Calculation of structural and defect properties of α-U3O8

Abstract

The results are presented of a theoretical study on α-U₃O₈ using atomistic simulation techniques. Various electronic arrangements have been considered for U₃O₈ and it was found that a model employing an averaged uranium ion charge, (U^5⅓+)₃O₈, best reproduces the structural data. Calculations of the energetics of basic defect formation are presented. Anion Frenkel defects are predicted to dominate in the stoichiometric oxide, whilst the formation of non-stoichiometric U₃O_{8 –x} is demonstrated to occur, at least initially, by the creation of oxygen vacancies.