Risk informed inservice inspection of piping

This paper describes a Risk-Informed Inservice Inspection (RI-ISI) program developed by Westinghouse and the Westinghouse Owners Group (WOG). Two pilot plant applications have shown that the RI-ISI program will reduce overall operation and maintenance costs, and radiation exposure associated with the inspection of nuclear power plant piping while maintaining or improving upon a high level of safety. This paper will describe the steps necessary to develop an implement an RI-ISI program. within the framework of the US Nuclear Regulatory Commission (NRC) risk-informed regulatory process. The tools and processes created or adapted for this program will be described. The program benefits in terms of focus on plant safety, reduction of plant welds receiving nondestructive examination (and the resulting outage-related cost savings), and reduction of worker radiation exposure will be described within the context of the two pilot plant results. Both plants performed full system scope program involving dozens of plant piping systems and hundreds of welds and other structural elements. (Author) 5 refs