Polymer oxidation mechanisms by thermal and radiation ageing for cables in nuclear power plant

Seguchi, Tadao*; Tamura, Kiyotoshi; Shimada, Akihiko; Idesaki, Akira; Oshima, Takeshi; Kudo, Hisaaki*

The degradation mechanisms of polymer materials as PE, EPR for cable insulations in a nuclear power plant were studied by accelerated thermal and radiation ageing. The contribution of stabilizers to polymer degradation was investigated by the measurements of oxidation products, content of stabilizers, and also mechanical properties. It was found that an antioxidant among the stabilizers was very effective to decrease the thermal oxidation but less effective to the radiation induced oxidation. The content of the antioxidant decreases by evaporation during thermal ageing and by decomposition with dose during radiation ageing. The new degradation mechanisms in polymer ageing are proposed.