Chlorine (Cl) is naturally composed of 76% 35Cl, which through neutron capture forms 36Cl, a long-lived gamma emitter (t1/2 = 301 000 years), and sulfur 36S, which accelerates corrosion phenomena, and 24% 37Cl with a drastically lower neutron capture section. A supply of 37Cl is therefore necessary in order to operate these reactors. Techniques currently exist that enable the enrichment of chlorine, such as ultracentrifugation, liquid-phase thermal diffusion, or laser isotope separation. The enrichment of chlorine by liquid-liquid extraction technics has been recently developed within CEA. The objective of the thesis is to identify and implement chemical systems allowing the 37Cl enrichment by a separative chemistry process. The thesis subject aims to identify on the basis of literature data initially, the families of ligands and, within these families, the best candidates for the 37Cl enrichment. Next, the synthesis and purification of the selected molecules will be carried out in the laboratory. Finally, the enrichment properties of the successfully synthesised ligands will be evaluated by separative chemistry, by quantification of chlorine isotopes using Inductively coupled plasma mass spectrometry (ICP-MS).
The thesis will be carried out at the recycling and energy recovery processes laboratory (LRVE) at the CEA in Marcoule.
The ideal candidate will be a Master's student in their second or third year of engineering school, studying chemistry, organic chemistry or analytical chemistry. The multidisciplinary nature of the skills acquired and the rigour developed by the student during the experiments undertaken will be valuable assets for the future PhD student.