PWR reactor vessel (RV) head has a number of penetration nozzles, including nozzles with thermal sleeve for control rod drive mechanisms (CRDM) and without thermal sleeve. These nozzles are typically made of nickel-based Alloy 600 or 690 and welded to the inside of the RPV head. Cracking has been reported in Alloy 600 nozzles and the J-weld regions. These nozzles are normally inspected by eddy ...

Ultrasonic testing (UT) is widely applied for the inspection to various plants and structures. However, in the application to the inspection of high attenuation materials such as austenitic weld joints and the inspection near the surface, the SNR (Signal-to-Noise Ratio) decreases and it makes it difficult to assess the testing results. To solve this issue, systems of a signal processing by the ...