Irradiation Effect on the Interface of the Composites Used as the Insulation Materials in the Nuclear Fusion Reactor

In ITER (International Thermonuclear Experimental Reactor), the insulation materials containing polymeric matrix are the most radiation-sensitive among the materials constituting the superconducting magnet in the nuclear fusion reactor. Insulation materials are fabricated by impregnating the polymeric material into the stacks of alternating layers of polyimide films and glass cloth. There are a lot of studies about irradiation property of each constituent material, whereas few studies are reported about the irradiation effect on the resin -glass cloth and the resin –polyimide film boundary. In this study, we focused on the degradation of the resin-glass cloth boundary. The influence of the surface treatment and the weaving density of the glass cloth on the boundary degradation was evaluated by the mechanical properties before and after irradiation. The composite material specimens were prepared using the glass cloth with different surface treatment, and with different weaving density. The inter laminar shear strength (ILSS) test was conducted to examine the influence of the boundary on the radiation effect. In addition, the fracture mechanism were evaluated by optical micro-scope. Based on the results, it was indicated that the weaving density of the glass cloth is small influence on the irradiation effect and the radiation resistance was improved by the surface treatment.