Calculations of thermodynamical properties of U3Si2

Abstract

International audienceUranium silicide compounds, especially U3Si2, have been studied as a potential replacement for uranium dioxide fuel in pressurized water reactors. These compounds offer several superior properties as a larger thermal conductivity and a higher uranium density. The thermodynamical quantities (specific heat, thermal expansion and conductivity…) are crucial to drive the fuel design. They are directly related to the atomic vibrations and more specifically, they can be extracted from the phonon spectra and the crystal structure.In this work we calculate the phonon spectra of different structures of the U3Si2 compound, up to the meltin curve, by taking into account the anharmonic effects and by using the TDEP method[1]. The thermodynamical properties extracted from these phonon spectra will then be compared to the previous calculations and the available experimental data. We show that the unique features of the crystallographic structure of this compound drive its behaviour in temperature