Effect of Gamma-ray Irradiation on Ageing of LDPE Micro/Nanocomposites Estimated by DCIC Method

With the rapid development of nuclear power technology, the safety of electrical equipment in nuclear power plants (NPP) has received widespread attention. NPPs are exposed to extreme environments with gamma-ray irradiation for long periods, which can lead to the deterioration of insulation. In order to ensure the safe and stable operation of NPPs, it is necessary to accurately evaluate the ageing status of cable insulation. The direct current integral charge (DCIC-Q(t)) method is a non-destructive detection method that can evaluate the degree of charge accumulation in materials. In this paper, the LDPE and LDPE/BN/TiO
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composites were prepared and irradiated with gamma-ray at different total doses. The charge characteristics of LDPE and composites were investigated based on the DCIC-Q(t) method. The ratio of charges was proposed as a basis for judging the irradiation ageing state of the materials. The changes in the microstructure of the materials before and after ageing were analyzed using Fourier Transform Infrared (FTIR), and the correlation between Q(t) and microstructure was established. The results showed that with the increase of irradiation dose, the charge ratio of LDPE showed a trend of slight increase and then rapid increase; the composites with added micro-nanoparticles can inhibit the injection and accumulation of charge.