Evaluation of Tritium Permeation in Solid Breeder Blanket Cooled by Supercritical Water

As a part of design study of candidate DEMO blanket in Japan, evaluations of tritium permeation in solid breeder blankets cooled by supercritical water was performed. The evaluations were performed under detail design of the blankets with nuclear and thermal analyses. F82H was selected as the structural material and the temperature of cooling tubes in the tritium breeder zone was evaluated between 673K and 783K. In this temperature range, tritium permeation rate through the cooling tubes in tritium breeder zone was evaluated and also tritium permeation into the first wall cooling water by the implantation of tritium particle was evaluated. In addition, requirements for preventing tritium permeation into the cooling water have been examined.