| The dual fluid reactor（DFR）is a novel conceptual reactor using molten Pu Cl3-UCl3 salt as the fuel and lead as the coolant.It has superior characteristics like high-power density,high fuel utilization,high thermal efficiency and compact structure.Based on the concept,this paper carried out miniaturized design and proposed a small modular Dual Fluid Reactor（smDFR）.In view of the complex design conditions and its new design concept,the research on this reactor type is still in the early stage,so there are still many research topics to be carried out.Taking smDFR as the main research object,this paper focused on the structural design optimization and analysis of the reactor based on the fluid-thermal and fluid-structure couplings.In the fluid-thermal calculation,the molten salt in the core is given as the fixed heat source.The temperature field and velocity field of 1/6 reactor are analyzed and described in detail.In order to simplify the calculation,1/6 reactor is simplified to 1/12 reactor,which is verified as well to keep the consistency.For the distribution area,the external structure parameters are selected for the orthogonal test optimization under three factors and three levels.Based on the dimensionless quantity,a set of preliminary optimal design parameters is obtained by range analysis and variance analysis.Then the inlet of the diversion area is optimized,and the two flow modes of downstream and countercurrent are compared.In the calculation of fluid-induced vibration,the dry and wet modal analysis of the pipe is carried out.The correctness of one-way and two-way fluid structure coupling is verified by theory and numerical simulation.The single circle tube bundle model is calculated for the one-way fluid structure coupling calculation to explore the influence of the flow velocity of molten salt and lead on the deformation of the tube bundle.The two-way fluid-solid coupling calculation is carried out on the simplified lead pipe and molten salt pipe models,the main vibration frequencies of the two pipes are determined,the changes of displacement and stress under different velocity,and the time history changes of displacement and stress at different nodes under different velocity are analyzed.The time domain is transformed into frequency domain by Fourier transform,and the relationship between displacement Power Spectral Density（PSD）and velocity at different nodes is analyzed.In this paper,the most complex and comprehensive flow and heat transfer calculation of geometric structure is carried out for smDFR,and the flow induced vibration is considered in the calculation for the first time.Compared with existing studies,this calculation is more sufficient and detailed,and the results are more reliable than the previous calculation,it plays a positive role in the continuous development and engineering practice of the reactor. |
