New monitoring by thermogravimetry for radiation degradation of EVA

• Radiation degradation of EVA cable jacket was tested by dynamic and isothermal TGA.
• Thermal stability of degraded EVA cable measured by TGA depends on access of oxygen.
• The larger the dose absorbed, the higher the thermal stability of EVA jacket observed.

The radiation ageing of ethylene vinyl-acetate copolymer (EVA) as the jacket of cable applied in nuclear power plant was carried out by gamma rays irradiation, and the degradation was monitored by a thermo-gravimetric analysis (TGA). The EVA decomposition rate in air by the isothermal at 400 °C decreased with increase of dose and also with decrease of the dose rate. The behavior of EVA jacket of cable indicated that the decomposition rate at 400 °C was reduced with increase of oxidation. The elongation at break by tensile test for the radiation aged EVA was closely related to the decomposition rate at 400 °C; therefore, the TGA might be applied for a diagnostic technique of the cable degradation.