Helium-to-vacancy ratio of helium bubbles in RAFM steels irradiated in STIP: A new perspective via MD simulation

IF 3.2 2区工程技术 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Nuclear Materials Pub Date : 2025-08-06 DOI:10.1016/j.jnucmat.2025.156096

Yeshang Hu , Lei Peng , Jingyi Shi , Yiyi Ma , Yao Xie , Zhenyu Wei , Yongjie Sun , Yuanxi Wan

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Abstract

The helium-to-vacancy (He/V) ratio plays a crucial role in the helium bubble-induced damage mechanisms caused by neutron irradiation in reduced activation ferritic/martensitic (RAFM) steels, which are main candidate structural materials for fusion reactors. Based on the results of hardening induced by helium bubble in RAFM steel specimens irradiated in the Swiss spallation neutron source, molecular dynamics (MD) simulations were conducted to investigate the interaction between edge dislocation and helium bubble with varying sizes and He/V ratios. The barrier strength of helium bubbles were calculated based on the dispersed barrier hardening model. From a new perspective, the He/V ratio of helium bubbles in STIP specimens was evaluated through comparing the barrier strength obtained from experimental hardening data and MD simulations. The results showed that the barrier strength of bubbles initially increased slightly as the He/V ratio increased from 0 to 0.8, reached its peak within the He/V ratio range of 0.8 to 1.1, and then decreased rapidly to a very low level. By comparing the simulated and experimental barrier strength, the He/V ratio range of bubbles in RAFM steel specimens was estimated. The He/V ratio of He bubbles in RAFM steel specimens with middle doses is found to be within the high He/V ratio range of 1.2–1.4, whereas those with low doses and a high dose are situated within the He/V ratio range of 0.8–1.1. Furthermore, the He/V ratio of the helium bubbles in RAFM steels was analyzed in conjunction with existing results.

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在stp辐照下RAFM钢中氦气泡的氦空位比：MD模拟的新视角

低活化铁素体/马氏体（RAFM）钢是核聚变反应堆的主要候选结构材料，氦空位比（He/V）在中子辐照氦泡损伤机制中起着至关重要的作用。基于瑞士散裂中子源辐照下RAFM钢试样中氦泡诱导硬化的结果，采用分子动力学（MD）模拟研究了不同尺寸和He/V比的氦泡与边缘位错之间的相互作用。基于分散势垒硬化模型计算了氦气泡的势垒强度。从新的角度出发，通过对比实验硬化数据和MD模拟得到的阻挡强度，评估了STIP试样中氦气泡的He/V比。结果表明：当He/V比从0增加到0.8时，气泡的阻挡强度开始略有增加，在He/V比为0.8 ~ 1.1时达到峰值，随后迅速下降到很低的水平；通过对比模拟和实验阻挡强度，估算了RAFM钢试样中气泡的He/V比范围。中剂量RAFM钢试样中He气泡的He/V比值在1.2 ~ 1.4的高He/V比值范围内，低剂量和高剂量RAFM钢试样中He气泡的He/V比值在0.8 ~ 1.1的He/V比值范围内。此外，结合已有的结果，分析了RAFM钢中氦气泡的He/V比。

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

Journal of Nuclear Materials 工程技术-材料科学：综合

CiteScore

5.70

自引率

25.80%

发文量

601

审稿时长

63 days

期刊介绍： The Journal of Nuclear Materials publishes high quality papers in materials research for nuclear applications, primarily fission reactors, fusion reactors, and similar environments including radiation areas of charged particle accelerators. Both original research and critical review papers covering experimental, theoretical, and computational aspects of either fundamental or applied nature are welcome. The breadth of the field is such that a wide range of processes and properties in the field of materials science and engineering is of interest to the readership, spanning atom-scale processes, microstructures, thermodynamics, mechanical properties, physical properties, and corrosion, for example. Topics covered by JNM Fission reactor materials, including fuels, cladding, core structures, pressure vessels, coolant interactions with materials, moderator and control components, fission product behavior. Materials aspects of the entire fuel cycle. Materials aspects of the actinides and their compounds. Performance of nuclear waste materials; materials aspects of the immobilization of wastes. Fusion reactor materials, including first walls, blankets, insulators and magnets. Neutron and charged particle radiation effects in materials, including defects, transmutations, microstructures, phase changes and macroscopic properties. Interaction of plasmas, ion beams, electron beams and electromagnetic radiation with materials relevant to nuclear systems.