Wavelet approach for analysis of neutronic power using data of Ringhals stability benchmark

We have studied neutronic power oscillation in a boiling water nuclear reactor for three different scenarios of the Ringhals stability benchmark with a proposed wavelets-based method: the first scenario is a stable operating state which was considered as a base case in this study, and the last two correspond to unstable operating conditions of in-phase and out-of-phase events. The results obtained with the methodology presented here suggest that a wavelet-based method can help the understanding and monitoring of the power dynamics in boiling water nuclear reactors. The stability parameters frequency and decay ratio were calculated as a function of time, based on the theory of wavelet ridges. This method allows us to analyze both stationary and highly non-stationary signals. The resonant frequencies of the oscillation are consistent with previous measurements or calculated values.