Ab initio calculation of static and dynamic properties of liquid uranium dioxide.*

A detailed knowledge of the structural and dynamic behavior of molten UO₂ is essential in order to improve the safety of fission power reactors.
X-ray diffraction and containerless levitation techniques allowed in 2014 the first measurement of the structure factor, S(q), of liquid UO₂ [1]. Yet, atomistic simulations can provide further insight into its porperties. While classical molecular dynamics correctly described the S(q) of UO₂ [1,2], the use of pair potentials may hinder a proper description of higher order correlations or dynamic properties.

Using accurate ab initio simulations we have studied the static and dynamic properties of liquid UO₂. We obtain excellent comparison with the experimental S(q), as well as information on various dynamic properties (diffusion coefficients, viscosity, sound velocity, dispersion relations), all of them crucial for correctly characterizing the dynamic behavior of liquid UO₂.

Overall, we provide an accurate atomistic description of liquid UO₂ that, coupled with experimental data, will shed light into the structural and dynamic behavior of liquid UO₂ for future applications.

[1] LB Skinner et al, Science 346, 984 (2014)
[2] CJ Benmore et al, J. Phys.: Condens. Matter 28, 015012 (2016)