Acoustic emission/flaw relationships for inservice monitoring of LWRs : Pacific Northwest Laboratory, Richland, Washington (United States), NUREG/CR-5645, PNL-7479, 120 pp. (Oct. 1991)

P.H Hutton,R.J Kurtz,M.A Friesel,J.R Skorpik,J.F Dawson

doi:10.1016/0963-8695(94)90484-7

Abstract

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. The program has been supported by the US Nuclear Regulatory Commission, Office of Nuclear Regulatory Research. Research and development has been performed by Pacific Northwest Laboratory, operated for the Department of Energy by Battelle Memorial Institute. The program has shown the feasibility of continuous, on-line AE monitoring to detect crack growth and produced validated methods for applying the technology. Included are relationships for 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. 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.

Highlights

Acoustic emission (AE) denotes a nondestructive method for volumetric surveillance of metal or composite structures to detect cracking
Some of the few AE event counts occurred around small, relatively uniform load drops following yielding, some around load increases associated with increasing crosshead speed
Because of problems encountered with the design of the heavy-section cylindrical bend (HSCB) loading frame and because a more extensive evaluation of the affect of 550*F water was being planned for Phase II of the program, the HSCB test was terminated

Summary

Introduction

Acoustic emission (AE) denotes a nondestructive method for volumetric surveillance of metal or composite structures to detect cracking. Since AE systems are inherently very sensitive and operate in real-time on signals from a source, they are effective in detecting leakage of fluid from a crack or other opening. This is true of high pressure-high temperature fluids leaking to atmosphere through a crack in the wall of a container. Work under a separate program has indicated that the acoustic data can be interpreted to estimate leak rate as well as leak location In this perspective, the AE method is complementary to other forms of nondestructive inspection (ultrasonic, eddy current, radiography, etc.).

Methods

Results

Conclusion