The Materials Impact on Fusion Reactor Safety

Seven potential safety concerns for deuteriumtritium fusion reactors were examined and the influence of blanket material choice determined. This influence was quantified in terms of relative consequence indices (RCIs) according to prescribed consequence criteria. Selected combinations of structural material (Type 316 stainless steel, HT-9, vanadium alloy, or TZM), primary coolant (pressurized water, helium, lithium, or flibe), and tritium breeder (LiAlO₂, lithium, or Li₁₇Pb₈₃) were examined. The analyses and indices were structured to focus on the specific material properties that influence the results, which allows for comparison of materials not included in the present study. The safety concerns that were found to be relatively insensitive (differing by less than an order of magnitude) to material choice are the rate of temperature increase from continued plasma heating following loss of coolant and electromagnetic effects of plasma disruptions. The range of the RCIs was about an order of magnitude for problems concerning after-heat removal, corrosion, and the thermal effects of disruptions. The following problems were found to range in severity over several orders of magnitude according to material choice: potential public health effects from radioactivity release, rapid structural oxidation, blanket chemical combustion, and coolant pressurization.