Self-Diffusion of Oxygen in Superstoichiomertric Uranium Dioxide in the Range of the Superion Phase Transition / Kupryazhkin A. Ya.,Svetlichnyi D. G.,Zhiganov A. N. // TECHNICAL PHYSICS. - 2011. - V. 56, l. 2. - P. 221-225.

ISSN/EISSN:

1063-7842 / 1090-6525

Type:

Article

Abstract:

The self-diffusion of oxygen in the superion transition range (1300-3000 K) of superstoichiometric uranium dioxide UO2 (+) (x) is studied by the method of molecular dynamics using the pair interaction potential recovered from data for the thermal expansion of the UO2 lattice. It is shown that three portions can be distinguished in the temperature dependence of the coefficient of oxygen self-diffusion in UO2 + x, lnD = f(1/T), for all the compositions studied (x = 0, 0.008, and 0.030). These portions, each being described by the Arrhenius relationship, correspond to the crystalline, transition, and superion states of UO2 + x. At low temperatures (1300-1820 K), the activation energies of oxygen diffusion for the above compositions are, respectively, 2.66 +/- 0.44, 1.33 +/- 0.10, and 1.00 +/- 0.09 eV. At the beginning of the transition region, these activation energies rise to 3.40 +/- 0.11, 2.24 +/- 0.10, and 1.66 +/- 0.60 eV. In the superion state, the activation energy of oxygen diffusion for all the compositions is the same, 1.25 +/- 0.15 eV, within the error limit. As the oxygen content in UO2 + x grows, the phase transition temperature decreases considerably and may reach 1600 K at x = 0.2. Comparison with experimental data for the low-temperature oxygen diffusion coefficient and with the data of UO2 simulation using graphic processors shows good agreement of the results. By comparing the concentration dependences of the oxygen diffusion coefficient that are obtained by magnetic dynamics simulation with experimental data, it is shown that quantitative calculation of these dependences in the case of UO2 + x can be carried out only for compositions with x < 0.03 if the given type of potential is used.

Author keywords:

SIMULATION; UO2

DOI:

10.1134/S1063784211020198

Web of Science ID:

ISI:000288762000010

Соавторы в МНС:

Другие поля

Поле	Значение
Month	FEB
Publisher	MAIK NAUKA/INTERPERIODICA/SPRINGER
Address	233 SPRING ST, NEW YORK, NY 10013-1578 USA
Language	English
EISSN	1090-6525
Keywords-Plus	SIMULATION; UO2
Research-Areas	Physics
Web-of-Science-Categories	Physics, Applied
Author-Email	kupr@dpt.ustu.ru
Number-of-Cited-References	13
Usage-Count-Last-180-days	3
Usage-Count-Since-2013	21
Journal-ISO	Tech. Phys.
Doc-Delivery-Number	739ZV