Numerical analysis of heat transfer in rod-bundle setup

Heat transfer in case of Loss of Coolant Accident (LOCA) in case of an advanced reactor has been analysed in this work. The maximum temperature at any location on a heater rod was restricted to 600C. Heat removal capability for each of the boundary conditions studied was obtained using energy balance. Numerical simulation of the results for all the cases for which experiments were run were conducted using FLUENT. The rod bundle was divided into six sectors so that azimuthal symmetry could be utilized, and computational time and effort minimized. In case of an accident situation, decay heat removal happens by combined radiation and natural convection. Percentage contribution of heat transfer by each mode is obtained for each of the cases simulated. The temperature of the heater rod varies along the length hence radiation interaction with the surrounding rods is non-uniform. (author)