Abstract
This paper discusses the problems and risks exiting in the in-service inspection of RCP-RRA and connection inlet valve of nuclear power plant, and puts forward the method of optimizing the in-service inspection strategy according to the essence of risk-informed technology. Taking a domestic PWR nuclear power plant as an example, the application process of the optimization method is demonstrated through the combination of determinism and probability theory. The results show that it is acceptable to extend the disassembly inspection cycle of RCP-RRA connection inlet valve,verify the feasibility of the optimization method, and point out the impact of valve monitoring measures on the optimization method, so as to support the comprehensive decision-making and safety review of nuclear power plants.