Non-Destructive Condition Monitoring of Nuclear Power Plant Power Cables

The safety operation of nuclear power plants depends on an enormous amount of instrumentation, control and low voltage power cables. The environmental conditions in these plants are characterized by high temperature and gamma- radiations which affect greatly the insulating materials of these cables. Polymer materials are commonly used in the nuclear environment and they must function properly during the longterm operation time of the station and during the accident events such as loss of coolant accident. To extend the operation time of these plants, a nondestructive condition monitoring techniques must be applied to evaluate the condition of these cables. In this research work, a low voltage nuclear power plant power cable samples were thermally accelerated aged followed by a mechanical bending stress. The effect of these stresses was investigated by using the advanced voltage response method, extended voltage response. The extended Voltage response measurements incorporate both return voltage and decay voltage slopes. After each cycle of thermal stress and mechanical bending stress, these two slopes were measured and as a result, A decrease in the return voltage slope with increasing the thermal aging period was experienced however, it increased after the mechanical bending. The slope of voltage decay had an opposite trend.