Radiation resistance of insulating material for ITER superconducting coil; Gas evolution

Idesaki, Akira; Gokan, Mayo*; Morishita, Norio; Oshima, Takeshi; Koizumi, Norikiyo; Sugimoto, Makoto; Okuno, Kiyoshi

A laminated material composed of glass cloth/polyimide film/epoxy resin will be used as an insulating material for superconducting coil of ITER. In order to keep safe and stable operation of the superconducting coil system, it is indispensable to evaluate radiation resistance of the material, because the material is exposed to high radiation field of 10MGy at low temperature of 4K. In this work, the gas evolution from the laminated material by ray irradiation at liquid nitrogen temperature (77K) was investigated, and the difference of gas evolution behavior due to difference of components in the epoxy resin was discussed. As a result, it was found that the main gases from the epoxy resin by the irradiation were hydrogen, carbon monoxide and carbon dioxide, and that the amount of the gases from epoxy resin containing cyanate ester was 30-40% less than that from the epoxy resin containing tetraglycidyl-diaminophenylmethane (TGDDM).