Improving the Scientific Basis for Managing DOE's Excess Nuclear Materials and Spent Nuclear Fuel (2003) / Chapter Skim
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4 Spent DOE Nuclear Fuel
4 Spent DOE Nuclear Fuel
Pages 43-51
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From page 43... ...
The inventory also includes irradiated fuel and targets assemblies that were placed in storage when DOE stopped reprocessing nuclear fuel for production purposes in 1992. Altogether there are over 250 different fuel types that have different enrichments, fissile materials, cladding, and geometries (DOE, 2000c)
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From page 44... ...
Because DOE has only recently begun to prepare a license application for Yucca Mountain, significant uncertainty exists in what the waste acceptance criteria will be for many of the categories of DOE spent fuel. Commitments for waste form characteristics made during the 3Quantities of nuclear fuel are reported in terms of the mass of heavy metals, principally uranium but in some cases including plutonium, used in their fabrication.
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From page 45... ...
TOTAL 2,470 99.8 Source: Duguid et al., 2002; BSC, 2001. Yucca Mountain licensing phase will affect the accuracy required for characterizi ng the spent fuel isotopic and chemical composition prior to waste acceptance and the nature of any spent fuel conditioning that will be required.
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From page 46... ...
The different characteristics affect the spent fuel's chemical stability and potential for gas generation, the decay heat generation and the potential for thermal damage under different storage and accident conditions, the potential for inadvertent nuclear criticality, the potential doses for workers, and the attractiveness of the material for theft. Assessments are further hampered when current instruments and records are inadequate to characterize the chemical and isotopic composition of the fuel sufficiently.
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From page 47... ...
The fissioning or "burnup" of DOE SNF is lower but much more variable than that of commercial SNF, for which maximizing burnup for energy production is important economically. While the technical challenges of removing decay heat are thus lower, thermal safety analysis requires accurate characterization of the isotopic composition of the spent fuel.
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From page 48... ...
A previous committee provided research recommendations to the EMSP for improving sensor technology and remote monitoring techniques (NRC, 2002~. Research Needs and Opportunities The Environmenta/ Management Science Program should support research to help ensure safe and secure storage and disposal of DOE SNF.
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From page 49... ...
Because such dry reprocessing methods are incapable of separating plutonium and curium, the method allows accurate tracking of the plutonium inventory (Greenspan et al., 1998~. Stability in Storage For spent fuels of relatively low chemical stability, such as DOE aluminum-clad fuels, some conditioning is likely to be needed to ensure that they remain stable enough to meet safe storage requirements until they can be emplaced in a disposal facility (NRC, 1998~.
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From page 50... ...
Research to further develop lower-temperature reprocessing options, where the spent fuel is dissolved in a molten salt or an aqueous solution, and separate streams of well-characterized materials are created, may help to address the specific issues of high enrichment and low cladding chemical stability that distinguish many DOE spent fuels from commercial spent fuel. There are opportunities for collaboration with the new DOE Advanced Fuel Cycle Initiative (AFCI)
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From page 51... ...
Such research will need to be integrated with ongoing repository licensing processes, to develop approaches to meet the waste acceptance criteria as these emerge, and to provide feedback to defining the waste acceptance criteria so these criteria do not inadvertently exclude materials for reasons that are not justified from the perspective of safety. Examples of appropriate research in this area could include the development of less soluble neutron poisons, and model ing of the interactions between spent nuclear fuel and waste glass if they are to be co-disposed in a single waste container.
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