Nuclear reactor graphite under irradiation: insights on microstructural degradation and deformation mechanisms from advanced transmission electron microscopy analysis

IF 5.5 3区材料科学 Q2 CHEMISTRY, MULTIDISCIPLINARY

Carbon Letters Pub Date : 2025-01-18 DOI:10.1007/s42823-024-00844-9

Ram Krishna, Dinesh Kumar Madheswaran, Paul M. Mummery

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引用次数: 0

Abstract

Graphite cores in nuclear reactors are critical components subjected to severe irradiation conditions. Despite the known susceptibility of graphite to radiation-induced damage, detailed microstructural analyses are limited. Existing works of literature have identified changes in crystallite morphology and orientation as early indicators of structural degradation, but the precise micro-mechanisms are not fully understood. This research explicates these micro-mechanisms using advanced analytical transmission electron microscopy (TEM) to examine irradiated graphite at doses up to 1 dpa (displacements per atom). TEM imaging and diffraction analysis captured detailed changes in crystallite structure. Even at low radiation doses (~ 0.1 dpa), a 15% alteration in crystallite morphology and orientation was observed. Significant crystal lattice rotations up to 5 degrees and micro-deformations were also detected. Additionally, the formation of micro-kinks and kink bands, ranging from 50 to 200 nm, were identified as potential deformation processes, consistent with phenomena in other layered materials. These results advance our understanding of the micro-mechanisms driving structural degradation and deformation in irradiated graphite. This research has significant implications for developing improved models and strategies to enhance the performance and longevity of graphite cores in nuclear reactors, contributing to the advancement of nuclear energy technology.

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辐照下的核反应堆石墨：从先进的透射电子显微镜分析中对微观结构退化和变形机制的见解

石墨堆芯是核反应堆中受辐照条件影响的关键部件。尽管已知石墨对辐射损伤的敏感性，但详细的微观结构分析是有限的。现有的文献已经确定了晶体形态和取向的变化是结构降解的早期指标，但精确的微观机制尚未完全了解。本研究利用先进的透射电子显微镜（TEM）分析了这些微观机制，以高达1dpa（每原子位移）的剂量检查辐照石墨。透射电镜成像和衍射分析捕捉到了晶体结构的详细变化。即使在低辐射剂量（~ 0.1 dpa）下，晶体形态和取向也发生了15%的变化。显著的晶格旋转高达5度和微变形也被检测到。此外，微扭结和扭结带的形成范围在50 ~ 200 nm之间，被认为是潜在的变形过程，与其他层状材料的现象一致。这些结果促进了我们对辐照石墨结构退化和变形的微观机制的理解。该研究对提高核反应堆石墨芯的性能和寿命的改进模型和策略具有重要意义，有助于核能技术的进步。

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

Carbon Letters CHEMISTRY, MULTIDISCIPLINARY-MATERIALS SCIENCE, MULTIDISCIPLINARY

CiteScore

7.30

自引率

20.00%

发文量

118

期刊介绍： Carbon Letters aims to be a comprehensive journal with complete coverage of carbon materials and carbon-rich molecules. These materials range from, but are not limited to, diamond and graphite through chars, semicokes, mesophase substances, carbon fibers, carbon nanotubes, graphenes, carbon blacks, activated carbons, pyrolytic carbons, glass-like carbons, etc. Papers on the secondary production of new carbon and composite materials from the above mentioned various carbons are within the scope of the journal. Papers on organic substances, including coals, will be considered only if the research has close relation to the resulting carbon materials. Carbon Letters also seeks to keep abreast of new developments in their specialist fields and to unite in finding alternative energy solutions to current issues such as the greenhouse effect and the depletion of the ozone layer. The renewable energy basics, energy storage and conversion, solar energy, wind energy, water energy, nuclear energy, biomass energy, hydrogen production technology, and other clean energy technologies are also within the scope of the journal. Carbon Letters invites original reports of fundamental research in all branches of the theory and practice of carbon science and technology.