Development of Rotation Uniform Eddy Current Probe and Field Mock-up Test for Steam Generator Tubes on Nuclear Power Plant

摘要

Ensuring the security of the steam generator tubes of the pressurized water reactor (PWR) in the nuclear power plants is a key factor in their safe exploitation. Accordingly, the eddy current testing is used for the reason of high accuracy and high speed because the test must be done in a limited period. We developed a rotating type probe that can detect cracks with distinction between axial and circumferential cracks. The probe is composed with two excitation coils of axial and circumferential windings and a pickup coil. The excitation coil of this probe is able to generate uniform eddy current distribution on a wide area compared with the detection area of the pickup coil. We carried out evaluation of field mock-up testing. From measurement results by the field mock-up testing, the probe is confirmed to be able to measure small cracks on circumstances of the steam generator in the nuclear power plant.