Effects of irradiation dose rate and thermal aging on changes in the properties of elastomeric materials (EPR-CSPE) for cable insulation and sheathing

In order to estimate cable service life in PWR plants, a research program has been established and performed on EPR/CSPE (ethylene-propylene rubber/chlorosulfonated polyethylene) LOCA (loss-of-coolant accident) cables based on a study of the dose and dose rate effects and the temperature. The authors present the results of accelerated tests and physicochemical studies (IR, mechanical properties, oxidation (EPR), and chlorine (CSPE) stabilities) carried out to characterize the degree of degradation of the materials. EPR seems to be sensitive to the dose rate effect with oxidation at low dose rate and crosslinking at high dose rate. CSPE is degraded by crosslinking. For both EPR and CSPE, the activation energy of oxidation stability and dehydrochlorination, respectively, have been evaluated as a function of the thermal aging.<<ETX>>