Feasibility Studies on Plutonium and Minor Actinide Burning in Fast Reactors

Abstract

Systematic parameter studies were implemented to investigate the basic characteristics [plutonium and minor actinide (MA)-burning rate, burnup reactivity loss, Doppler coefficient, sodium void reactivity, maximum linear heat rate, etc.] of plutonium and MA-burning fast reactors and also to clarify the feasibility of such plutonium and MA burner fast reactors. Highly enriched mixed-oxide (MOX) fuels and plutonium fuels without uranium were consideredfor plutonium-burning enhancement. It was found that plutonium consumption rates essentially depend on plutonium enrichment. Both burnup reactivity loss and Doppler coefficient are important criteria for highly enriched MOX fuel cores. Cores without uranium were found to consume the plutonium at a very large burnup rate close to the theoretically maximum value of 110 to 120 kg/TW · h(electric). The introduction of UO2 in an internal blanket is effective in enhancing the Doppler coefficient; it causes a minor increase in the sodium void reactivity in nonuranium cores. The MA transmutation in a fast reactor core has no serious drawbacks in terms of core performance, provided that the homogeneous loading method can be employed with a small fraction of MA fuel (∼5 wt%). Fast reactors have a strong potential for burning plutonium and MA effectively.