Lead-Cooled Breeders and Burners - Are the Latter Even Necessary?

This paper compares neutronics, transuranic burning capabilities and safety aspects of lead-cooled self-breeders and burners employing uraniumand thorium-based fuels. Both fast reactors are optimized with respect to minor actinide (MA) transmutation performance in the start-up cores. The Monte Carlo code MCB is used for the neutronic and burn-up analyses; accidental behavior is studied by EAC-2 and STAR-CD codes. We show that lead-cooled fast reactors (LFRs) can be used both as breeders and burners of transuranics from spent LWR fuel and that minor actinides are incinerated in self-breeder cores nearly as effectively as in dedicated critical burners. In optimized 600 MWe LFR self-breeders about 100 kg of MAs can be transmuted per year. This corresponds to an annual production of minor actinides in two EPRs. We demonstrate that the same reactor (self-breeder) can be used for breeding only or for breeding combined with MA burning, depending on the core load composition. Regarding safety, LFRs feature favorable characteristics in coping with investigated accident initiators (unprotected Loss-of-Flow and Loss-of-Heat Sink). The reasons are good natural circulation behavior together with the high boiling point of the lead coolant.