A novel method to estimate the high-order flux moment under the isotropic source assumption

IF 2.3 3区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY

Annals of Nuclear Energy Pub Date : 2025-09-05 DOI:10.1016/j.anucene.2025.111840

Jinchao Zhang , Qian Zhang , Shuai Qin , Wei Cao , Shifu Wu , Qiang Zhao , Kun Zhuang

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引用次数: 0

Abstract

Collapsing coarse-group high-order scattering matrix using the accurate flux moment is important for the fast reactor calculations. However, current methods for calculating the flux moment are time-consuming because of the treatment of the anisotropic source and the slow convergence rate. To address this issue, this study proposes a novel method to estimate the high-order flux moment based on the isotropic source assumption. The transport equation is solved using the Method of Characteristics transport method under the time-saving isotropic source assumption. The flux moment is calculated with the angular flux saved during the source iterations and is used to collapse coarse-group high-order scattering matrix as an approximation of the actual flux moment.

To validate the proposed method, two simplified problems are used to assess its performance and two 2-D fast reactor problems are employed to explore its range of applicability. Numerical results for the simplified problems indicate that the high-order scattering matrix collapsed using the proposed method achieves accuracy comparable to that obtained under the anisotropic source assumption. For the 2-D problems, the results demonstrate the effectiveness of the proposed method, with the eigenvalue error within −200 pcm and the maximum relative error of assembly power within 1%. These findings highlight the accuracy and efficiency of the proposed method in predicting the flux moment.

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在各向同性源假设下估计高阶磁通矩的新方法

利用精确通量矩坍缩粗群高阶散射矩阵对快堆计算具有重要意义。但是，目前计算磁通矩的方法由于处理各向异性源和收敛速度慢而费时。针对这一问题，本文提出了一种基于各向同性震源假设的高阶磁通矩估计方法。在省时的各向同性源假设下，采用特征输运法求解输运方程。利用源迭代过程中保存的角通量计算磁通矩，并将其作为实际磁通矩的近似，用于折叠粗群高阶散射矩阵。为了验证该方法的有效性，采用两个简化问题来评估其性能，并采用两个二维快堆问题来探索其适用范围。对简化问题的数值计算结果表明，采用该方法对高阶散射矩阵进行分解的精度与各向异性源假设下的精度相当。对于二维问题，结果证明了该方法的有效性，特征值误差在- 200 pcm以内，装配功率的最大相对误差在1%以内。这些结果突出了该方法在通量矩预测中的准确性和有效性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Annals of Nuclear Energy 工程技术-核科学技术

CiteScore

4.30

自引率

21.10%

发文量

632

审稿时长

7.3 months

期刊介绍： Annals of Nuclear Energy provides an international medium for the communication of original research, ideas and developments in all areas of the field of nuclear energy science and technology. Its scope embraces nuclear fuel reserves, fuel cycles and cost, materials, processing, system and component technology (fission only), design and optimization, direct conversion of nuclear energy sources, environmental control, reactor physics, heat transfer and fluid dynamics, structural analysis, fuel management, future developments, nuclear fuel and safety, nuclear aerosol, neutron physics, computer technology (both software and hardware), risk assessment, radioactive waste disposal and reactor thermal hydraulics. Papers submitted to Annals need to demonstrate a clear link to nuclear power generation/nuclear engineering. Papers which deal with pure nuclear physics, pure health physics, imaging, or attenuation and shielding properties of concretes and various geological materials are not within the scope of the journal. Also, papers that deal with policy or economics are not within the scope of the journal.