Degradation mechanism of lead-vanado-iodoapatite in NaCl solution

Wang, Yachun; Yao, Tiankai; Fa-Yuan, Xi; Lei, Penghui; Guo, Xiaolei; He, Lingfeng; Frankel, G. S.; Lian, Jie

doi:10.1016/j.corsci.2020.108720

Cited by 3 publications

(7 citation statements)

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“…To provide enough nucleation sites for apatite crystals, one sample was intentionally roughened to 600 grit prior to immersion in 6 M NaCl solution. The major results of I-APT corrosion in different NaCl concentrations, including iodine release, degradation mechanisms, alteration layer formation, and microstructure evolution, were reported in a separate paper 28 . Here, we briefly discuss the morphology variation and secondary phase formation in the chloride solutions as benchmarking experiments, which are useful for comparison with the behavior of the I-APT upon interaction with SS with drastically changed solution chemistry, specifically high Cl − concentrations, in the confined crevice.…”

Section: Discussionmentioning

confidence: 99%

Corrosion interactions between stainless steel and lead vanado-iodoapatite nuclear waste form part II

et al. 2020

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This paper studied the release of iodine from lead vanado-iodoapatite (I-APT, Pb 9.85 (VO 4) 6 I 1.7), a potential nuclear waste form for the radioactive waste element of I-129, which can be enhanced when crevice corrosion of stainless steel (SS) occurring nearby. Reference corrosion studies of I-APT were performed in different bulk solutions including DI water, 0.6 M and 6 M NaCl, and 0.1 M HNO 3 without metal crevice corrosion interactions. The localized enrichment of Cl − , one of the major consequences of SS crevice corrosion, was found to be the decisive factor that led to the enhanced release of iodine. A surface alteration layer consisting of a mixture of nanocrystalline I-APT and Cl-rich apatite (Cl-APT) formed on I-APT surface. Meanwhile, large Cl-APT crystals formed at the crevice mouth on the I-APT surface. This study reveals a new near-field corrosion mechanism for ceramic waste forms when they are exposed to aggressive local corrosive conditions created by the electrochemical reactions of nearby metals. The insight gained in this study could be beneficial for a more accurate prediction of waste form degradation.

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Section: Discussionmentioning

confidence: 99%

Corrosion interactions between stainless steel and lead vanado-iodoapatite nuclear waste form part II

et al. 2020

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“…Cl-apatite precipitated on the surface of the apatite during corrosion in NaCl solutions with different Cl − concentrations ranging from 0.6 to 6 M, and the particle size increased at higher Cl − concentrations and on samples with rough surfaces (Figures 24d and 24e). 250,251,307 Nonstoichiometric (incongruent) dissolution with a much higher release rate of I than Pb and V was observed. Higher Cl − concentrations in the leachate further enhanced the accumulation of iodine in bulk solutions and increased the depth of the alteration layer to as high as 260 μm.…”

Section: Modeling Of Chemical Durability and Dissolution Kineticsmentioning

confidence: 96%

“…Copyright 2019 Elsevier. (b–e) Morphologies and microstructures of the surface alteration of I-apatite under different aqueous conditions. , Adapted with permission from Yao et al Copyright 2020 The Author(s) under Creative Commons CC BY license, . (f–i) Elemental mappings (green, Cl; purple, iodine) of the I-apatite altered in 6 M NaCl showing ion replacement and grain subdivision.…”

Section: Corrosion Of Crystalline Ceramics In Aqueous Environmentsmentioning

confidence: 99%

“…(f–i) Elemental mappings (green, Cl; purple, iodine) of the I-apatite altered in 6 M NaCl showing ion replacement and grain subdivision. Reproduced with permission from ref . Copyright 2020 Elsevier.…”

Section: Corrosion Of Crystalline Ceramics In Aqueous Environmentsmentioning

confidence: 99%

Section: Corrosion Of Crystalline Ceramics In Aqueous Environmentsmentioning

confidence: 99%

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Recent Advances in Corrosion Science Applicable To Disposal of High-Level Nuclear Waste

et al. 2021

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High-level radioactive waste is accumulating at temporary storage locations around the world and will eventually be placed in deep geological repositories. The waste forms and containers will be constructed from glass, crystalline ceramic, and metallic materials, which will eventually come into contact with water, considering that the period of performance required to allow sufficient decay of dangerous radionuclides is on the order of 105–106 years. Corrosion of the containers and waste forms in the aqueous repository environment is therefore a concern. This Review describes the recent advances of the field of materials corrosion that are relevant to fundamental materials science issues associated with the long-term performance assessment and the design of materials with improved performance, where performance is defined as resistance to aqueous corrosion. Glass, crystalline ceramics, and metals are discussed separately, and the near-field interactions of these different material classes are also briefly addressed. Finally, recommendations for future directions of study are provided.

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Computational Materials Design for Ceramic Nuclear Waste Forms Using Machine Learning, First-Principles Calculations, and Kinetics Rate Theory

2023

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Ceramic waste forms are designed to immobilize radionuclides for permanent disposal in geological repositories. One of the principal criteria for the effective incorporation of waste elements is their compatibility with the host material. In terms of performance under environmental conditions, the resistance of the waste forms to degradation over long periods of time is a critical concern when they are exposed to natural environments. Due to their unique crystallographic features and behavior in nature environment as exemplified by their natural analogues, ceramic waste forms are capable of incorporating problematic nuclear waste elements while showing promising chemical durability in aqueous environments. Recent studies of apatite- and hollandite-structured waste forms demonstrated an approach that can predict the compositions of ceramic waste forms and their long-term dissolution rate by a combination of computational techniques including machine learning, first-principles thermodynamics calculations, and modeling using kinetic rate equations based on critical laboratory experiments. By integrating the predictions of elemental incorporation and degradation kinetics in a holistic framework, the approach could be promising for the design of advanced ceramic waste forms with optimized incorporation capacity and environmental degradation performance. Such an approach could provide a path for accelerated ceramic waste form development and performance prediction for problematic nuclear waste elements.

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Degradation mechanism of lead-vanado-iodoapatite in NaCl solution

Cited by 3 publications

References 33 publications

Corrosion interactions between stainless steel and lead vanado-iodoapatite nuclear waste form part II

Corrosion interactions between stainless steel and lead vanado-iodoapatite nuclear waste form part II

Recent Advances in Corrosion Science Applicable To Disposal of High-Level Nuclear Waste

Computational Materials Design for Ceramic Nuclear Waste Forms Using Machine Learning, First-Principles Calculations, and Kinetics Rate Theory

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