First-principles study of defects and fission product behavior in uranium diboride

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  • Ericmoore Jossou
  • Dotun Oladimeji
  • Linu Malakkal
  • Simon Middleburgh
    Westinghouse Electric Sweden AB
  • Barbara Szpunar
  • Jerzy Szpunar
A Systematic study of defects and incorporation of xenon (Xe) and zirconium (Zr) fission products in uranium diboride (UB2) has been investigated using density functional theory (DFT) calculations as implemented in Quantum ESPRESSO code. The incorporation and solution energies show that both FPs (Xe and Zr) are most stable in U vacancies with Zr being more stable than Xe. A volume expansion is observed as the concentration of Xe increases in the fuel matrix while Zr incorporation leads to a contraction. Bader charge analysis is used to establish the formation of Zr-B ionic/covalent bond due to large electron transfer observed while there is only a weak electronic interaction between Xe and the UB2 lattice. Finally, using climbing-image nudged elastic band calculation, we found that the energy barrier of U in UB2 is 0.08 eV higher than B migration energy. (C) 2017 Elsevier B.V. All rights reserved.
Original languageEnglish
Pages (from-to)147-156
Number of pages10
JournalJournal of Nuclear Materials
Volume494
Early online date13 Jul 2017
DOIs
Publication statusPublished - 1 Oct 2017
Externally publishedYes
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