Enhanced PAUT method with pulse compression for heavy-walled CASSs in nuclear power plants

Heavy-walled cast austenitic stainless steels (CASSs) are usually used as the primary circuit pipelines in many nuclear power plants, but detecting the small defects in these materials has been a difficult problem for many years. To improve the defect-detecting ability and signal-to-noise ratio (SNR) of ultrasonic testing for CASSs with serious sound attenuation and scattering, an enhanced phased array ultrasonic testing (PAUT) method with pulse compression is developed in this work. A simplified numerical model of the PAUT for CASSs was established. Numerical simulations were carried out to verify the increasing SNR of the enhanced PAUT method with pulse compression compared with the conventional PAUT based on this model. Finally, an enhanced PAUT system with pulse compression technology was developed to inspect the defects in the heavy-walled CASSs. Experiment results prove the effectiveness of the enhanced PAUT method and system.