自适应蒙特卡罗方法计算海水淡化堆非能动系统物理过程失效概率

Calculation of Physical Process Failure Probability of Passive Systems in NDR by Adaptive Monte Carlo Method

物理过程失效的研究对于非能动系统十分重要。目前,已被广泛应用的重要抽样蒙特卡罗方法需要依赖改进的一次二阶矩法寻找设计点。本文应用自适应蒙特卡罗方法,利用自适应方法确定重要密度函数,避免了改进的一次二阶矩法的不足,提高了抽样效率,而且在相同的模拟条件下,可较好地改善相对误差。以245 MW海水淡化堆非能动系统为研究对象,用自适应蒙特卡罗方法和目前已有的其他方法研究非能动系统的物理失效概率,最后对各方法在非能动系统上的适用性进行比较分析。

Physical process failure plays a crucial role in the passive systems. Presently, the importance sampling Monte Carlo method is most widely used in the research of physical process failure probability, but it has to rely on the improved first-order second-moment （ FOSM ） method in searching of design point, and can not avoid the shortcomings of FOSM. The adaptive Monte Carlo method introduced in this paper chooses the important probabilistic distribution function by adaptive method, avoiding the shortcomings of FOSM, improving the sampling efficiency and the accuracy. Taking the passive system of nuclear desalination reactor （ NDR ） for an＇example, this paper evaluates the physical process failure probability by the adaptive Monte Carlo method and the presently used methods, and then compares and analyzes the adaptiveness of various methods on the passive systems.