Evaluation of machine learning tools for inspection of steam generator tube structures using pulsed eddy current

Degradation of nuclear steam generator (SG) tubes and support structures can result in a loss of reactor efficiency. Regular in-service inspection, by conventional eddy current testing (ECT), permits detection of cracks, measurement of wall loss, and identification of other SG tube degradation modes. However, ECT is challenged by overlapping degradation modes such as might occur for SG tube fretting accompanied by tube off-set within a corroding ferromagnetic support structure. Pulsed eddy current (PEC) is an emerging technology examined here for inspection of Alloy-800 SG tubes and associated carbon steel drilled support structures. Support structure hole size was varied to simulate uniform corrosion, while SG tube was off-set relative to hole axis. PEC measurements were performed using a single driver with an 8 pick-up coil configuration in the presence of flat-bottom rectangular frets as an overlapping degradation mode. A modified principal component analysis (MPCA) was performed on the time-voltage da...

[1]  Thomas W. Krause,et al.  Pulsed Eddy Current Inspection of Support Structures in Steam Generators , 2015, IEEE Sensors Journal.

[2]  Ki-Wahn Ryu,et al.  Prediction of Fretting Wear Depth for Steam Generator Tubes Based on Various Types of Wear Scars , 2010 .

[3]  Thomas W. Krause,et al.  Pulsed eddy current detection of cracks in F/A-18 inner wing spar without wing skin removal using Modified Principal Component Analysis , 2013 .

[4]  Noritaka Yusa,et al.  Profile reconstruction of simulated natural cracks from eddy current signals , 2002 .

[5]  Kazuyuki Demachi,et al.  Neural network for inverse mapping in eddy current testing , 1999, IJCNN'99. International Joint Conference on Neural Networks. Proceedings (Cat. No.99CH36339).

[6]  M. Helmi Attia,et al.  Fretting fatigue and wear damage of structural components in nuclear power stations—Fitness for service and life management perspective , 2006 .

[7]  R. L. Tapping,et al.  CANDU steam generator life management , 2000 .

[8]  Luis S. Rosado,et al.  Defect Characterization With Eddy Current Testing Using Nonlinear-Regression Feature Extraction and Artificial Neural Networks , 2013, IEEE Transactions on Instrumentation and Measurement.

[9]  Luigi Ferrigno,et al.  Crack Shape Reconstruction in Eddy Current Testing Using Machine Learning Systems for Regression , 2008, IEEE Transactions on Instrumentation and Measurement.

[10]  David M. Skapura,et al.  Neural networks - algorithms, applications, and programming techniques , 1991, Computation and neural systems series.

[11]  Thomas W. Krause,et al.  A pulsed eddy current probe for inspection of support plates from within Alloy-800 steam generator tubes , 2014 .

[12]  Sun-Yuan Kung,et al.  Principal Component Neural Networks: Theory and Applications , 1996 .

[13]  Mengchun Pan,et al.  Support vector machine and optimised feature extraction in integrated eddy current instrument , 2013 .

[14]  Colette A. Stott,et al.  Pulsed Eddy Current Detection of Cracks in Multilayer Aluminum Lap Joints , 2015, IEEE Sensors Journal.

[15]  Thomas W. Krause,et al.  Simultaneous Multiparameter Measurement in Pulsed Eddy Current Steam Generator Data Using Artificial Neural Networks , 2016, IEEE Transactions on Instrumentation and Measurement.

[16]  Tadeusz Stepinski,et al.  Automatic detecting and classifying defects during Eddy current inspection of riveted lap-joints , 2000 .

[17]  Kenzo Miya,et al.  Approximate inverse mapping in ECT, based on aperture shifting and neural network regression , 1998 .

[18]  Nam Hoon Jo,et al.  A novel feature extraction for eddy current testing of steam generator tubes , 2009 .

[19]  Xiaowei Wang,et al.  Reconstruction of Stress Corrosion Cracks Based on Pulsed Eddy Current Signals , 2012, 2012 Sixth International Conference on Electromagnetic Field Problems and Applications.

[20]  Thomas W. Krause,et al.  Analysis of pulsed eddy current data using regression models for steam generator tube support structure inspection , 2016 .