Edge Detection on Eddy Current Image to Increase Defect Characterization

As the nuclear yard ages, the control of steam generator tubes (SGT) must deal with new problems. In fact new defects appear, especially in the area of the tube sheet, of the tube support or at the U-bend area. Eddy current testing using Rotating Probe Coil (absolute mode) gives a better resolution. These measurements allow smaller defects to be detected along different orientations, especially defects along the circumference in the rolling transition. Signals collected during the exploration of the tube internal wall with this coil contain the useful information which is represented in the form of a cartography (or image) for each of the signal complex components

Effect of broaching on high-temperature fatigue behavior in notched specimens of INCONEL 718

Notches were machined in specimens of INCONEL 718 by a broaching process, where differing broaching runs led to differing extents of subsurface deformation and surface roughness. Fatigue tests were carried out at 600°C with a trapezoidal loading waveform at 0.25 Hz. The broaching process that led to the more severe subsurface deformation (but lower surface roughness) showed the worst fatigue performance. Analysis of total strain amplitude in the notch root with the aid of an elasto-plastic finite-element (FE) model showed that the work hardening related to the subsurface deformation caused by the different broaching can account for the difference in fatigue lives. Differences in initiation and growth behavior were seen for the two broached finishes as well as for broached and subsequently polished samples. These differences are discussed in terms of a change in crack growth initiation and growth mechanisms due to the presence of the work-hardened layer

Rotating Excitation Probe for Inspecting PWR SG Tubes

The basic method for inspecting the soundness of steam generator tubes is multifrequency eddy currents. The standard inspection of steam generator tubes of nuclear power reactors is now carried out using bobbin coil and Motorized Rotating Probe Coil (tube support plate, tube sheet and U-bend areas).</p

An Eddy Current Model Based on Parametric Description of Induced Current Loops

Our objective is to design a “forward model” for steam generator tube flaw characterization, using eddy current technique. An investigation of the existing forward models was made.</p

Edge Detection on Eddy Current Image to Increase Defect Characterization

As the nuclear yard ages, the control of steam generator tubes (SGT) must deal with new problems. In fact new defects appear, especially in the area of the tube sheet, of the tube support or at the U-bend area. Eddy current testing using Rotating Probe Coil (absolute mode) gives a better resolution. These measurements allow smaller defects to be detected along different orientations, especially defects along the circumference in the rolling transition. Signals collected during the exploration of the tube internal wall with this coil contain the useful information which is represented in the form of a cartography (or image) for each of the signal complex components.</p