MET. ΣQ CALCULATION USING MEASURED AND CALCULATED TEMPERATURE RISES

Martin Šašek, ŠKODA JS a.s, Plzeň, Czech Republic

22nd Symposium of AER on VVER Reactor Physics and Reactor Safety (2012, Průhonice, Czech Republic)
ENGINEERING FACTORS

Abstract

Methodological ? q was calculated using two different sets of data. In the first case the
standard deviation was used of the differences between thermocouples (TC) temperature rises
calculated by the MOBY-DICK software and measured at the Dukovany NPP. In the second
case the standard deviation was used of the differences between relative fuel assembly power
values calculated directly by the MOBY-DICK software and reconstructed by the Scorpio
VVER measurement and control system. ? q calculated using TC temperature rises was 0.020
or lower for Units 1 ? 3 on Dukovany NPP a and 0.025 on Unit 4 when calculated in 60 deg.
geometry and 0.026 or lower for Units 1 ? 3 and 0.046 for Unit 4 when calculated in 360 deg.
geometry. Systematical deviation in average absolute differences between calculated and
measured TC temperature rises for the fuel assemblies 1 st year in the active zone was found.
The influence of the cleaning of the reactor shaft bottom and the throttling orifices on the
methodological ?q was analyzed for Unit 4 of Dukovany NPP.

Presentation / full paper