Abstract

INTRODUCTION: Steam generators of French nuclear power plants are systematically tested using Eddy currents. The expansion zone, at the top of the tube sheet, is subject to specific inspection using a rotating pancake coil (RPC).

To complete the Eddy current inspection and to improve the detection of external circumferential flaws, LOGITEST has developped an automated ultrasonic inspection system at EW's request. This system is composed of a digital ultrasonic instrument, a programmable pusher/puller, a multi-transducer rotating probe.

The system's performance and its qualification according to EW's specifications have been successfully achieved by LOGITEST in 1995. The first inspections on site have been performed in the spring of 1996. Results on mock-up and real tubes demonstrated the system's ability to detect, position and size cracks of internal or external origin to a depth of more than 20% of the thickness of the tube. The correlation between the ultrasounds measurement and the real size of flaws have been established. Ultrasounds results have been compared with Eddy Currents results.

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Source: Conference Proceedings of the 4th International Conference of the Slovenian Society for Nondestructive Testing, 24 - 25 April 1997, Ljubljana, Slovenia.
Pages:359 - 365

Publisher:
Slovenian Society for Nondestructive Testing, Faculty of Mechanical Engineering, Askerceva 6, SLO 1000 Ljubljana, Slovenia. Tel +386 61 177 12 03, Fax +386 61 218 567, Email: janez.grum@fs.uni-lj.si.