A Density Functional Theory Study on the Diffusion of Fission Gas Atoms in Uranium Dioxide

2018 ◽  
Vol 4 (3) ◽  
Author(s):  
Qiang Zhao ◽  
Zheng Zhang ◽  
Xiaoping Ouyang
Keyword(s):  
Density Functional Theory ◽  
Oxygen Vacancy ◽  
Oxygen Atom ◽  
Uranium Dioxide ◽  
Density Functional ◽  
Nuclear Reactor ◽  
Functional Theory ◽  
Fission Gas ◽  
Vacancy Site ◽  
He Atom

Uranium dioxide (UO2) is the typical fuel that is used in the current nuclear power plant; fission gas atoms are produced during and after the nuclear reactor operation; the fission gas atoms have a significant effect on the performance of UO2 fuel in the nuclear reactor. In this paper, we investigated the diffusion of the fission gas atoms in the UO2 fuel by using the first-principles calculation method based on the density functional theory (DFT). The results indicate that the volume of the UO2 cell increased when there is a fission gas atom enters in the UO2 supercell; the elastic properties of UO2 are in good agreement with other simulation results and experimental data and the fission gas atoms make the ductility of UO2 decreased; the fission gas atoms prefer to occupy the octahedral interstitial site (OIS) over the uranium vacancy site and the oxygen vacancy site, and the oxygen vacancy site is the most difficult occupied site due to the formation of an oxygen vacancy is more difficult than that of the uranium vacancy; the diffusion barrier of a He atom in the UO2 supercell is higher than that of an oxygen atom, that means that the diffusion of the He atom in UO2 fuel is weaker than that of the oxygen atom. Our works may shed some light on the formation mechanism of the bubbles caused by the fission gas atoms in the UO2 fuel.

Diffusion of Fission Gas in Uranium Dioxide: A First-Principles Study

2017 ◽  
Author(s):  
Qiang Zhao ◽  
Zheng Zhang ◽  
Yang Li ◽  
Xiaoping Ouyang
Keyword(s):  
Oxygen Vacancy ◽  
Uranium Dioxide ◽  
First Principles ◽  
Density Functional ◽  
Interstitial Site ◽  
First Principles Calculation ◽  
Spent Fuel ◽  
Octahedral Interstitial Site ◽  
Fission Gas ◽  
Vacancy Site

Uranium dioxide (UO2) is the typical fuel that is used in nuclear fission reactor, fission gas are produced during and after the reactor operation, and the fission gas have a significant impact on the performance of UO2 in reactor. In this paper, we investigated the effects of the fission gas on the performance of UO2 by using the first-principles calculation method based on the density functional theory. The results are that, the volume of UO2 increased when there is a fission gas atom enter in UO2 supercell; fission gas prefer to occupy the octahedral interstitial site over the uranium vacancy site and the oxygen vacancy site, and the oxygen vacancy site is the most difficult occupied site due to the formation of an oxygen vacancy is more difficult than that of the uranium vacancy; our results of the UO2 elastic constants are in good agreement with other simulation results and experimental data, and the fission gas atoms make the ductility of UO2 decreased. Our works may shed some light on the development of the UO2 fuel and the spent fuel reprocessing.

Oxygen vacancy migration in CSZ using density functional theory

2008 ◽  
Vol 1122 ◽  
Author(s):  
Byeong-Eon Lee ◽  
Dae-Hee Kim ◽  
Yeong-Cheol Kim
Keyword(s):  
Density Functional Theory ◽  
Oxygen Vacancy ◽  
Density Functional ◽  
Oxygen Vacancies ◽  
Nearest Neighbor ◽  
Functional Theory ◽  
The Third ◽  
Vacancy Migration ◽  
Neighbor Site ◽  
Formation Energies

AbstractWe studied oxygen migration in calcia-stabilized cubic zirconia (CSZ) using density functional theory. A Ca atom was substituted for a Zr atom in a 2×2×2 ZrO2 cubic supercell, and an oxygen vacancy was produced to satisfy the charge neutrality condition. We found that the formation energies of an oxygen vacancy, as a function of its location with respect to the Ca atom, were varied. The relative formation energies of the oxygen vacancies located at the first-, second-, third-, and fourth-nearest-neighbors were 0.0, −0.07, 0.19, and 0.19 eV, respectively. Therefore, the oxygen vacancy located at the second-nearest-neighbor site of the Ca atom was the most favorable, the oxygen vacancy located at the first-nearest-neighbor site was the second most favorable, and the oxygen vacancies at the third- and fourth-nearest-neighbor sites were the least favorable. We also calculated the energy barriers for the oxygen vacancy migration between oxygen sites. The energy barriers between the first and the second nearest sites, the second and third nearest sites, and the third and fourth nearest sites were 0.11, 0.46, and 0.23 eV, respectively. Therefore, the oxygen vacancies favored the first- and second-nearest-neighbor oxygen sites when they drifted under an electric field.

