Multiscale analysis of the radiooxidative degradation of EVA/EPDM composites. ATH filler and dose rate effect

This study is focused on the radiooxidative degradation of polymeric insulation of electric cables used in Nuclear Power Plants (NPPs). In order to investigate the degradation mechanisms of the insulation, model composites with ATH (Aluminium TriHydrate) filler and blends (without filler) based on a cross-linked mixture of EVA (Ethylene Vinyl Acetate) and EPDM (Ethylene Propylene Diene Monomer) were submitted to gamma-rays. In normal operating conditions of a NPP, the dose rate which electric cables are exposed to is around 0.1Gyh−1. In this work, artificial accelerated ageing test process has been applied at a relatively low dose rate of 7Gyh−1. Gamma-irradiations at higher dose rates typically used to accelerate the ageing, in the range 0.2–1kGyh−1, were also carried out.