期刊名称：Journal of Earth Sciences and Geotechnical Engineering
印刷版ISSN：1792-9040
出版年度：2019
卷号：9
期号：3
页码：65-100
语种：English
出版社：Scienpress Ltd
摘要：Environmental protection by isolation of radionuclides escaped from High-LevelRadioactive Waste stored underground in crystalline rock can be achieved bysurrounding the metal canisters by smectite clay, which provides hindrance ofradionuclides to migrate into the surroundings, and ductile embedment of them forabsorbing seismic and tectonic displacements in the host rock. The waste-isolatingcapacity of the expansive clay is explained by its high hydrophilic capacity andlarge specific surface area giving low porosity and limited interconnectivity of thevoids, which both makes such clay low-permeable and gives it a very low through-diffusion rate of anionic species like iodine, and of some cationic radionuclides. Theexpandability of such clay means that it can swell and undergo self-healing in caseof microstructural contraction caused by heating. The mechanisms involved inpermeation and ion exchange are described based on conceptual microstructuralmodels and their theoretical analogies. Stress/strain phenomena involved insaturation with fluids, desiccation, shearing under deviatoric conditions, and creepstrain under stable conditions or at failure are described as well. Longevity matters,which have been richly treated in the literature, is given limited space.
