On the relation between lattice parameter and O/M ratio for uranium dioxide-trivalent rare earth oxide solid solution

Ohmichi, Toshihiko; Fukushima, Susumu; Maeda, Atsushi; Watanabe, Hitoshi

doi:10.1016/0022-3115(81)90544-4

Cited by 180 publications

(84 citation statements)

References 13 publications

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“…Therefore, the half of lattice parameter for cubic Pu 2 O 3 was estimated to be 5.570Å by Schmitz et al [19], 5.534Å by Benedict et al [20] and 5.561Å by Ohmichi et al [21] at room temperature. In order to obtain a more reliable potential parameter, the thermal expansion and compressibility data should be also referred to.…”

Section: Interatomic Potential Function and Procedures Of MD Simulationmentioning

confidence: 99%

“…Ohmichi et al [21] discussed the change of lattice parameter of U 1−y 4+ Pu 2x 3+ Pu y−2x 4+ O 2−x 2− in terms of radii of cations, oxygen and oxygen vacancy. Therefore, the half of lattice parameter for cubic Pu 2 O 3 was estimated to be 5.570Å by Schmitz et al [19], 5.534Å by Benedict et al [20] and 5.561Å by Ohmichi et al [21] at room temperature.…”

Section: Interatomic Potential Function and Procedures Of MD Simulationmentioning

confidence: 99%

“…r a,i is the atomic radius of the point defect i, and here it is interpreted as the radius of ion [40] or oxygen vacancy [21]. The ε parameter means the magnitude of the lattice strain generated by the point defect, where ε is taken to be 25.85 [1].…”

Section: Theoretical Modeling Of Thermal Conductivity For Hypostoichimentioning

confidence: 99%

See 2 more Smart Citations

Evaluation of thermal conductivity of hypostoichiometric (U, Pu)O2−x solid solution by molecular dynamics simulation at temperatures up to 2000K

Arima

Yamasaki

Inagaki

et al. 2006

Journal of Alloys and Compounds

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Section: Interatomic Potential Function and Procedures Of MD Simulationmentioning

confidence: 99%

Section: Interatomic Potential Function and Procedures Of MD Simulationmentioning

confidence: 99%

See 1 more Smart Citation

Evaluation of thermal conductivity of hypostoichiometric (U, Pu)O2−x solid solution by molecular dynamics simulation at temperatures up to 2000K

Arima

Yamasaki

Inagaki

et al. 2006

Journal of Alloys and Compounds

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“…It is generally known that the change of lattice parameters with the change of dopant concentrations depends on the effective ionic radii of component atoms and the oxygen vacancy, unless no interactions among them exist. Providing this relationship is correct, the lattice parameter of Gd-doped thoria would slightly increase with an increase in Gd-dopant fraction since the effective ionic radius of an oxygen vacancy (0.14 nm) 33) is larger than that of Th(IV) (0.106 nm), 34) while the effective ionic radius of Gd(III) with an oxygen coordination number of 8 (0.106 nm) 34) is the same as that of Th(IV). The monotonic decrease tendencies of the lattice parameters would appear in the case of Gd(III) with an oxygen coordination number of 6 (0.094 nm).…”

Section: Resultsmentioning

confidence: 99%

Molecular Dynamics Study on Defect Structure of Gadolinia-Doped Thoria

Osaka

Adachi

Kurosaki

et al. 2007

Journal of Nuclear Science and Technology

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A molecular dynamics study on the defect structure of Gd-doped thoria was carried out. The partially ionic two-body potential was used with empirically obtained parameters for Th, Gd and O ions in the fluorite structure. Different defect structures were assumed and their effects on the lattice parameter were investigated. Molecular dynamics simulations were carried out with Gd fractions and temperatures ranging from 0 to 45% and from 298 to 1200 K, respectively. Diffusion coefficients of O ions in the Gd-doped thoria having various Gd fractions were also calculated at 1273 K. Comparison of the calculated results with the experimental ones lead to the conclusion that the Gd-oxygen vacancy-Gd type cluster is the most likely defect structure in the Gd-doped thoria.

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“…Owing to their ionic radii (in their oxides) that are comparable with those of fuel constituents (U and Pu), the rare earths are significantly soluble in the mixed oxide fuel matrix [5]. The studies on the solid solubility of EuO 1.5 in UO 2 , oxygen potentials of uraniumeuropium solid solutions, as well as their defect chemistry, have been reported in the literature [5][6][7][8][9]. Heat capacity data on uranium-europium mixed oxides with europium content of 4.4 and 9.0 mol% have been reported by Matsui et al [10].…”

Section: Introductionmentioning

confidence: 99%

Thermophysical properties of uranium–europium mixed oxides

et al. 2015

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Uranium-europium mixed oxides (U 1y Eu y )O 2x (y = 0.2-0.8) were prepared by the citrate gel combustion technique and characterized by X-ray diffraction (XRD). Single phase fluorite structure was observed in those solid solutions with y ≤ 0.6. The solid solutions with y > 0.6 were found to be biphasic, with the second phase being cubic Eu 2 O 3 . Heat capacity and enthalpy increment measurements were carried out by using differential scanning calorimeter (DSC) and drop calorimeter in the temperature range 298-800 K and 800-1800 K, respectively. The , p m C values at 298 K for (U 1y Eu y )O 2x (y = 0.2, 0.4, 0.6) are 64.8, 64.6, and 63.5 J·K 1 ·mol 1 , respectively. An anomalous increase was observed in the heat capacity in all of the solid solutions with the onset temperature around 950 K. This could be attributed to the contribution from Frenkel pair oxygen defects. From the excess heat capacity data, the enthalpy for the formation of these defects was computed and found to be in the range of 2.10±0.02 eV.

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On the relation between lattice parameter and O/M ratio for uranium dioxide-trivalent rare earth oxide solid solution

Cited by 180 publications

References 13 publications

Evaluation of thermal conductivity of hypostoichiometric (U, Pu)O2−x solid solution by molecular dynamics simulation at temperatures up to 2000K

Evaluation of thermal conductivity of hypostoichiometric (U, Pu)O2−x solid solution by molecular dynamics simulation at temperatures up to 2000K

Molecular Dynamics Study on Defect Structure of Gadolinia-Doped Thoria

Thermophysical properties of uranium–europium mixed oxides

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