Correlation between Hydrogen Isotope Permeation through Niobium and Bulk Oxygen Concentration: Possible Influence of Oxygen on Tritium Recovery from Pb-Li by Vacuum Permeator
Correlation between Hydrogen Isotope Permeation through Niobium and Bulk Oxygen Concentration: Possible Influence of Oxygen on Tritium Recovery from Pb-Li by Vacuum Permeator
复制标题
铌氢同位素渗透与氧气浓度之间的相关性：氧气对真空渗透器从 Pb-Li 中回收氚的可能影响
DOI：
10.13182/fst07-a1623
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
M. Matsuyama
中科院分区：
文献类型：
--
作者：
Y. Hatano;A. Busnyuk;A. Livshits;H. Homma;M. Matsuyama
摘要铌是从Pb-17 Li液体包层系统中回收氚的真空渗透器中一种有潜力的管材料。从这个角度来看，通过Nb膜的氢的渗透进行了研究与超高真空装置的条件下的毯系统，其中没有氧化膜可以保留在膜表面上。然而，发现渗透速率随着膜本体中的氧浓度的增加而急剧降低;例如，在IPa的上游H2压力和700°C的膜温度下，在对应于Pb-17 Li中的氧势（0.054at%）的氧浓度下的渗透速率被评估为从Nb中的氢溶解度和扩散率预期的值的1/5。这种小的渗透速率归因于存在的氧单分子层形成的表面偏析从散装。通过Pd涂层的表面改性被发现，由于Pd和Nb之间的相互扩散引起的涂层效果的退化，仅得到有限的改善。讨论了提高钯涂层高温稳定性的方法。
Abstract Niobium is a potential candidate of tube material in vacuum permeator for tritium recovery from Pb-17Li liquid blanket system. From this viewpoint, the permeation of hydrogen through a Nb membrane was investigated with an ultra-high vacuum apparatus under the conditions relevant to the blanket system where no oxide films could be retained on the membrane surfaces. It was, however, found that the permeation rate sharply decreased with increasing oxygen concentration in the bulk of membrane; at upstream H2 pressure of 1 Pa and membrane temperature of 700°C, for example, the permeation rate at oxygen concentration corresponding to oxygen potential in Pb-17Li (0.054 at%) was evaluated to be 1/5 of the value expected from hydrogen solubility and diffusivity in Nb. Such small permeation rate was ascribed to the presence of oxygen monolayer formed by surface segregation from the bulk. Surface modification by Pd coating was found to give only limited improvement due to degradation in coating effect induced by interdiffusion between Pd and Nb. Methods to improve the high temperature stability of Pd coating was discussed.