The effect of composition on the leaching of three nuclear waste glasses: R7T7, AVM and VRZ

Frugier, Pierre; Martin, Christelle; Ribet, I.; Advocat, T.; Gin, Stéṕhane

doi:10.1016/j.jnucmat.2005.06.023

Cited by 111 publications

(101 citation statements)

References 10 publications

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“…The value of r r was increased by K > Li≈B > Na and decreased by Al > Si > Fe. Frugier et al 74 identified significant impacts of small composition changes on the r r measured under static conditions. The valence state of multivalent elements within the glass such as transition metal (Fe, Cr, Mn, Tc…), lanthanides or actinides could impact glass durability in different ways.…”

Section: Overview Of Silicate Glass Corrosionmentioning

confidence: 99%

A comparative review of the aqueous corrosion of glasses, crystalline ceramics, and metals

et al. 2018

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All materials can suffer from environmental degradation; the rate and extent of degradation depend on the details of the material composition and structure as well as the environment. The corrosion of silicate glasses, crystalline ceramics, and metals, particularly as related to nuclear waste forms, has received a lot of attention. The corrosion phenomena and mechanisms of these materials are different, but also have many similarities. This review compares and contrasts the mechanisms of environmental degradation of glass, crystalline ceramics, and metals, with the goal of identifying commonalities that can seed synergistic activities and advance the current knowledge in each area.npj Materials Degradation (2018) 2:15 ; doi:10.1038/s41529-018-0037-2 INTRODUCTIONNew research activity focused on the environmental degradation of silicate glasses, crystalline ceramics, and metals relevant to nuclear waste forms and containers has recently been described.

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Section: Overview Of Silicate Glass Corrosionmentioning

confidence: 99%

A comparative review of the aqueous corrosion of glasses, crystalline ceramics, and metals

et al. 2018

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“…3 . This series will be used to determine how the concentration of boron will affect the Ca 2 + ion distribution and preferential charge balancing when the molybdenum content is around its solubility limit and no alkalis are present.…”

Section: Glass Compositions and Synthesis Techniquementioning

confidence: 99%

“…The composition of CBO was determined based on the eutectic point of the SiO 2 -CaO system [35] and was used as a marker for boron incorporation sites. The CM series tests the effect of increasing [MoO 3 ] in a calcium borosilicate matrix normalized to inactive French nuclear waste glass 3 and Gd 2 O 3 . Synthesis was conducted at atmosphere in a platinum-rhodium (90/10) crucible.…”

Section: Glass Compositions and Synthesis Techniquementioning

confidence: 99%

“…Amorphous structures are ideal waste form candidates as they are able to incorporate a wide array of nuclides with varying charge and are resistant to internal radiation [2]. Moreover, they can be synthesized at reasonable conditions and show good chemical stability when subjected to aqueous environments [1,3]. Though they have proved beneficial in many regards, there are material limitations introduced by insoluble species that can result in unexpected phase separation [4][5][6] and thus degradation of physical properties [7,8].…”

Section: Introductionmentioning

confidence: 99%

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Impacts of composition and beta irradiation on phase separation in multiphase amorphous calcium borosilicates

Patel

Boizot

Facq

et al. 2017

Journal of Non-Crystalline Solids

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A B S T R A C TBorosilicate glasses for nuclear waste applications are limited in waste loading by the precipitation of watersoluble molybdates. In order to increase storage efficiency, new compositions are sought out that trap molybdenum in a water-durable CaMoO 4 crystalline phase. Factors affecting CaMoO 4 combination and glass-inglass phase separation in calcium borosilicate systems as a function of changing [MoO 3 ] and [B 2 O 3 ] are examined in this study in order to understand how competition for charge balancers affects phase separation. It further examines the influence of radiation damage on structural modifications using 0.77 to 1.34 GGy of 2.5 MeV electron radiation that replicates inelastic collisions predicted to occur over long-term storage. The resulting microstructure of separated phases and the defect structure were analyzed using electron microscopy, XRD, Raman and EPR spectroscopy prior to and post irradiation. Synthesized calcium borosilicates are observed to form an unusual heterogeneous microstructure composed of three embedded amorphous phases with a solubility limit~2.5 mol% MoO 3. Increasing [B 2 O 3 ] increased the areas of immiscibility and order of (MoO 4 ) 2 − anions, while increasing [MoO 3 ] increased both the phase separation and crystallization temperature resulting in phases closer to metastable equilibrium, and initiated clustered crystallization for [MoO 3 ] > 2.5 mol%. β-irradiation was found to have favorable properties in amorphous systems by creating structural disorder and defect assisted ion migration that thus prevented crystallization. It also increased reticulation in the borosilicate network through 6-membered boroxyl ring and Si ring cleavage to form smaller rings and isolated units. This occurred alongside an increased reduction of Mo 6 + with dose that can be correlated to molybdenum solubility.In compositions with existing CaMoO 4 crystallites, radiation caused a scattering effect, though the crystal content remained unchanged. Therefore β-irradiation can preferentially prevent crystallization in calcium borosilicates for [MoO 3 ] < 2.5 mol%, but has a smaller impact on systems with existing CaMoO 4 crystallites.

