The insulation integrity of power and instrumentation & control cables plays a crucial role in the safe and reliable operation of nuclear power plants. Different stresses affect the insulating materials of these cables, which significantly contribute the structural changes results in the polymeric insulation. Consequently, the polymer material loses its mechanical and electrical properties causing cable insulation degradation. In this work, samples of low voltage nuclear power cable have been studied with accelerated aging tests. Combined simultaneous thermal and mechanical stresses have been applied to all samples under study. While the samples being placed in an air circulating oven at 120?°C temperature, they are coiled on a cylinder with diameter of 15?cm. The dielectric properties, capacitance and dissipation factor were measured by frequency swapping from 100 mHz to 1 kHz using a commercial dielectric response analyzer. Also, the shore D hardness was measured to investigate the changes in the mechanical property of the test specimens. Over the whole frequency range, the capacitance showed a downward trend with aging. In addition, the tan δ increased with aging for frequencies higher 10 Hz. A correlation between tan δ at 100 Hz and the insulation hardness was obtained.
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