[4C3] Effectiveness of substituting phased array ultrasonic testing (PAUT) for radiographic testing (RT) of tube welds in thermal power plant facilities
I Park, Y Choi and S Cho
Seoul National University of Science and Technology, Korea
Being the core facility in thermal power plants, a boiler has to undergo non-destructive testing during fabrication, construction and preventative maintenance to ensure structural integrity and reduced losses from damage. Radiographic testing (RT) is mainly performed for volumetric non-destructive testing during fabrication, construction and preventative maintenance. However, there are increasing demands for replacing conventional radiographic testing with phased array
ultrasonic testing (PAUT), owing to the delays in construction and maintenance resulting from the strengthened regulation
of nuclear safety. The PAUT technique has advantages in the application in power plant facilities because it has an excellent recordability and detection rate. To apply a new inspection technique, the effectiveness of the PAUT technique must be verified. In general, data acquisition and verification was performed through tests in the laboratory environment or simulations. However, there are limitations because it is difficult to apply the parameters generated in the field environment and conditions. Thus, demonstration research through specimens, inspection systems and inspectors considering the field condition are required. In this study, the effectiveness of substituting PAUT for RT of thermal power plants was evaluated through a mock-up fabricated with identical materials, specifications and welding procedures to those used in the thermal power plant. Blind RRT was performed with the participation of experienced and qualified inspectors using a commercial inspection system. Quantitative reliability analysis such as POD and RMSE was performed on the test results and the results were presented. Through this demonstration research, the effectiveness of the substitution of RT with PAUT was confirmed.
