Helium behavior in oxide nuclear fuels: First principles modeling

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

卷:268

Article; Proceedings Paper

Gryaznov, D.¹  Rashkeev, S.²  Kotomin, E. A.³  Heifets, E.¹  Zhukovskii, Y.³ 

[1] Commiss European Communities, Joint Res Ctr, Inst Transuranium Elements, D-76125 Karlsruhe, Germany

[2] Idaho Natl Lab, Ctr Adv Modeling & Simulat, Idaho Falls, ID 83415 USA

[3] Latvian State Univ, Inst Solid State Phys, LV-1063 Riga, Latvia

关键词: DFT;    Actinide oxide;    Correlation correction;    Incorporation energy;   

DOI  :  10.1016/j.nimb.2010.05.054

来源: Elsevier

【 摘 要 】

UO2 and (U, Pu)O-2 solid solutions (the so-called MOX) nowadays are used as commercial nuclear fuels in many countries. One of the safety issues during the storage of these fuels is related to their self-irradiation that produces and accumulates point defects and helium therein. We present density functional theory (OFT) calculations for UO2, PuO2 and MOX containing He atoms in octahedral interstitial positions. In particular, we calculated basic MOX properties and He incorporation energies as functions of Pu concentration within the spin-polarized, generalized gradient approximation (GGA) DFT calculations. We also included the on-site electron correlation corrections using the Hubbard model (in the framework of the so-called DFT + U approach). We found that PuO2 remains semiconducting with He in the octahedral position while UO2 requires a specific lattice distortion. Both materials reveal a positive energy for He incorporation, which, therefore, is an exothermic process. The He incorporation energy increases with the Pu concentration in the MOX fuel. (C) 2010 Elsevier B.V. All rights reserved.

【 授权许可】

Free