A new data-driven sampling-based framework was developed for uncertainty quantification (UQ) of the homogenized kinetic parameters calculated by lattice physics codes such as TRITON and Polaris. In this study, extension of the database for the delayed neutron data (DND) is performed by exploring more delayed neutron experiments and adding additional isotopes/actinides to the data libraries. Afterwards, the framework is utilized to obtain a deeper knowledge of the kinetic parameters’ sensitivity and uncertainty. The kinetic parameters include precursor-group-wise delayed neutron fraction (DNF) and decay constant. Input uncertainties include nuclear data (i.e., cross-sections) and DND (i.e., precursor group parameters and fractional delayed neutron yield). It is found that kinetic parameters, especially DNFs, have large uncertainties. The DNF uncertainty is driven by the cross-section uncertainties for LWR designs, while decay constant uncertainty is dominated by the DND uncertainties. The usage of correlated U-235 thermal DND in the UQ process significantly reduces the DND uncertainty contribution on the kinetic parameters. Large void fraction and presence of neutron absorber (e.g., control rod) increase the DNF uncertainty due to the hardening of neutron spectrum. High correlation between the DNF groups () is observed, while the decay constant groups () show weak correlation to each other and also to DNF groups. The DNF uncertainties of the dominant precursor group 4 for PWR, BWR, and VVER are about 7.5%, 9.4%, and 7.6%, respectively. The DNF uncertainty grows to larger values after fuel burnup. Kinetic parameters’ values and uncertainties provided here can be efficiently used in subsequent core calculations, point reactor kinetics, and other applications.

中文翻译：

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UAM基准下晶格动力学参数的数据驱动和前体组不确定性传播

开发了一个新的基于数据采样的框架，用于对由TRITON和Polaris等晶格物理代码计算出的均匀化动力学参数进行不确定性量化（UQ）。在这项研究中，通过探索更多的延迟中子实验并向数据库中添加其他同位素/ to系元素来扩展延迟中子数据（DND）数据库。之后，利用该框架获得对动力学参数的敏感性和不确定性的更深入的了解。动力学参数包括前体组延迟中子分数（DNF）和衰减常数。输入不确定性包括核数据（即横截面）和DND（即前体组参数和分数延迟中子产率）。发现动力学参数，特别是DNF，具有很大的不确定性。DNF不确定性由LWR设计的横截面不确定性驱动，而衰减常数不确定性则由DND不确定性主导。在UQ过程中使用相关的U-235热DND可以显着降低DND对动力学参数的不确定性贡献。由于中子谱的硬化，大的空隙率和中子吸收剂（例如控制棒）的存在增加了DNF的不确定性。DNF组之间的高度相关性（控制棒）由于中子光谱的硬化而增加了DNF的不确定性。DNF组之间的高度相关性（控制棒）由于中子光谱的硬化而增加了DNF的不确定性。DNF组之间的高度相关性（），而衰减常数组（）彼此之间以及与DNF组之间都显示出弱相关性。对于PWR，BWR和VVER，主要前体组4的DNF不确定度分别约为7.5％，9.4％和7.6％。燃料燃尽后，DNF不确定度会增大。此处提供的动力学参数值和不确定性可以有效地用于后续堆芯计算，点反应器动力学和其他应用中。