Decontamination of candidate materials for ITER remote handling equipment exposed to tritiated moisture

To optimize tritium removal procedure, behavior on typical materials used in the key parts of the ITER remote handling equipment, has been studied. The samples used in this study were stainless steel 304 with three types of surface finish, aluminum alloy A-5052 with two types of surface finish, three types of O-ring and two types of carbon fiber reinforced plastic. After the samples were exposed in the tritiated moisture environment, the concentration of tritium adsorbed on the specimen was measured and the decontamination experiments using gas purges with three different moisture concentrations were performed. It is found that tritium does not adsorb on stainless much and oxide layer adsorbs significant tritium in Al alloy. The amount of tritium in rubber is found to relate with the permeability, solubility and tolerance for water vapor. In case of carbon fiber reinforced plastic, almost adsorbed tritium could not removed by gas purge.