Keywords: advanced loose parts monitoring system, ALPMS, LPMS, loose parts detection, Fourier transform, continuous wavelet transform, scalogram, wavelet coherence, nuclear reactors, nuclear energy, nuclear power, nuclear technology, nuclear science, Hungary, wavelet analysis
The Advanced Loose Parts Monitoring System (ALPS) and wavelet analysis
The Advanced Loose Parts monitoring System (ALPS), is installed in each Unit of Paks NPP. Its characteristics and some interesting results are presented. Wavelet analysis is being introduced to data evaluation techniques. The short-time Fourier transform and the continuous wavelet transform techniques have been used to present the time signal in a time-frequency and time-scale plane. Characteristic frequencies of the physical acoustic system and the growing frequencies of spectrum components during the start-up of the main coolant pumps are clearly seen on those pictures. The newly applied wavelet coherence promises to find new oscillation in the pair of signals, which remain hidden in time-dependent autospectra.