| 研究概要 |
Quantitative non-destructive evaluation of wall thinning in carbon steel piping is a difficult and urgent issue for safety of nuclear power plants. In this research, The feasibility of the magnetic saturation PECT method for wall thinning detection in carbon steel piping is validated through numerical simulations. Firstly, the simulated polarization approach is adopted for the calculation of the static magnetic field distribution generated by the electromagnetic magnet, then the material permeability distribution is predicted according to the B-H curve of the targeted material. Finally the efficient PECT forward simulation tool is updated for the carbon steel based on the Ar (reduced A) method and the Fourier series strategy to validate the wall thinning detection in carbon steel material.
The results reveal that, ECT signals affected by permeability are investigated which shows ECT signal becomes larger as permeability is smaller. PECT signals under saturated case and not saturated case for wall thinning detection are also investigated and the result under saturated case is larger. In addition, the saturated PECT signal can be improved more than 10 times, while the saturated ECT signals can only be improved about 2 times which reveals that the saturated PECT method is more efficient for inspection of defect in ferromagnetic material. Finally, the promising detection capacity of wall thinning in carbon steel piping based on magnetic saturation PECT method has been demonstrated using simulation way.
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