Ultrasonic Defect Detection of Helium-Cooling Pipeline: A Simulation and Experimental Study

Herein,we addressed the ultrasonic detection of defects of helium cooling pipeline,installed in the large vacuum chamber of China Fusion Engineering Test Reactor(CFETR).The interaction,of the ultrasonic-wave with an artificial macroscopic crack in stainless steel pipeline,was mathematically modeled,theoretically analyzed,numerically simulated in finite element method and experimentally evaluated.The influence of the crack's position on the detection accuracy was also investigated.The preliminary results show that when it comes to a well-defined large crack,the non-destructive ultrasonic defect detection may obviously outperform the conventional helium mass spectroscopy leak detection.For instance,an artificial crack(1 mm×4 mm×0.5 mm) was rapidly,easily and accurately detected in a "single shot";and the simulated and measured results were in good agreement.However,much work remains to be done to regularly detect irregularly-shaped tiny little hole(s) in the vacuum pipeline.