Abstract Best estimate plus uncertainty (BEPU) analysis has been widely adopted for safety evaluation of the nuclear reactor, and the sensitivity analysis is an important part of the BEPU methodology. Local sensitivity analysis methods are still widely utilized in the methodology, which is not suitable for complex non-linear nuclear systems. The global sensitivity analysis is essential but the biggest problem is that the computational cost can hardly be accepted. In this study, the moment-independent global method was adopted and optimized, and a low-cost method was obtained and assessed. The sensitivity analysis of a large break loss of coolant accident (LBLOCA) of the LOFT facility was carried out by using the method. Results show that the optimized method can well evaluate the sensitivity indices with very low cost and relatively high accuracy, and the result obtained through the optimized method is much more reliable than that of the local sensitivity analysis method.

中文翻译：

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基于优化矩无关法的冷却液事故LOFT大破口损失全局敏感性分析

摘要 最佳估计加不确定性（BEPU）分析已被广泛用于核反应堆的安全评价，敏感性分析是BEPU方法论的重要组成部分。局部灵敏度分析方法在该方法论中仍被广泛使用，不适用于复杂的非线性核系统。全局敏感性分析必不可少，但最大的问题是计算成本难以接受。本研究采用并优化了矩无关全局方法，获得并评估了一种低成本的方法。应用该方法对一起LOFT设施冷却剂大漏失事故（LBLOCA）进行了敏感性分析。结果表明，优化后的方法可以很好地评价敏感度指标，成本极低，准确度较高，