地震概率安全分析中地震易损度不确定性分布的研究

Study on the uncertainty distribution of seismic fragility in seismic PSA

核电厂地震概率安全分析(PSA)中,构筑物和设备的地震易损度是在给定地面运动强度条件下的条件失效概率。地震易损度的不确定性分布较为复杂,在地震PSA定量化过程中难于处理。本文针对地震易损度的数学模型进行研究,采用数值方法求解地震易损度的均值和方差。在均值和方差相等的条件下,以几种常见的不确定性分布类型近似地震易损度的不确定性分布。通过比较可以看出,Beta分布可以较为准确地描述地震易损度的不确定性分布。

In seismic PSA for nuclear power plant, the fragility of a structure or equipment is defined as the conditional probability of its failure at a given ground motion level. The complicated uncertainty distribution of seismic fragility makes it difficult to complete the quantification in seismic PSA. This paper studies the mathematical model of seismic fragility, and then calculates the mean value and the variance of fragility by numerical method. Several common uncertainty distribution types are used to approximate the distribution of seismic fragility, with the same mean value and the variance. The results show that Beta distribution can be used to approximate the seismic fragility distribution with a high level of accuracy.