On Reliability And Maintenance For AOVs Of Nuclear Power Plants

Early warning of the equipments for nuclear power plants and the application of the reliability centered maintenance (RCM) theory are important issues and highly desired for the nuclear power plants. Based on the analysis the air operation valves (AOVs) failure modes and their results, the thesis discusses the issues of the application of RCM, optimization of preventive maintenance program, and state monitoring of AOVs. Moreover, an online early warming monitor is set up for the AOVs of the deaerator systems (D/A) using higher-order statistics, which is an essential technique for the application of RCM theory. The contributions of the work are summarized as follows:1). The work reveals the importance of the application of RCM theory to the AOVs in the nuclear power plant, and figures out the requirement of the AOVs' preventive maintenance program.2). An online monitor for the D/A level control system is proposed. Based on the higher-order statistics, the operation performance of the AOVs is assessed by analyzing the process routine data. The results show that the monitor has ability to issue early warming before any abnormal behavior coming up, which provides a solid tool to support necessary maintenance action.3). By carefully analysis of the failure modes and their results, the thesis proposes an optimized strategy for the AOVs preventive maintenance.