Radiation Damage in Liquid-Protected First-Wall Materials for IFE-Reactors

Material damage through displacements per atom (DPA) and helium gas production, as well as the tritium breeding and energy absorption in an IFE (Inertial Fusion Energy) reactor chamber have been investigated with variable coolant zone thickness using different liquids. Examples are given for HYLIFE-II (an IFE reactor design) energy conversion chambers using Flibe (Li₂BeF₄), natural lithium and Li₁₇Pb₈₃ cutectic as both coolant and wall protection. To achieve a useful energy density for energy conversion purposes with sufficient tritium breeding (TBR= 1.1), material protection (DPA < 100 and He < 500 appm in 30 years of operation) and shallow burial criteria, coolant zone thickness values are found to be 56 cm for Flibe, 160 cm for natural lithium and 170 cm for Li₁₇Pb₈₃ with SS-304 as structural material.

Material damage investigations are extended to structural materials made of SiC and graphite for the same blanket. DPA values and He production rates in graphite turn out to be comparable to those in SS-304. However, they are higher in SiC, as compared to SS-304 and graphite.