Evaluation of Pulsed Eddy Current Response and Detection of the Thickness Variation in the Stainless Steel

The pulsed eddy current (PEC) system has been developed for the detection of the wall thinning in the pipelines of nuclear power plants (NPPs) without removing the insulation. The PEC signal response from the stainless steel sample which the thickness varies from 1 mm to 5 mm was investigated at the position of 6 mm above the sample surface. A LabVIEW based data acquisition program was developed to continuously display the thickness variation of the tested sample. The signal analysis technique such as power spectrum density (PSD) of Fourier transform is applied to obtain an optimum parameter to describe the wall thinning of pipeline steel. This technique can be used as a potential tool to detect the local wall thinning of a pipe without the removal of the insulation.