“华龙一号”安全壳喷淋系统可靠性评估模型

Reliability Assessment Model for the Containment Spray System(CSS)of HPR1000

“华龙一号”是由我国自主研发、具有完全知识产权的第三代核电机组。安全壳喷淋系统(CSS)是其重要的安全保护系统之一,因此须对它的可靠性进行评估。但是,传统的可靠性评估方法在处理系统事件的多态性和事件间的不确定逻辑关系方面存在不足。为了解决这一问题,本文首先应用失效模式与影响分析(FMEA)方法,分析CSS部件的失效模式、失效原因和失效影响;随后应用故障树分析(FTA)方法,分析上述事件间的确定性逻辑关系,构建了CSS故障树;最后应用贝叶斯网络(BN)方法,基于CSS故障树,修正了条件概率表来表达系统事件的多态性和事件间的不确定逻辑关系,建立“华龙一号”CSS可靠性评估模型。应用所建立的模型对福清核电“华龙一号”CSS进行了可靠性评估,结果表明,“华龙一号”CSS失效概率为1.787×10^(−5);同时,分析了“华龙一号”CSS的关键事件,明确了改进其可靠性的方向。

Hualong Pressurized Reactor(HPR1000)is the advanced Generation-Ⅲnuclear power plant,which is independently developed by China with complete intellectual property right.The containment spray system(CSS)is one of the important safety systems for HPR1000,so it is essential to carry out the reliability assessment for the CSS of HPR1000.However,the traditional reliability assessment methods have some shortcomings in dealing with the event polymorphism and the non-deterministic logical relationship between events.In order to solve this problem,firstly,the failure modes,failure causes,and failure effects for the system components were analyzed by failure mode and effect analysis(FMEA)method.Then,the fault tree(FT)which could describe the deterministic logical relationship between failure modes,failure causes,and failure effects was established by fault tree analysis(FTA)method,and finally,the Bayesian network(BN)method was used to express the event polymorphism and non-deterministic logical relationship between events by correcting the conditional probability tables based on the FT,and the reliability assessment model for the CSS of HPR1000 was established.The established reliability assessment model was applied to calculate the failure probability of CSS of HPR1000 in East China and the results were 1.787e-05.In addition,the orientation for improving the CSS reliability of HPR1000 was clarified by identifying all its critical events.