Modelling of wear defects under Anti Vibration Bars in U-bend for the Eddy Current inspection of Steam Generator tube

Abstract

The purpose of the anti-vibration bars (AVBs) positioned on both sides of the U-bend part of the steam generator tubes is to limit the vibratory phenomena. These tubes are prone to localized rubbing against the AVBs, resulting in friction-induced wear. To address this issue, eddy current (EC) monitoring and analysis tools like simulation are developed [1]. The objective of the joint study conducted by CEA LIST and IRSN, is to simulate the wear signal under the AVB and to assess the influence of the main geometric parameters on this signal. Within this context, new advanced geometric tools, such as the vibratory movement of an object have been developed to enhance the CIVA model developed at CEA LIST, [2][3]. This 3D numerical model has been experimentally validated on simple configurations involving a machined tube with rectangular-bottomed flats and an AVB, inspected by two axial bobbin coils. The obtained results demonstrate that the presence of AVBs significantly influences the signature of defects near them, especially for thin defect.