A newly and efficient virtual mesh based CMFD acceleration method for pebble-bed HTGR with cylindrical geometry

IF 1.9 3区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY Annals of Nuclear Energy Pub Date : 2025-03-17 DOI:10.1016/j.anucene.2025.111349

Yuchen Wen, Chen Hao, Yizhen Wang

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Abstract

Three-dimensional method of characteristic (3D-MOC) codes have been developed to conduct neutronic simulation for pebble-bed high temperature gas-cooled rector (HTGR). Although parallel strategy such as domain decomposition and acceleration method such as coarse mesh finite difference (CMFD) are applied in these codes, whole core simulation still faces huge computational burden which needs more efficient acceleration method to enhance simulation efficiency. Moreover, considering the cylindrical geometry of pebble-bed HTGR, differential length of coarse meshes will gradually increase along radial direction which will lead convergence problem in conventional CMFD method. In this paper, a virtual mesh based CMFD method is proposed to overcome this issue. Virtual coarse meshes are generated by further dividing CMFD coarse meshes along circumferential direction to reduce the optical thickness of peripheral coarse meshes. The performance of proposed virtual coarse mesh based CMFD acceleration method is verified in a simplified cylindrical pebble-bed model and HTR-10 whole core problem. Numerical results show that virtual coarse mesh based CMFD method can reduce around 30% source iterations of MOC compared with original CMFD method.

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目前已开发出三维特征法（3D-MOC）代码，用于对卵石床高温气冷堆（HTGR）进行中子模拟。虽然在这些代码中应用了并行策略，如域分解和加速方法，如粗网格有限差分（CMFD），但整个堆芯模拟仍然面临巨大的计算负担，需要更有效的加速方法来提高模拟效率。此外，考虑到卵石床高温气冷堆的圆柱形几何结构，粗网格的差分长度将沿径向逐渐增加，这将导致传统 CMFD 方法的收敛问题。本文提出了一种基于虚拟网格的 CMFD 方法来克服这一问题。通过沿圆周方向进一步划分 CMFD 粗网格来生成虚拟粗网格，以减少外围粗网格的光学厚度。基于虚拟粗网格的 CMFD 加速方法的性能在简化的圆柱形卵石床模型和 HTR-10 整芯问题中得到了验证。数值结果表明，与原始 CMFD 方法相比，基于虚拟粗网格的 CMFD 方法可减少约 30% 的 MOC 源迭代。

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.