STUDY OF CORE SUPPORT BARREL VIBRATION MONITORING USING EX-CORE NEUTRON NOISE ANALYSIS AND FUZZY LOGIC ALGORITHM

다국어 초록 (Multilingual Abstract)

The application of neutron noise analysis (NNA) to the ex-core neutron detector signal formonitoring the vibration characteristics of a reactor core support barrel (CSB) wasinvestigated.
Ex-core flux data were generated by using a nonanalog Monte Carlo neutron transportmethod in a simulated CSB model where the implicit capture and Russian roulette techniquewere utilized. First and third order beam and shell modes of CSB vibration weremodeled based on parallel processing simulation. A NNA module was developed to analyzethe ex-core flux data based on its time variation, normalized power spectral density,normalized cross-power spectral density, coherence, and phase differences. The data werethen analyzed with a fuzzy logic module to determine the vibration characteristics.
The ex-core neutron signal fluctuation was directly proportional to the CSB's vibrationobserved at 8Hz and15Hzin thebeammodevibration, and at 8Hz inthe shellmodevibration.
The coherence result between flux pairs was unity at the vibration peak frequencies.
A distinct pattern of phase differences was observed for each of the vibration models.
The developed fuzzy logic module demonstrated successful recognition of the vibrationfrequencies, modes, orders, directions, and phase differences within 0.4 ms for the beamand shell mode vibrations

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