A Simplified Approach for Detectability Evaluation of ECT probes

Abstract

Aiming at the effective evaluation of the detectability of Eddy Current Testing(ECT) probes utilized in the nondestructive evaluation of Steam Generator(SG) tubing in Pressurized Water Reactor(PWR) type nuclear power plant, a new approach has been developed in this paper based on a simplified relation newly proposed for connecting induced eddy currents in SG tubing to the exciting magnetic field. To approximate the effect of the eddy current perturbation due to a small surface breaking crack, the ring current model has been improved to consider the crack opening through introducing a new set of ring currents. The proposed new model and simplified relation were validated by comparing eddy current distribution and the scattering magnetic field predicted by the present method and those calculated by an accurate numerical code. The applications to the S/N ratio analyses of several ECT probes and to the simulation of scan signals show this new method is feasible in the actual design and optimization of ECT probes.