NECP-Atlas中协方差数据制作模块的开发与验证  

Development and verification of covariance data generation module in NECP-Atlas

作　　者：黄义涵 祖铁军[1] 曹良志[1] 吴宏春[1] HUANG Yihan;ZU Tiejun;CAO Liangzhi;WU Hongchun(School of Nuclear Science and Technology,Xi'an Jiaotong University,Xi'an 710049,China)

机构地区：[1]西安交通大学核科学与技术学院,西安710049

出　　处：《核技术》2024年第7期90-98,共9页Nuclear Techniques

基　　金：国家重点研发计划(No.2022YFB1902600);国家自然科学基金(No.12075183)资助。

摘　　要：不确定度量化已经成为反应堆物理分析的普遍需求,核数据的协方差数据是开展不确定度量化的基础数据。在核数据处理程序NECP-Atlas中开发了协方差数据产生模块covar_calc,产生适用于蒙特卡罗程序的连续能量协方差数据库与确定论程序的多群协方差数据库。covar_calc可根据不同核数据在评价核数据库中的存储格式及不同的计算方法,分别处理评价核数据库给出的所有协方差数据,包括:平均裂变中子数、截面、次级粒子角度分布、裂变谱、共振参数、中子活化截面等数据的协方差数据。通过与核数据处理程序NJOY21中协方差数据制作模块的对比验证,表明NECP-Atlas制作的多群协方差数据库的精度与NJOY21相当,最大偏差小于0.1%。在此基础上使用蒙特卡罗计算程序NECP-MCX和不确定度量化程序NECP-UNICORN分别计算得到不同基准题的灵敏度系数,并分别结合连续能量协方差数据库和多群协方差数据库,利用“三明治公式”计算得到最终的不确定度。结果表明,基于NECP-Atlas制作的多群协方差数据库计算得到的不确定度具有与NJOY21相当的精度。连续能量协方差和多群协方差制作精确,满足蒙特卡罗程序和确定论程序使用需求。[Background]The quantification of uncertainty has become a common requirement in reactor physics analysis whilst the covariance data of nuclear data serves as the foundational data for conducting uncertainty quantification.[Purpose]This study aims to develop a covariance data generation module,named covar_calc,embedded in the nuclear data processing software NECP-Atlas,a nuclear data processing program independently developed by the laboratory of nuclear engineering computational physics(NECP)of Xi'an Jiaotong University,to produce continuous energy covariance data for Monte Carlo programs and multi-group covariance data for deterministic programs.[Methods]Within the framework of NECP-Atlas,covar_calc module was developed to process all covariance data provided in evaluated nuclear data,according to the different storage formats of nuclear data and different computational methods.Covariance data of various parameters such as average fission neutron multiplicities,cross sections,angular distributions of secondary particles,fission spectrum,resonance parameters,and neutron activation cross-sections,were all be processed by covar_calc.Comparative verification was carried out with the covariance data production module in the nuclear data processing software NJOY21.Finally,sensitivity coefficients for different benchmarks were calculated using both the Monte Carlo calculation code NECP-MCX and uncertainty analysis code NECP-UNICORN,and the final uncertainties were computed by incorporating both continuous energy covariance data and multi-group covariance data,and utilizing the"Sandwich formula".[Results]Comparison results demonstrate that the accuracy of the multi-group covariance data produced by NECP-Atlas is equivalent to that of NJOY21 and the maximum bias is less than 0.1%.The uncertainties calculated using the multi-group covariance data generated by NECP-Atlas exhibit comparable accuracy to those obtained with NJOY21.[Conclusions]The precision in creating both continuous energy covariance and multi-group covari

关 键 词：协方差数据 不确定度量化 评价核数据 核数据处理 协方差计算 

分 类 号：TL32[核科学技术—核技术及应用]