核电厂事件序列的分阶段分析  

Accident Analysis by Phase-mission Methods in Nuclear Plant

作　　者：玉宇[1] 童节娟[1] 刘涛[1] 赵军[1] 张阿玲[1] 

机构地区：[1]清华大学核能与新能源技术研究院,北京100084

出　　处：《科技导报》2009年第15期83-86,共4页Science & Technology Review

摘　　要：概率安全评价(PSA)常用的技术手段是事件树(ET)结合故障树(FT)的分析方法,由于ET/FT都是以布尔逻辑为基础的静态分析技术,对于事件发生时间不同所引起的事故进程的变化缺乏足够的处理能力。然而,事件发生的准确时间对确定事故情景的发展有时是十分关键的。本研究针对压水堆核电厂丧失主给水后辅助给水系统失效时间对事故进程的影响,采用可靠性框图和事件树方法,分阶段对该事故序列进行评价,结果表明,此事故进程中,提高操纵员执行U1规程的可靠性有利于降低本事故情景下发生堆芯损坏的可能性。简要分析了该方法的适用性。Probabilistic Safety Assessment （PSA） is a systematic engineering evaluation technology, widely used in the nuclear power plant safety evaluation. In PSA, the Event Tree （ET） and Fault Tree （FT） are commonly used. However, it is. common that a mission in different phases is executed by different systems or function modules in an engineering project. Conventional ET/FT are static analysis methods based on Boolean logic technology, not flexible enough to handle the dynamic problems directly, e.g. to change the accident scenario evolution at different stages. Sometimes the accurate timing of the events is important for the accident sequence development. The method to evaluate the accident sequence in different phases can be used to solve the problem. The basic idea of this method is to convert the multi-phase system to several singlephase systems to be analyzed separately, and then the results are combined to get the final consequence. Reliability diagram and event tree are two of the important analysis methods for phased analysis. In this paper, they are used to analyze the accident of loss of the main feed water in different phases. It is shown that to improve the reliability of execution process, UI can help to reduce the probability of core damage in this accident. At last, the applicability of the two methods are discussed briefly. In the reliability diagram, since the real condition of the accident cannot be reflected completely, the illogical cut set should be deleted by hand. In the event tree, since the logical order can be partially reflected, the illogical cut set can be avoided. The two methods are both based on FT or ET eventually, so the accident development with the time cannot be described entirely, and the result is conservative. When the mission time is short, this deviation can be accepted.

关 键 词：分阶段 事故序列 系统可靠性 故障树 事件树 

分 类 号：TM623[电气工程—电力系统及自动化]