Oumar I. Traoré, Laurent Pantera, Nathalie
Favretto-Cristini, Paul Cristini, S. Viguier-Pla,
(2018)
Impact of the Test Device on Acoustic Emission
Signals from Nuclear Safety Experiments:
Contribution of Wave Propagation Modeling to
Signal Processing.
IEEE Transactions on Nuclear Science
65 9 2479-2489
Print ISSN: 0018-9499,
Online ISSN: 1558-1578, DOI: 10.1109/TNS.2018.2844291
- Classification
- 34K08, 35P05, 76Q99
- Keywords
Acoustic Emission, Reactivity Initiated Accident,
Wave Propagation, Spectral Element Modeling
Abstract : A strongly energetic spectral component has been
observed in the operating noise of a research reactor before
the beginning of reactivity initiated accidents (RIA). We identify
the source of this component by means of analytical derivations
of torsional wave propagation in the test device. Numerical
simulations, performed with a spectral-element method, confirm
that this component is a resonant frequency of the device, and
allow to evaluate the impact of wave travelpath in the test
device on the acoustic emission signals recorded during RIA
experiments. The transfer function of the test device is strongly
dependent on both the source and the receiver locations, which
precludes signal processing by deconvolution when the location of
the AE source mechanism is unknown. Moreover, the geometry
and the configuration of the test device may not influence signals
in the low-frequency range, and hence the signals generated by
source mechanisms located on the fuel clad such as clad failures.
Finally, replacing the heat transfer fluid (pressurized water) by
sodium leads to an increase in the recorded signal amplitude
and a small shift of the frequency content towards the high
frequencies. The results obtained in this paper may be useful
to improve design of future RIA experiments. They are also
useful to understand wave propagation in the core of the reactor
and to choose appropriate signal processing tools for recovering
the source of acoustic emission signals generated during RIA
experiments.