Developments on Implementation of WOG Risk-Informed Inservice Inspection Methodology

The Westinghouse Owners Group (WOG) risk-informed inservice inspection (ISI) methodology has been in use for over three years as an alternative to current regulatory requirements in the development and implementation of ISI programs for nuclear plant piping systems. This paper builds upon technical papers presented at ICONE-8 and ICONE-9 that reported on the risk-informed ISI applications being developed and implemented within the U.S. and several other countries. While many applications are nearing completion around the globe, much progress has been made in extending the WOG risk-informed ISI approach to several other initiatives. This paper summarizes the results from the development and implementation of the WOG risk-informed ISI methodology in the U.S., Europe and Asia for limited Class 1 scope through full scope applications. References for associated activities in risk-informing the safety classification of pressure boundary components in support of Option 2 and redefining large break loss-of-coolant accident technical requirements as part of Option 3 in risk-informing 10CFR Part 50 are identified. The current status of program maintenance of the risk-informed living program and direct application of the methodology in modifying requirements for augmented examinations for high energy line break in break exclusion regions are summarized.