRC, I I r . I _~ `~ · . I I r 2000a), deactivation and decommissioning (NRC, 2000c, 2001 b), and transuranic and mixed wastes problem areas. Non-radioactive wastes (in particular, toxic inorganic materials and dense non-aqueous phase liquids) are addressed in two previous NRC reports: Research Needs in Subsurface Science (NRC, 2000a), and Groundwater and Soil Cleanup: Improving Management of Persistent Contaminants (NRC,1999d). I on~-term instih~tion~l m~n~ement IBM. such ~s site monitoring ~ . . . . . . in. . . . . . . . after tank closure, have been briefly addressed in this report. Long-term research needs and other broader issues related to institutional manage- ment, such as the problem of data storage, are addressed in a more comprehensive two-phase NRC study entitled Long-Term Institutional Management of U.S. DOE Legacy Waste Sites (NRC, 2000d). Finally, there are many questions related to the proposed HLW repository. These issues are the territory of DOE's Office of Civilian Radioactive Waste Management (OCRWM), not the EM; therefore, they are beyond this statement of task and are not addressed in this report. Committees Methodology During this study, the committee met six times to gather informa- tion, review relevant literature, and develop this report. DOE and its contractors fully cooperated with the committee during the three infor- mation-gathering meetings and follow-up questions on the four major HLW sites in the country (the Hanford Site, the Savannah River Site, the Idaho Engineering and Environmental Laboratory, and the West Val ley Demonstration Project). The committee also visited the Hanford Site and the Savannah River Site. The list of briefings received during the open-session meetings is reported in Appendix F. Relevant literature reviewed by the committee included previous NRC reports focusing on the EMSP (NRC, 1997a, 2000a) and on HLW management at DOE sites (N RC,1999a,1999b, 2000b). In recom- mending research topics, the committee considered the EMSP basic 3This report is expected in Fall 2002. n t r o d u c t i o n
research program plan (DOE-EMSP, 2001 ) in relation to the agendas of more applied research and development activities encompassed by other H LW-re I ated research programs with i n the EM. The com m ittee also considered research activities in HLW management taking place in foreign countries. At the halfway poi nt of th is study, the committee released an i nteri m report, reproduced in Appendix A, to address selected issues meriting early attention and action by the EMSP during the preparation of a request for proposals (REP) for HLW-related research. The main findings and recommendations from Appendix A are included in the body of this report. DOE's Office of Science (SC), in collaboration with EM, published the RFP in January 2001 (Federal Register, 2001 ) and both offices were reviewing the proposals received when this report was released. Since the interim report, the committee gathered additional information and approached HLW cleanup issues from a broader per- spective to fully address the statement of task. Organization of This Report Chapter 2 presents an overview of HLW management challenges at DOE sites. Chapters 3 through 6 identify issues and research needs in the HLW management process areas (waste characterization, retrieval, pretreatment,4 immobilization, tank closure, and other long-term issues). Chapter 7 addresses the issue of technological risk, and pro- vides some programmatic considerations for the EMSP research portfo- lio. Chapter 8 presents a summary (in Table 8.1 ) of the long-term basic research needs, listed according to their objectives and respective process areas. Table 8.1 indicates whether the purpose of the research activity is to provide contingency approaches or to improve process effectiveness. The table also indicates whether each research activity addresses "already identified" or "future potential" problems. 4Waste pretreatment (see Chapter 4) consists of a series of processes to sepa- rate constituents that are radioactive, hazardous, or detrimental for the immobi- lization step from the bulk of the waste. H ~ G H - L E V E E W A S T E 12
