Application of Modelling for Enhanced Ultrasonic Inspection of stainless steel welds

International audienceThe ultrasonic inspection of the primary coolant piping of Pressurized Water Reactors (PWR) is a major concernfor the nuclear industry. Numerous studies have been undertaken over some years by EDF R&D in collaborationwith the French Atomic Energy Commission (CEA) to improve the non-destructive testing (NDT)process for these applications and to help towards their qualifi cation. More particularly, a great deal of workwas carried out on the inspection of austenitic stainless steel welds. Indeed, the anisotropic, heterogeneousand coarse granular structures of these welds lead to important disturbances of the ultrasonic propagation:beam skewing and splitting, attenuation, backscattering and ghost echoes. This paper presents the methodologydeveloped for modelling the ultrasonic inspection of austenitic welds, which is based on an accuratecharacterization of the material. Two numerical approaches are presented: a fi nite elements code, ATHENA,developed by EDF, and a semi-analytical code that is a part of the CIVA simulation platform developed by theCEA. These codes simulate the propagation of the ultrasonic beam in the weld and calculate the defect-beaminteraction. Ultrasonic beam disturbances are illustrated from experimental and numerical results for differentapplications. In particular, the infl uence of variations in the weld structure on NDT performance is discussed.This comparison between experiment and modelling shows the modelling methodology to be valid