Research on CFD Calculation and Analysis Technology of Porous Media in Sodium Cooled Fast Reactor Core

Abstract The composition of sodium cooled fast reactor fuel components is relatively simple, without too many complex structures. Therefore, it is necessary to carry out thermal hydraulic simulation of the entire core and large watershed. However, Due to the complexity of the existing CFD refined methods in modeling and grid partitioning, the long calculation time lead to the inconvenience of the real time analysis. Therefore, the porous medium method is used for CFD analysis in the entire core and inter-wrapper flow of sodium cooled fast reactors. At the same time, the conjugate heat transfer method is used to simulate the fuel assembly box wall and separate the flow inside and between the boxes for research. The research results indicate that the porous media method can greatly simplify the difficulty of modeling and the number of grid divisions. Through comparative analysis and verification, it is found that the influence of inter-wrapper flow on the flow inside the core is limited. Therefore, in actual modeling, the inter-wrapper flow, as well as components with extremely low power flow rates such as neutron sources and reflector layers, are ignored. Only fuel components are analyzed, while other components are ignored. On this basis, flow partitioning was applied to the core, and the results were compared with those without partitioning. The results showed that flow partitioning promoted the flattening of the core outlet temperature. Finally, the calculation results will be compared with experimental data to demonstrate the effectiveness of the method using porous media. The calculation has achieved sub real-time and has good engineering application value.