Experimental Studies on Guided Waves for the On-Line Inspection of Steam Generator Tubes

Abstract

Deployment of an advanced on-line monitoring of the component integrity offers the prospect of improved performance, enhanced safety, and reduced overall cost for nuclear power plants. Guided ultrasonic waves have been known as one of promising techniques that could be utilized for on-line monitoring. The present work is aimed at developing a new method for on-line monitoring of the pipes during the operation period of nuclear power plants. For this purpose, Steam generator (S/G) tube was selected as the object of the experiment. Dispersion curves and the incident angles corresponding to the specific modes were calculated for the S/G tube. The modes of guided wave were identified by time-frequency diagrams obtained by short time Fourier transform. Group velocities were also determined from the time-frequency diagrams obtained at the different separations of transducers. It was experimentally confirmed that there was no mode conversion when the guided ultrasound passed curved region of the S/G tube. The optimum mode of guided wave for the S/G tube was suggested and verified by experiments

Development of a 16-Channel Broadband Piezoelectric Micro Ultrasonic Transducer Array Probe for Pipeline Butt-Welded Defect Detection

“…Since the weld and the steel pipeline have some difference in the Young’s modulus and density, and because the multimodal and dispersion characteristics of the guided waves cannot be ignored, there are reflection waves in both the weld and the defects. Considering that these reflection waves are always superimposed, their waveforms are too complicated to analyze [ 10 , 18 , 19 , 20 ]. Moreover, the interpretation of the guided wave-based detection data is highly dependent on well-experienced practitioners, which may result in lower detection efficiency and higher cost [ 21 ].…”

Magnetostrictive Guided Wave Technique Verification for Detection and Monitoring Defects in the Pipe Weld

“…However, the actual ultrasonic signal is complicated due to the geometrical complexity of the welded portion, the heterogeneous connection part, the deformed pipe, the pipe support, and the various valves. Also, most of the defects’ signals are generated at welds and pipe supports, making it difficult to distinguish between them [7]. It is difficult for guided wave ultrasonic testing of long-distance piping to distinguish between internal/external defects.…”