These projects are centred on the Joint Research Centre of the European Commission which, in its roles of Operating Agent and Reference Laboratory, manages the programme. OECD/Nuclear Energy Agency, provides the Secretariat of the PISC Managing Board, which consists of representatives of 14 countries (10 European Union (EU) and 4 non-EU countries). The objective of Action 5 of PISC Ill is the experimental evaluation of the performance of test procedures and techniques in use for steam generator tubes in nuclear power plants during inservice inspection. The definition of the programme was based on the interest of the participating countries in a large variety of failure mechanisms. The exercise was characterised by the tube material (Inconel 600), the large number of flaws, and the inspection techniques (predominantly eddy current with a few teams using ultrasonics).The programme (sample matrix and test schedule) of the capability tests on loose tubes was formulated and started early 1990 with the circulation of training boxes. The Blind Test Tubes of the Round Robin Test were circulated to the 29 participating organisations of 9 different countries from June 1991 until end of 1993. Data collection, adaptation, evaluation and discussion took about 3 years.
There were several procedures which demonstrated good detection capability of major flaws in typical locations of the steam generator. For procedure based on Eddy current Testing (ET), the detection of axial flaws deeper than 40% of the wall Thickness (T) was often good. This capability of detection fell markedly for external flaws with a depth less than 40%T of the wall thickness. In general detection was not effective at the notification level of 20%T. For procedures based on Ultrasonic Testing (UT) only, detection was excellent for axial flaws deeper than 20%T.
Overall, the flaw sizing results show large dispersion. However for some types and sizes of flaws this dispersion was reduced; e.g. the length sizing of axial cracking.
Conclusions of this exercise indicate that there was a wide dispersion of detection and sizing performance from apparently similar procedures and even from similar techniques and that capability demonstration is necessary to qualify in service inspection procedures for steam generator tubes.
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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