Clays in Natural and Engineered Barriers for Radioactive Waste Confinement: an introduction

Norris, Simon

doi:10.1144/sp400.43

Cited by 9 publications

(3 citation statements)

References 44 publications

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“…The sources of gas (such as hydrogen) are anoxic corrosion of metallic structural components (Ortiz et al 2002), radioactive decay of the disposed radioactive waste, radiolysis and the microbial breakdown (Pekala et al 2019) of organic materials. The production of these gases may continue for over 100,000 years after the waste emplacement (Norris 2014).…”

Section: Introductionmentioning

confidence: 99%

Phenomenological Model of Nonlinear Dynamics and Deterministic Chaotic Gas Migration in Bentonite: Experimental Evidence and Diagnostic Parameters

et al. 2022

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Understanding gas migration in compacted clay materials, e.g., bentonite and claystone, is important for the design and performance assessment of an engineered barrier system of a radioactive waste repository system, as well as many practical applications. Existing field and laboratory data on gas migration processes in low-permeability clay materials demonstrate the complexity of flow and transport processes, including various types of instabilities, caused by nonlinear dynamics of coupled processes of liquid–gas exchange, dilation, fracturing, fracture healing, etc., which cannot be described by classical models of fluid dynamics in porous media. We here show that the complexity of gas migration processes can be explained using a phenomenological concept of nonlinear dynamics and deterministic chaos theory. To do so, we analyzed gas pressure and gas influx (i.e., input) and outflux (i.e., output), recorded during the gas injection experiment in the compact Mx80-D bentonite sample, and calculated a set of the diagnostic parameters of nonlinear dynamics and chaos, such a global embedding dimension, a correlation dimension, an information dimension, and a spectrum of Lyapunov exponents, as well as plotted 2D and 3D pseudo-phase-space strange attractors, based on the univariate influx and outflux time series data. These results indicate the presence of phenomena of low-dimensional deterministic chaotic behavior of gas migration in bentonite. In particular, during the onset of gas influx in the bentonite core, before the breakthrough, the development of gas flow pathways is characterized by the process of chaotic gas diffusion. After the breakthrough, with inlet-to-outlet movement of gas, the prevailing process is chaotic advection. During the final phase of the experiment, with no influx to the sample, the relaxation pattern of gas outflux is resumed back to a process of chaotic diffusion. The types of data analysis and a proposed phenomenological model can be used to establish the basic principles of experimental data-gathering, modeling predictions, and a research design.

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Section: Introductionmentioning

confidence: 99%

Phenomenological Model of Nonlinear Dynamics and Deterministic Chaotic Gas Migration in Bentonite: Experimental Evidence and Diagnostic Parameters

et al. 2022

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“…Cd retention on several sorbents has been studied for years, considering either synthetic materials [ 9 , 10 ] or natural minerals and soils [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. Clayey rocks are often used as barrier materials because they are long-lasting, environmentally safe, abundant, and cheap [ 19 , 20 , 21 ].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Cadmium Retention Mechanisms by a Smectite Clay in the Presence of Carbonates

Missana¹,

Alonso²,

Mayordomo

et al. 2023

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Cadmium (Cd) is a toxic heavy metal with very low permissible exposure limits and is, thus, a very dangerous pollutant for the environment and public health and is considered by the World Health Organisation as one of the ten chemicals of major public concern. Adsorption onto solid phases and (co)precipitation processes are the most powerful mechanisms to retain pollutants and limit their migration; thus, the understanding of these processes is fundamental for assessing the risks of their presence in the environment. In this study, the immobilisation of Cd by smectite clay has been investigated by batch sorption tests, and the experimental data were interpreted with a thermodynamic model, including cation exchange and surface complexation processes. The model can describe the adsorption of Cd in smectite under a wide range of experimental conditions (pH, ionic strength, and Cd concentration). Under the conditions analysed in this study, the precipitation of otavite (CdCO3) is shown to have a limited contribution to Cd immobilisation.

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“…After each of these conferences, a special issue of a journal was published which focused on clay radioactive waste (radwaste), research which has contributed in a significant way to the outstanding scientific level of the research in this field (e.g. Landais & Aranyossy, 2011;Landais et al, 2013;Norris et al, 2014). Therefore, Clay Minerals -Journal of Fine Particle Science, is happy to be able to provide the present compilation of recent HLW-disposal research in clay mineralogy in an open access issue.…”

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confidence: 99%

Overview of the clay-mineralogy studies presented at the ‘Clays in natural and engineered barriers for radioactive waste confinement’ meeting, Brussels, March 2015

Geet

Dohrmann

2016

Clay miner.

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Clays in Natural and Engineered Barriers for Radioactive Waste Confinement: an introduction

Cited by 9 publications

References 44 publications

Phenomenological Model of Nonlinear Dynamics and Deterministic Chaotic Gas Migration in Bentonite: Experimental Evidence and Diagnostic Parameters

Phenomenological Model of Nonlinear Dynamics and Deterministic Chaotic Gas Migration in Bentonite: Experimental Evidence and Diagnostic Parameters

Analysis of Cadmium Retention Mechanisms by a Smectite Clay in the Presence of Carbonates

Overview of the clay-mineralogy studies presented at the ‘Clays in natural and engineered barriers for radioactive waste confinement’ meeting, Brussels, March 2015

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