Qualification of the resin for the ITER TF coil insulation

Abstract Fiber reinforced composites impregnated with mixtures of cyanate ester and epoxy resin demonstrated their excellent performance at the ITER design fluence and beyond. Slight modifications of the resin were necessary to extend the pot-life to more than 100 h due to the complexity of the coil structure. Two CE blends were supplied by Huntsman, Switzerland, and CTD, USA, according to the ITER TF coil specification, in order to be qualified for ITER. Sets of test samples were produced under exactly the same conditions. The insulation systems consist of a wrapped R-glass/polyimide reinforcement, vacuum impregnated with the cyanate ester/epoxy blends. The mechanical properties were characterized prior to and after irradiation to a fast neutron fluence of 2 × 10 22  m −2 ( E  > 0.1 MeV), i.e. twice the ITER design fluence, in tension and interlaminar shear at 77 K. In addition, tension–tension fatigue measurements were carried out in order to simulate the pulsed operation of ITER. The results show that the mechanical properties of both materials are hardly affected by neutron irradiation.