Observation of tritium distribution in iron oxide with tritium micro autoradiography

Isobe, Kanetsugu; Hayashi, Takumi; Nakamura, Hirofumi; Kobayashi, Kazuhiro; Yamanishi, Toshihiko; Okuno, Kenji*

Tritium permeation is one of key issues from the viewpoint of safety and tritium cycle. The oxide formed on metal surface was reported to act as barrier for hydrogen permeation due to its characters, such as low diffusivity and low solubility of hydrogen. On the other hand, the tritium behavior in the oxide as well as the interface of oxide (oxide-metal, oxide-water) is not clarified. The tritium permeation through pure iron, which was coated with its oxide, into water has been studied. Although some characteristics of tritium permeation through the oxide were found, the permeation mechanism through the oxide has not been clarified yet. The tritium distribution in the oxide can give us useful information of tritium behavior in the oxide / oxide-interface and help to understand the mechanism of tritium permeation through the oxide. In the present study, tritium distribution in the iron oxide is observed with tritium micro autoradiography.