Molecular Dynamics Calculations: PuO2 Thermophysical Properties

R Calabrese, 27TH INTERNATIONAL CONFERENCE NUCLEAR ENERGY FOR NEW EUROPE (NENE 2018) (2018).

The literature pointed out that a high level of safety in all the processes in which uranium-plutonium mixed oxide (MOX) fuel is considered (fabrication, operation, recycling) is a relevant issue for the future of nuclear power. In this view, the toxicity of plutonium and its high radiation levels make the execution of experiments difficult. These experiments are usually costly, and require long irradiation periods. Moreover, plutonium dioxide may undergo changes in stoichiometry during measurements especially at high temperatures. Numerical approaches are recognized to be viable options to overcome these obstacles. Over the last decade several atomistic methodologies using molecular dynamics (MD) simulations have been refined and several studies published on the thermophysical properties of UO2 and MOX fuel. The paper presents MD calculations focused on the thermophysical properties of PuO2 that is an aspect certainly relevant for the analysis of MOX. Preliminary results of thermal expansion, specific heat, thermal conductivity, and melting temperature are discussed. For this purpose, four potentials published in the literature are applied in the temperature domain 300-3200 K. The code employed for these analyses is LAMMPS (Large-Scale Atomic/Molecular Massively Parallel Simulator).

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