First principles analysis of oxygen vacancy formation and migration in Sr2BMoO6 (B = Mg, Co, Ni)

RSC Advances ◽  
2016 ◽  
Vol 6 (38) ◽  
pp. 31968-31975 ◽  
Author(s):  
Shuai Zhao ◽  
Liguo Gao ◽  
Chunfeng Lan ◽  
Shyam S. Pandey ◽  
Shuzi Hayase ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Oxygen Vacancy ◽  
First Principles ◽  
Density Functional ◽  
Dft Method ◽  
Double Perovskites ◽  
Functional Theory ◽  
Oxygen Vacancy Formation ◽  
The Density Functional Theory ◽  
And Migration

In this work, we present a detailed first-principles investigation on the stoichiometric and oxygen-deficient structures of double perovskites, Sr2BMoO6 (B = Mg, Co and Ni), using the density functional theory (DFT) method.

scholarly journals Oxygen Vacancy Induced Magnetism in Anti-Perovskite Topological Dirac Semimetal Ba3SnO

2021 ◽  
Author(s):  
Javaria Batool ◽  
Syed Muhammad Alay-e-Abbas ◽  
Gustav Johansson ◽  
Waqas Zulfiqar ◽  
Muhammad Arsam Danish ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Oxygen Vacancy ◽  
Electronic Properties ◽  
Thermodynamic Stability ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Vacancy Defect ◽  
Functional Theory ◽  
Dirac Semimetal

The thermodynamic, structural, magnetic and electronic properties of pristine and intrinsic vacancy defect containing topological Dirac semimetal Ba3SnO are studied using first-principles density functional theory calculations. The thermodynamic stability of...

First-Principles Study on Initial Oxidation of NiAl(110)

2007 ◽  
Vol 546-549 ◽  
pp. 1455-1460 ◽  
Author(s):  
Jun Min Hu ◽  
Jia Xiang Shang ◽  
Yue Zhang ◽  
Chun Gen Zhou ◽  
Hui Bin Xu
Keyword(s):  
Density Functional Theory ◽  
Charge Transfer ◽  
Oxygen Atom ◽  
Chemical Bond ◽  
First Principles ◽  
Density Functional ◽  
Bridge Site ◽  
Initial Oxidation ◽  
Functional Theory ◽  
Oxidation Stage

The oxygen atom adsorption at Al-Al bridge, Ni-Ni bridge, Al top and Ni top site on the NiAl(110) surface by first-principles method within density functional theory has been studied in this paper. It has been found that the preferred adsorption position of the oxygen was at the Al-Al bridge site then the Ni-Ni bridge site. The charge transfer took place obviously between the O atom and the nearest Al atoms, but no charge transferred from the nearest Ni atoms to O atom. For the Al-Al (Ni-Ni) bridge adsorption site, the bond lengths of Al-O and Ni-O were about 1.741 Å (1.700Å) and 2.369Å (2.012Å), respectively, which means that the Al atom is easier to be oxidized than the Ni atom. It is revealed that the Al atom oxidized selectively and the chemical bond formed between the O ion and the nearest Al ions during the initial oxidation stage.

Density Functional Theory Calculation of Properties of Point Defects in δ-Plutonium

2012 ◽  
Vol 627 ◽  
pp. 672-677
Author(s):  
Ru Song Li ◽  
Bin He ◽  
Quan Hu Zhang ◽  
Guo Xun Ji
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Interstitial Atom ◽  
Local Density ◽  
Density Functional Theory Calculation ◽  
Functional Theory ◽  
Vacancy Site ◽  
Theory Calculation ◽  
Fcc Structure ◽  
Peak Value

Local density approximation (LDA) +U within the framework of density functional theory (DFT) was used to study the properties of vacancy and self-interstitial atom (SIA) in δ-Pu. The results show that mono-vacancy, di-vacancy and tri-vacancy existing in δ-Pu shift rightward the f shell peak of the projected density of states (PDOS), the peak values of mono-vacancy and di-vacancy decrease, while the peak value of tri-vacancy increases. The saddle point during vacancy migration shifts leftward the f shell peak of PDOS, and the peak value decreases. The octahedral SIA, the tetrahedral SIA, the split SIA shift leftward the f shell peak of PDOS, and the peak values decreases. Finally, the recombination behavior of vacancy and SIA were studied at both the spin-restricted and the spin-unrestricted level, SIA migrates to vacancy site, and exhibits a tendency to forming the perfect fcc structure.

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