Simulation of error in suppression of Xenon oscillations in a WWER-1000 nuclear reactor

Abstract

AbstractErrors in suppression of xenon oscillations refer to anticipated operational occurrences. Such errors could be treated as a long-term absence of some special actions used to stabilize the power field or incorrect movements of the control and protection system absorber rod. In this study, the movement of control rod, causing maximum power tilt, has been simulated in a WWER-1000 reactor by using NJOY and MCNPX codes and also a single heated channel model for thermal hydraulic calculations. The results of developed single heated channel model have been checked with RELAP5 results for WWER-1000. Analyses are based on linear heat rate of the most-powered fuel rod in the beginning of cycle and end of cycle. First, we determined the position of this most-powered fuel rod at the beginning and end of cycle separately. Then the most-powered fuel rod is segmented axially into equally spaced zones to study the effect of axial linear heat rate profile. Finally, the results have been compared with Final Safety Analysis Report of WWER-1000 reactor. It is seen that there is a great similarity between calculated and reported results.