Included are relationships for more » estimating flaw severity from AE data and field applications at Watts Bar Unit 1 Reactor, Limerick Unit 1 Reactor, and the High Flux Isotope Reactor.
The program has shown the feasibility of continuous, on-line AE monitoring to detect crack growth and produced validated methods for applying the technology. Research and development has been performed by Pacific Northwest Laboratory, operated for the Department of Energy by Battelle Memorial Institute. The program has been supported by the US Nuclear Regulatory Commission, Office of Nuclear Regulatory Research. The program concerning Acoustic Emission/Flaw Relationships for Inservice Monitoring of LWRs was initiated in FY76 with the objective of validating the application of acoustic emission (AE) to monitor nuclear reactor pressure-containing components during operation to detect cracking.
This report discusses the program scope and organization, the three program phases and the results obtained, standard and code activities, and instrumentation and software developed under this program. This report discusses the results obtained from the AE monitoring over the period May 1989 to March 1992 (two fuel = , AE instrumentation was installed by PNL and PECO to monitor the flaw indication during two complete fuel cycles. The existence of this flaw indication offered a long sought opportunity to validate AE surveillance to detect and evaluate crack growth during reactor operation.
Evaluation of the flaw indication showed that it could remain in place during the subsequent fuel cycle without compromising safety. A flaw indication was identified during normal inservice inspection of piping at Philadelphia Electric Company (PECO) Limerick Unit 1 reactor during the 1989 refueling outage.
The technology was validated off-reactor in several major tests, but it had not been validated by monitoring crack growth on an operating reactor system. Acoustic emission (AE) technology for continuous surveillance of a reactor component(s) to detect crack initiation and/or crack growth has been developed at Pacific Northwest Laboratory (PNL).