Availability Monitoring and Improvement Method for In-Service Nuclear Power Plants Based on High-Precision Prediction of Availability

A high-precision availability prediction, availability monitoring, and availability improvement method for in-service nuclear power plants has been proposed. The calculation formula for availability characteristic quantities and categories of planned maintenance for nuclear power plants are introduced. For nuclear power plants that have been in operation for less than 5 years, an availability prediction method based on statistical data is adopted to predict the equivalent availability factor of nuclear power plants. For nuclear power plants with operation years greater than or equal to 5 years, an availability prediction method based on power function and polynomial is adopted to predict the equivalent availability factor of nuclear power plants, and an accuracy verification method of availability prediction for nuclear power plants is provided. Based on availability prediction values and qualification criteria for availability monitoring, the availability monitoring of nuclear power plants is carried out. The optimization for numbers of planned maintenance days and newly added unplanned maintenance days based on different planned maintenance years promote the availability improvement of nuclear power plants. The relative error of availability prediction for an 1000 MW nuclear power plant and application example of optimized maintenance measures for different planned maintenance years are provided. The results show that the availability prediction method based on power function has high prediction accuracy and conforms to the availability trend of nuclear power plants. Based on the high-precision prediction results of availability, optimizing the number of planned maintenance days for different planned maintenance years can promote the availability improvement of in-service nuclear power plants.