Effect of Celestite Precipitation in Compacted Illite on the Diffusion of HTO, 36Cl-, and 22Na+
Effect of Celestite Precipitation in Compacted Illite on the Diffusion of HTO, 36Cl-, and 22Na+
复制标题
压实伊利石中天青石沉淀对 HTO、36Cl- 和 22Na 扩散的影响
DOI：
10.1016/j.egypro.2017.09.450
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Takehiko Tsukahara
中科院分区：
文献类型：
--
作者：
Yuta Fukatsu;L. R. Loon;A. Shafizadeh;D. Grolimund;Y. Ikeda;Takehiko Tsukahara
从处置系统的长期安全评估的观点来看，它已成为一个重要的问题，以澄清压实伊利石的孔隙度对非吸附物种，阳离子和阴离子的扩散行为的影响。因此，在这项研究中，天青石沉淀是人工诱导的压实伊利石球团，和沉淀物的数量和位置进行了测量中子射线分析。中子图像显示在压实伊利石的孔隙中的选择性堵塞。此外，示踪剂扩散实验，使用含有氚化水（HTO），阳离子22 Na+，和阴离子36 Cl-的溶液进行。发现HTO和~（22）Na ~+通过沉淀后的致密伊利石，而~（36）Cl ~-没有发生扩散。这一事实表明HTO和22 Na+能够扩散，但发生了36 Cl-的阴离子排斥。沉淀后致密伊利石中HTO和22 Na+的有效扩散系数值远低于未沉淀的伊利石。这些结果表明，水，阳离子和阴离子在压实伊利石的小尺寸孔隙中的扩散行为受到天青石沉淀的限制，并强烈地受到伊利石颗粒的孔隙度和排列的影响。
From viewpoints of long-term safety assessments of disposal systems, it has become an important issue to clarify effects of porosity in compacted illite on diffusion behavior of non-sorbed species, cations, and anions. Therefore, in this study, celestite precipitation was artificially induced in pellets of compacted illite, and the amount and position of the precipitates were measured by neutron radiographic analysis. Neutron images showed selective clogging in the pores of the compacted illite. Moreover, a tracer-diffusion experiment using a solution containing tritiated water (HTO), cationic22Na+, and anionic36Cl-was performed. I was found that HTO and22Na+passed through the compacted illite which had been subjected to precipitation, while diffusion of36Cl-did not occur. This fact indicates that HTO and22Na+were able to diffuse, but anion exclusion of36Cl-occurred. The effective diffusion coefficient values of HTO and22Na+in compacted illite subjected to precipitation were much lower than for illite not subjected to precipitation. These results signify that the diffusion behavior of water, cation, and anion in small-sized pores of compacted illite is restricted by celestite precipitation, and is strongly influenced by the porosity and the arrangement of the illite particles.