Numerical Verification On Similarity Theory Of Fluid-Structure Coupled Dynamics For Fast Reactor Vessel And Internals

Sodium-cooled fast reactor is one of the fourth-generation nuclear reactor under researching in China.It has the characteristics of large volume and thin walls,and it also contains nearly 1,700 tonnes of liquid sodium.When the earthquake happend,the liquid sodium will slosh,which will cause fluid-structural interaction effect between the wall and the internal components in the vessel.The pressure may damage the structure of the reactor vessel.Therefore,it is necessary to consider the fluid-structure interaction caused by liquid sloshing during the seismic design of the fast reactor.In previous studies on the fluid-structural interaction of the reactor vessel,the empirical formulas and numerical simulations always provided by ASME.The empirical formulas were only applicable to simple ring domains and could not be accurately applied to the fast reactor main vessels.Lack of test verification to ensure the reliability of the simulation,so it is important to carry out tests.In addition,for large-scale buildings such as fast reactor reactors,it is very difficult to perform a 1:1 scale model to test,and only scaled models can be uesd in the test.In the previous fluid-structure interaction scale model tests,most of them cannot strictly guarantee that the Froude number is equal,and the acceleration similarity ratio between the prototype and the model is 1,so that the data obtained by model cannot be accurately used into the prototype,so when designing the scale model,it is necessary to consider the similarity relationship included fluid effect,structural effect is,and the fluid-structure interaction.In view of the above problems,based on investigating of analysis methods and test methods all over the world,this paper got a kind of simulation methods for fast reactor vessel seismic test consider fluid-structure interaction.It can ensure that the fluid and structure are similar,and the fluid-structure interaction is also similar.When predecessors used this modeling method to conduct shaking table tests,they only compared the numerical simulation results and experimental results of the model,did not compare the results of the model with the prototype,and did not consider the damping effect of the fluid.In order to verify the reliability of the scaling method,two experimental scale-down models are carried out,the scale of the models is 1:2,the weight ratio of fluid to structure is also similar to the original stack.The model was subjected to modal analysis and transient analysis by ANSYS APDL,and the experimental method was used to obtain the damping ratio of fluid sloshing in the main vessel of the fast reactor,which was used as an input in numerical simulation.the results of numerical simulation were compared.The results show that the seismic response parameters of the two models meet the above theoretical criteria,and the feasibility of the modeling method is demonstrated by numerical simulation.This method can provide theoretical basis for fluid-structure interaction experiments of fast reactors.The damping ratio can also used in the numerical calculations on fast reactor vessel as a experimental basis.