Search for reality of solid breeder blanket for DEMO

For a tokamak fusion DEMO reactor with the fusion output of 2.95 GW, neutronic and thermal design of blanket is under way to find a feasible blanket concept. For the continuity with the Japanese ITER-TBM options, this study considered water-cooled blanket with solid breeding materials of Li ceramics (Li4SiO4, Li2TiO3 and Li2ZrO3) and Be multipliers (Be and Be12Ti). Based on a neutronics-heat coupled analysis, the tritium breeding ratio was evaluated so as to satisfy constraints of the operating temperature of ≤900 °C for Li ceramics and Be12Ti, and ≤600 °C for Be. Cooling water condition was assumed to be 23 MPa and 290–360 °C. The result indicates that surplus tritium production in lower neutron wall load (Pn) blanket compensates a shortfall in higher Pn blanket and thus the overall tritium production can marginally satisfy fuel self-sufficiency.