With the revival of nuclear power in France, the CEA is playing a key role in the nuclear industry of the future. In this context, engineers and researchers are mobilised to meet the growing needs of this industry. Plutonium is a key element in the nuclear fuel cycle. Acquiring molecular data is crucial to optimising and rationalising the mechanisms involved in separating this element.
Plutonium(IV) is one of the most common cationic forms in the nuclear fuel cycle. Its study by theoretical chemistry presents difficulties both in ab initio modelling (occupied f-block orbitals) and in classical atomistic simulations. In classical molecular dynamics simulation, the models necessarily require the addition of the polarisation effect, and sometimes even the addition of charge transfer, in order to reproduce the system's behaviour correctly. As a result, classical simulations containing plutonium (IV) are almost completely absent from the scientific literature. In addition, the speciation of this cation is sensitive to the acidity of the medium, which has to be taken into account in the simulations, adding a further difficulty.
The aim of this thesis is to use molecular dynamics (classical and ab initio) to simulate solutions containing plutonium, taking into account the effect of acidity. The PhD student will be faced with two main issues: the choice or development of a force field for the Pu4+ cation, and the design of a method for including acidity in the solutions. A crucial step in the process will be to compare the results with the available experimental data in order to conclude on the ability of the models to reproduce the experimental data. This thesis will be carried out in a multidisciplinary laboratory, combining experimental chemistry and theoretical modelling, while conducting both applied and fundamental research.