Distribution coefficients for the sorption of Th, U, Np, Pu, and Am on Opalinus Clay

Amayri, Samer; Fröhlich, Daniel R.; Kaplan, Ugras; Trautmann, Ν.; Reich, Tobias

doi:10.1515/ract-2015-2409

Cited by 23 publications

(10 citation statements)

References 45 publications

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“…For the Pu and Am sorption experiments, a 1 × 10 -5 M 239 Pu(III) solution and a 6 × 10 -6 M 241 Am(III) solution, each in 1 M HClO 4 , were used. The preparation of the stock solutions is described elsewhere (Amayri et al 2016).…”

Section: Stock Solutionsmentioning

confidence: 99%

Uptake of actinides by calcium silicate hydrate (C-S-H) phases

Häußler

Amayri

Beck

et al. 2018

Applied Geochemistry

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Section: Stock Solutionsmentioning

confidence: 99%

Uptake of actinides by calcium silicate hydrate (C-S-H) phases

Häußler

Amayri

Beck

et al. 2018

Applied Geochemistry

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“…Only a limited number of studies address the environmental reactivity of Pu(V) and Pu(VI) within complex natural barrier materials. Amayri et al 29 studied the sorption of Pu and other actinides on OPA material by batch sorption experiments. This study showed that the affinity for the solid surfaces depends strongly on the oxidation state of the actinides.…”

Section: Introductionmentioning

confidence: 99%

Geochemical Interactions of Plutonium with Opalinus Clay Studied by Spatially Resolved Synchrotron Radiation Techniques

Kaplan

Amayri

Drebert

et al. 2017

Environ. Sci. Technol.

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Plutonium plays an important role within nuclear waste materials because of its long half-life and high radiotoxicity. The aim of this study was to investigate with high spatial resolution the reactivity of the more oxidized forms of Pu(V,VI) within Opalinus Clay (OPA) rock, a heterogeneous, natural argillaceous rock considered as a potential repository host. A combination of synchrotron based X-ray microprobe and bulk techniques was used to study the spatial distribution and molecular speciation of Pu within OPA after diffusion and sorption processes. Microscopic chemical images revealed a pronounced impact of geochemical heterogeneities concerning the reactivity of the natural barrier material. Spatially resolved X-ray absorption spectroscopy documented a reduction of the highly soluble Pu(V,VI) to the less mobile Pu(IV) within the argillaceous rock material, while bulk investigations showed second-shell scattering contributions, indicating an inner-sphere sorption of Pu on OPA components. Microdiffraction imaging identified the clay mineral kaolinite to play a key role in the immobilization of the reduced Pu. The findings provide strong evidence that reduction and immobilization do not occur as linked processes on a single reactive phase but as decoupled, subsequent, and spatially separated reactions involving different phases of the OPA.

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“…The Fe(II)-bearing mineral pyrite has been identified in previous sorption experiments as a redox-active component of Opalinus Clay rock (OPA), that is involved in the reduction and immobilization of Pu [ 3 , 35 ]. Micrometer-sized pyrite particles were extracted from calcite-saturated, aqueous suspensions of OPA and manually sorted under a microscope.…”

Section: Methodsmentioning

confidence: 99%

“…Among others, clay rock is considered as a possible host rock, and cementitious materials will be part of the technical barrier [2]. Migration and sorption studies evaluating clay rock and cementitious materials as geological and technical barriers for long-term nuclear waste storage are conducted using environmentally relevant actinide concentrations (10 −7 to 10 −9 mol/L) [3][4][5][6]. Investigating the interactions of radionuclides with these exceedingly heterogeneous materials requires an analytical method with both high spatial resolution and sensitivity.…”

Section: Introductionmentioning

confidence: 99%

Development, characterization, and first application of a resonant laser secondary neutral mass spectrometry setup for the research of plutonium in the context of long-term nuclear waste storage

et al. 2021

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Plutonium is a major contributor to the radiotoxicity in a long-term nuclear waste repository; therefore, many studies have focused on interactions of plutonium with the technical, geotechnical, and geological barriers of a possible nuclear waste storage site. In order to gain new insights into the sorption on surfaces and diffusion of actinides through these complex heterogeneous materials, a highly sensitive method with spatial resolution is required. Resonant laser secondary neutral mass spectrometry (Laser-SNMS) uses the spatial resolution available in time-of-flight secondary ion mass spectrometry (TOF-SIMS) in combination with the high selectivity, sensitivity, and low background noise of resonance ionization mass spectrometry (RIMS) and is, therefore, a promising method for the study and analysis of the geochemical behavior of plutonium in long-term nuclear waste storage. The authors present an approach with a combined setup consisting of a commercial TOF-SIMS instrument and a Ti:sapphire (Ti:Sa) laser system, as well as its optimization, characterization, and improvements compared to the original proof of concept by Erdmann et al. (2009). As a first application, the spatial distributions of plutonium and other elements on the surface of a pyrite particle and a cement thin section were measured by Laser-SNMS and TOF-SIMS, respectively. These results exemplify the potential of these techniques for the surface analysis of heterogeneous materials in the context of nuclear safety research.

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Distribution coefficients for the sorption of Th, U, Np, Pu, and Am on Opalinus Clay

Abstract: but still more than two orders of magnitude higher compared to the values obtained for U(VI) and Np(V). This discrepancy is attributed to the partial reduction of Pu(VI) to Pu(IV) during sorption.

Cited by 23 publications

References 45 publications

Uptake of actinides by calcium silicate hydrate (C-S-H) phases

Uptake of actinides by calcium silicate hydrate (C-S-H) phases

Geochemical Interactions of Plutonium with Opalinus Clay Studied by Spatially Resolved Synchrotron Radiation Techniques

Development, characterization, and first application of a resonant laser secondary neutral mass spectrometry setup for the research of plutonium in the context of long-term nuclear waste storage

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