Application of Risk-Informed Approach in Emergency Compressor Emergency Backup Function Test

The emergency compressed air production system is a part of the compressed air production system of the nuclear power plant. Its function is to provide the necessary compressed air to the nuclear island when the main air compressor fails and cannot provide compressed air. Each unit of the nuclear power plant has two emergency air compressors to provide backup air source for the compressed air distribution system for instrumentation. Under normal working conditions, one emergency air compressor is in the basic load state and the other is in the standby state. The two emergency air compressors will automatically start according to the degree of pressure drop of the compressed air production system. The purpose of the emergency backup function of the emergency air compressor is to verify that the two air compressors will start up as the system pressure drops in different states, and to verify the operating parameters of the two emergency air compressors. The test period is one week. Periodic testing is an important activity for nuclear power plants to ensure the availability of equipment that performs important functions. However, periodic testing exceeding a certain frequency may reduce the safety of the power plant and increase the unnecessary burden of the power plant. At present, PSA has been widely used in nuclear power plant operation guidance, maintenance rules and many other fields, PSA has developed into an important tool for safety assessment and decision-making. With the development of PSA technology, the risk-oriented model combining probability theory and determinism has also been applied in the optimization of the periodic test cycle of nuclear power plants, so that the resource allocation of power plants can be optimized under the premise of ensuring sufficient safety of nuclear power plants. Improve regulatory and operational efficiency. This paper will take the emergency compressed air production system of Fangjiashan Nuclear Power Plant (FSJ NPP) as an example to introduce the application method of the risk-oriented periodic test optimization method.