Seismic Response Analysis Of AP1000 Shielding Building Considering Fluid Solid Interaction

There is a gravity tank which can meet the 72 hour water supply of the nuclear power plant on the top of AP1000 shielding structure.The gravity tank is an annular large container with a volume of about 2800 cubic meters.When AP1000 nuclear power plant is subjected to ground motion,the water in gravity tank and the wall can produce strong oscillations,which will have a certain effect on the response of the shielding building.So the fluid solid coupling interaction between the water and the wall of the water tank should be considered.This paper takes the AP1000 shielding building as the research object,and research on the shielding building's dynamic response with fluid solid coupling interaction under safety shutdown earthquake by large general finite element ANSYS 18.1 software,the influence of 0m,5.1m,6.8m,7.7m,8.6m,9.7m and 10.7m water level on the natural frequency of the shielding building is analyzed,the influence rules of different seismic input and water level on the dynamic response of the shielding building are revealed,the most appropriate damping level of gravity water tank under the action of earthquake is explored.The main conclusions of this paper are as follows:(1)The SOLID65 solid unit and FLUID30 fluid unit are used to establish the finite element model of AP1000 shielding factory structure considering fluid solid coupling interaction.And the modal analysis is carried out on shielding building with different water level height.The influence of the fluid-solid coupling between water and water tank wall at different water levels on the dynamic characteristics of the shield building is studied.The results show that the variation of the water level has a great influence on the fourth order natural frequency of the shielding house,but has little effect on the fifth and sixth order natural frequencies.(2)Based on the finite element model of 7 different water level shielding building,7 groups of seismic waves corresponding to RG1.60 design response spectrum are selected.The acceleration response,displacement response,floor response spectrum and bottom shear are analyzed under the two direction and three direction safe shutdown seismic response,and the influence of the fluid solid coupling between water and water tank on the seismic response of the shield building structure is studied.With the increase of the height of the water level,the acceleration and displacement of the structure of the shielding factory show a trend of first increasing,then decreasing and then increasing.When the height of the water level is at 8.6m,the acceleration and displacement of the shielded workshop are the smallest.(3)In view of shielding building with isolation devices,the seismic response of the isolating and shielding factory building under different water levels is analyzed by using the high damping rubber bearing to simulate the isolation bearing.The fluid solid coupling interaction of water and tank walls on the seismic response of isolated building structures is explored.The horizontal acceleration and displacement of the shielded factory buildings show a slight decrease,then increase,then decrease and finally increase with the increase of the water level.