MICRO EDDY-CURRENT TESTING BY MICRO MAGNETIC SENSOR ARRAY

A micro Eddy Current Testing (ECT) system for planar thin specimens ma de of INCONEL 600 with flaws was proposed and developed. A micro ECT p robe used here consists of a conventional pancake-type coil as an exci ting coil and a micro magnetic sensor array as a set of pickup coils. Magnetic field perturbation due to a flaw was measured with high spati al resolution and signal-to-noise (S/N) ratio. The measured signals fr om the array were compared with numerical results obtained by a three- dimensional A-phi code. It was confirmed that the micro ECT system has the potential to evaluate the length and depth of a flaw with better accuracy than that of a conventional pancake-type ECT in the steam gen erator tubings in a pressurized water nuclear reactor.