The identification and monitoring of critical components for nuclear life extension

The US Department of Energy has a program to develop predictive performance monitoring and reliability/safety technology to enhance the operational lives of nuclear power plants. An effective equipment monitoring program can provide improved reliability and safety during a plant's initial license term, thus providing valuable data to support extending the life of a facility. Probabilistic risk assessment (PRA) techniques were initially used to help identify components that were critical to safe operation. Equipment was identified for which it is important to maintain initial reliability levels and for which it would be important to improve reliability levels. Of the equipment for which it is important to maintain initial reliability levels, three component types were further evaluated in this study: swing-check valves, motor-driven centrifugal pumps, and motor-operated valves. Component failure and degradation mechanisms were determined and then related to physical parameters and potential measurement techniques. Four types of monitoring were found to have the potential for widespread application in equipment monitoring. These are the use of ultrasonic probing, vibration monitoring, infrared emission monitoring, and acoustic emission monitoring. Efforts are continuing by the US Department of Energy, in cooperation with the US nuclear power industry, to develop specific monitoring techniques