Open pool type research reactor is widely designed and operated in consideration of the reactor utilization and accessibility. Reactor structure assembly is placed at the pool bottom. Fuel assembly is installed on the grid plate inside a reactor structure assembly. Grid plate is the component of the reactor structure assembly.
Primary coolant is dumped into the reactor pool and goes to the fuel assembly through the flow guide structure in the downward flow type research reactor. Heat generated from the fuel assembly is removed by the primary coolant. Grid plate also generates the heat while the reactor is in normal operation. This heat shall be removed to avoid the hot temperature region in the grid plate. Generally, cooling line is designed to remove the heat from the grid plate. In this research, flow path of the primary coolant in the reactor pool is designed to remove the heat from the grid plate. Cooling of the grid plate is numerically simulated through the dumped primary coolant.