液氦温区大型低温制冷系统的可靠性评估

Reliability evaluation of large-scale helium cryogenic system

针对改进Claude循环的大型氦低温制冷系统,以制冷量不足为顶事件建立了故障树模型。利用结构法对故障树模型进行定性分析,分析得到系统的最小割集为18个。利用来自不同数据库的部件失效率对故障树模型进行定量计算,得到了不同的结果,并分析其原因。对各部件的关键重要度进行了计算,以衡量各个部件对系统发生故障的贡献程度。并通过增加系统冗余部件和提高关键部件可靠度等措施,为提高系统可靠性找到了有效的解决途径。

Fault tree model of the modified Claude cycle of large-scale helium cryogenic system were presented, top event of which base on shortage of refrigeration capacity. Qualitative analysis of the fault tree model was carried out by using structure method. It is found that the minimal cut sets of system were 18. The fault tree model was calculated quantitatively based on component failure rate of different database and the reasons of different results were presented. The key importance of each components was calculated to evaluate its contribution to the system failure. By increasing the redundancy of the system and improving the reliability of key components, the reliability of system was improved.