ICONE23-1585 THE AXIAL REACTION RATE DISTRIBUTION INTERPOLATION METHOD FOR FID SIGNALS IN MHI'S CORE MONITORING SYSTEM VISION

Abstract

This paper describes the robust interpolation method for axial reaction rate (RR) distributions measured by fixed in-core detectors (FID) employed in Mitsubishi online core monitoring system VISION. Contrast to the movable detector (M/D), axial power distributions measured with FIDs have to be interpolated in order to obtain power profiles, because FID's signals are discretely measured. Therefore, the interpolation method is very important for the FID system. Besides, the lack of measurement RR data due to detector failures affects strongly the power profiles. Thus, the FID system has to use the robust interpolation method. The developed interpolation method is based on the calibration method of calculated axial RR distributions with measurement values. This means, the measured RR distribution is obtained by calibrating calculated RRs to fit discrete FIDs measured values. Applicability of the present method to PWRs was confirmed by the virtual FID data, which were made from M/D measurements in a typical PWR. Then we applied the present method to the virtual FID data to reconstruct the RR distribution of M/D. The reconstructed distributions were in good agreement with the measured M/D RR distributions. We confirmed that this method is applicable to the FID system in PWR.