Combustion characteristics analysis of cross-linked polyethylene(XLPE) insulated cable used in the nuclear power plant

This study focuses on XLPE-insulated cables used in nuclear power plants. A cone calorimeter was employed to measure the combustion characteristics of the cables, and Pearson correlation analysis was innovatively introduced to evaluate the relationships among the combustion characteristic parameters. The results indicate that both thermal and non-thermal risks associated with the cables increase with rising external heat flux. The Time to Ignition (TTI) at a radiant heat flux of 25 kW m−2 is approximately five times greater than that at 50 kW m−2, and about ten times greater than that at 75 kW m−2. The TTI of the cables exhibits a linear correlation with their refractory properties. A strong positive linear relationship is observed between the peak of Heat Release Rate (HRR) and radiant heat flux, as well as between the mean of HRR and Mass Loss Rate (MLR). Both MLR and HRR demonstrate higher peaks and shorter times to peak under elevated heat flux conditions. Additionally, the sheath's physical properties significantly influence the cable's combustion characteristics; specifically, HRR decreases as the number of conductors in the cable increases and as the cable diameter expands. XLPE, when used as an insulating layer, provides superior flame retardancy compared to its use as a sheath.