Impact of ceramic coating deposition on the tritium permeation in the Japanese ITER-TBM

An effective coating for a tritium permeation barrier was developed by a chemical densified coating (CDC) method. This will help realize a reasonable design of the Japanese Test Blanket Module (TBM) of the International Thermonuclear Experiment Reactor (ITER). It was confirmed from results of tritium permeation experiments that the permeation reduction factor (PRF) of F82H steel with this coating reached about 300 at 600 °C. Furthermore, it was revealed by diffusion coefficient measurements that with this coating, diffusivity of deuterium is very low. With these measured tritium transport properties, a preliminary tritium permeation analysis was carried out for the Japanese ITER-TBM. It was indicated that tritium permeation through the F82H cooling pipe with the coating will be four orders of magnitude smaller than that without the coating.