中文摘要：

根据单值因果图的推理方法，采用中值法比较模糊概率，提出了单值因果图在模糊条件下进行推理的两种算法。最后，以核电站的一个子系统为例，分别讨论两种算法在不同模糊数下实现的推理，实验结果与实际一致，推理方法可行。研究表明：单值因果图的推理算法能实现模糊条件下的因果图推理，有效地进行故障分析。

英文摘要：

In this paper, based on the reasoning method of （SCD）, middle-value method is applied to compare fuzzy probability, and two reasoning algorithm is proposed to deal with fuzzy reasoning of SCD. The result of numerical simulating of a subsystem in nuclear plant is coincident with the fact, and it shows the fuzzy reasoning method of SCD is effective. The research shows that the fuzzy reasoning algorithm of SCD is so effective in fault analysis.