Alpha-decay induced amorphization of Cm-doped Gd2TiZrO7

Yudinsev, S.V.; Lukinykh, A. N.; Tomilin, S. V.; Lizin, A. A.; Stefanovsky, S. V.

doi:10.1016/j.jnucmat.2008.09.036

Cited by 16 publications

(5 citation statements)

References 14 publications

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“…Let us compare these data with the results on the stability of other matrices [1][2][3][6][7][8][9][10]. It is conve nient to use the values of doses expressed in diplace ments by one atom of the framework (dpa).…”

Section: Phase Composition and Radiation Stability Of Matrices For Ismentioning

confidence: 99%

“…With account for this, amorphiza tion of monoclinic titanate occurs above 0.3 dpa, whereas disordering of the zirconate pyrochlore struc ture is not observed even at a dose higher by one order of magnitude. The change in the pyrochlore composi tion (decrease in the ratios of the [8] A and [6] [10].…”

Section: Phase Composition and Radiation Stability Of Matrices For Ismentioning

confidence: 99%

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Phase composition and radiation stability of matrices for isolation of REE-actinide waste

Лаверов

Yudintsev

Stefanovsky³

et al. 2012

Dokl. Earth Sc.

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526Safe treatment with highly radioactive wastes from processing of irradiated fuel is a key problem at the final stage of the nuclear energy cycle. The waste prod ucts are currently immobilized in glassy matrices for loading in underground storage [1]. Glasses are insuf ficiently stable for isolation of long living radionu clides, including actinides. It is suggested to fraction ate such wastes and include long living nuclides in the most stable crystalline matrices in order to increase safety [2]. The available technologies allow us to sepa rate actinides (U, Np, Pu), the REE-actinide compo nent, and products of decay.Zirconates and titanates with the structures of pyrochlore, zirconolite, perovskite, murataite, and others are suggested for isolation of actinide wastes [1-10 and others]. Materials with wastes of simple composition (plutonium and its imitators) were basi cally studied in these investigations; less attention was given to matrices for immobilization of the REEactinide fraction. Its approximate composition is the following (wt %): 80-90 REE + 10-20 actinides, where light lanthanides (La, Ce, Pr, Nd, and Sm) pre vail among REEs, and actinides are mainly repre sented by Am and Cm. The structure of matrices undergoes changes during actinide decay, which may influence their isolation properties.In this paper we report the new data on the struc tural peculiarities of perspective matrices for the REE actinide fraction and their radiation stability during irradiation by accelerated krypton ions.The starting charge was prepared from TiO 2 , ZrO 2 , and a mixture of REE oxides taken in proportions cor responding to the ideal formula (REE) 2 Zr 2 -x Ti x O 7 , where х = 0 (Sample Z) or 2 (Sample T). The propor tions of elements in the REE mixture are the following (wt %): La 4.7 (or in atomic proportions: 0.24La + 0.46Ce + 0.21Pr + 0.75Nd + 0.15Sm + 0.02Eu + 0.03Gd + 0.14Y); they reflect the proportions between them in the REEactinide fraction of wastes from reprocessing of irradi ated nuclear fuel. The size of the Nd 3+ cation is close to the sizes of the Am 3+ and Cm 3+ cations, that is why it was an imitator of these actinides. The mixtures were homogenized carefully and pressed into tablets at 200 atm and 25°С, and after that they were loaded in the oven for 5 h at 1550°С (х = 0) or 1400°С (х = 2). Reaching equilibrium in the zirconate system requires higher temperatures for acceleration of the phase for mation during synthesis. The samples were studied by X ray diffraction (XRD) and on a scanning electron microscope equipped with an energy dispersive spec trometer (SEM/EDS). They were irradiated in the Argonne National Laboratory (United States) on an accelerator combined with a transmission electron microscope [7]. This approach allows us to observe disordering of atoms in the framework and destruction upon irradiation. This method is an express way to determine the doses of amorphization in a wide tem perature range [1-3, 6-8, and others].According to the XRD data, Sample Z consists of dominating pyro...

