The Role of Smectite Clay Barriers for Isolating High-Level Radioactive Waste (HLW) In Shallow and Deep Repositories

Pusch, Roland; Kasbohm, Jörn; Knutsson, Sven; Yang, Ting; Nguyen-Thanh, Lan

doi:10.1016/j.proeps.2015.08.084

Cited by 16 publications

(7 citation statements)

References 13 publications

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“…Due to peak overlap we cannot distinguish between this line shape and a symmetrical but broad Lorentzian line shape. The relative intensity of this component, no matter its shape, is smaller at 173 K than at 193 K. This decrease is consistent with previously published 2 H NMR results of Ishimaru and Ryuichi for synthetic Na–hectorite equilibrated at 100% RH, which show a similar decrease and complete loss of the Lorentzian component at 150 K. Thus, for their sample at 150 K all water molecules are rigidly held, with reorientation and dipole rotation frequencies < ∼10 4 Hz (slow exchange regime). If our NMR instrument had been able to operate at lower temperatures, the spectra of our samples would probably also contain only this resonance.…”

Section: Resultssupporting

confidence: 91%

Water Structure and Dynamics in Smectites: X-ray Diffraction and ²H NMR Spectroscopy of Mg–, Ca–, Sr–, Na–, Cs–, and Pb–Hectorite

et al. 2016

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Variable-temperature X-ray diffraction and 2 H NMR spectroscopy of the smectite mineral, hectorite, containing interlayer Na + , K + , Cs + , Mg 2+ , Ca 2+ , Sr 2+ , and Pb 2+ equilibrated at 43% relative humidity (RH) and mixed with 2 H 2 O to form a paste provide a comprehensive picture of the structural environments and dynamics of interlayer 2 H 2 O and the relationships of these properties to interlayer hydration state, the hydration energy and polarizability of the cation, temperature, and the formation of ice-1h in the interparticle pores. The variation in basal spacing shown by the XRD data correlates well with the 2 H NMR behavior, and the XRD data show for the first time in hectorites that crystallization of interparticle ice-1h causes a decrease in the interlayer spacing, likely due to removal of interlayer 2 H 2 O. The variation of the 2 H NMR behavior of all the samples with decreasing temperature reflects decreasing frequencies of motion for the rotation of the 2 H 2 O molecules around their dipoles, reorientation of the 2 H 2 O molecules, and exchange of the 2 H 2 O molecules between interlayer sites coordinated to and not coordinated to the cations.

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Section: Resultssupporting

confidence: 91%

Water Structure and Dynamics in Smectites: X-ray Diffraction and ²H NMR Spectroscopy of Mg–, Ca–, Sr–, Na–, Cs–, and Pb–Hectorite

et al. 2016

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“…For example, the specific density of magnetite (Fe 3 O 4 ) is about one half that of iron (Fe 0 ). It implies that after corrosion a space twice larger than the initial space is occupied [108][109][110]. While it can be assumed that H 2 escapes from each open system, no free expansion of oxides in porous systems (e.g., water filters, reactive walls) can be assumed [26].…”

Section: Physical Aspectsmentioning

confidence: 99%

“…While it can be assumed that H 2 escapes from each open system, no free expansion of oxides in porous systems (e.g., water filters, reactive walls) can be assumed [26]. External or internal free expansion occurs in metallic pipes [111,112] and on the walls of steel canister for radioactive waste repositories [110,113]. On the contrary, free expansion cannot be expected in steel-reinforced concrete structures [108,109].…”

Section: Physical Aspectsmentioning

confidence: 99%

Metallic Iron for Environmental Remediation: Starting an Overdue Progress in Knowledge

Yang²,

Tao³

et al. 2020

Water

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A critical survey of the abundant literature on environmental remediation and water treatment using metallic iron (Fe0) as reactive agent raises two major concerns: (i) the peculiar properties of the used materials are not properly considered and characterized, and, (ii) the literature review in individual publications is very selective, thereby excluding some fundamental principles. Fe0 specimens for water treatment are typically small in size. Before the advent of this technology and its application for environmental remediation, such small Fe0 particles have never been allowed to freely corrode for the long-term spanning several years. As concerning the selective literature review, the root cause is that Fe0 was considered as a (strong) reducing agent under environmental conditions. Subsequent interpretation of research results was mainly directed at supporting this mistaken view. The net result is that, within three decades, the Fe0 research community has developed itself to a sort of modern knowledge system. This communication is a further attempt to bring Fe0 research back to the highway of mainstream corrosion science, where the fundamentals of Fe0 technology are rooted. The inherent errors of selected approaches, currently considered as countermeasures to address the inherent limitations of the Fe0 technology are demonstrated. The misuse of the terms “reactivity”, and “efficiency”, and adsorption kinetics and isotherm models for Fe0 systems is also elucidated. The immense importance of Fe0/H2O systems in solving the long-lasting issue of universal safe drinking water provision and wastewater treatment calls for a science-based system design.

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“…Smectite clay is widely used as "buffer" barrier in engineered radioactive waste containment systems, owing to their low permeability and high sorption capacity [1]. The performance of the engineering barrier in a high-level waste repository is highly affected by structural changes caused by alteration of the original in different proportions on smectite [10] and the progressive formation of illite-montmorillonite mixed layers [11,12].…”

Section: Introductionmentioning

confidence: 99%

Influence of pH, layer charge location and crystal thickness distribution on U(VI) sorption onto heterogeneous dioctahedral smectite

Guimarães

Rodríguez‐Castellón

Algarra

et al. 2016

Journal of Hazardous Materials

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The Role of Smectite Clay Barriers for Isolating High-Level Radioactive Waste (HLW) In Shallow and Deep Repositories

Cited by 16 publications

References 13 publications

Water Structure and Dynamics in Smectites: X-ray Diffraction and ²H NMR Spectroscopy of Mg–, Ca–, Sr–, Na–, Cs–, and Pb–Hectorite

Water Structure and Dynamics in Smectites: X-ray Diffraction and ²H NMR Spectroscopy of Mg–, Ca–, Sr–, Na–, Cs–, and Pb–Hectorite

Metallic Iron for Environmental Remediation: Starting an Overdue Progress in Knowledge

Influence of pH, layer charge location and crystal thickness distribution on U(VI) sorption onto heterogeneous dioctahedral smectite

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The Role of Smectite Clay Barriers for Isolating High-Level Radioactive Waste (HLW) In Shallow and Deep Repositories

Cited by 16 publications

References 13 publications

Water Structure and Dynamics in Smectites: X-ray Diffraction and 2H NMR Spectroscopy of Mg–, Ca–, Sr–, Na–, Cs–, and Pb–Hectorite

Water Structure and Dynamics in Smectites: X-ray Diffraction and 2H NMR Spectroscopy of Mg–, Ca–, Sr–, Na–, Cs–, and Pb–Hectorite

Metallic Iron for Environmental Remediation: Starting an Overdue Progress in Knowledge

Influence of pH, layer charge location and crystal thickness distribution on U(VI) sorption onto heterogeneous dioctahedral smectite

Contact Info

Product

Resources

About

Water Structure and Dynamics in Smectites: X-ray Diffraction and ²H NMR Spectroscopy of Mg–, Ca–, Sr–, Na–, Cs–, and Pb–Hectorite

Water Structure and Dynamics in Smectites: X-ray Diffraction and ²H NMR Spectroscopy of Mg–, Ca–, Sr–, Na–, Cs–, and Pb–Hectorite