Tolnai I, Osan J, Czompoly O, Sulyok A, Fabian M
HUN-REN Centre for Energy Research, Konkoly Thege St. 29-33., Budapest, 1121, Hungary.
Sci Rep. 2023 Nov 21;13(1):20381. doi: 10.1038/s41598-023-47578-8.
Deep geological storage is the accepted solution for the final disposal of high-level radioactive waste therefore, it is necessary to study the host rock of the planned Hungarian waste repository and the materials involved in the engineered barriers. The main goal was to understand the characteristics and stability of the glass/steel/claystone system, from the structural properties of the vitrified waste (borosilicate glasses) to the clay response in the repository. Repository conditions were applied during the experiments to understand the chemical evolution of the system. A triplicate setup was kept at 80 °C for 3, 7 and 12 months and post-mortem characterization was performed. No alteration products were observed with scanning electron microscopy energy dispersive X-ray spectroscopy measurements on the surface of the glass and Fe or in the clay after the end of the experimental period. Based on the elemental analysis of the liquid phase, the released amount of B, K, Si and Na increased, while that of Ca and Mg decreased compared to the baseline. The concentrations of Cl and SO did not change significantly. Ca- and Mg-silicate precipitation was observed by X-ray photoelectron spectroscopy at the surface range of the borosilicate glasses because of the synthetic porewater treatment.
深部地质储存是高放废物最终处置的公认解决方案，因此，有必要研究匈牙利计划中的废物处置库的主岩以及工程屏障中涉及的材料。主要目标是了解玻璃/钢/泥岩系统的特性和稳定性，从玻璃化废物（硼硅酸盐玻璃）的结构特性到处置库中的黏土响应。在实验过程中采用处置库条件来了解该系统的化学演化。设置了三组重复实验，在80°C下保持3个月、7个月和12个月，并进行了实验后表征。实验期结束后，通过扫描电子显微镜能量色散X射线光谱测量，在玻璃表面、铁或黏土中均未观察到蚀变产物。基于液相的元素分析，与基线相比，硼、钾、硅和钠的释放量增加，而钙和镁的释放量减少。氯和硫酸根的浓度没有显著变化。由于进行了合成孔隙水处理，通过X射线光电子能谱在硼硅酸盐玻璃的表面范围内观察到了钙硅酸盐和镁硅酸盐沉淀。
