Study on tritium accountancy in fusion DEMO plant at JAERI

Tritium accountancy in the fusion DEMO plant has been studied at JAERI. Tritium accountancy is indispensable from the viewpoints of safety and plant operation because of the large amount of tritium used as fuel. DEMO is the quasi-steady continuous operation machine to demonstrate the feasibility of a fusion reactor as a commercial power production machine and it has functions of power production and tritium breeding. In addition to the basic accounting techniques for large amount of tritium in the tritium plant of the fusion system, which will be established in the ITER project, it is necessary to establish accounting techniques for tritium consumption and production. Dynamic accounting techniques have to be much improved or developed for optimum and safe control of the continuously operating fuel system of DEMO.