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A differential probe which is used in the pulsed eddy current (PEC) system has been fabricated for the detection of wall thinning of insulated pipelines in a nuclear power plant (NPP). The differential PEC probe consists of two hall sensors in a differential arrangement. The tested sample is a stainless steel of thickness variation from 1 to 5 mm, the flat side of the sample is laminated by a plastic insulation having a uniform thickness to simulate the pipelines in NPP. The PEC response to varying metal thickness was measured at various thicknesses of insulations on the tested sample. The time-domain feature such as peak value of the detected pulse is used to interpret the thickness of the test sample. The signal analysis technique, such as power spectrum density, 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 corrosion or the wall thinning of the pipelines without removing the insulation.

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The effects of ion irradiation on a giant magnetoimpedance (GMI) have been investigated for a Co-based amorphous ribbon with various kinds of ions such as Xe, Ar, and N. The GMI ratio and M-H loop parameters were used to characterize the samples before and after the ion irradiation. The GMI ratio increased considerably in the ion irradiated samples and the GMI response showed a strong dependence on the irradiated ion species and driving frequencies. It was shown that the ion irradiations lead to a substantial modification of the magnetic properties including a large coercivity and shearing of the in-plane magnetization loops, thus suggesting the reduction of an exchange coupling.

The variation in magnetic properties of a Fe–1%Cu model alloy due to a cold rolling and a thermal aging has been evaluated to simulate the radiation damage of reactor pressure vessel of nuclear power plant. The thermal aging was conducted at 500 °C with different aging times in series. The hysteresis loops, magnetic Barkhausen noise (BN) and Vickers microhardness were measured for prestrained, strained, and thermal aged samples. The coercivity increased by a plastic strain and decreased by thermal aging, The BN decreased in the prestrained and strained samples but large changes were observed in the strained sample. These results were interpreted in terms of the domain wall motion signified by a change in the mean free path associated with microinternal stress and copper rich precipitates.