Uranium exhibited a high temperature body-centered cubic allotrope that was often stabilized by alloying with transition metals such as Zr, Mo, and Nb for technological applications. One such application involves U–Zr as nuclear fuel, where radiation damage and diffusion (processes heavily dependent on point defects) were of vital importance. Several systems of U were examined within a density functional theory framework utilizing projector augmented wave pseudopotentials. Two separate generalized gradient approximations of the exchange-correlation were used to calculate defect properties and were compared. The bulk modulus, the lattice constant, and the Birch–Murnaghan equation of state for the defect free body-centered cubic uranium allotrope were calculated. Defect parameters calculated include energies of formation of vacancies in the α and γ allotropes, as well as self-interstitials, Zr interstitials, and Zr substitutional defects for the γ allotrope. The results for vacancies agreed very well with experimental and previous computational studies. The most probable self-interstitial site in γ-U was the <110> dumb-bell, and the most probable defect location for dilute Zr in γ-U was the substitutional site. This was the first detailed study of self-defects in the body-centered cubic allotrope of U and also the first comprehensive study of dilute Zr defects in γ-U.

First Principles Calculations for Defects in U. B.Beeler, B.Good, S.Rashkeev, C.Deo, M.Baskes, M.Okuniewski: Journal of Physics - Condensed Matter, 2010, 22[50], 505703