High level nuclear waste glass corrosion in synthetic clay pore solution and retention of actinides in secondary phases

Bosbach, Dirk; Luckscheiter, B.; Brendebach, Boris; Denecke, Melissa A.; Finck, N.

doi:10.1016/j.jnucmat.2008.12.044

Cited by 14 publications

(9 citation statements)

References 16 publications

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“…It has also been suggested the gel layer constantly re‐equilibrates with a silica‐saturated pore solution by hydrolysis/condensation reactions between the pore solution and the residual glass, which may result in a dense and strongly polymerized alteration layer . Secondary phases may also precipitate at the “gel” layer/solution interface, which may affect the stability of the gel layer as their growth consumes Si and other solute elements …”

Section: Introductionmentioning

confidence: 80%

“…31,32,35 It has also been suggested the gel layer constantly re-equilibrates with a silica-saturated pore solution by hydrolysis/condensation reactions between the pore solution and the residual glass, which may result in a dense and strongly polymerized alteration layer. [36][37][38] Secondary phases may also precipitate at the "gel" layer/solution interface, 13,39 which may affect the stability of the gel layer as their growth consumes Si and other solute elements. 13 Here, we present results of corrosion experiments with a simple ternary Na borosilicate and a chemically more complex, U-bearing silicate glass under static conditions with a low surface-to-solution ratio to mimic natural conditions.…”

Section: Introductionmentioning

confidence: 99%

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Pattern Formation in Silicate Glass Corrosion Zones

Dohmen

Lenting

Fonseca

et al. 2013

Int J of Appl Glass Sci

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Alteration zones of archeological glasses often show intriguing lamellar patterns in backscattered electron images. Here, we report results of static glass corrosion experiments with two different silicate glasses that revealed laminar porosity and subordinately chemical patterns inside silica-based corrosion zones that resemble those seen in naturally altered, ancient glasses. Aside from common laminar patterns, more complex patterns were observed in corrosion zones that developed along a fracture network. The formation of such patterns cannot be explained by any of the existing glass corrosion models. We suggest that silica-based corrosion zones form by a process that involves the congruent dissolution of the glass network, which is spatially and temporally coupled to the deposition of amorphous silica at an inwardly moving reaction interface. The patterns likely form in response to fluctuations of the pH and salinity in the interfacial solution, which govern the silica solubility, deposition, and dissolution rate, and thus, its microstructure and porosity, and, in turn, are controlled by the dissolution rate of the glass and the transport properties of the silica reaction layers. However, the exact feedback mechanism producing pH fluctuations in the interfacial solution has not yet been identified and is an open question for future research.

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Section: Introductionmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Pattern Formation in Silicate Glass Corrosion Zones

Dohmen

Lenting

Fonseca

et al. 2013

Int J of Appl Glass Sci

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“…In contrast to this, markedly saline conditions are found in ground water characteristic of clay formations in northern Germany (I > 3.5 M). 13 Thus it becomes necessary to assess the effect of ionic strength and temperature on Np(V) complexation with LMWO to predict its potential mobilisation from a nuclear waste repository in specific scenarios. Although the interaction of Np(V) with LMWO is particularly relevant in this context, only a few studies have aimed at determining the corresponding complex formation constants.…”

Section: Introductionmentioning

confidence: 99%

Np(v) complexation with propionate in 0.5–4 M NaCl solutions at 20–85 °C

et al. 2015

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Low molecular weight organics (LMWO; e.g. acetate, propionate, lactate) can significantly impact the speciation and mobility of radionuclides in aqueous media. Natural clay rock formation, considered as a potential host rock for nuclear waste disposal, can contain a significant amount of organic matter. There are less thermodynamic data reported for the complexation of pentavalent actinides with LMWO, especially under elevated temperature conditions, relevant for assessing the long-term safety of disposal options for heat-producing high-level nuclear waste. In the present study, the complexation of Np(v) with propionate is studied using spectroscopic techniques in 0.5-4 M NaCl solutions by systematic variation of the ligand concentration and temperature. Slope analysis shows the formation of the 1 : 1 NpO2-propionate complex (NpO2Prop). The local structure of the NpO2-propionate complex is determined by extended X-ray absorption fine structure spectroscopy, the results of which suggest that propionate binds to Np(v) in a bidentate mode. Using the specific ion interaction theory (SIT), the stability constant at zero ionic strength and 25 °C is determined as log β°1,1 = 1.26 ± 0.03. The stability constants increase continuously with increasing temperature between 20 and 85 °C. The log β0 values are linearly correlated with the reciprocal temperature, indicating ΔrH = const. and ΔrC = 0, allowing the calculation of ΔrH and ΔrS for the formation of the NpO2-propionate complex using the integrated van't Hoff equation. The thermodynamic evaluation indicates that the reaction is endothermic and entropy driven.

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“…However, only few works included a cation exchange reaction to achieve the doping. In those cases, either the mineral structure of the clay was broken into enstatite to obtain the luminescent material, or the obtained materials showed only weak rare earth ions' (RE 3+ ) luminescence comparable to that obtained from pure aqueous solutions of RE 3+ because of the efficient non‐radiative relaxation via O–H vibrations . Lezhnina et al highlighted in their work that in order to obtain an efficient luminescent material from the doping of RE 3+ into clay minerals, it is necessary either to use co‐doping to allow energy transfer (e.g.…”

Section: Introductionmentioning

confidence: 99%

Red‐ and green‐emitting nano‐clay materials doped with Eu³⁺ and/or Tb³⁺

et al. 2018

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Trivalent europium (Eu3+) and terbium (Tb3+) ions are important activator centers used in different host lattices to produce red and green emitting materials. The current work shows the design of new clay minerals to act as host lattices for rare earth (RE) ions. Based on the hectorite structure, nano‐chlorohectorites and nano‐fluorohectorites were developed by replacing the OH− present in the hectorite structure with Cl− or F−, thus avoiding the luminescence quenching expected due to the OH− groups. The produced matrices were characterized through X‐ray powder diffraction (XPD), transmission electron microscopy (TEM), FT‐IR, 29Si MAS (magic angle spinning) NMR, nitrogen sorption, thermogravimetry‐differential scanning calorimetry (TGA‐DSC) and luminescence measurements, indicating all good features expected from a host lattice for RE ions. The nano‐clay materials were successfully doped with Eu3+ and/or Tb3+ to yield materials preserving the hectorite crystal structure and showing the related luminescence emissions. Thus, the present work shows that efficient RE3+ luminescence can be obtained from clays without the use of organic ‘antenna’ molecules.

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High level nuclear waste glass corrosion in synthetic clay pore solution and retention of actinides in secondary phases

Cited by 14 publications

References 16 publications

Pattern Formation in Silicate Glass Corrosion Zones

Pattern Formation in Silicate Glass Corrosion Zones

Np(v) complexation with propionate in 0.5–4 M NaCl solutions at 20–85 °C

Red‐ and green‐emitting nano‐clay materials doped with Eu³⁺ and/or Tb³⁺

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High level nuclear waste glass corrosion in synthetic clay pore solution and retention of actinides in secondary phases

Cited by 14 publications

References 16 publications

Pattern Formation in Silicate Glass Corrosion Zones

Pattern Formation in Silicate Glass Corrosion Zones

Np(v) complexation with propionate in 0.5–4 M NaCl solutions at 20–85 °C

Red‐ and green‐emitting nano‐clay materials doped with Eu3+ and/or Tb3+

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Product

Resources

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Red‐ and green‐emitting nano‐clay materials doped with Eu³⁺ and/or Tb³⁺