超设计地震作用下核岛结构三维震动响应与控制研究

摘要

A three-dimensional finite element model of AP1000 nuclear island structure (shield building and containment vessel) was built by using ANSYS program.In order to ensure the accuracy of the finite element model,the model was analyzed in two finite element analysis software sets and the results from the two analyses were compared.Moreover,the ANSYS results were compared with the results in literature.The finite element model in ANSYS was used to study the three-dimensional seismic vibration response of nuclear island structure under safe shutdown earthquake and beyond-design basis earthquake.The seismic isolation technology was introduced,and analysis was performed to investigate its effectiveness under beyond-design basis earthquake.The seismic responses of the non-isolated nuclear island structure increased remarkably under the beyond-design basis earthquake compared to the safe shutdown earthquake;the top horizontal and vertical acceleration increased by 3.31 and 3.33 times,respectively,and the seismic stresses in the shield building structure exceeded the allowable stresses of materials.Compared to the non-isolated nuclear island structure,the base seismic isolation system had largely reduced horizontal accelerations,superstructure displacements,seismic stresses and base shear force under the beyond-design basis earthquake.With the base isolation,the rate of reduction in the base shear force was more than 78％.Therefore the base seismic isolation system can effectively ensure the safety of a nuclear island structure under the beyond-design basis earthquake.%建立了AP1000核岛结构(屏蔽厂房和钢制安全壳)的ANSYS有限元模型,将ANSYS模态分析结果与既有研究成果和Midas Gen计算结果对比,验证了核岛结构有限元模型的正确性,基于此模型开展安全停堆和超设计地震下的核岛结构三维震动响应研究,引入基础隔震控制技术,研究隔震核岛结构在超设计地震作用下的震动控制效果.研究结果表明,AP1000核岛结构在超设计地震作用下,水平和竖向加速度响应剧烈,顶点最大水平和竖向加速度分别为安全停堆地震下的3.31倍和3.33倍,屏蔽厂房结构应力超过材料容许应力进入非线性状态.采用基础隔震控制后核岛结构在超设计地震下的相对水平加速度、上部结构相对水平位移、构件内力和基底剪力等地震反应大幅降低,基底剪力减小率均达78％以上,隔震控制效果理想,基础隔震技术能有效地解决超设计地震下核岛结构的地震安全问题.