Eddy-current inspection for steam-generator tubing program. Quarterly progress report for period ending September 30, 1978

Technical Report · Fri Dec 01 04:00:00 EST 1978

DOI:https://doi.org/10.2172/6472544· OSTI ID:6472544

Dodd, C V; Deeds, W E; McClung, R W

Eddy-current methods provide the best in-service inspection of steam generator tubing, but present techniques can produce ambiguity because many independent variables affect the signals. The current development program will use mathematical models and develop or modify computer programs to design optimum probes, instrumentation, and techniques for multifrequency, multiproperty examinations. Interactive calculations and experimental measurements are made with the use of modular eddy-current instrumentation and a minicomputer. These establish the coefficients for the complex equations that define the values of the desired properties (and the attainable accuracy), despite changes in other significant variables. The final eddy-current instruments will contain on-board microcomputers for real-time data processing and interpretation. The computer programs for calculating the accuracy with which various properties can be measured indicate that the tubing wall thickness and the defect size can be measured much more accurately than is currently required, even when other properties are varying. A prototype model of the modular three-frequency eddy-current instrument with its own internal microcomputer has been completed and tested. Alloy 600 tubing standards have been machined, with variations in diameter wall thickness, and defect size and location; tube support plates with various inner diameters have also been machined.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6472544
• Report Number(s): NUREG/CR-0520; ORNL/NUREG/TM-284
• Country of Publication: United States
• Language: English

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