双约束核素筛选与燃耗链压缩算法研究

在进行反应堆燃耗计算时，由于评价核数据库中各核素反应截面、寿命差异大，因此形成的燃耗矩阵规模大、刚性强。为降低燃耗矩阵规模、改善矩阵病态程度，有必要研究适用于多种堆芯设计研发需求的燃耗链压缩算法，并形成压缩燃耗链和数据库。首先建立了核素筛选标准，根据各个核素对中子吸收率和重要核素核子密度的贡献率对核素重要性进行排序筛选，研究了基于中子吸收率和重要核素产量贡献率的双约束燃耗链压缩算法，并完成相关程序模块的开发。通过对Kylin-2程序数据库压缩的计算分析，验证了该燃耗链压缩算法的可行性。采用压缩数据库可使其在保持原有计算精度的基础上大幅减少计算时间、提高计算效率；通过燃耗链压缩算法的研究与压缩数据库的实现，为从评价数据库出发制作压缩数据库提供了技术支撑。 

Research on Dual-restricted Nuclide Selection and Burnup Chain Compression Algorithm

In the burnup calculation of the reactor core, due to the large difference in the reaction cross sections and lives of nuclides in the evaluation nuclear database, the burnup matrix has large scale and strong rigidity. In order to reduce the scale of burnup matrix and improve the ill conditioned degree of matrix, it is necessary to study the burnup chain compression algorithm suitable for various core design and R & D requirements, and form a compression burnup chain and database. First, the nuclide selection criteria are established, and the nuclide importance is sorted and screened according to the contribution rate of each nuclide to neutron absorptivity and important nuclide nucleon density. The dual-restricted burnup chain compression algorithm based on neutron absorption rate and contribution rate of important nuclide production is studied, and the development of related program modules is completed. Through the calculation and analysis of Kylin-2 program database compression, the feasibility of the burnup chain compression algorithm is verified. The use of compression database can greatly reduce the calculation time and improve the calculation efficiency on the basis of keeping the original calculation accuracy. Through the research of burnup chain compression algorithm and the implementation of compression database, it provides technical support for making compression database from the evaluation database.