Wavelet analysis for sub-criticality monitoring

PNC TN9410 97-011, 45 Pages, 1997/01

PNC-TN9410-97-011.pdf:1.51MB

In the study for the development of the sub-criticality monitoring system for the nuclear fuel facilities, wavelet analysis was applied to detect the neutron multiplication system is approaching to critical. Neutron noise signal is the measured data for the monitoring, and the data was accumulated in the multi-channel scaler of the neutron detection system. From the point of view of the simplicity of numerical calculations of the MCS data, discrete wavelet transform by using the Cardinal spline functions was selected in the varaiety of wavelet funtions. Simulated noise data of the system without neutron multiplication was numerically produced and also transformed by the wavelet analysis procedure to be compared to the results from the nutron multiplication system. The approach to the critical can be detected by checking the difference of the two kinds of transformed results, with and without neutron multiplications. The method was applied to the neutron noise signal obtained at the Deuterium Critical Assembly(DCA), and it was confirmed that approaching to critical can be detected by tbe present method.