Measurement of Tube to Support Plate Gap for Alloy 800 Steam Generator Tubes using Transient Eddy Current

摘要

Inspection of steel support plates from within Alloy 800 Steam generator (SG) tubes in CANDU® nuclear reactors is a critical challenge, since support plate degradation and fouling can lead to tube damage and loss of SG efficiency. Transient eddy current (TEC) technology is being developed to measure the gap between SG tube and support plates, which will facilitate determination of support plate condition. Results from a prototype probe, designed based on finite element modelling, demonstrate the capability to measure small tube to support plate gap variations, providing information, which in turn may be used to assess support plate condition.