SURVEILLANCE METHOD OF REACTOR CORE STABILITY FOR BOILING WATER NUCLEAR REACTOR

摘要

PURPOSE:To improve plant operability by obtaining a width reduction ratio on a real time basis from an autoregression coefficient and also by presuming the width reduction ratio with a specific precision through making a time constant for a successive calculation of the autoregression coefficient, to be variable, accordingly to the presumed width reduction ratio. CONSTITUTION:A plant signal measured at a plant is converted to a digital signal by an A/D converter 1. This digital signal is fed to a pre-processor 2 to filter out unnecessary low frequency component. AR coefficient calculators 3 and 4 select optionally a sequential process or a batch process and then calculate the AR coefficient with a specific time interval, from a certain time series data which is an output of the pre-processor 2. The AR coefficient obtained from the AR coefficient calculators 3 or 4 is fed to a width reduction ratio calculator and the width reduction ratio is calculated there. The width reduction ratio is fed to a time constant setting device 6 and the time constant is obtained accordingly to an equation 1. The width reduction ratio obtained by the width reduction coefficient calculator 5 is displayed on a display device 7 and an alarm is generated when a specific value is exceeded.