Deuterium Retention in Tungsten-rhenium Alloy

Tungsten (W) is a candidate plasma facing material for fusion reactors. Irradiation by fusion neutrons will result in defect formation and transmutation to rhenium (Re). The presence of Re in W can change the solubility and diffusion properties of hydrogen isotopes, affecting tritium inventory in a fusion reactor. In this study, we focus on clarifying how Re affects the hydrogen trapping behavior by investigating the temperature dependence (300~700 K) of deuterium (D) retention behavior in undamaged W-Re samples. For W-Re (3% wt.) samples at T < 550 K, D-retention in W-Re alloy was one order of magnitude smaller than pure-W samples. At T > 550 K, D-retention was similar for both samples. Thermal desorption spectra suggest such differences arise from different penetration depths (i.e. diffusivity). We discuss whether such differences can be directly attributed to Re or arise due to microstructural differences.