Inspection ability comparison analysis of different ET probes for steam generator tube defects

In order to investigate the inspection ability of steam generator tube defects with different probes, inspection comparison test of bobbin, MRPC (Motorized rotating probe coil) and array probes were conducted on free span defects as holes, notches, wears, fatigue cracks, rolling zone defects as holes, notches, and resolving ability test was also carried out. The test results showed both MRPC and array probes had almost same sensitivities for these defects, especially obviously better than bobbin probe for small spacing defects and combined defects such as defects on rolling zone.