Study of Local Fuel Temperature Distribution Effects Using Coupled Lattice Physics and Thermal Hydraulics Codes

Abstract

The fuel pin power distributions and the resulting temperature distributions under steady state conditions are analyzed for the CANDU-Type fuel bundle.  The physics lattice code WIMS-AECL and the fuel heat transfer code FEAT are used to obtain consistent two dimensional distributions of fission power and fuel temperature within the fuel pins. Simulated power distributions inside the pins deviate from the cylindrical symmetry that is typically assumed, resulting in the variation of fuel temperature around the pin circumference and the peak temperature being displaced from the pin center. Application of distributed fuel temperatures in the lattice physics simulation has an impact on the pin power distributions, on the distributions of plutonium and fission products, and on the reactivity of the bundle. A volume weighted average temperature is evaluated for the fuel bundle and the lattice physics results are compared to simulations with distributed fuel temperature.