Neutron noise spectra in nuclear reactors are a convolution of multiple effects. For the IBR-2M pulsed reactor (JINR, Dubna), one part of these is represented by the reactivities induced by the two moving auxiliary reflectors and another part of these by other sources that are moderately stable. The study of neutron noise involves, foremostly, knowing its frequency spectral distribution, hence Fourier transforms of the noise. Traditional methods compute the Fourier transform of the autocorrelation function. We show in the present study that this is neither natural nor real-time adapted, for both the autocorrelation function and the Fourier transform are highly CPU intensive. We present flash algorithms for processing the Fourier-like transforms of the noise spectra.

This work is devoted to investigation of fluctuations of pulse energy of the IBR-2M reactor by the method of statistical analysis. There is a description of structural features of the IBR-2M reactor in this work and its main parameters are given. The principle of the creation of neutron pulses is shown. The work also contains a description of the method of statistical analysis and further calculations made by this method. Having the received data, a comparison of the estimates of the standard deviation with the available results for 2012 was made.