Utilization of Non-Destructive Methods for Monitoring Fatigue Crack Growth in Power Plant Material

conference paper

English

A methodology for non-destructive evaluation of the fatigue crack growth behaviour by acoustic emission and potential drop technique has been proposed. A nuclear Cr–Ni–Mo–V ferritic steel, known as GOST 15Ch(Kh)2NMFA, has been chosen for this study. This material is used for the production of a key component of a nuclear power plant - reactor pressure vessel type VVER-1000. The serviceability of pressure vessels and piping is determined by the mechanical properties of the steels being used and, in particular, by the cyclic crack resistance of the base metal and its welded joints. Therefore, the main goal of this work is to propose a suitable methodology to predict a fatigue crack growth behaviour and to simulate the material behaviour during pressure test using non-destructive techniques. The acoustic emission monitoring has been used, together with electric potential difference measurements for monitoring crack growth, to correlate the signal parameters (such as the acoustic emission counts, evolution of the frequency spectrum and the energy) and the waveform-based analysis with the defect formation mechanisms and to provide a quantified estimate of failure probability. It has been found that most of the acoustic emission hits at loading frequency of 10 Hz and stress ratio of 0,1 are generated during the decrease phase of the loading force (crack closure), especially in its lower half, and less hits are generated during the increase phase of the loading force (crack opening). The results showed that non-destructive techniques used in this work can be very useful to fatigue crack growth assessment in Cr-Ni-Mo-V steel.

acoustic emission, potential drop, fatigue crack growth, power plant material

KOULA, V.; VLAŠIC, F.; DRÁB, M.; SLUNEČKO, T.; VOLÁK, J.

2014

6. 10. 2014

VUT v Brně

Praha

978-80-214-5018-9

XIth European Conference on NDT - Conference proceedings

AEI-1

AEI-11

11

http://ecndt2014.com/