非能动安全系统可靠性评估方法初步研究

摘要

非能动安全系统可靠性的分析是广泛采用非能动设计的新一代核电厂概率安全评价（PSA）的重要内容，其量化分析需根据非能动安全系统可靠性评估对象，确定影响系统运行的关键参数，结合事件序列对非能动系统进行研究。本文以AP1000非能动余热排出系统（PRHRS）设计阶段的可靠性研究为例，结合丧失主给水事故，根据燃料包壳完整性以及系统稳定性的功能准则，确定影响PRHRS的关键参数和设计参数。采用拉丁超立方抽样（LHS）确定输入参数组合，运用RELAP5／MOD3程序进行不确定性传递计算，进行关键参数对系统功能敏感性评价与确认，进行系统功能可靠性分析，为AP1000概率安全评价提供PRHRS可靠性估计。%The reliability evaluation of passive safety system plays an important part in probabilistie safety assessment （PSA） of nuclear power plant appling passive safety design, which depends quantitatively on reliabilities of passive safety system. According to the object of reliability assessment of passive safety system, relevant parameters are identified. Then passive system behavior during accident scenarios are studied. A practical example of this method is given for the case of reliability assessment of AP1000 pas- sive heat removal system in loss of normal feedwater accident. Key and design parameters of PRHRS are identified and functional failure criteria are established. Parameter combinations acquired by Latin hyper- cube sampling （LHS） in possible parametric ranges are input and calculations of uncertainty propagation through RELAPS/MOD3 code are carried out. Based on the calculations, sensitivity assessment on PRHRS functional criteria and reliability evaluation of the system are presented, which might provide fur- ther PSA with PRHR system reliability.