Neutronics And Thermal-Hydraulic Coupling Research For SmDFR Based On Serpent And OpenFOAM

The small modular dual-fluid molten-salt reactor(smDFR)adopts the mixture of liquid uranium and plutonium chloride as fuel and the lead as coolant.With its small size,light weight,and inherent safety,smDFR can be used as a mobile energy supply equipment for vehicles or ships.At present,the researches of smDFR are still in the stage of design optimization and validation.Its steady-state analysis is still based on a single physical field with uniform material parameters.And the neutronic physics calculation have not consider the thermal-hydraulic feedback caused by the doppler effect and density changes of the fuel,which brought about obvious errors in the calculation results.To provide reliable three-dimensional parameter distribution for core design optimization,based on smDFR model,this work developed a coupled calculation program named PySOCCT by Python to achieve data interaction and coupling between the Monte Carlo program Serpent2 and the CFD program Open FOAM.For reducing input errors and improving the calculation efficiency,the sub-programs about creating input files automatically and mesh pre-processing have been developed in the coupled framework.Two validation cases are set to verify the accuracy of PySOCCT.The reference results were set as standard values.One case is a single PWR rod with different fuel enrichment distributions,another is a PWR 3×3 lattice with a guide tube.The coupled calculation results show that in the first case,the maximum relative deviation of the coolant temperature distribution is 0.62%,and the one in density field is 1.16%.Second case shows the maximum relative deviation of the coolant temperature distribution is 0.63%,the one in density field is1.24%,and the maximum deviation of power factor distribution is 0.54%.The verification results illustrate that the program with high accuracy in coupled calculation.The temperature and density distribution of all materials have been calculated based on single smDFR fuel tube by PySOCCT.Moreover,the influence of fuel thermal properties and inlet velocity have been analyzed with rated power.Through comparison between different mapping schemes,the results calculated by PySOCCT can figure out the dependence of specific parameters and help to reduce the mapping errors.Based on the above results,the smDFR core model is built with symmetric mapping scheme to improve the calculation efficiency.The calculation results show that the neutron flux distribution,and three-dimensional distribution of the temperature and density of fuel and coolant.These parameters can be important reference for the multi-physical coupling research of smDFR system.