Estimation of sizes of cracks on pipes in nuclear power plants using dipole moment and finite element methods

•Simulate alternating magnetic field around a crack in a small-bore piping system.•Good agreement among proposed simulation method, experiment and FEM.•The simulation method is easier and faster than the FEM.•Crack volume can be estimated.

The dipole model method (DMM) for simulating an alternating magnetic field around a hole-type crack in a small-bore pipe as a nondestructive evaluation method is proposed in the present paper. Simulation results were compared with those of the finite element method (FEM) and experimental results obtained using a bobbin-type magnetic camera, and they were found to be in good agreement; thus validating the DMM. The DMM was also found to be faster and easier to implement compared to the FEM. Furthermore, the crack volume could be estimated by linear approximations with a good correlation among the three methods.

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