(Institución)
 
 

Docu-menta > Fisión Nuclear > Artículos de Fisión Nuclear >

Por favor, use este identificador para citar o enlazar este ítem: http://documenta.ciemat.es/handle/123456789/4467

Título : The hydration of bentonite buffer material revealed by modeling analysis of a long-term in situ test
Autor : Zheng, Liange
Xu, Hao
Rutqvist, Jonny
Reagan, Matthew
Birkholzer, Jens
Villar, María Victoria
Palabras clave : Bentonite
Hydration
THMC
Modeling
In Situ test
Fecha de publicación : 24-nov-2019
Citación : Liange Zheng, Hao Xu, Jonny Rutqvist, Matthew Reagan, Jens Birkholzer, María Victoria Villar, Ana María Fernández, The hydration of bentonite buffer material revealed by modeling analysis of a long-term in situ test, Applied Clay Science, Volume 185, 2020, 105360, https://doi.org/10.1016/j.clay.2019.105360.
Citación : Applied Clay Science;185
Resumen : The hydration of a bentonite barrier in the early stage of a geologic nuclear waste repository with a bentonite buffer is a critical issue for its long-term performance and safety because bentonite might be permanently altered and subsequently affect the function of bentonite barrier. Large scale in situ testing integrated with modeling analysis is an effective way to study the key processes affecting the hydration of a bentonite barrier. In this paper, through the comparison between coupled thermal, hydrological, mechanical, and chemical (THMC) models and data from a long term in situ test, we attempt to pinpoint the importance of non-Darcian flow, thermal osmosis, and hydro-mechanical coupling (porosity and permeability change due to swelling) to the hydration rate of the bentonite barrier under heating conditions. We found that a TH model equipped with non-Darcian flow severely underestimates the relative humidity and water content measured in the bentonite. Calibration of the parameters associated with relative permeability overshadows the contribution of non-Darcian flow, and non-Darcian flow under unsaturated conditions is not yet fully understood. An empirical relationship between saturated permeability and dry density was found to work better than a saturated permeability that is the function of effective stress in matching the relative humidity, water content data, and the chloride concentration in pore water. We also found that chemical data are actually helpful in calibrating the THM model. A question regarding the relevance of thermal osmosis to the hydration process, in terms of matching models and data, remains unanswered. Although a THMC model with thermal osmosis matches all THMC data nicely, similar goodness-of-fit can also be achieved by a THMC model without thermal osmosis but with lower permeability. We learned that the robustness of the model could be increased if the model is tested against long-term data and multiple types of data, and given that non-uniqueness is inevitable, more independent measurements of key parameters and multi-scale and multi-physics tests may help approximate the right model for evaluating the safety of the repository.
URI : http://documenta.ciemat.es/handle/123456789/4467
ISSN : 0169-1317
Aparece en las colecciones: Artículos de Fisión Nuclear

Ficheros en este ítem:

Fichero Descripción Tamaño Formato
2020_Zheng et al_ACS.pdf1.68 MBAdobe PDFVisualizar/Abrir
2020_Zheng et al_ACS.pdf1.68 MBAdobe PDFVisualizar/Abrir
View Statistics

Los ítems de Docu-menta están protegidos por una Licencia Creative Commons, con derechos reservados.

 

Información y consultas: documenta@ciemat.es | Documento legal