Extending the finite elements neutronic code FENNECS to the Discontinuous Galerkin method

IF 1.9 3区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY

Annals of Nuclear Energy Pub Date : 2024-09-27 DOI:10.1016/j.anucene.2024.110927

Romain Henry, Jérémy Bousquet, Armin Seubert

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Abstract

The finite element method (FEM) neutronics code FENNECS was originally developed at GRS for unstructured geometry and first applied to fast reactors. It has recently been applied to light water reactors (LWRs). Indeed, most of the currently envisaged Small modular reactors (SMRs) concepts are based on well-proven LWR techniques. However, significant discrepancies were observed in terms of power distribution for the FENNECS prediction. The identified limitation is due to the implementation of the continuous Galerkin (CG) method, which enforces flux continuity between elements. This is incorrect due to the cross-section homogenization process. To overcome this problem, discontinuity factors can be introduced to allow for a more accurate description of the physics in LWR. Within the FEM frameworks, the modelling of discontinuous variables can be introduced using the discontinuous Galerkin (DG) formalism. FENNECS has been extended with the implementation of a new method based on the DG method. The method’s verification and validation were successfully achieved by comparing the assembly power distribution with a reference Monte Carlo solution for the NuScale SMR benchmark. Compared to the continuous approach, the discrepancies were significantly reduced from 20% to less than 4%.

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将有限元中子代码 FENNECS 扩展为非连续伽勒金方法

有限元法（FEM）中子电子学代码 FENNECS 最初是由 GRS 开发的，用于非结构几何，并首先应用于快堆。最近，它又被应用于轻水反应堆（LWR）。事实上，目前设想的大多数小型模块化反应堆（SMRs）概念都是基于成熟的轻水反应堆技术。然而，在 FENNECS 预测的功率分布方面却发现了明显的差异。所发现的局限性是由于采用了连续伽勒金（CG）方法，该方法强制要求元素之间的通量连续性。由于横截面均质化过程，这是不正确的。为了克服这一问题，可以引入不连续因子，以便更准确地描述低温反应堆的物理特性。在有限元框架内，不连续变量的建模可采用不连续加勒金（DG）形式。FENNECS 已通过实施基于 DG 方法的新方法进行了扩展。通过比较装配功率分布和 NuScale SMR 基准的蒙特卡洛参考解，成功实现了该方法的验证和确认。与连续方法相比，差异从 20% 显著降低到 4% 以下。

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.