Ageing Analysis of Power Cable used in Nuclear Power Plant

The aim of nuclear power plant ageing management and assessment is to maintain an adequate safety level throughout the life time of the plant and helps in determining the useful operation. Various factors involved in the insulation of polymeric cables such as continuous heat, radiation and atmosphere result in the alteration of chemical and physical properties as well as lowers the service life of material. PVC (Poly Vinyl Chloride) is the most commonly used insulation material in NPP (Nuclear Power Plant). Purpose of this work is to predict the service life of PVC insulation cable for which extrapolation ageing has been performed. Ageing mechanism proceeds in laboratory scale rig to provide temperature and radiation sources. The variation in temperature is regulated and monitored through thermocouple. At higher temperature, semi crystalline free radical may escape out resulting in the degradation of polymer. Different tests have been carried out like shore hardness testing, tensile testing, Differential Scanning Calorimeter and Thermo gravimetric Analysis before and after ageing to analyze the Ageing effect. The impact of ageing days upon yield strength of single stress ageing has been carried out in this research work and it is found that aging has significant effect on service life of cables used in power plants.