基于分段高斯积分的在线多温度核截面生成方法研究  

On-the-fly Doppler broadening method based on piecewise Gauss quadrature for generating neutron cross section

作　　者：陈锐[1,2] 郝丽娟[1] 宋婧[1] 吴斌[1] 何鹏[1] 

机构地区：[1]中国科学院核能安全技术研究所中国科学院中子输运理论与辐射安全重点实验室,合肥230031 [2]中国科学技术大学,合肥230027

出　　处：《核技术》2017年第4期49-54,共6页Nuclear Techniques

基　　金：国家自然科学基金(No.11305203;No.11405204)资助~~

摘　　要：反应堆运行过程中温度不断变化,在模拟中常采用在线多普勒展宽方法生成各种温度下的中子核截面。已有的在线截面生成方法中,SIGMA1方法精度较高,但由于其使用了误差函数及泰勒级数展开方法,截面的生成效率偏低。本文基于FDS团队自主研发的超级蒙特卡罗核模拟软件系统SuperMC,针对不同能段截面的特点,发展了基于分段高斯积分的在线多温度核截面生成方法,在多普勒展宽共振峰较密集的区域使用高斯-厄米特积分方法,在低能区域使用高斯-勒让德积分方法,在保证核截面精度的同时提高了截面生成效率。通过典型核素截面的对比以及临界安全基准例题与多普勒反应性系数基准例题的测试,本文方法与SIGMA1方法相比平均计算效率提高5倍以上,且展宽温度越高,效率提升越明显。证明了该方法能够快速并准确地生成各种温度下的中子核截面,可用于反应堆多物理耦合计算。Background： As temperatures are constantly changing in nuclear reactor operation, on-the-fly Doppler broadening methods are commonly adopted for generating nuclear cross section for various temperatures in transport simulation. Among the existing methods, the SIGMA1 approach is exact but inefficient due to involving of error function and Taylor series expansion. Purpose： In this paper, we proposed a piecewise Gauss quadrature method for on-the-fly Doppler broadening based on SuperMC to improve efficiency with given accuracy. Methods： According to the cross section features of different energy regions, Gauss-Legendre quadrature was used in low-energy region, while the Gauss-Hermite quadrature used in high-energy region. Results： The comparison of typical nuclides cross section and benchmarking with Godiva and Doppler coefficient of reactivity were presented in detail, which indicated that the new method could generate neutron cross section rapidly and precisely at various temperatures. Compared with SIGMA1 method, the proposed method improved the computing efficiency by an average of 5 times, and higher temperature could promote the broadening efficiency. Conclusion： It showed the method could be applied in multi-physical coupling calculation of reactor.

关 键 词：中子截面 高斯积分 在线 多普勒展宽 SuperMC 

分 类 号：TL329.2[核科学技术—核技术及应用]