基于CMS的核电厂安全壳设计地震动确定方法

A study on the input ground motion of the containment vessel of nuclear power plants based on conditional mean spectrum

选取符合核电厂设计要求的输入地震动进行结构动力时程反应分析是保障核电厂抗震能力的重要环节。基于条件均值谱(CMS)的输入地震动选取方法具有既考虑结构自身动力特性又考虑场地地震危险性特征的优点,已经在地震工程相关领域得到应用。以核电厂安全壳结构为研究对象,从概率地震危险性分析出发,以条件均值谱为输入地震动目标谱,给出了核电厂安全壳输入地震动目标谱的计算流程;在国内外选取的18次典型地震的2 480条地震动数据库中,选取了与目标谱匹配良好的40条地震动;再利用epsilon方法在上述地震动数据库中各选取40条地震动,将这两组地震动分别输入安全壳有限元模型中进行动力时程分析,通过对比两种方法顶点的最大位移平均值与标准差,发现CMS方法选取的地震动记录无偏性最好,是一种高效合理的输入地震动选取方法。

Performing nonlinear time history analyses on structures of nuclear power plants with applicable input ground motions is important to improve the design of nuclear power plants.The selection of input ground motion based on conditional mean spectrum has been accepted by researchers because it can incorporate the behaviors of ground motions and the dynamic features of structures.Based on the probabilistic seismic hazard analysis,a condition mean spectrum was used as the target spectrum to select ground motions and40ground motion records have been selected in a database which is consisted by2480records derived from18earthquakes.In addition,the procedures of computing the target spectrum based on the conditional mean spectrum was provided.An other group of ground motions with40records have also been selected by the epsilon method.The two groups of ground motions were input in an FEM model of vessel of nuclear power plants and the largest displacements at the top of vessel were achieved.The results show that the CMS method is an applicable selection method.