Research on Qualification Requirements for Electrical and Instrumentation Equipment Based on Safety Classification

Abstract In 2014, the IAEA issued new safety classification guidelines for nuclear power plants called Safety Classification of Structures, Systems and Components in Nuclear Power Plants. It is stipulated that items are classified based on their function importance, and after determining the safety class, equipment qualification requirements need to be determined to ensure that items have suitable quality under all expected operating conditions and to ensure the realization of safety functions. Therefore, it is necessary to identify safety important items that can perform their necessary expected functions throughout their entire design operating life and under dominant environmental conditions, including maintenance and testing of nuclear power plants. The qualification procedure for important safety items must take into account the aging effects caused by various environmental factors (such as vibration, radiation, humidity, temperature) during the expected lifespan of safety important items. Therefore, it is necessary to clarify the qualification requirements for equipment and carry out equipment qualification activities from the perspective of equipment selection. This article investigates the relevant codes and standards such as RCC-E and IEEE as well as different reactor experiences, and analyzes the actual environmental conditions under which electrical and instrumentation equipment performs its functions. This includes determining the environmental and load conditions for device execution, the timing and duration of device execution, and the type of function performed by the device.