A First Simulation Study of Hydrogen Isotope Accumulation and Diffusion in Tungsten First Wall of HiPER Inertial Fusion Facility

The study of the retention and desorption of hydrogen isotopes and helium atoms in first-wall materials is key for the design of future fusion reactors, not only for the effect of the materials on the degradation of the wall properties but also for the implications in tritium management strategies. A diffusion model of the implanted H, D, T, and He species in a 1-mm-thick first wall of tungsten for the two initial phases of the proposed European laser fusion project HiPER (namely, phases 4a and 4b) has been implemented using the tritium migration analysis program TMAP7. The effects of the abrupt temperature increases, working temperatures, and the operational pulsing modes on the diffusion are studied. Although a detailed treatment of the different trapping mechanisms has been omitted, meaningful quantitative results on the accumulation, desorption, and time intervals to reach a stationary state are presented and discussed.