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Title: Eddy-current inspection for steam generator tubing program. Annual progress report for period ending December 31, 1979

Eddy-current methods provide the best in-service inspection of steam generator tubing, but present techniques can produce ambiguity because of the many independent variables that affect the signals. The current development program has used mathematical models and developed or modified computer programs to design optimum probes, instrumentation, and techniques for multifrequency, multiproperty examinations. Interactive calculations and experimental measurements have been 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 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. Our experimental measurements have confirmed these results, although more testing is needed for all the different combinations of cases and different types of defects. To facilitate the extensive laboratory scanning of the matrix of specimens that are necessary to develop algorithms for detection and analysis for all the possible combinations of positions of flaws, tube supports, and probe coils, we have designed, constructed, andmore » begun operation of a computer-controlled automatic positioner. We have demonstrated the ability to overcome the large signals produced by the edge of the tube supports. An advanced microcomputer has been designed, constructed, and installed in the instrumentation to control the examination and provide real-time calculations of the desired properties for display recording during the scanning of the tube.« less
Authors:
; ;
Publication Date:
OSTI Identifier:
5454348
Report Number(s):
NUREG/CR-1563; ORNL/NUREG/TM-398
ON: TI85015902
DOE Contract Number:
AC05-84OR21400
Resource Type:
Technical Report
Research Org:
Oak Ridge National Lab., TN (USA)
Country of Publication:
United States
Language:
English
Subject:
22 GENERAL STUDIES OF NUCLEAR REACTORS; 42 ENGINEERING; STEAM GENERATORS; EDDY CURRENT TESTING; COMPUTER CODES; INSPECTION; RESEARCH PROGRAMS; TUBES; BOILERS; ELECTROMAGNETIC TESTING; MATERIALS TESTING; NONDESTRUCTIVE TESTING; TESTING; VAPOR GENERATORS 220200* -- Nuclear Reactor Technology-- Components & Accessories; 420500 -- Engineering-- Materials Testing