Mo is considered as a candidate for plasma facing materials, because tritium inventory in Mo is small as Mo has small hydrogen solubility, and the melting point is high. In this study, hydrogen isotopes retention behavior in Mo was studied using Tritium Beam Test System (TBTS), where a beam hydrogen isotopes, including tritium, was irradiated at room temperature, followed by the thermal desorption spectroscopy (TDS) measurements.
According to the results, the hydrogen isotopes retention in Mo was observed to increase as the molecular weight decreased. Further comparison showed that the retained amount of protium (H) tended to saturate at lower fluence than deuterium (D). On the other hand, the retention of deuterium at an irradiation temperature of 400K tended to saturate at lower fluence than that of room temperature.