Radiochemical characteristics of tritium to be considered in fusion reactor facility design

Ohira, Shigeru; Hayashi, Takumi; Shu, Wataru; Yamanishi, Toshihiko

Radiochemical characteristics of tritium, such as self-catalyzed reactions by beta decay in room temperature, radiolysis, decay to helium in metal, etc., to be considered in a D-T fusion reactor facility design are reviewed with some practical examples taken into account into the systems of ITER. Tritium used in a D-T fusion reactor has varieties of chemical form besides elemental form, e.g. water, hydride, hydrocarbons, etc. Such many faces of tritium shall be taken into account for process design, safety, accountancy and waste managements. Especially, in some process treating tritium of high specific activity, like that of exhaust gas produced when tritium recovery from the ITER vacuum vessel is carried out, that of water contaminated after ICE, such characteristics shall be considered for the design appropriately. Other topics, such as, utilization of calorimetric methods to measure decay heat for tritium accountancy will be presented with some future issues.