The preparation of (U,Pu)O2 MOx fuel (Mixed oxide fuel), is based on the formation of actinide oxide species from purified uranium and plutonium aqueous solutions and constitutes one of the key steps for spent nuclear fuel recycling. More specifically, the formation of actinide oxide solid solutions is a pivotal point for the multi-recycling process with FNR (Fast Neutron reactors). In this framework, the ADOA process (Advanced Denitration in presence of Organic Additives) represents a potential pathway to prepare actinide oxides without the usual valence adjustment step and enables to prepare mixed oxides thanks to a very good cationic homogeneity. This process is based on the formation of a polymeric gel, which allows homogeneous immobilization of the cations, which is then dehydrated and calcinated, ultimately leading to the synthesis of an actinide mixed-oxide. However, an optimization of the physico-chemical parameters is still needed for this process to meet the industrial MOx fuel fabrication requirements.
The aim of this postdoctoral research project will be to determine the optimal experimental conditions for the polymerisation, dehydration and calcination steps and evaluate the process robustness. The impact of these conditions on the actinide oxide morphology and its impurity content (especially residual carbon content), ease of process implementation and its adequacy with the requirements for the MOx fuel fabrication process will also be investigated.
The candidate must have a PhD in radiochemistry or solid state chemistry. Since the main part of this study will be based on glovebox experiments with the study of radioactive ceramic materials, skills on glovebox handling and materials characterization will be an asset to get this position. The results obtained during this study will be featured in patents and/or scientific publications, opening job possibilities in academic or industrial research and development sectors.