Improvement of Flaw Delectability in Dented Region in SG Tube
K. Aizawa, S. Morioka, M. Tsuda, Japan Power Engineering and Inspection Corp. , Chiba, Japan; K. Miya, The University of Tokyo, Tokyo, Japan; S. Yamada, Kanazawa University, Kanazawa, Japan
ABSTRACT A large scale verification test project extending for seven years has been executed by a technical committee organised in Japan Power Engineering and Inspection Corporation with the financial support of the Ministry of International Trade and Industry. The global purpose of the project is to improve the detection capability of flaws possibly developed in a steam generator (SG) tube, and to verify the improved technique for mock-up of SG tubes of actual size. As a part of the project, an improvement was investigated for inspection of a flaw in dented region of the SG tube by non-destructive inspection using ultrasonic wave and eddy current. New probes were developed, in which rotating type ultrasonic wave transducers or eddy current coil of four small elements generating shear and lamb waves were equipped. The probe could be moved with satisfactory traceability by the contact mechanism. In addition, the signals from the probes were processed by the computerised systems in order to have excellent S/N ratio and noise elimination. As a result, very good delectability was proved: detection of artificially introduced SCC of 51% depth. By eddy current method and 22% depth by ultrasonic method.
Publication Source: First International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurised Components , 20 - 22 October 1998, Amsterdam, Netherlands. Held by the Joint Research Centre of the European Commission.
Publisher: Woodhead Publishing Limited
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