Ultrasonic Array Imaging for Defect Detection in the Nuclear Industry

Non-destructive evaluation of critical nuclear power plant components has to be rapid and reliable. Ultrasonic testing satisfies these requirements and is used extensively in the industry. Ultrasonic phased arrays offer higher sensitivity and more complete and intuitive data analysis in comparison to conventional single element probes. In the Canadian nuclear industry, components such as pressure tubes are typically tested with focused ultrasound. Phased array imaging, with focused parallel transmissions, is possible, but has not yet been considered in most industrial applications. This work tests a variation of the medical imaging algorithm Unified Pixel-Based Beamforming (UPBB) for a pressure tube inspection. The technique detects all of the considered discontinuities, but could require a long acquisition time. An adaptive, combined Plane Wave and UPBB imaging is proposed to improve performance with respect to inspection time. This combined inspection firstly provides an overview of the conditions in a large region of the component and then targets additional locations of interest with focused waves.