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Section: Phase Composition and Radiation Stability Of Matrices For Ismentioning

confidence: 99%

Section: Phase Composition and Radiation Stability Of Matrices For Ismentioning

confidence: 99%

Phase composition and radiation stability of matrices for isolation of REE-actinide waste

Лаверов

Yudintsev

Stefanovsky³

et al. 2012

Dokl. Earth Sc.

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“…Lang et al [3] examined how Ti concentration in gadolinium pyrochlores increases the damage cross section and alters the structure of ion tracks created by swift heavy ion irradiation. The results of Yudinsev et al [4] and Patel et al [5] suggest that the susceptibility of pyrochlores to radiation damage depends on the relative size of the cations in the crystal structure.…”

Section: Introductionmentioning

confidence: 99%

Electron–ion coupling effects on simulations of radiation damage in pyrochlore waste forms

Ismail¹,

Greathouse²,

Foiles³

2010

J. Phys.: Condens. Matter

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We have performed molecular dynamics simulations of cascade damage in the gadolinium pyrochlore Gd₂Zr₂O₇, comparing results obtained from traditional simulation methodologies that ignore the effect of electron-ion interactions with a 'two-temperature model' in which the electronic subsystem is modeled using a diffusion equation to determine the electronic temperature. We find that the electron-ion interaction friction coefficient γ(p) is a significant parameter in determining the behavior of the system following the formation of the primary knock-on atom (PKA; here, a U³(+) ion). The mean final PKA displacement and the number of defect atoms formed is shown to decrease uniformly with increasing γ(p); however, other properties, such as the final equilibrium temperature and the oxygen-oxygen radial distribution function, show a more complicated dependence on γ(p).

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“…Because the pyrochlore structure is a derivative of fluorite, it belongs to a large family of related structures. The interplay of short-and long-range order, especially in radiation-damaged pyrochlores, has drawn extensive attention as has amorphization and its recovery on annealing (Wang et al, 1998;Wang et al, 1999;Meldrum et al, 2001;Lian et al, 2002;Ewing et al, 2003;Lian et al, 2003a;Lian et al, 2004;Patel et al, 2008a;Patel et al, 2008b;Lang et al, 2009;Yudinsev et al, 2009;Lang et al, 2010;Xie et al, 2015;Shamblin et al, 2016a;Shamblin et al, 2016b;Kumari et al, 2016;Yang et al, 2017;Chung et al, 2018a;Chung et al, 2018b;Shamblin et al, 2018;Chung et al, 2019;Sherrod et al, 2021). Yet in a broader sense, pyrochlores are but one family of oxide materials.…”

Section: Introductionmentioning

confidence: 99%

A Comparison of Order-Disorder in Several Families of Cubic Oxides

et al. 2021

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Order-disorder on both cation and oxygen sites is a hallmark of fluorite-derived structures, including pyrochlores. Ordering can occur on long- and short-range scales and can result in persistent metastable states. In various cubic oxide systems, different types of disorder are seen. The purpose of this paper is to review and compare the types and energetics of order-disorder phenomena in several families of cubic oxides having pyrochlore, weberite, defect fluorite, perovskite, rocksalt, and spinel structures. The goal is to better understand how structure, composition, and thermodynamic parameters (enthalpy and entropy) determine the feasibility of different competing ordering processes and structures in these diverse systems.

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Alpha-decay induced amorphization of Cm-doped Gd2TiZrO7

Cited by 16 publications

References 14 publications

Phase composition and radiation stability of matrices for isolation of REE-actinide waste

Phase composition and radiation stability of matrices for isolation of REE-actinide waste

Electron–ion coupling effects on simulations of radiation damage in pyrochlore waste forms

A Comparison of Order-Disorder in Several Families of Cubic Oxides

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