  UO$_{2}$ and UO$_{2.07}$ were characterized from
25-1000$\,^{\circ}\mathrm{C}$ using neutron total scattering in order to
evaluate effects of temperature and phase boundaries on local and average
structures. Analyses of unit cell parameters showed that both materials exhibit
very similar thermal expansion behavior and thermal expansion data lay along
the upper bound of uncertainty for standard empirical models, indicating a
slightly faster thermal expansion rate. Atomic displacement parameters of
UO$_{2.07}$ showed evidence for U$_{4}$O$_{9}$ phase boundaries in accordance
with the established phase diagram, despite the suppression of U$_{4}$O$_{9}$
superlattice peaks in the measured diffraction patterns. Pair distribution
functions revealed that the differences in local structure between UO$_{2}$ and
UO$_{2.07}$ were very small and PDF features are dominated by thermal effects.
The rate of contraction of the first nearest-neighbor U-O distances of UO$_{2}$
and UO$_{2.07}$ between 25-1000$\,^{\circ}\mathrm{C}$ were shown to agree with
molecular dynamics simulations and local structure analyses previously
performed on UO$_{2}$ above 1000$\,^{\circ}\mathrm{C}$.
