Title: Helium behaviour in Oxide Nuclear Fuels: First Principles Modelling
Authors: GRYAZNOV DenisRASHKEEV SKOTOMIN E.HEIFETS E.ZHUKOVSKII Y.
Citation: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS vol. 268 no. 19 p. 3090-3094
Publisher: ELSEVIER SCIENCE BV
Publication Year: 2010
JRC N°: JRC56044
ISSN: 0168-583X
URI: www.elsevier.com/locate/nimb
http://publications.jrc.ec.europa.eu/repository/handle/JRC56044
DOI: 10.1016/j.nimb.2010.05.054
Type: Articles in Journals
Abstract: UO2 and (U,Pu)O2 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 (DFT) 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.
JRC Institute:Institute for Transuranium Elements

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