文章基本信息

标题：Transport Mechanisms in Smectite Clay Control Migration of Radionuclides Escaped from Disposed Nuclear Waste
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作者：Roland Pusch
期刊名称：Journal of Earth Sciences and Geotechnical Engineering
印刷版ISSN：1792-9040
出版年度：2020
卷号：10
期号：5
页码：131-160
DOI：10.47260/jesge.vol10_5_7
语种：English
出版社：Scienpress Ltd
摘要：At present two ideologies appear to govern the international selection of conceptsfor isolation of radionuclides escaped from High-Level Radioactive Waste (HLW)stored underground: “shallow” burial in mined repositories in crystalline rock, anddeep geologic disposal in holes bored in crystalline or sedimentary rock, makinguse of metal canisters isolated from the rock by concrete or dense expansive clay.The present paper describes disposal in smectite clay for delaying or preventingradionuclides from reaching the biosphere when they can still cause great havoc.This is achieved by utilizing the great waste-isolating capacity of the expansive claythrough its high hydrophilic capacity and large specific surface area, providing lowporosity and limited interconnectivity of the voids, which both makes such claylow-permeable and operating with a very low through-diffusion rate of anionicspecies like iodine, and of some cationic radionuclides. The expandability of suchclay means that it can swell and undergo self-healing in case of microstructuralcontraction caused by heating. The mechanisms involved in permeation and ionexchange are described based on conceptual microstructural models and theirtheoretical analogies. Stress/strain phenomena involved in saturation with fluids,desiccation, shearing under deviatoric conditions, and creep strain under stableconditions or at failure are described as well. Longevity matters are given limitedspace.
关键词：Nuclear Waste; High-Level Radioactive Waste (HLW); smectiteclay; migration of radionuclides.