动态故障树在反应堆保护系统可靠性评估中的实践应用

Application of dynamic fault tree in reliability assessment of reactor protection system

开展动态故障树(Dynamic Fault Tree,DFT)在反应堆保护系统(Reactor Protection System,RPS)可靠性评估中的应用研究,建立RPS动态故障树模型,采用动态二叉树法对RPS失效概率进行定量分析,使用拉丁超立方抽样对RPS失效概率的不确定性进行数值仿真,获得RPS置信度为95%的失效概率区间及各部件的敏感度,并在相同条件下与传统静态故障树方法进行对比。案例分析结果表明:1)DFT方法能够更精确地对RPS进行可靠性建模评估,更加客观地反映RPS实际运行状态和真实失效场景;2)拉丁超立方抽样能够有效获取设备的全面失效信息,充分模拟RPS的极限失效情况;3)用DFT方法的评估结果更加真实有效,有益于未来RPS的可靠性优化设计。

[Background]Reactor protection system(RPS)has complex structure,numerous equipment,and continuous failure behaviors.The traditional static fault tree cannot accurately simulate the sequential failure behaviors of the RPS.[Purpose]This study aims to obtain the failure probability of related system of RPS and the sensitivity of each component by simulating the sequential failure behaviors of RPS,and provide suggestions for the optimal design and optimization of RPS in the future.[Methods]First of all,the dynamic fault tree(DFT)modeling tools was employed to model the reliability of the RPS,a dynamic binary tree method was applied to quantitative analysis of the DFT model.Then,the Latin hypercube sampling method was adopted to quantitatively analyze the uncertainty of the RPS failure probability,and compared with the traditional static fault tree method under the same conditions.[Results]Simulation results show that the failure probability with 0.95 confidence interval of RPS is 0.015306~0.015721.The two most sensitive components are the undervoltage drive card and the undervoltage relay.[Conclusions]DFT can accurately simulate the reliability of RPS,and provide more accurate results,which is beneficial for optimization design in the future.