CFD Analysis of Thermal Stratification of China Lead Alloy Cooled Research Reactor (CLEAR-I)

Thermal stratification phenomena is observed in the upper plenum under the reactor scram transient of CLEAR-I. This will bring a bad effect on the natural circulation of the coolant Lead bismuth eutectic (LBE) in the primary circuit, which give rise to thermal stress on structural components. A CFD analysis of 2D axisymmetric domain to predict thermal stratification in scram conditions from full power operation has been performed by commercial code ANSYS 14.0. From the result, it can be seen that the thermal stratification can be formed in the hot pool under reactor scram conditions, the interface of the clear stratification was located below the inlet window of heat exchanger, but it will never stop the natural circulation of the primary circuit. The results obtained will be used to make an optimized design of China Lead Alloy Cooled Research Reactor (CLEAR-I).