Distinctive radiation durability of an ion exchange membrane in the SPE water electrolyzer for the ITER water detritiation system

The radiation durability of a Nafion® ion exchange membrane in the solid-polymer-electrolyte (SPE) water electrolyzer component of the ITER water detritiation system was investigated from various viewpoints. Nafion® is composed of a PTFE (polytetrafluoroethylene) backbone and side chains terminating with sulfonic acid. Nevertheless under the condition that polymer specimens are soaked in water, degradation of Nafion® by γ-ray irradiation differs significantly from that of PTFE. It is made clear that the durability of Nafion® is distinctively higher than that judged from its backbone structure. No serious damage was observed in the membrane properties up to ITER-WDS requirement (530 kGy).