Technology Insights and Perspectives for Nuclear Fuel Cycle Concepts

Abstract

This report characterizes fuel cycle options in four areas -resource utilization, radioactive waste, fuel cycle safety, and proliferation resistance and physical protection. Graphs and tables provide insights regarding which features of a fuel cycle option most impact performance for a given characteristic. For example, some characteristics are insensitive to reactor technology but very sensitive to whether and what is recycled. Sometimes it is variations within a class of options that matter. For still other characteristics, the pattern is that a feature impacts performance only under certain situations and is irrelevant in others.Resource utilization: The utilization of uranium ranges from <1% for all thermal reactor concepts, up to ~10% for fast reactors with no fuel recycle, and approaching 100% for sustained recycle with fast reactors. The patterns for utilization of thorium are less clear due to less study of option space.Radioactive waste: There are many possible ways to reduce radiotoxicity and/or the mass of waste streams having both high-heat and high long-term radiotoxicity. The combination of decay heat and radiotoxicity complicates waste disposal and there is no international precedent for disposal of waste that has both high decay heat and high long-term radiotoxicity. The value of a given improvement method can range from very little to orders of magnitude depending on which other improvement methods are also used in a fuel cycle. For example, low processing loss of transuranic material to waste has little value in a single-recycle strategy but can have orders of magnitude impact in sustained recycle.Fuel cycle safety: Safety is too important to ignore during concept selection and development. Historical experience suggests that some types of safety issues are easier to resolve in concept development, detailed design, and/or operation than others. "Easier" can mean lower design cost to add safety systems as a design goes from concept to details, fewer iterations and delays with regulators, easier operation, a more transparent safety case engendering higher trust, less chance for expensive changes during construction, less chance of expensive retrofitting during operation, etc. Co-location of facilities, e.g., separation and fuel fabrication, is one of the ways that the potential risk of future fuel cycles may be reduced. Although the radiological risk from transportation has been shown to be low, public concerns are high and any industrial transport involves common daily transportation risks.Proliferation resistance and physical protection: There are many perspectives in this area, but there is no tool and no single indicator that covers the entire area and all four stages from material acquisition, transportation, transformation of material, and weapon fabrication. Conflicting claims can be often be better understood if it is realized that each claim can be valid within its subset of the entire area. Technology Insights and Perspectivesiv September 30, 2010 SUMMARYThis report characterize...

A Game Theoretic Approach to Nuclear Safeguards Selection and Optimization

“…A FOM value cannot be calculated for chopped spent fuel (SF) pieces, as spent fuel has an infinite bare-sphere critical mass [87]. A value of 0.50 was assigned to SF pieces for the purposes of this work.…”

Framework For Human-Automation Collaboration: Proj

“…For example, there are a number of important technical differences, and associated advantages and disadvantages, in using sodium versus water as the primary coolant. Some of these differences are highlighted in Table 1, which was adapted from Bays et al (2010). Since the coolant in PRISM is chemically reactive, one key safety feature PRISM has that PWRs lack is the use of double-wall steam generator piping where sodium-potassium exchanges heat with water.…”

“…Further, the PRISM's design and coolant type differ from PWRs in that the PRISM design manages the core's fissile inventory such that there is very little excess reactivity available for power excursions to occur. The sodium coolant has a high heat capacity that makes high-power-density cores feasible and facilitates a very slow thermal response (Tester et al, 2005;Bays et al, 2010). Figure 1 below provides high-level conceptualizations of PWRs and PRISM displaying the similarities and key differences between these two reactor types.…”

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