考虑地震动不确定性的核电厂楼层反应谱分析

核电厂的楼层反应谱对评价核电结构和设备的抗震安全性具有重要意义.核电设计中一般采用确定性的方法计算楼层反应谱,实际上,地震的发生具有明显的随机性.根据我国地震影响区和厂址地震发生概率的特性分析,采用Monte Carlo概率统计方法,研究了地震动的不确定性对核电厂结构地震响应的影响.实际算例的计算结果表明,在满足90%保证率的前提下,考虑地震动不确定性计算的楼层反应谱将比按确定性方法计算的楼层反应谱在峰值频段有较大幅度的降低.研究结果将加深对核电设计保守性的了解.

Analysis of floor response spectrum in nuclear power plants taking into consideration uncertainty of ground motion input

The floor response spectrum has great significance for the seismic safety assessment of structures and equipments of nuclear power plant(NPP).Deterministic methods are generally employed to evaluate the floor response spectrum in NPP design.Taking into consideration of the randomness of earthquake occurrence,based on the seismic risk analysis of earthquake affected zone and the probability density of earthquake occurrence at the sites of NPP in China,by employing Monte Carlo probabilistic statistics method,the effect of seismic uncertainty on the dynamic response of NPP structure is investigated.As indicated by the results of numerical example,with a probability of nonexceedance no less than 90%,the peak value of floor response spectrum obtained by considering the aforementioned uncertainties is somewhat lower than that obtained by ignoring the uncertainties.The research results offer a better understanding of the conservatism in NPP design.