Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Nuclear reactor noise analysis using a deconvolution method

Thesis/Dissertation ·
OSTI ID:6111696
The true amplitude modulation of the resonant signal from the ex-core neutron sensors of a pressurized water reactor (PWR) was studied. A power-spectral-density curve of the fluctuating signal from an ex-core neutron sensor of the H.B. Robinson II PWR shows a resonant peak centered at 6.64 Hz. The modulation of an oscillatory signal within a selected frequency band carries information which is not present in the frequency itself. The extraction of the signal of interest in the presence of noise is generally performed by a band-pass filter, but the signal is distorted by this filtering process and a deconvolution method is developed to restore the true amplitude modulation of the signal after this distortion. The amplitude of the band-pass filtered signal is generated by the Hilbert transform, this amplitude is deconvolved with the amplitude of the impulse response of the band pass filter and a successive approximation technique is employed for a deconvolution procedure. Lateral core barrel motion and the response of the ex-core neutron sensors were simulated to study the correlation between the signals of ex-core neutron sensors located 90/sup 0/ apart around the core. From the analysis of the simulated signal it was demonstrated that the Lissajous curve derived from the band-pass filtered signal may not represent the true core barrel motion, and it is suggested that the use of the deconvolution procedure provides a closer approximation of the true core barrel motion. Results indicate that, from the analysis of the deconvolved amplitude of neutron fluctuation of the H.B. Robinson II PWR, the core barrel motion shows short bursts of resonance.
Research Organization:
North Carolina State Univ., Raleigh (USA)
OSTI ID:
6111696
Country of Publication:
United States
Language:
English