基于经典微扰理论的特征值灵敏度和不确定度分析  

Eigenvalue Sensitivity and Uncertainty Analysis Based on Classical Perturbation Theory

作　　者：刘勇[1] 曹良志[1] 吴宏春[1] 祖铁军[1] 

机构地区：[1]西安交通大学核科学与技术学院,陕西西安710049

出　　处：《原子能科学技术》2015年第7期1247-1253,共7页Atomic Energy Science and Technology

基　　金：国家自然科学基金资助项目(91226106)

摘　　要：核数据不确定度作为组件/栅元计算不确定度的重要来源,备受重视和研究。本文采用经典微扰理论,推导输运计算中keff对于核数据的灵敏度系数和不确定度的计算方法。基于ENDF/B-Ⅶ.1制作多群协方差数据库,并根据所采用的组件输运求解程序的截面模型对分反应道协方差矩阵进行归并。开发灵敏度和不确定度分析程序COLEUS,对传统压水堆燃料栅元进行计算分析。数值结果表明,栅元计算的keff对235 U每次裂变中子产额的扰动最为敏感,238 U俘获截面对keff不确定度的贡献最大。目前的核数据的不确定度会给keff带来0.4%~0.5%的不确定度。The uncertainty of nuclear data is being paid to more and more attention because it is one of the most important uncertainty sources in lattice calculation.The expressions of sensitivity and uncertainty of keff with respect to the cross sections were deduced based on the classical perturbation theory.A covariance library was made based on ENDF/B-Ⅶ.1,and the individual covariance matrices of cross section were combined according to the cross section model for lattice calculation in this work.A code COLEUS（calculation tool for evaluating uncertainty and sensitivity）was developed for the sensitivity and uncertainty analysis,and a traditional PWR fuel pin cell problem was calculated and analyzed.Numerical results indicate that keffof lattice calculation is the most sensitive to the perturbation of the average number of neutrons released per fission of 235 U,while the capture cross section of 238 U has the biggest contribution to the final uncertainty.The measuring accuracy of present nuclear data will bring an uncertainty about 0.4%-0.5%for keff.

关 键 词：微扰理论 协方差 灵敏度 不确定度 

分 类 号：TL32[核科学技术—核技术及应用]