Anti-seismic Performance Of Base Isolation Structure For Lead-bismuth Cooled Reactor

With the advancement of science and technology,increasing energy demand and increasing attention to environmental protection,clean and efficient nuclear power generation has become the focus of development in the world.As we all know,nuclear power plant accidents can cause serious environmental pollution,heavy economic losses and severe social problems.In a sense,earthquake accidents at nuclear power plants are not allowed.Due to the randomness of earthquakes and the complexity of nuclear power plant systems,the seismic safety of nuclear power plants still faces enormous challenges.There is still a large gap between the seismic safety of the nuclear power plant structure and actual demand,and it is of great research value to improve the seismic safety of nuclear power plants.Based on the structure of lead-bismuth alloy cooling reactor and the study of isolated nuclear power plant,in this paper the lead-bismuth reactor pressure vessel and building construction of SPIC is taken as the research object,decreasing the earthquake response of the main structure of nuclear power plant is proposed as the research purposes,Structural properties study of lead-bismuth pressure vessels,dynamic analysis of support structure,Comparison of anti-seismic performance to traditional non-isolation and isolation structure are taken.The specific research content and main conclusions are as follows:Firstly,applying the theoretical formula of Housner's reservoir model,the approximate theoretical formula of the liquid vibration model of the lead-bismuth pressure vessel is provided.A simplified analysis model of lead-bismuth pressure vessel is established by concentrated mass method.By comparing with ANSYS computational model,the equivalent method of the pressure vessel of the lead-bismuth reactor is practicable.it is indicated that the simplified model can be used for seismic analysis of structures with high precision and efficiency.Secondly,around the structural characteristics of the nuclear power plant and the lead-bismuth reactor building,the isolation lead-bismuth reactor building has been constructed.Compared with the non-isolation structure,the isolation structure of lead-bismuth reactor building has a good shock absorption effect.Under the action of seismic wave of AP1000 nuclear power plant,the isolation structure of lead-bismuth reactor building has 77% damping effect on the base shear force.Although the displacement response of the isolation structure is large,the displacement is mainly concentrated in the isolation layer,and the structure of the lead-bismuth reactor is relatively small.Thirdly,it is proposed that the structure of nuclear power plant not only requires significant damping effect,but also has stable anti-seismic robustness and site adaptability.By matching the characteristics of isolation structure,the seismic response of the lead-bismuth reactor building is about twice as high as that of the site class I under the site class II-IV.In all the conditions of the site,the isolation structure of the lead-bismuth reactor has a stable damping effect on the base shear force.It reveals that the lead-bismuth reactor has good applicability and anti-seismic robustness.