Influences of ^7Li enrichment on Th-U fuel breeding for an Improved Molten Salt Fast Reactor(IMSFR)

摘要

The molten salt fast reactor(MSFR) shows great promise with high breeding ratio(BR),large negative temperature coefficient of reactivity,high thermal-electric conversion efficiency,inherent safety,and online reprocessing.Based on an improved MSFR optimized by adding axial fertile salt and a graphite reflector,the influences of ~7Li enrichment on Th-U breeding are investigated,aiming to provide a feasible selection for the molten salt with high fissile breeding and a relatively low technology requirement for ~7Li concentration.With the self-developed molten salt reactor reprocessing sequence based on SCALE6.1,the burn-up calculations with online reprocessing are carried out.Parameters are explored including BR,^(233)U production,double time(DT),spectrum,~6Li inventory,neutron absorption,and the tritium production.The results show that the Li enrichment of 99.95% is appropriate in the fast fission reactor.In this case,BR above 1.10 can be achieved for a long time,corresponding to the ^(233)U production of130 kg per year and DT of 36 years.After 80 years' operation,the tritium production for 99.5% is only about 7kg,and there is no obvious increase compared to that for 99.9995%.