Effects of Exposure to Radiation and Steam on Silicone Rubber Cables Removed From a Nuclear Power Plant

Low-voltage cables insulated with silicone rubber were harvested from three locations in the primary containment vessel of a boiling water nuclear power plant (NPP). Subsequently, the cable, which was placed in an ambient environment with a relatively higher temperature and the highest rate, was cut into four shorter ones. These cables were subjected to several treatments simulating design basis accident conditions, which included irradiation with gamma rays and exposure to water steam. For these cables and those harvested from the NPP, the leakage current through each cable insulation was measured with the current integration method. Consequently, all the leakage currents measured for the three cables harvested from the NPP and those treated to simulate the designed accidents are very low. Therefore, it is evident that the cables harvested from the NPP maintain good insulation integrity, even when subjected to simulated degradation.