化工学报

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LiF-BeF2熔盐微观结构及扩散特性的分子动力学研究

贺国达1,2,3, 汤睿1,2, 段学志4, 谢雷东1, 傅杰1,2, 戴建兴1, 钱渊1,2, 王建强1,2,5   

  1. 1 中国科学院上海应用物理研究所, 上海 201800;
    2 中国科学院微观界面物理与探测重点实验室, 上海 201800;
    3 中国科学院大学, 北京 100049;
    4 华东理工大学化学工程联合国家重点实验室, 上海 200237;
    5 中国科学院洁净能源创新研究院, 大连 116023
  • 收稿日期:2020-04-03 修回日期:2020-05-13 出版日期:2023-04-17 发布日期:2020-05-25
  • 通讯作者: 汤睿(1985-),男,高级工程师,tangrui@sinap.ac.cn E-mail:tangrui@sinap.ac.cn
  • 作者简介:贺国达(1994-),男,硕士研究生,heguoda@sinap.ac.cn
  • 基金资助:
    中国科学院战略性先导科技专项(XDA02010000,XDA21000000);中国科学院青年人才专项(Y929021031)

Molecular dynamics investigation on microstructure and diffusion properties of molten LiF-BeF2 salt

HE Guoda1,2,3, TANG Rui1,2, DUAN Xuezhi4, XIE Leidong1, FU Jie1,2, DAI Jianxing1, QIAN Yuan1,2, WANG Jianqiang1,2,5   

  1. 1 Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China;
    2 Key Laboratory of Interfacial Physics and Technology, Chinese Academy of Sciences, Shanghai 201800, China;
    3 University of Chinese Academy of Science, Beijing 100049, China;
    4 State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China;
    5 Dalian National Laboratory for Clean Energy, Dalian 116023, China
  • Received:2020-04-03 Revised:2020-05-13 Online:2023-04-17 Published:2020-05-25

摘要: LiF-BeF2熔盐作为熔盐堆的冷却剂及核燃料溶剂近年来备受关注,其扩散行为与核燃料的相容性和结构材料的腐蚀性密切相关。本文采用Car-Parrinello分子动力学模拟研究了LiF-BeF2熔盐的微观结构及基于此结构的扩散行为。研究结果表明Be2+具有较强的络合能力,易形成中性网络聚合体,且其数量随温度的增加而减少;液态LiF-BeF2熔盐中除了包含聚合体,还包含游离的F-、Li+、BeF3-和BeF42-,而非完全游离的F-、Li+和Be2+。基于此微观结构获得的自扩散系数及电导率与实验结果吻合较好,且电导率随温度变化符合阿伦尼乌斯模型,而不是目前文献认为的无限稀释溶液的线性模型。

关键词: LiF-BeF2熔盐, 分子模拟, 微观结构, 扩散, 电导率

Abstract: Molten LiF-BeF2 salt has been paid much attention in recent years as a coolant and nuclear fuel solvent for molten salt reactor, and its diffusion behavior is closely related to the compatibility of nuclear fuel and the corrosion of structural materials. In this paper, Car-Parrinello molecular dynamics simulation was used to investigate the microstructure and diffusion behavior of LiF-BeF2 melts. The results show that Be2+ has a strong complexation ability to form neutral clusters, and its number decrease with the increase of temperature. Liquid LiF-BeF2 consist of neutral clusters and free F-,Li+, BeF3- and BeF42-, rather than completely free F-, Li+and Be2+. The calculated self-diffusion coefficient and the conductivity based on this microstructure are in good agreement with the experimental results, and the conductivity changes with temperature in accordance with the Arrhenius model, rather than the linear model of infinite dilution solution as the present literature suggests.

Key words: LiF-BeF2 molten salt, molecular dynamics, microstructure, diffusion, conductivity

中图分类号: 

  • O645.4
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