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“…Firstly, under some conditions, layers are not protective [66,67]. Secondly, according to "dynamic percolation" mechanism and model [14,51], in a steady state, the glass dissolves at its initial rate and recondensation of silanol groups leads to the formation of a gel as a secondary phase.…”

Section: Diffusion Barrier Concept and Modelsmentioning

confidence: 99%

A mechanistic model for long-term nuclear waste glass dissolution integrating chemical affinity and interfacial diffusion barrier

Jivkov

et al. 2017

Journal of Nuclear Materials

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Abstract:Understanding the alteration of nuclear waste glass in geological repository conditions is critical element of the analysis of repository retention function. Experimental observations of glass alterations provide a general agreement on the following regimes: inter-diffusion, hydrolysis process, rate drop, residual rate and, under very particular conditions, resumption of alteration. Of these, the mechanisms controlling the rate drop and the residual rate remain a subject of dispute. This paper offers a critical review of the two most competitive models related to these regimes: affinity-limited dissolution and diffusion barrier. The limitations of these models are highlighted by comparison of their predictions with available experimental evidence. Based on the comprehensive discussion of the existing models, a new mechanistic model is proposed as a combination of the chemical affinity and diffusion barrier concepts. It is demonstrated how the model can explain experimental phenomena and data, for which the existing models are shown to be not fully adequate.Key words: nuclear waste glasses, long-term dissolution, mechanisms, modelling IntroductionRadioactivity wastes are generated at all stages of the nuclear fuel cycle, including the decommissioning of nuclear facilities, as well as from military applications. Of particular concern for the storage/disposal of radioactivity wastes are those containing long-lived radionuclides [1].The current plan ( countries such as Belgium, Finland , Sweden , France etc.)for long-term management of such wastes is to store them in deep, stable and lowpermeable geological formations [2].The storage design is based on the so-called multi-barrier concept, where several barriers prevent for a period of time, or slow down the release and migration of radionuclides through the geosphere [3,4].Within this concept, hazardous nuclides are immobilized into solidified bodies. The wasteform selection is difficult, since durability is not the sole criterion [5]. Currently, vitrification is regarded as the best solution for immobilizing radionuclides. This technology has been progressively developed over the last half-century, has matured and has become industrially robust.Data collected to date suggest that glass waste forms offer the advantages that they can accommodate a wide range of waste streams, are resistant to radiation damage, and are relatively inert to both chemical and thermal perturbations [6].The use of natural and archeological analogues supported further the durability argument of glass as waste forms [7][8][9][10][11]. Except for the alumino-phosphate glass used in Russia, the borosilicate glass has been universally selected by all other nations [12].In order to make scientifically-underpinned safety cases, the long-term behaviour of glassy wasteforms requires further understanding and assessment. Half-lives of some radionuclides extend to millions of years, requiring isolation for geological periods, while the period of investigation possible in the field and the la...

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The effect of composition on the leaching of three nuclear waste glasses: R7T7, AVM and VRZ

Cited by 111 publications

References 10 publications

A comparative review of the aqueous corrosion of glasses, crystalline ceramics, and metals

A comparative review of the aqueous corrosion of glasses, crystalline ceramics, and metals

Impacts of composition and beta irradiation on phase separation in multiphase amorphous calcium borosilicates

A mechanistic model for long-term nuclear waste glass dissolution integrating chemical affinity and interfacial diffusion barrier

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