Using “radioparagenesis” to design robust nuclear waste forms

Jiang, Chao; Uberuaga, Blas P.; Sickafus, Kurt E.; Nortier, F.M.; Kitten, J. J.; Marks, Nigel A.; Stanek, Christopher R.

doi:10.1039/b915493k

Cited by 20 publications

(16 citation statements)

References 22 publications

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“…The emitted electron could be captured by a variable valance metal ion in the structure and the 129-Xe could remain in the structure as a defect or diffuse away as a gas molecule. Thus, apatite-structured phases may be tolerant against or has potential to mitigate the aging effect of radionuclides from a process socalled radioparagenesis (Jiang et al, 2009(Jiang et al, , 2010, a structural and chemical transformation process resulting from radioactive decay of radionuclides in a solid phase.…”

Section: Introductionmentioning

confidence: 99%

Incorporation of iodine into apatite structure: a crystal chemistry approach using Artificial Neural Network

Wang

2015

Front. Earth Sci.

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Materials with apatite crystal structure have a great potential for incorporating the long-lived radioactive iodine isotope (129 I) in the form of iodide (I −) from nuclear waste streams. Because of its durability and potentially high iodine content, the apatite waste form can reduce iodine release rate and minimize the waste volume. Crystal structure and composition of apatite (A 5 (XO 4) 3 Z) was investigated for iodide incorporation into the channel of the structure using Artificial Neural Network. A total of 86 experimentally determined apatite crystal structures of different compositions were compiled from literature, and 44 of them were used to train the networks and 42 were used to test the performance of the trained networks. The results show that the performances of the networks are satisfactory for predictions of unit cell parameters a and c and channel size of the structure. The trained and tested networks were then used to predict unknown compositions of apatite that incorporates iodide. With a crystal chemistry consideration, chemical compositions that lead to matching the size of the structural channel to the size of iodide were then predicted to be able to incorporate iodide in the structural channel. The calculations suggest that combinations of A site cations of Ag + , K + , Sr 2+ , Pb 2+ , Ba 2+ , and Cs + , and X site cations, mostly formed tetrahedron, of Mn 5+ , As 5+ , Cr 5+ , V 5+ , Mo 5+ , Si 4+ , Ge 4+ , and Re 7+ are possible apatite compositions that are able to incorporate iodide. The charge balance of different apatite compositions can be achieved by multiple substitutions at a single site or coupled substitutions at both A and X sites. The results give important clues for designing experiments to synthesize new apatite compositions and also provide a fundamental understanding how iodide is incorporated in the apatite structure. This understanding can provide important insights for apatite waste forms design by optimizing the chemical composition and synthesis procedure.

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Section: Introductionmentioning

confidence: 99%

Incorporation of iodine into apatite structure: a crystal chemistry approach using Artificial Neural Network

Wang

2015

Front. Earth Sci.

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“…While Monte Carlo methods [15][16][17][18] are routinely applied to compute the stochastic effects induced by β-particles in biological systems, the local effects due to transmutation have not been studied using atomistic simulation. Indeed, aside from calculations of beta-decay in solids [19][20][21], and some early work on decay-induced excited states in molecules [22,23], we are unaware of any remotely similar studies. Figure 1b provides the starting point of our computational studies of transmutation.…”

Section: Andmentioning

confidence: 99%

Carbon-14 decay as a source of non-canonical bases in DNA

Sassi

Carter

Uberuaga

et al. 2014

Biochimica et Biophysica Acta (BBA) - General Subjects

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Our findings raise questions such as how the genetic apparatus deals with the appearance of an extra nitrogen in the canonical bases. It is not obvious whether or not the DNA repair mechanism detects this modification nor how DNA replication is affected by a non-canonical nucleobase. Accordingly, (14)C may prove to be a source of genetic alteration that is impossible to avoid due to the universal presence of radiocarbon in the environment.

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“…[ 2 ] Despite the importance of this class of materials, the origins of their enhanced properties in several instances remain unknown. The critical factors that favor the use of nanostructured materials at the atomic level is the behavior of defects in the presence of interfaces and grain boundaries that make up a larger volume fraction within the material.…”

Section: Introductionmentioning

confidence: 99%

Linking Interfacial Step Structure and Chemistry with Locally Enhanced Radiation‐Induced Amorphization at Oxide Heterointerfaces

Aguiar

Dholabhai

et al. 2014

Adv Materials Inter

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Nanostructured materials and their interfaces have attracted recent interest for their functionality in a wide variety of different applications. However, the origins of these properties in several instances remain unknown. One promising aspect of nanomaterials is their role in materials design for mitigating radiation damage. In particular, engineered radiation tolerant materials would exploit the presence of internal interfaces to act as recombination centers and suppress damage accumulation. Realizing this promise, however, requires a fundamental understanding of how radiation‐induced defects interact with interfaces. Thus, studying the interfacial atomic structure and chemistry before and after irradiation is critical. In this study, we have performed transmission electron microscopy on a series of pristine and ion‐irradiated oxide interfaces to probe radiation‐induced effects. The CeO2/SrTiO3 interface, chosen as a model system for these studies, is characterized by differences in SrTiO3 terminations or steps. Our salient result is that steps are centers for preferential amorphization in SrTiO3, which we attribute to defect flow across the interface induced by non‐stoichiometry in CeO2. The study concludes the interfacial atomic ordering in the form of steps thereby modifies the response to ion irradiation and suggests interface patterning as another parameter to functionalize radiation tolerant materials.

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Using “radioparagenesis” to design robust nuclear waste forms

Abstract: Recently, using first principles theoretical methods, we have predicted that unconventional compounds and crystal structures may form via the chemical transmutation that occurs during radioactive decay (e.g. rock salt 137 BaCl formation from the bdecay of 137 CsCl) (C.

Cited by 20 publications

References 22 publications

Incorporation of iodine into apatite structure: a crystal chemistry approach using Artificial Neural Network

Incorporation of iodine into apatite structure: a crystal chemistry approach using Artificial Neural Network

Carbon-14 decay as a source of non-canonical bases in DNA

Linking Interfacial Step Structure and Chemistry with Locally Enhanced Radiation‐Induced Amorphization at Oxide Heterointerfaces

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