氧在LBE中扩散行为以及与LBE相互作用机制研究

Accelerator-driven systems (ADS) has been cosidered as one of the most promising ways to disproval the nuclear waste treatment processing solution. Lead-bismuth eutectic (LBE) was considered as first candidate of coolant and spallation target materials of ADS transmutation system due to their favorable thermal-physical properties. One of the key issues for using LBE in ADS is its corrosion of structural materials in LBE，and the formation of protective oxide layer on the surface of structral materials by controlling the concetration of oxygen in LBE is a effective way to improve the corrosion resistance of materials, but there is a lack of microscopic theory study on the oxygen diffusion mechanism and some deviation of the exsiting experimental data. The present research is mainly to achieve a basic understanding of the micromophology of oxygen in LBE and diffusion mechanism of oxygen in LBE, and combined with series of experiments, which were performed to investigate the effect of temperature, flowing velocity of LBE on the varition of oxygen concetration, the diffusion coefficient of oxygen in LBE can be obtained and also the effect of LBE temperature and flowing velocity on the inteaction mechanism between LBE and oxygen can be invastigated.The research is useful and innovative for the oxygen measurment and control technology in LBE for the lead-bismuth cooled reactor for ADS system.

加速器驱动次临界系统（ADS）被认为是可有效处理核废料的途径之一。ADS系统散裂靶兼冷却剂主选材料液态铅铋合金共晶体（LBE）对材料的腐蚀是亟待解决的关键问题之一，合理控制LBE中的氧浓度使结构材料表面形成稳定的氧化层是提高材料耐蚀性的有效途径之一，国际上已针对氧测控技术开展广泛研究，但缺乏对氧扩散等机制的微观理论研究，已有实验数据也存在一定偏差。本课题拟开展氧在液态铅铋中微观状态、扩散行为以及氧与LBE中铅、铋原子之间相互作用机制的微观理论研究，并结合不同LBE温度、流速下氧浓度的实验测量结果，获得不同LBE工况下氧的扩散系数以及系统研究LBE温度与流速等因素对氧与LBE相互作用的影响规律，研究成果可为液态铅铋堆中氧浓度测量控制技术研究提供理论指导和实验依据，对ADS系统液态铅铋堆关键科学技术问题研究具有的指导意义和创新价值。

铅基堆冷却剂铅铋合金共晶体（LBE）中的氧浓度控制，是提高结构材料耐蚀性的有效途径之一，开展氧扩散规律以及行为机制等微观理论的基础研究，对氧浓度测量与控制技术的发展与应用具有重要的指导意义。本项目开展氧在液态铅铋中微观状态、扩散行为以及氧与LBE中铅、铋原子之间相互作用机制的微观理论研究，并结合不同LBE温度、流速下氧浓度的实验测量结果，获得了不同LBE工况下氧的扩散系数，较为系统研究了LBE温度与流速等因素对氧在LBE变化的影响规律。结果显示，温度升高、流速增大均对氧扩散速率具有加速作用，实验结果与理论计算一致，有力验证了氧的结构状态与扩散行为的理论模型。同时LBE中Fe等溶解元素的化学反应对氧变化也有一定影响。研究成果可为液态铅铋堆中氧浓度测量控制技术研究提供理论指导和实验依据，对铅铋堆关键科学技术问题研究具有的指导意义和创新价值。