NDTnet 1998 Aug, Vol.3 No.8

Abstract

ISO 9000 requires the periodic calibration of measurement devices to guarantee accuracy and reproducibility in the measurements performed. For this issue, several actions have been initiated for eddy current (ET) instruments:
• Since 1992, EDF required that ET instruments used for steam generators (SG) inspection be calibrated with a system called SYSMAT 3CF. In 1996 in order to sharpen calibration criteria, EDF released specifications (ISP).
• An "ad hoc" working group from the french COFREND is preparing a document defended by french experts in European normalization working sessions for the future ET instruments verification standard.
Like all service companies, INTERCONTROLE must calibrate its ET equipment used for SG inspections. Due to the evolution of ISP specifications, new calibration means for higher performance had to be developed to replace the existing calibration system.
The objective of calibration is to check electronic characteristics of ET instrument such as:
• probe excitation signals,
• bandwidth, amplitude and phase linearity, differential balance, absolute signal integrity, cross-talk between channels
• probes are replaced by passive coupling circuits, electrically equivalent to actual probes.
The new calibration system, called SELFIC, fulfills the following objectives:
• Comply with the new EDF ISP specifications and with the European project of a standard for ET instrument calibration.
• Allow for an automatic step by step process: all measurements are carried out without operator for an improved productivity (a complete calibration is performed in less than 8 hours).
• Use conventional electrical measurement instruments which can be calibrated by their manufacturer or by specialized laboratories at a reasonable cost.
The SELFIC calibration system can produce, in less than 5 hours, a complete report for ten ET inspection configurations, corresponding to up to 280 measurements.

Abstract Source:
Book of Abstracts, 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN: 87-986898-0-00

Full-Text Source:
Proceedings of the 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN:

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