Abstract
In a context of nuclear safety experiment monitoring with the non destructive testing method of acoustic emission, we study the impact of the test device on the interpretation of the recorded physical signals by using spectral finite element modeling. The numerical results are validated by comparison with real acoustic emission data obtained from previous experiments. The results show that several parameters can have significant impacts on acoustic wave propagation and then on the interpretation of the physical signals. The potential position of the source mechanism, the positions of the receivers and the nature of the coolant fluid have to be taken into account in the definition a pre-processing strategy of the real acoustic emission signals. In order to show the relevance of such an approach, we use the results to propose an optimization of the positions of the acoustic emission sensors in order to reduce the estimation bias of the time-delay and then improve the localization of the source mechanisms.
Highlights
R EACTIVITY Initiated Accident (RIA) is a nuclear reactor accident that involves an unexpected and very fast increase in fission rate and reactor power due to the ejection of a control rod
The objective of this article was to use numerical modeling to analyze the impact of the structure of the test device on recorded physical acoustic emission (AE) signals in the case of RIA experiments
A resonant frequency of the test device observed in physical signals has been identified with the help numerical computations
Summary
R EACTIVITY Initiated Accident (RIA) is a nuclear reactor accident that involves an unexpected and very fast increase in fission rate and reactor power due to the ejection of a control rod. When the structure is complex such as the test device of a nuclear safety experiment reactor, the potential impacts of several parameters have to be taken into account, making difficult the estimation of the transfer function by experimental methods. The main objective of this article is to use the numerical modeling in the particular case of RIA experiments in order to explore different scenarios of wave propagation in test device and compare the associated transfer functions. The obtained numerical signals are analyzed and the impacts of the position of the source mechanisms, of the position the sensors and of a change of coolant fluid are studied. We discuss the results and analyze their impact on the experimental protocol
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