N,N-dialkylamides (or monoamides) are promising extractant molecules for the development of new processes for nuclear fuel reprocessing. In this context, these extractant molecules are exposed to radiolysis caused by ionizing radiation from radionuclides, which leads to the formation of new compounds through the breaking or modification of chemical bonds. Such changes in solution composition can alter the extractive properties, particularly in terms of efficiency and selectivity.
This thesis aims to study the impact of radiolysis on the speciation of actinide-ligand complexes in solution, in order to improve the understanding of the phenomena observed under ionizing radiation. We propose an approach combining experimental studies (chromatographic and spectroscopic techniques) with theoretical calculations (such as bond dissociation energies, identification of probable radical attack sites, stability of metal-ligand complexes, etc.) to describe the molecular speciation of species in solution. Organic compounds formed during radiation and the metallic complexes will be characterized to evaluate the modifications caused by radiation.