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Abstract
Two metal fueled sub-critical fast reactor concepts, cooled by PbLi and PbBi, respectively, for a Fusion Transmutation of Waste Reactor (FTWR) were developed. Heat removal, radiation damage, etc. design constraints were applied to the FTWR to ensure a realistic and credible design. The standard linear stability model for critical systems was extended for evaluation of the linear stability of sub-critical systems, and the FTWR was shown to be stable to power excursions even when substantial positive fuel and coolant temperature coefficients exist. The reactor design concepts were calculated to remain subcritical for a wide range of off-normal conditions.
Fuel cycle analyses were performed to evaluate the impacts of further transmutation of spent nuclear fuel on high-level and low-level waste mass flows into repositories, on the composition and toxicity of the high-level waste, on the capacity of high-level waste repositories, and on the proliferation-resistance of the high-level waste. Storage intact of LWR spent nuclear fuel, a single recycle in a LWR of the plutonium as MOX fuel, and the repeated recycle of the transuranics in critical and sub-critical fast reactors are compared. Sub-critical reactors based on both accelerator and fusion neutron sources were considered.
The overall conclusions are that repeated recycling of the transuranics from spent nuclear fuel would significantly increase the capacity of high-level waste repositories per unit of nuclear energy produced, significantly increase the nuclear energy production per unit mass of uranium ore mined, significantly reduce the radio-toxicity of the waste streams per unit of nuclear energy produced, and significantly enhance the proliferation-resistance of the material stored in high-level waste repositories.
