Estimation of depth and volume for defects by eddy current testing

The full-length inspection of tubes in steam generator to detect defects using the signal measured by ECT (eddy current testing) is performed in a PWR (pressurized water reactor) plant. According to the technological advances of NDE (non-destructive examination), an estimation of defect shape is required. In this study, by characterization of ECT signals using imitative defects, we express the relation with defect shape in approximate functions, and estimate the defect shape using this function. In our estimation of the depth and volume of defects, the depth estimation error was reduced to 19.7% or less and the volume estimation error to 27.2% or less. © 1999 Scripta Technica, Electr Eng Jpn, 127(4): 29–38, 1999