Improved eddy-current inspection for steam generator tubing

Conference · Mon Jan 01 04:00:00 EST 1990

OSTI ID:6492414

Dodd, C V; Pate, J R

Oak Ridge National Laboratory has been engaged in the research and development of eddy-current tests for a wide range of different problems. Recent advances have been made on our multiple-property techniques. This technique generates a set of coefficients that correlate the readings from an eddy-current instrument to the properties of the test that produce the readings. While this technique will work with reflection probes, pancake probes, or bobbin probes, we have concentrated on the latter since this type of test is the most widely used in the commercial inspection of steam generators. The test properties varied include tube supports, tube sheets, copper deposits, magnetite deposits, denting, wastage, pitting, cracking and IGA. While our multiple-property technique has given good results for several years, recent advances in personal computers have considerably improved the results. Fits have been run for the differential bobbin probe that have included over 95,000 different sets of property values and their corresponding readings. Multiple-property fits of these readings have given defect size fits with root-mean-square errors under 5% of the wall thickness for ASME Section XI standards. Although the actual measurement of the defect depths is not that good (without corrections), the signal-to-noise ratio is very good, even at copper and magnetite interfaces. Different types of function fits have been tested for the various types of probes and defects, and optimum functions have been determined for each. 3 refs., 8 figs., 1 tab.

• Research Organization: Oak Ridge National Lab., TN (USA)
• Sponsoring Organization: NRC
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6492414
• Report Number(s): CONF-9010185-9; ON: DE91002860
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220200* -- Nuclear Reactor Technology-- Components & Accessories
440800 -- Miscellaneous Instrumentation-- (1990-)
47 OTHER INSTRUMENTATION
BOILERS
CHALCOGENIDES
COPPER
DEFECTS
DEPOSITS
EDDY CURRENT TESTING
ELECTROMAGNETIC TESTING
ELEMENTS
IRON COMPOUNDS
IRON ORES
IRON OXIDES
MAGNETITE
MATERIALS TESTING
MEASURING METHODS
METALS
MINERALS
NONDESTRUCTIVE TESTING
ORES
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PROBES
STEAM GENERATORS
TESTING
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TUBES
VAPOR GENERATORS