CFD-analysis of the moderator water flow in the HPLWR

The first part of this work is a numerical analysis of the upward directed flow path of the moderator water in the gaps between the fuel assemblies for the HPLWR1. The modeling of this flow has been done with help of a porous media approach. For this purpose, the CFD-software Star-CD 3.26 has been used. The main objective is to avoid local temperature peaks of the moderator water above the pseudo-critical point and to cause stable temperature stratification in the gaps to ensure a steady neutron flux at full load and part load cases. The second part of this work is the analysis of the downward directed moderator water flow in the channels of the reflector. Therefore a classical CFD-approach with the well-known Navier-Stokes equations is used. The aim of this second analysis is to investigate temperature peaks inside of the reflector channels and to exclude natural convection phenomena there. Both analyses confirm that the chosen configuration is stable in the entire load range. (authors)