An inversion scheme for sizing of wall thinning defects from pulsed eddy current testing signals

In this paper, an inversion algorithm has been proposed and validated, based on a fast simulator of pulsed eddy current testing (PECT) signals and a deterministic optimization strategy, for the profile reconstruction of wall thinning in pipes of nuclear power plants. Local wall thinning is modelled as a group of planar defects with different length and depth, reconstructed from two-dimensional PECT signals. Through inverse analysis of simulated signals and signals with random noise, the efficiency and the robustness of the proposed algorithm have been demonstrated.