Comparison of Inelastic Response of Type 316 Stainless Steel and HT-9 Materials on the Fusion Reactor First Wall

An analysis based on available materials property data has been performed to compare the inelastic response of first-wall structural materials. The first wall is assumed to be operated under the conditions of the pulse surface heat load, coolant pressure, and bombardment from energetic particles. An axisymmetric inelastic stress analysis calculates the long-term redistribution of the stress in a thin-walled plate element of a cylindrical module that is subjected to membrane load. The plate is free to expand but is constrained from bending. The redistribution is caused by inelastic deformation from irradiation creep and swelling. The present effort has concentrated on the performance of two candidate structural materials, namely, Type 316 stainless steel and HT-9 ferritic steel. The results obtained indicate a lower cyclic stress and a lower mean stress for the HT-9 ferritic steel than for stainless steel under the conditions of interest. Therefore HT-9 ferritic steel is quite attractive for future application of the fusion reactor first wall.