Eddy Current Testing of a Steam Generator with a Support Plate

Industrial steam generators serve an important role in a variety of industries, including the chemical and petrochemical industry, engineering industry, and nuclear applications. These devices are used to produce steam that can be used for a variety of purposes, such as heating and sterilization. In order to ensure the safety of a steam generator, nondestructive testing (NDT) techniques are applied. Tube support plates (TSPs) maintain tubes, make sure they are properly spaced, and help avoid fretting. However, TSPs are regarded as disturbing signals for tubes. In this paper, we investigate the influence of the support plate on eddy current testing (ECT) using a differential probe of a steam generator tube made of Inconel 600 and carrying a defect. The modeling of eddy current testing is based on solving a 2D axisymmetric finite element formulation under steady-state conditions via Comsol Multiphysics Software. The impedance of the differential coil is calculated using the direct method, and the signal of the difference impedance is obtained from two simulations: with flaws and without flaws.

The simulation of the studied system under the abovementioned conditions lets us conclude with the following points:

• The signal of the impedance difference is higher when the TSP is introduced in the simulation.
• The amplitude of the impedance difference increases as the TSP approaches the tube.