Abstract Best estimate plus uncertainty methodology is an advanced technology for licensing application of the nuclear power plants, but some aspects can still be improved in the conventional input-driven methodologies. For instance, uncertainties of the closure models are not properly handled; local sensitivity analysis methods not suitable for complex nuclear systems are still widely utilized; the sensitivity analysis process needs to be performed again every time new parameters are identified. Optimization researches were carried out in the study. A structural method was proposed to quantify the uncertainties of the closure models, and a low-cost moment-independent global sensitivity analysis method was developed to improve the sensitivity analysis framework. By integrating the improvements into the conventional input-driven framework, an uncertainty method with model treatment and improved sensitivity analysis was obtained. Finally, the method was validated through a large break loss of coolant accident in a three-loop pressurized water reactor.

中文翻译：

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用模型处理和优化全局灵敏度分析改进不确定性方法及其在压水堆中的应用

摘要 最佳估算加不确定性方法是核电厂许可申请的一项先进技术，但传统的投入驱动方法在某些方面仍有待改进。例如，闭合模型的不确定性没有得到妥善处理；不适合复杂核系统的局部灵敏度分析方法仍在广泛使用；每次确定新参数时，都需要再次执行敏感性分析过程。研究中进行了优化研究。提出了一种结构化方法来量化闭合模型的不确定性，并开发了一种低成本的与矩无关的全局敏感性分析方法来改进敏感性分析框架。通过将改进集成到传统的输入驱动框架中，获得了一种具有模型处理和改进的敏感性分析的不确定性方法。最后，该方法通过三回路压水反应堆中冷却剂的大量断裂损失事故得到了验证。