Experimental studies of lithium-based surface chemistry for fusion plasma-facing materials applications
Experimental studies of lithium-based surface chemistry for fusion plasma-facing materials applications
复制标题
DOI：
10.1016/j.jnucmat.2009.01.242
复制
发表时间：
2009-06
影响因子：
3.1
通讯作者：
J. Allain;D. Rokusek;S. S. Harilal-S.;M. Nieto-Pérez;C. Skinner;H. Kugel;B. Heim;R. Kaita;R. Maje
中科院分区：
文献类型：
--
作者：
J. Allain;D. Rokusek;S. S. Harilal-S.;M. Nieto-Pérez;C. Skinner;H. Kugel;B. Heim;R. Kaita;R. Maje
锂增强了聚变装置的操作性能，如：TFTR，CDX-U，FTU，T-11 M和NSTX。在实验室实验中，人们对固态和液态的锂进行了广泛的研究，包括其侵蚀和储氢性能。已测量到氘化固体和液体锂表面的物理溅射减少高达40-60%。计算模型表明，锂中氘的体积保留率可能高达1：1。本文介绍了在实验室原位系统研究锂沉积下ATJ石墨表面化学演变的结果。结果进行了比较，类似的锂表面涂层暴露在氘放电等离子体在NSTX石墨的事后分析。NSTX中面向等离子体的部件上的锂涂层已经显示出氢循环的大幅减少。问题仍然存在于石墨衬底上的锂表面化学对粒子溅射（物理和化学）以及氢同位素再循环的作用。这特别是由于缺乏对NSTX等托克马克中等离子体与表面相互作用的原位测量。结果表明，ATJ石墨上的锂键合状态是过氧化锂，并且在充分暴露于环境空气条件下，生成碳酸锂。这两个结果之间的相关性是用来评估锂化学的作用，对锂键合状态和影响氢泵和锂溅射。此外，还测量了与纯锂或碳相比，锂化石墨的物理溅射减少的10至30倍之间的减少。
Lithium has enhanced the operational performance of fusion devices such as: TFTR, CDX-U, FTU, T-11M, and NSTX. Lithium in the solid and liquid state has been studied extensively in laboratory experiments including its erosion and hydrogen-retaining properties. Reductions in physical sputtering up to 40–60% have been measured for deuterated solid and liquid lithium surfaces. Computational modeling indicates that up to a 1:1 deuterium volumetric retention in lithium is possible. This paper presents the results of systematic in situ laboratory experimental studies on the surface chemistry evolution of ATJ graphite under lithium deposition. Results are compared to post-mortem analysis of similar lithium surface coatings on graphite exposed to deuterium discharge plasmas in NSTX. Lithium coatings on plasma-facing components in NSTX have shown substantial reduction of hydrogenic recycling. Questions remain on the role lithium surface chemistry on a graphite substrate has on particle sputtering (physical and chemical) as well as hydrogen isotope recycling. This is particularly due to the lack of in situ measurements of plasma-surface interactions in tokamaks such as NSTX. Results suggest that the lithium bonding state on ATJ graphite is lithium peroxide and with sufficient exposure to ambient air conditions, lithium carbonate is generated. Correlation between both results is used to assess the role of lithium chemistry on the state of lithium bonding and implications on hydrogen pumping and lithium sputtering. In addition, reduction of factors between 10 and 30 reduction in physical sputtering from lithiated graphite compared to pure lithium or carbon is also measured.