期刊
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
卷 149, 期 -, 页码 244-257出版社
ELSEVIER
DOI: 10.1016/j.psep.2020.10.053
关键词
Bentonite; Gas transport; Engineered barrier; Saturation; Porosity; Interface
资金
- European Atomic Energy Community's Seventh Framework Programme (FP7/2007-2011) [230357]
- European Union's Horizon 2020 Research and Innovation Programme [847593]
Gas generation in a deep geological nuclear waste repository can be affected by different processes, with gas transport mechanisms across barriers playing a crucial role in security assessment. Laboratory tests using FEBEX bentonite showed that dry density influenced gas breakthrough pressure values in saturated samples, while a sealed bentonite interface did not significantly affect breakthrough pressure or gas permeability.
In a deep geological nuclear waste repository gas can be generated by different processes. Understanding the gas transport mechanisms across the engineered and natural barriers in a repository is relevant for its security assessment, both in terms of mechanical stability and of radionuclide transport. The engineered barrier may be composed of compacted blocks of bentonite and the interfaces between these blocks might evolve into preferential fluid pathways, in particular for the gas generated around the waste canisters. Small-scale laboratory tests were performed in sound samples and in samples crossed by an interface to determine gas breakthrough pressure values after saturation and the effect on them of the interface. The FEBEX bentonite, a Spanish bentonite composed mainly of montmorillonite, was used in the tests. The gas breakthrough pressure of the saturated compacted samples increased with dry density and was higher than the swelling pressure of the bentonite. Gas breakthrough could take place either in an instantaneous or in a gradual way, the difference between both modes being the flow rate, much higher in the first case. The gas transport mechanism would be microscopic pathway dilation, with microfracturing in the case of the instantaneous episodes. A sealed interface along the bentonite did not seem to affect the breakthrough pressure or gas permeability values, since the behaviour patterns were similar in both kinds of samples, depending mostly on the bentonite dry density. (c)& nbsp;2020 The Authors. Published by Elsevier B.V. on behalf of Institution of Chemical Engineers. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据