Design of Limiter for a fusion demo reactor

Kudo, Hironobu; Watanabe, Kazuhito; Hiwatari, Ryoji; Asakura, Nobuyuki; Tokunaga, Shinsuke; Someya, Yoji; Nozawa, Takashi; Tanigawa, Hiroyasu

In a fusion demo reactor, a rump-up scenario of the plasma is studied. The plasma is growing up and contacting on the first wall surface (limiter-phase) before shifting to diverter phase. Heat load of this time is a transient thing of the dozens seconds. However, it is bigger than the heat load which the first wall receives at the steady state. Therefore there are two idea to be taken with a demo reactor for this heat load. One is that addition a function of limiter to blanket oneself. Another one is design limiter as the independent structure. It is necessary to finally compare the superiority and inferiority of both in TBR (Tritium Breeding ratio) influenced by thickness of the surface tungsten layer and occupation area. This study perform conceptual design of independent limiter.