Study on the potential ability of clay buffer material to work as a barrier for migration of anionic radionuclides

压实钠基膨润土是高放废物地质处置的候选缓冲材料，其主要矿物为钠基蒙脱石。碳钢容器在缓冲材料中腐蚀后，铁腐蚀产物可能与缓冲材料相互作用，导致钠蒙脱石的变化，包括用Fe(II)离子取代可交换的Na+阳离子。因此，有必要了解改性对膨润土缓冲材料性能的影响。本文根据非稳态扩散实验和贯通扩散实验的结果，结合化学和元素分析，研究了氯离子在实验室制备的Fe(III)-蒙脱石样品中的扩散行为。

Compacted Na-bentonite, of which major mineral is Na-montmorillonite, is a candidate buffer material for the geological disposal of high level radioactive waste. After a carbon steel container corrodes in the buffer material, iron corrosion products may interact with the buffer materials, resulting in the alterations of Na-montmorillonite including replacements of exchangeable cations of Na+ with Fe(II) ions. Therefore, it is necessary to understand the effects of the alteration on the performance of bentonite buffer material. In this study, diffusion behavior of Cl- ions in Fe(III)-montmorillonite sample, which had been prepared in a laboratory, was studied based on the results of both non-steady diffusion and through-diffusion experiments, together with chemical and elemental analyses of Fe(III)-montmorillonite sample.