基于故障树分析的AP1000非能动余热排出系统的设计与优化

摘要

非能动余热排出(PRHR)系统是AP1000核电站重要安全系统之一.采用故障树方法对该系统可靠性进行评价,得到系统可能失效机理,并运用Risk Spectrum软件进行定量分析,得出系统失效概率约为9.215×10-5.结果表明,余热排出热交换器入口管线上电动阀失效关闭是导致系统失效的最主要因素.基于计算结果提出两种方法对系统进行优化:1)在另一回路增加同样1套PRHR系统；2)在原有系统基础上增加一PRHR热交换器.通过故障树分析计算,并分别从系统可靠性、复杂性、经济性等方面对两种方法进行比较发现,方法2更具可行性,建议工程上采用此方法对系统进行优化.%Passive residual heat removal (PRHR) system of AP1000 nuclear power plant is one of the important safety systems. The reliability of PRHR system was estimated by using fault tree analysis (FTA), and the potential failure mechanism of PRHR system was got. The software of Risk Spectrum was used to make quantitative analysis of PRHR system, and the probability for failure of the system was about 9. 215×10-5. The final result shows that the motor-operated isolation valve of the PRHR heat exchanger inlet failure to open is the most important factor leading to the system failure. Based on the results, two methods were put forward to optimize the system: 1) The same PRHR system was added in another loop; 2) The PRHR heat exchanger was added in original system. By the fault tree analysis and calculation, and comparing the two methods separately from the system reliability, complexity, economic and other aspects, method 2 is more feasibility, and this method is proposed to be used to optimize the system.