For nuclear reactor physics, uncertainties in the multigroup cross sections inevitably exist, and these uncertainties are considered as the most significant uncertainty source. Based on the home-developed 3D high-fidelity neutron transport code HNET, the perturbation theory was used to directly calculate the sensitivity coefficient of k_eff to the multigroup cross sections, and a reasonable relative covariance matrix with a specific energy group structure was generated directly from the evaluated covariance data by using the transforming method. Then, the “Sandwich Rule” was applied to quantify the uncertainty of k_eff. Based on these methods, a new SU module in HNET was developed to directly quantify the k_eff uncertainty with one-step deterministic transport methods. To verify the accuracy of the sensitivity and uncertainty analysis of HNET, an infinite-medium problem and the 2D pin-cell problem were used to perform SU analysis, and the numerical results demonstrate that acceptable accuracy of sensitivity and uncertainty analysis of the HNET are achievable. Finally, k_eff SU analysis of a 3D minicore was analyzed by using the HNET, and some important conclusions were also drawn from the numerical results.

中文翻译：

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基于2D / 1D传输码的基于扰动理论的全核特征值敏感性和不确定性（SU）分析

对于核反应堆物理而言，不可避免地存在多组截面中的不确定性，这些不确定性被认为是最重要的不确定性来源。基于自制的3D高保真中子输运代码HNET，利用扰动理论直接计算k _eff对多组截面的敏感系数，并直接生成具有特定能级结构的合理相对协方差矩阵通过使用变换方法从评估的协方差数据中提取。然后，使用“三明治法则”来量化k _eff的不确定性。基于这些方法，在HNET中开发了一个新的SU模块以直接量化k _eff一步确定性运输方法的不确定性。为了验证HNET灵敏度和不确定度分析的准确性，使用无限介质问题和2D引脚单元问题进行SU分析，数值结果表明，可以实现可接受的HNET灵敏度和不确定度分析精度。最后，使用HNET对3D微型核的k _eff SU分析进行了分析，并从数值结果中得出了一些重要的结论。