Numerical Simulation of Axial Coolant Flow in Rod Bundles of a Nuclear Reactor

Numerical simulation of coolant flow inside the rod bundle of a nuclear reactor is of great engineering interest. In the design of innovative core solutions, such as high conversion tight lattice cores for Light Water Reactors (LWR), as flow distribution cannot be calculated with exact analytical methods, numerical modeling plays a vital role. A computational fluid dynamics (CFD) methodology is proposed to investigate the thermal-hydraulic characteristics in a rod bundle. Using a three dimensional numerical solution, the characteristics of an isotropic k-epsilon turbulence model for use in modeling turbulent interchange mixing within rod arrays was investigated. The model used to predict the radial component of turbulent eddy viscosity and wall shear. Existing data of Nusselt number distributions in the axial direction obtained by different authors have been employed to validate the CFD model.