The Riddle Of Nde For Embrittlemient Detection

Abstract

ABSTRACTThe ability to nondestructively determine the level of irradiation induced degradation in nuclear reactor pressure vessels (RPVs) would enhance the integrity assessment currently used by the nuclear industry. Presently, destructive testing of Charpy specimens from surveillance capsules is used to approximate the RPV upper shelf energy and the ductile-to-brittle transition temperature, and approved models and guidelines are used to determine the state of embrittlement. However, these models and surveillance programs do not always provide enough accurate information to support decisions for premature RPV life termination, life continuation to license expiration, or life renewal and extension by means of annealing. Effective nondestructive techniques would extend the usefulness of the surveillance material by reducing the amount of material used for destructive studies, and ultimately by allowing tests to be performed directly on the RPV. Nondestructive techniques, ranging from electrical resistivity to hyperfine interactions, have been, and continue to be, explored for use in embrittlement assessment. The current states of these various techniques are discussed, and future directions for research are suggested.