Breeding potential of candidate breeders for the US Demo power plant

The US Demo will utilize either liquid metal (LM) or solid breeder (SB) for tritium breeding. A prime goal for the breeder is to provide tritium self-sufficiency that ensures the self-sustaining operation of the Demo plant. Neutronics analysis have been performed for 20 breeders to examine their ability to breed tritium and multiply the neutron energy. A few promising LM (Li and Li₁₇Pb₈₃) and SB (Li₂O and Li₂TiO₃) were selected for further analysis to illustrate the impact on breeding of the candidate low activation structures (V, SiC, and FS) and neutron multipliers (Be, Be₂C, BeO, and Pb). Among the various breeders considered in the analysis, lithium provides the highest breeding followed by lithium lead, then Li₂O. The study has concluded that Li and Li₁₇Pb₈₃ have the potential for tritium self-sufficiency without a neutron multiplier. Solid breeders will most likely require a neutron multiplier to achieve net breeding in realistic designs. All structures degrade the breeding and enhance the energy multiplication, except SiC which degrades both. Vanadium has the least impact on the breeding of LM and SB, followed by FS and SiC, except for Li₁₇Pb₈₃. All multipliers significantly enhance the SB breeding, except BeO, and the SB energy multiplication, except Pb. Besides neutronics performance, other features of LM and SB will be key factors in selecting the Demo materials