基于敏感性分析的核数据调整模块开发与验证

Development and validation of a nuclear data adjustment module based on sensitivity analysis

  • 摘要: 随着中子学计算方法的发展和精确建模能力的提高,核反应堆物理计算程序中模型近似和离散方法带来的误差逐渐减小,而核数据因其测量难度高,成为影响计算精度的关键输入参数。因此,基于自主研发的敏感性和不确定性分析平台SUPES,开发了基于敏感性分析和广义线性最小二乘算法的核数据调整模块。首先,由敏感性分析获取响应关于输入参数的变化规律;其次,通过相似性分析筛选中子学层面上相似程度高的实验装置参与核数据调整;最后,采用广义线性最小二乘算法使得计算值与实测值之间的误差最小,获得核数据调整量。根据临界基准题HEU-MET-FAST-078中的22个算例,对ACE格式连续能量数据库进行调整,数值结果表明,有效增殖因子keff的均方根误差从3.10×10−3降低到1.53×10−3。通过数值结果对比分析,验证了所开发的核数据调整模块的正确性。

     

    Abstract:
    Background With the development of neutron calculation methods and improved modeling capabilities, the errors introduced by model approximations and discretization methods in nuclear reactor physics calculations have gradually decreased. However, nuclear data, due to the challenges in measurement, have become the key input parameter affecting computational accuracy.
    Purpose In this study, a nuclear data adjustment module based on sensitivity analysis and the generalized linear least squares algorithm was developed within the self-developed sensitivity and uncertainty analysis platform, SUPES.
    Methods First, sensitivity analysis was used to determine the relationship between system responses and input parameter variations. Next, similarity analysis was applied to select experimental setups with high similarity at the neutron physics level. Finally, the generalized linear least squares algorithm was employed to minimize the error between computed and measured values, resulting in nuclear data adjustments.
    Results The adjustment of the ACE format continuous energy database was performed on 22 cases from the critical benchmark HEU-MET-FAST-078. The numerical results show that the root mean square error of the effective multiplication factor (keff) was reduced from 3.10×10−3 to 1.53×10−3.
    Conclusions The comparison and analysis verified the correctness of the developed nuclear data adjustment module.

     

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