NDTnet 1998 Aug, Vol.3 No.8

Abstract

In MW PWRS, some Primary Pump thermal barriers can be affected by thermal fatigue cracking. In 1996, EDF defined a specific maintenance program for the rehabilitation of the nuclear power generation.

This process which comprises both repair and new spare parts delivery is based on an ultrasonic testing program of the flange implemented, among other things, in order to identify the most affected barriers.

The subject of this paper is to present the NDE technique used and developed in cooperation with JEUMONT INDUSTRIE, FRAMATOME and CTE/NORDTEST. It was requested in the specifications that the inspections had to be performed by keeping the hydraulics in place.

The technical difficulties are due to the material, the accessibility and the geometry of the flange.

They required a feasibility study with a prototype material before the industrialization of the final equipment, and led to the following definitions and realizations:

• specific focused transducers that, in contact with the cylindrical ring made by the upper radius of the flange, allow the detection and sizing of cracks after a 200 mm UT course beam propagation in wrought austenitic steel,

• a modular manipulator compatible with the integration of complementary techniques for potential inspection of others areas on the present or modified flanges,

• mock-up representing the part and its environment.

  The qualification of the equipment has been pronounced at after tests on artificial defects and real cracks affecting a flange removed form service.

  In service inspections are performed since April 97.

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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