MATERIALS ANALYSIS OF THE TITAN-I REVERSED-FIELD-PINCH FUSION POWER CORE

The operating conditions of a compact, high-neutron-wall-loading fusio n reactor severely limit the choices for structural, shield, insulator , and breeder materials. In particular the response of plasma-facing m aterials to radiation, thermal and pressure stresses, and their compat ibility with coolants are of primary concern. Material selection issue s are investigated for the compact, high mass-power-density TITAN-I re actor design study. In this paper the major findings regarding materia l performance are discussed. The retention of mechanical strength at r elatively high temperatures, low thermal stresses, and compatibility w ith liquid lithium make vanadium-base alloys a promising material for structural components. Based on limited data, the thermal creep behavi our of V-3Ti-1Si and V-15Cr-5Ti alloys is approximated using the modif ied minimum committment method. In addition, the effects of irradiatio n and helium generation are superimposed on the creep behavior of V-3T i-1Si. Coolant compatibility issues are investigated. The liquid lithi um compatibility of the two vanadium alloys, V-15Cr-5Ti and V-3Ti-1Si, are compared, and the latter was chosen as the primary structural-mat erial candidate for the liquid-lithium-cooled TITAN-I reactor. Electri cally insulating materials, capable of operating at high temperatures are necessary throughout the fusion reactor device. Electrical insulat or-material issues of concern include irradiation induced swelling and conductivity. Both issues are investigated and operating temperatures for minimum swelling and dielectric breakdown strength are identified for spinel (MgAl2O4).