Study on life estimation of cable insulation by gas evolution and oxygen consumption during radiation and thermal aging

Ethylene-propylene rubber (EP rubber), as cable insulating material used in Japanese domestic nuclear power plants, is exposed to γ-rays, and aged in an oxygen atmosphere. Oxygen consumption and CO₂ evolution during γ-radiation and thermal aging are measured by gas chromatography. Elongation at the break of aged EP rubber is found to be related to oxygen consumption and CO₂ evolution during the degradation, and is scarcely affected by radiation dose and temperature. These O₂ and CO₂ measurements may be useful to estimate quantitatively the degree of polymer degradation