核电厂安全壳近场地震动下易损性分析

Fragility Analysis of Nuclear Power Plant Containment under Near-site Vibration

安全壳结构作为核电厂最重要的结构之一,其地震易损性是核电厂结构概率地震安全评价工作中关注的重点。结合非线性有限元分析技术和增量动力分析方法,对核电厂安全壳在近场地震动作用下的易损性展开分析。此外,为克服传统基于顶点位移的安全壳结构整体损伤指标的局限性,本文提出了基于能量的整体损伤指标,并验证其有效性。最后提出了考虑地震易损性参数统计不确定性的易损性曲线构造方法。研究结果表明:本文提出的安全壳结构整体损伤指标能很好地反映安全壳结构整体变形特性,并且其变异性小于基于顶点位移整体损伤指标的变异性。统计不确定性对安全壳结构不同损伤性能水准下对应的易损性曲线的整体影响可以忽略,但对易损性曲线下尾部分有一定影响。

Containment structure is one of the most important structures in nuclear power plant,and its seismic fragility is the focus of probabilistic seismic safety assessment of nuclear power plant structure.Combined with nonlinear finite element analysis technology and incremental dynamic analysis method,the fragility of nuclear power plant containment under near-site vibration is analyzed.In addition,in order to overcome the limitations of the traditional global damage index of containment structure based on top displacement,an energy based global damage index is proposed and its effectiveness is verified.Finally,a fragility curve construction method considering the statistical uncertainty of seismic fragility parameters is proposed.The research results show that the global damage index of the containment structure proposed in this paper can reflect the overall deformation characteristics of the containment structure well,and its variability is smaller than that of the global damage index based on top displacement.The overall impact of statistical uncertainty on the corresponding fragility curve of containment structure under different damage performance levels can be ignored,but it has a certain impact on the lower tail of the fragility curve.