Nuclear aspects of a solid wall blanket based on advanced ferritic steel and re-circulating Flibe

Nuclear analysis was performed for a solid wall blanket concept that uses the nano-composited ferritic (NCF) steel alloy 12YWT as structural material with Pb as the neutron multiplier and Flibe (Li₂BeF₄) as the tritium breeder and coolant. With an enrichment of 40% ⁶Li the overall tritium breeding ratio is expected to be ∼1.16 and the blanket energy multiplication is 1.13. The peak structure dpa and helium production rates are 77.6 dpa/FPY and 955 He appm/FPY, respectively, implying a lifetime of ∼3 FPY. The NCF structure dominates the total activity and decay heat. The Mo content in the NCF needs to be reduced from 0.02% to <0.01% for the structure waste to qualify as low level class C waste.