Application of Modelling for Enhanced Ultrasonic Inspection of stainless steel welds
Résumé
The ultrasonic inspection of the primary coolant piping of Pressurized Water Reactors (PWR) is a major concern
for the nuclear industry. Numerous studies have been undertaken over some years by EDF R&D in collaboration
with 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 work
was carried out on the inspection of austenitic stainless steel welds. Indeed, the anisotropic, heterogeneous
and 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 methodology
developed for modelling the ultrasonic inspection of austenitic welds, which is based on an accurate
characterization 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 the
CEA. These codes simulate the propagation of the ultrasonic beam in the weld and calculate the defect-beam
interaction. Ultrasonic beam disturbances are illustrated from experimental and numerical results for different
applications. 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.