Risk-based inspection priorities for PWR high-pressure injection system components

Under U.S. Nuclear Regulatory Commission sponsorship, Pacific Northwest Laboratory developed a risk-based method that can be used to establish in-service inspection priorities for nuclear power plant components. The overall goal of this effort was to develop technical bases for improvements of inspection plans and to provide recommendations for revisions of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Sec. XI. The developed method used results of probabilistic risk assessment in combination with the failure modes and effects analysis (FMEA) technique to establish in-service inspection priorities for systems and components. The Surry nuclear power station, unit 1 (Surry-1) was selected for study. Inspection priorities for several pressure boundary systems at Surry-1 were determined in the early phase of the project. To complete the study, the remaining safety systems, plus balance of plant, have been analyzed; one of these is the high-pressure injection (HPI) system. This paper presents the results of inspection priorities for the HPI system.