High-precision molecular dynamics simulation of UO2-PuO2: Anion self-diffusion in UO2 / Potashnikov S. I.,Boyarchenkov A. S.,Nekrasov K. A.,Kupryazhkin A. Ya. // JOURNAL OF NUCLEAR MATERIALS. - 2013. - V. 433, l. 1-3. - P. 215-226.

ISSN/EISSN:

0022-3115 / нет данных

Type:

Article

Abstract:

Our series of articles is devoted to high-precision molecular dynamics simulation of mixed actinide-oxide (MOX) fuel in the approximation of rigid ions and pair interactions (RIPI) using high-performance graphics processors (GPU). In this article we study self-diffusion mechanisms of oxygen anions in uranium dioxide (UO2) with the 10 recent and widely used sets of interatomic pair potentials (SPP) under periodic (PBC) and isolated (IBC) boundary conditions. Wide range of measured diffusion coefficients (from 10(-3) cm(2)/s at melting point down to 10(-12) cm(2)/s at 1400 K) made possible a direct comparison (without extrapolation) of the simulation results with the experimental data, which have been known only at low temperatures (T < 1500 K). A highly detailed (with the temperature step of 1 K) calculation of the diffusion coefficient allowed us to plot temperature dependences of the diffusion activation energy and its derivative, both of which show a wide (similar to 1000 K) superionic transition region confirming the broad lambda-peaks of heat capacity obtained by us earlier. It is shown that regardless of SPP the anion self-diffusion in model crystals without surface or artificially embedded defects goes on via exchange mechanism, rather than interstitial or vacancy mechanisms suggested by the previous works. The activation energy of exchange diffusion turned out to coincide with the anti-Frenkel defect formation energy calculated by the lattice statics. (c) 2012 Elsevier B.V. All rights reserved.

Author keywords:

NEUTRON-SCATTERING TECHNIQUES; URANIUM-DIOXIDE; THERMAL-PROPERTIES; OXYGEN DIFFUSION; ACTINIDE OXIDES; THO2; POTENTIALS; DEFECTS; PUO2; HEAT

DOI:

10.1016/j.jnucmat.2012.08.033

Web of Science ID:

ISI:000316153800029

Соавторы в МНС:

Другие поля

Поле	Значение
Month	FEB
Publisher	ELSEVIER SCIENCE BV
Address	PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS
Language	English
Keywords-Plus	NEUTRON-SCATTERING TECHNIQUES; URANIUM-DIOXIDE; THERMAL-PROPERTIES; OXYGEN DIFFUSION; ACTINIDE OXIDES; THO2; POTENTIALS; DEFECTS; PUO2; HEAT
Research-Areas	Materials Science; Nuclear Science \& Technology
Web-of-Science-Categories	Materials Science, Multidisciplinary; Nuclear Science \& Technology
Author-Email	potashnikov@gmail.com boyarchenkov@gmail.com kirillnkr@mail.ru kupr@dpt.ustu.ru
ORCID-Numbers	Boyarchenkov, Anton/0000-0002-4083-9201
Number-of-Cited-References	48
Usage-Count-Last-180-days	6
Usage-Count-Since-2013	82
Journal-ISO	J. Nucl. Mater.
Doc-Delivery-Number	106OG