基于质量矩阵集总技术的非结构网格二维有限元屏蔽计算程序研发  

A two-dimensional finite element shielding calculation code with mass-matrix lumping technique and unstructured meshes

作　　者：宗智伟 程懋松[1] ZONG Zhiwei;CHENG Maosong(Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China)

机构地区：[1]中国科学院上海应用物理研究所,上海201800

出　　处：《核技术》2023年第2期75-83,共9页Nuclear Techniques

基　　金：中国科学院科技战略先导项目(No.XD02001005)资助。

摘　　要：精细化几何建模是高保真中子输运计算的重要基础,而非结构网格对复杂几何模型具有较强的适应性,能弥补结构网格建模能力的不足。为了提高屏蔽计算程序对复杂模型的建模能力,从一阶中子输运方程出发,建立了二维离散纵标-伽辽金有限元求解模型,对比分析了连续有限元和间断有限元方法的计算性能,进一步采用质量矩阵集总技术以提高求解模型的可靠性,并开发了相应的计算程序ThorSNIPE。选用BWR cell临界基准题、阿贡实验室5-A1固定源基准题和Dog leg duct基准题,验证ThorSNIPE程序的正确性。数值计算结果表明:ThorSNIPE程序的计算结果与基准值吻合较好,初步验证了程序的正确性,ThorSNIPE程序适用于复杂屏蔽计算分析;质量矩阵集总技术在不影响计算精度的情况下,能够有效抑制非物理振荡问题。[Background] The high-fidelity neutron transport calculation requires refined geometric modeling whilst the unstructured meshes have strong adaptability to copy with the changes bring by complex geometry structure, and overcome the deficiencies of structured meshes in modeling capability. [Purpose] This study aims to develop and validate a two-dimensional shielding calculation code ThorSNIPE which can be used to improve the modeling ability for analysis complex problems. [Methods] First of all, problem solving model was established with discrete ordinates method and finite element method on the basis of the first order Boltzmann transport equation. The computational performance of continuous finite element method and discontinuous finite element method were compared and analyzed. Mass-matrix lumping technique was further applied to improve the reliability of solving model. Then, a two-dimensional discrete ordinate-finite element shielding calculation program ThorSNIPE was developed on the basis of above model. Finally, the code was validated by BWR cell critical benchmark, Argonne-5-A1 fixed source benchmark and Dog leg duct benchmark. [Results & Conclusions] The numerical results show that calculation value provided by ThorSNIPE is in good agreement with reference value, indicating that ThorSNIPE is suitable for complex shielding calculation, and Mass-matrix lumping technique can effectively suppress the non-physical spatial oscillations without reducing the calculation accuracy.

关 键 词：屏蔽计算 离散纵标法 有限元 非结构网格 质量矩阵集总技术 

分 类 号：TL328[核科学技术—核技术及应用]