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8 Summary In Chapters 3 through 6, the committee identifies a significant list of research topics, summarized in Table 8.1, where the EMSP can make a significant contribution in addressing HLW cleanup problems through its long-term basic research activities. The motivation driving the selec- tion of research activities is to provide contingency approaches and to improve process effectiveness, as explained below: Providing contingency approaches. The purpose of the recom- mended research activities is to reduce technological risk by focusing on potential problems that could disrupt the current EM-H LW management program. Part of the recommended research for waste pretreatment and immobilization are aimed toward this objective. Improving process effectiveness. The purpose of the recommend- ed research activities is to improve the effectiveness of the differ- ent HLW process areas (characterization, retrieval, pretreatment, immobi I ization, and tank closure). Research recommendations focus on better characterization methods for monitoring process functions, separation techniques to remove bulk non-hazardous material from the HLW streams, and methods to achieve higher waste loading in the immobilized waste forms. Table 8.1 summarizes the recommended long-term research activi- ties and identifies those providing contingency approaches and those improving process effectiveness. Some research activities could lead to both contingency approaches and process improvements. For instance, investigating the effect of crystal content in borosilicate glass is a con- tingency approach against problems with future waste streams but also could improve the effectiveness of the current immobilization process by increasing the waste loading. Table 8.1 also indicates whether the S u m m a r y 83

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TABLE 8.1 Summary of the ~ong-term basic research objectives where the EMSP can make significant contributions in accressing HEW cleanup problems. Time Scale Purpose of Research Objectives Identified Future Improved Long-Term Basic Research Problem Potential Contingency Process Objectives (where the EMSP can (affecting Problem Approach Effectiveness make significant contributions cleanup (the next (to reduce (to reduce in addressing HLW cleanup operations few technology risks,time, Process Area problems) now) decades) risks) end costs) Characterization Develop remote-sensing instruments X X (Chapter 3) Develop on-line or in situ instruments X X Improve solids-liquid separation methods X X X Retrieval and Improve underlying science and technology X X X pretreatment for sludge leaching operations (Chapter 4) Increase the efficiency of liquid X X X decontamination methods Immobilization Identify alternative immobilization media to X X (Chapter 5) overcome limitations of borosilicate-glasses Investigate the effect of increased crystal content X X X on the durability of the borosilicate glass matrix Improve phenomenological models to predict long-term leachability of various glass waste forms Evaluate advantages of using unreacted glass-forming chemicals versus premelted glass frit X X X X X Understand the mechanism offoaming in X X Joule-heated melter Mitigate effects of precipitation of noble metals X X and crystalline phases in Joule melters Improve Joule-heated melters to achieve X X X higher processing temperatures Develop alternatives to Joule-heated melting X X Tank closure and Develop highly innovative and effective retrieval X X X other long-term methods for removal of residual HLW from issues the tanks (Chapter 6) Develop highly innovative and effective retrieval X X X methods for removal of HLW materials from the pipelines Improve characterization of residual waste in tanks X X X Develop non-invasive near-field monitoring X X techniques Improve near-field containment methods X X through use of barriers aDetails can be found in the chapters indicated in parentheses. H I G H - L E V E L vv A s I t ~ A ~ 84

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recommended research addresses already identified or future potential problems. Some of the recommendations may address both types of problems. For instance, improving the characterization of residual waste . . . . . . . . . . . . s . prior to rank closure Is a problem that has been already identified by DOE. However, the first priority is to remove the bulk of the waste from the tanks, and only two tanks (see Chapter 6) have been closed so far. Nevertheless, this issue will become more pressing in the future, when retrieval of the bulk of the waste will be completed and the main task will be tank closure. Programmatic Considerations for the EMSP Research Portfolio In selecting long-term research topics for its portfolio, the EMSP should take into account technological risk and the following desired attributes. Examples and rationales for the recommendations are pro- vided in Chapter 7. Managing Technological Risk A technological risk in HEW management is the risk that existing technologies will fail to accomplish goals and performance require- ments set by environmental remediation policies or regulations. The EMSP can contribute to reducing technological risk by funding a basic research program focused on alternative processes and improved approaches to current baseline plans, as recommended in the foregoing chapters. It is important that the sites and EM collaborate to build research roadmaps identifying technological risk and including contin- gency approaches. Desired Attributes of the EMSP-H[W Research Portfolio In selecting projects for future proposal cycles, the committee rec- ommends consideration of the following attributes for the EMSP research portfolio: maintaining long-term vision, maintaining relevance, providing for contingencies, de ve lop ing working re la lion sh ips, a n d prioritizing objectives. S u m m a r y

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The committee recognizes that the EMSP cannot address all of the rec- ommended research areas equally in the next few years, nor can its portfolio acquire all of the recommended program attributes immedi- ately. However, the EM cleanup program is a planned multi-decade effort costing several billion dollars. Current plans to treat and dispose of HLW are fraught with technical uncertainties, and many of the planned treatment activities are first-of-a-kind efforts presenting enor- mous technical chal lenges. The recommendations in this report address contingency approach- es or improvements to the current HLW management baseline plans. The committee is aware of DOE's commitments and of the difficulties in implementing changes, both from a technology and regulatory point of view. However, given the long-term duration of this planned cleanup effort, it is expected that new technologies will emerge and that greater scientific understanding will be achieved in the next decades. The EMSP is the ideal setting in which to develop truly innovative approaches to the management of HLW in tanks and bins that could lead to scientific breakthroughs in the future. If a scientific break- through can help reduce risks, cleanup time, and costs, regulations can be revised accordingly and obstacles to implementing changes at the sites can be removed. In this respect, the EMSP is a small but vital ele- ment1 to the long-term success of the EM cleanup mission. This conclusion was also reached by the Ad Hoc Committee on Science and Innovation of the Environmental Management Advisory Board in EMAB (2001 ). H ~ G H - L E V E E W A S T E 86