重要厂用水系统地震情况下可靠性分析

摘要

Service water system is one of the important safety systems in nuclear power plant,whose failure probability is always gained by system reliability analysis.The probability of equipment failure under the earthquake is the function of the peak acceleration of earthquake motion,while the occurrence of earthquake is of randomicity,thus the traditional fault tree method in current probability safety assessment is not powerful enough to deal with such case of conditional probability problem.An analysis frame was put forward for system reliability evaluation in seismic condition in this paper,in which Monte Carlo simulation was used to deal with conditional probability problem.Annual failure probability of service water system was calculated,and failure probability of 1.46×104 per year was obtained.The analysis result is in accordance with the data which indicate equipment seismic resistance capability,and the rationality of the model is validated.%重要厂用水系统是核电厂重要的安全系统之一,其失效概率通常由系统可靠性分析获得.而地震情况下设备的失效概率是地震动峰值加速度的函数,且地震的发生又具有随机性,目前概率安全评价中传统的故障树分析方法对此种情况缺乏足够的处理能力.本文采用蒙特卡罗模拟方法解决条件概率的问题,针对地震情况系统可靠性分析,提出了评价模型,并对核电厂重要厂用水系统进行了分析计算,得到地震情况下重要厂用水系统的年失效概率为1.46×10-4.计算结果与设备抗震性能数据符合,验证了分析模型的合理性.