Analysis of coolant flow in central tube of VVER-440 fuel assemblies
21st Symposium of AER on VVER Reactor Physics and Reactor Safety (2011, Dresden, Germany)
Nuclear applications of three dimensional thermal hydraulics
Abstract
Three dimensional CFD model has been built to investigate the coolant flow in the
central tube of the VVER-440 fuel assemblies. The model was verified based on measured
data of the Kurchatov Institute 5. With the model calculations were performed for two fuel
assemblies used in Paks NPP. One of them has symmetrical and another has inclined pin
power profile. Ratios of the outlet mass fluxes of the central tube to the inlet mass fluxes of
the rod bundle were determined. Heat up ratios of the tube and rod bundle flows were
calculated too. Sensitivity of the results on the assembly power distribution, inlet temperature
and mass flow rate was investigated. The results of these simulations can be used as boundary
conditions of central tube in studies of coolant mixing in fuel assembly heads.