Design study of micro-fission chamber for ITER

Ishikawa, Masao; Kondoh, Takashi; Nishitani, Takeo; Kusama, Yoshinori

The microfission chambers provide time-resolved measurements of the global neutron source strength and fusion power from ITER. So far, the microfission chamber for low power operation (measurement range : fusion power of 100 W - 1 kW) has been designed and developed together with that for high power operation (measurement range: fusion power of 1 kW - 1 GW). In this design work, the placing route of the MI cables from the installation position of the microfission chamber to the feed-through in the upper port is designed. As far placing of the MI cable, since the MI cable is filled with Ar gas at 14.6 atom, the double pipe structure that the outer pipe covers the MI cable is adopted in order to prevent the gas leak into the vacuum vessel. The exhaust system of the double pipe is also designed for detection and exhaust of the leaked Ar gas.