Numerical Study on Effects of Shroud in Core Lower Plenum on Flow Field

A numerical simulation is carded out to investigate the influence of shroud in lower plenum on flow field. The geometrical model and boundary conditions in the simulation are the same as the integral hydraulic experiment which based on domestic CNP1000 nuclear power plant. CFD method is adopted, the detailed velocity and pressure distributions in core under different shroud diameters have been obtained by numerical analysis and validation between experimental and computational results. Finally the influence of shroud on mass flow and pressure distributions in core inlet and the mixing characteristics in lower plenum have been confirmed, which could be used for the optimization of core construction.