Studies and Developments of Tritium Recovery System for Blanket of Fusion Reactor in Japan Atomic Energy Agency

A water cooling solid breeder blanket is a prime candidate of the blanket of the fusion reactor in Japan. In this case, the blanket tritium recovery system will be composed of three processes: tritium recovery from the helium sweep gas as hydrogen, that as water vapor and tritium recovery from the coolant water. For these processes, the present authors have proposed a set of advanced systems, and have proved that the proposed systems would be feasible for a DEMO reactor. For tritium recovery as hydrogen, an electrochemical hydrogen pump with a ceramic proton conductor has been proposed. In this work, the correlation between the proton concentration in the ceramic and the hydrogen pressure in the gas phase has been investigated to describe the proton conductivity specifically. A ceramic electrolysis cell has been proposed to process the tritiated water vapor. In this work, the present authors have developed a new electrode that contained the cerium oxide, and it has shown a fairly large current density. For tritium recovery from the coolant water, the reduction of the processing water by tritium concentration is necessary. The present authors have studied about the fixed-bed adsorption process of synthetic zeolite, and the development of the adsorbent that can desorb water vapor easily is required. In this work, the effect of the silica/alumina ratio of the adsorbent on the separation factor was examined. NaY10.0 (faujasite-type, silica/alumina=10.0) showed quite unique characteristics for the water adsorption and desorption.