Influence of Sampling Interval Inaccuracy on Calculated Reactivity Error
16th Symposium of AER on VVER Reactor Physics and Reactor Safety (2006, Bratislava, Slovakia)
Core Surveillance and Monitoring
Abstract
Standard instrumentation systems at NPP are used for data acquisition, processing, transmission, archiving, etc. The standard systems carry out mentioned tasks with predetermined sampling period that should be constant during the time. Unfortunately, the real operating sampling interval does not have enough accuracy. If such standard system is used as a supplier of neutron flux for reactivity computer, the unstable sampling interval can influence calculated reactivity accuracy.
The influence of sampling interval inaccuracy on calculated reactivity error is analysed in this paper. At first the influence is investigated in the case of reactivity step change, then in the case of reactivity course obtained during reactor criticality achievement. On the basis of the gained results, the software module KRITEX in SCORPIO-Bohunice monitoring system that is used for monitoring of reactor criticality achievement was upgraded. The analysis results and some KRITEX test results are presented in the paper.