Study on risk-informed surveillance test interval optimization for emergency diesel generators in nuclear power plants

After years of development and practice of probabilistic safety assessment (PSA) technology, the application of risk-informed technology based on PSA in nuclear power plants has been widely recognized. Combined with the practical experience and actual needs of the nuclear power plant, this paper adopts the risk-informed method to analyze the optimization (extension) of the surveillance test interval of the emergency diesel generator of the nuclear power plant. The analysis results show that the operating experience feedback of emergency diesel generator is good since the commercial operation, and the surveillance test interval has base for optimization. According to traditional engineering analysis, the optimization of surveillance test interval satisfies the principle of defense in depth of nuclear power plant, and does not affect the safety margin of nuclear power pl ant. According to the probabilistic safety assessment, the increase of core damage frequency and large early release frequency after the optimization of the surveillance test interval is a small change with acceptable risk, and nuclear power plants can carry out the optimization of the surveillance test interval of emergency diesel generators.