ECT Signals Processing Technique for Removing TSP Influence for SG Tube Inspection

In this paper, the analysis of the eddy current testing(ECT) signals under the influence of the ferromagnetic tube support plate(TSP) was performed in steam generator(SG) tube of nuclear power plant. In order to remove the influence of the ferromagnetic TSP, a multi-frequency ECT was used. The models which were established for the analysis of the signals were calculated using numerical analysis of finite element method(FEM). Through the result of numerical analysis, improved signals were acquired considering the TSP influence using mixing of multi-frequency. This paper is presented the residual errors and the phase changes for analysis of the defect signals which should be considered when conducting a ECT using multi-frequency.