服役环境损伤对Al2O3阻氚涂层阻氢渗透效率影响的研究

The realization of the future commercial fusion reactor depends strongly on the self-sufficiency of tritium. As an active-control manner, tritium permeation barrier (TPB) relate closely to the sufficiency of tritium and tritium safety in CFETR and future fusion reactor. In real service environment, TPB will suffer from the damage from corrosion, thermal cycles and neutron irradiation, resulting in accumulation of various kinds of microstructural defects and macro-scale through damages. These damages will affect the permeation reduce factor (PRF) of the TPB, shortening the lifetime of TPB and having bad effect on the tritium safety. Until now, this issue has not yet been investigated systematically with little comprehensive understanding of the mechanism of the influence of microstructural defects and macro-scale through damages on the hydrogen permeation behavior in TPB. In this project, the Al2O3/Al TPB is chosen as the samples. High energy heavy ions irradiation is employed to simulate the neutron damage, and mechanical scratch/ strong acid corrosion is employed to simulate the macro-scale through damages. The gas-driven permeation device is applied to investigate the influence of microstructural defects and macro-scale through damages on the PRF of Al2O3 TPB. Combined with microstructural characterization means and a series of computer simulation, the experimental results are analyzed and the effect law and mechanism of these two kinds of damages are explained. These researches will provide data support to the prediction of the lifetime of the Al2O3 TPB, and supply solid theoretical support to the development of new TPB and analysis of tritium safety and sufficiency.

未来聚变电站的成功与否依赖于氚自持实现。阻氚涂层作为主动控制氚输运的手段，其稳定性直接影响CFETR及未来聚变堆的氚自持实现。在聚变堆服役环境中，阻氚涂层将受到腐蚀、热循环、中子辐照作用，产生多类微观缺陷和宏观贯通缺陷积累。这些缺陷将会严重影响到阻氚涂层的阻氢效率，缩短阻氚涂层寿命并影响氚安全。目前关于服役环境损伤对阻氚涂层阻氢渗透效率影响的研究较少，对于辐照微观缺陷以及宏观贯通缺陷的影响规律及机理缺乏系统的认识。本项目分别通过重离子辐照模拟中子辐照损伤、通过机械划痕/强酸腐蚀模拟宏观贯通损伤，借助气体驱动渗透平台，结合一系列微观表征分析手段和计算模拟，系统研究辐照微观缺陷和宏观贯通缺陷对Al2O3阻氚涂层阻氢渗透效率的影响，阐明两种类型缺陷对Al2O3阻氚涂层的影响规律及机理。项目成果能够为服役环境下阻氚涂层的寿命预测提供参考，为新型阻氚涂层材料的开发及CFETR氚安全分析提供科学支持。

在聚变堆服役环境中，阻氚涂层将受到腐蚀、热循环、中子辐照的作用，产生各类微观缺陷和宏观贯通缺陷积累。这些缺陷将会严重影响到阻氚涂层的阻氢效率，进而缩短阻氚涂层的寿命并影响氚安全。本项目依据任务书分别通过重离子辐照模拟中子辐照损伤、通过机械划痕引入宏观贯通损伤，进而利用气体驱动渗透平台，结合一系列微观表征分析手段和计算模拟，研究了辐照微观缺陷和宏观贯通缺陷对阻氚涂层阻氢渗透效率的影响。研究成果包括：1. 发现了低剂量离位损伤与氦元素引入阻氚材料后氘渗透率与原始未辐照样品接近，高剂量辐照导致氘渗透率相对于未辐照样品上升的现象，并根据正电子湮灭实验结果提出了基于空位型缺陷占据的机制解释；2. 通过第一性原理探究了α-Al2O3与γ-Al2O3可能的阻氢机制，发现α-Al2O3中铝空位团簇和氧间隙原子会减弱阻氚效率的现象。3. 阐明了宏观贯通缺陷面积对于Al2O3阻氢效率的影响规律，并探索了作用机制。 项目成果能够为服役环境下阻氚涂层的寿命预测提供参考，为新型阻氚涂层材料的开发及CFETR氚安全分析提供数据支持。