Accelerating Test Method of Thermal Aging for High Heat Generating Equipment in Nuclear Power Plant

In nuclear power plant, the electrical equipment which is qualified by procedures and rules of IEEE standard performs accident condition test after aging in many normal conditions of heat, radiation, mechanical and vibration. Because install life of the equipment is over 10 or 20 years, the accelerating aging test is applied for normal aging test. Especially in thermal aging test, Arrhenius equation, which defines relationship between activation energy of a material and chemical reaction rate, is used as a tool calculating the accelerated condition of the test. The equation enables to easily convert actual operating temperature in a long time into accelerated test condition with higher temperature of shortened period. However, temperature of components of the electric equipment often increases by heat sources such as power supply, electrical circuit and coil. This heat-rise makes difficulty for deciding the accelerated condition of thermal aging test. In addition, the number of components composing of the equipment and various temperatures of each component are an additional consideration of the difficulty. We proposed the effective method and technology of accelerated thermal aging test for heat-rise equipment in NPP and verified that the method could suggest the reasonable accelerating condition.