A Water cooled Lead Ceramic Breeder blanket for European DEMO

Abstract

The development of a demonstration fusion power plant (DEMO) is widely considered a crucial step beyond ITER leading toward fusion electricity. In a viable DEMO plant two major functions have to be achieved, namely to breed tritium for fuel self-sufficiency and to extract high-grade heat to allow an efficient electricity production. The breeding blanket is the key component to ensure these two functions. The solid breeder blanket is considered in the design of several ITER Test blankets and DEMO breeding blankets. In Europe, the helium cooled solid breeder blanket, so-called Helium Cooled Pebble Bed (HCPB) blanket, is one of the two driver blanket candidates selected for the European DEMO. In spite of the considerable progress and achievements, several potential issues inherent to the choice of the neutron multiplier and coolant remain with this concept. To overcome these challenges, research activities on an innovative concept (a Water cooled Lead Ceramic Breeder - WLCB), in which Lead/Lead-alloy is used as neutron multiplier, ceramic pebbles as tritium breeder, pressurized sub-cooled water as coolant, are on-going. This concept avoids the potential safety issue (exothermic hydrogen-producing Be-water reaction or PbLi-water reaction in case of water leakage) when Beryllium/Beryllide is used as neutron multiplier or lithium lead is used tritium breeder in a water cooled blanket concept. The neutronics, thermal hydraulics and mechanical performance figures of the above-mentioned innovative blanket concept are presented. This work concludes with possible future work and outlook towards the development of innovative alternative blanket concepts for the European demonstration fusion power plants.