Dielectric strength of irradiated fiber reinforced plastics

The insulation system for the toroidal field model coil of international th ermonuclear experimental reactor is a fiber reinforced plastic (FRP) lamina te, which consists of a combined Kapton/R-glass-fiber reinforcement tape, v acuum-impregnated with an epoxy DGEBA system. Pure disk-shaped laminates, d isk-shaped FRP/stainless-steel sandwiches, and conductor insulation prototy pes were irradiated at 5 K in a fission reactor up to a fast neutron fluenc e of 10(22) m(-2) (E > 0.1 MeV) to investigate the radiation induced degrad ation of the dielectric strength of the insulation system. After warm-up to room temperature, swelling, weight loss, and the breakdown strength were m easured at 77 K. The sandwich swells by 4% at a fluence of 5 x 10(21) m(-2) and by 9% at 1 x 10(22) m(-2). The weight loss of the FRP is 2% at 1 x 10( 22) m(-2) The dielectric strength remained unchanged over the whole dose ra nge. (C) 2001 Elsevier Science B.V. All rights reserved.