Combustion Characteristics of XLPE-Insulated Cables in Nuclear Power Plants

Strategic Insights -

Research at the China University of Mining and Technology Beijing has revealed critical insights into the combustion characteristics of XLPE-insulated cables used in nuclear power plants. The study employed a cone calorimeter to measure the combustible properties of the cables and introduced Pearson correlation analysis to evaluate the relationships among the combustion characteristic parameters. The research was supported by the Science and Technology Program of State Grid Jiangsu Electric Power Co., Ltd. The findings indicate that thermal and non-thermal risks associated with the cables increase with rising external heat flux, and the Time to Ignition (TTI) is significantly influenced by the cable's refractory properties.

Key Takeaways:

  • The study focused on XLPE-insulated cables used in nuclear power plants, measuring their combustion characteristics using a cone calorimeter.
  • Pearson correlation analysis was innovatively introduced to evaluate the relationships among the combustion characteristic parameters.
  • The research indicates that 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.
  • 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.

Statistics:

  • The TTI at a radiant heat flux of 25 kW m-2 is approximately five times greater than that at 50 kW m-2.
  • The TTI at a radiant heat flux of 50 kW m-2 is approximately ten times greater than that at 75 kW m-2.
  • The HRR peak demonstrates a strong positive linear relationship with radiant heat flux.
  • The MLR demonstrates a strong positive linear relationship with heat release rate.
  • The number of conductors in the cable influences the HRR, with more conductors resulting in lower HRR.

Sources:

  • Combustion Characteristics Analysis of Cross-linked Polyethylene(Xlpe) Insulated Cable Used In the Nuclear Power Plant. Journal of Thermal Analysis and Calorimetry, 2025.
  • Springer, Van Godewijckstraat 30, 3311 Gz Dordrecht, Netherlands. (www.springer.com; www.springerlink.com/content/1388-6150/)
  • Peng Chen, China University of Mining and Technology Beijing, Sch Emergency Management & Safety Engn, Beijing 100083, People's Republic of China.