Influence of temperature gradients on helium diffusion and clustering in tungsten: A molecular dynamics study

IF 1.9 3区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY Fusion Engineering and Design Pub Date : 2024-10-13 DOI:10.1016/j.fusengdes.2024.114687

Jingzhong Fang , Huiqiu Deng , Wangyu Hu , Ning Gao , Yonggang Tong , Yongle Hu , Shengjie Wang , Kaiming Wang

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Abstract

Tungsten and its alloys, used as plasma-facing materials in fusion reactors, endure high-flux, low-energy helium ion irradiation and temperature gradients induced by thermal load and shocks. This study utilizes molecular dynamics (MD) simulations to explore the diffusion and clustering behavior of helium (He) in tungsten (W) under temperature gradients. The migration behavior of isolated helium atoms, small helium clusters, and helium self-interstitial atom (He-SIA) clusters within tungsten is analyzed. It is revealed that both helium and He-SIA clusters tend to migrate towards higher temperature regions, exhibiting negative thermophoresis. The nucleation of helium clusters, the formation of Frenkel pairs, and the interactions between self-interstitial clusters and helium clusters are also investigated. The results indicate that helium concentration significantly impacts He nucleation behavior. Directional diffusion may lead to areas of high concentration over time, potentially promoting the formation of He clusters and bubbles. These insights enhance the understanding of tungsten's performance and durability as a plasma-facing component in fusion reactors.

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温度梯度对钨中氦扩散和聚类的影响：分子动力学研究

钨及其合金在聚变反应堆中用作面向等离子体的材料，需要承受高通量、低能量氦离子辐照以及热负荷和冲击引起的温度梯度。本研究利用分子动力学（MD）模拟来探索温度梯度下氦（He）在钨（W）中的扩散和聚类行为。研究分析了孤立氦原子、小氦原子团和氦自间隙原子（He-SIA）团在钨中的迁移行为。结果表明，氦原子和氦自间质原子团簇都倾向于向温度较高的区域迁移，表现出负的热泳现象。此外，还研究了氦团簇的成核、Frenkel 对的形成以及自间隙团簇和氦团簇之间的相互作用。结果表明，氦浓度对氦成核行为有显著影响。随着时间的推移，定向扩散可能会导致出现高浓度区域，从而有可能促进氦簇和气泡的形成。这些见解加深了人们对钨作为聚变反应堆中面向等离子体部件的性能和耐用性的理解。

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来源期刊

Fusion Engineering and Design 工程技术-核科学技术

CiteScore

3.50

自引率

23.50%

发文量

275

审稿时长

3.8 months

期刊介绍： The journal accepts papers about experiments (both plasma and technology), theory, models, methods, and designs in areas relating to technology, engineering, and applied science aspects of magnetic and inertial fusion energy. Specific areas of interest include: MFE and IFE design studies for experiments and reactors; fusion nuclear technologies and materials, including blankets and shields; analysis of reactor plasmas; plasma heating, fuelling, and vacuum systems; drivers, targets, and special technologies for IFE, controls and diagnostics; fuel cycle analysis and tritium reprocessing and handling; operations and remote maintenance of reactors; safety, decommissioning, and waste management; economic and environmental analysis of components and systems.