Use of distillation for the regeneration of solvent used in nuclear fuel reprocessing

The purpose of this study was to carry out a bibliographical approach to a particular stage of the nuclear fuel reprocessing process: the treatment of organic effluents. The role of this step is, from the distillation of the solvent phase, to realize: - the separation of the diluent (TPH), used for washing the aqueous phases of the extracted effluents, - the elimination of the degradation products of the short-chain solvent that lower its flash point, as well as the 'heavy' compounds partly responsible for the aging of the solvent. Combined with a chemical treatment of the solvent, it allows the solvent to find back most of its properties for its use in liquid-liquid extraction cycles. More generally, this study aimed to show the problems encountered in a 'classic' chemical process, such as distillation, applied to a particularly restrictive industry, the 'nuclear' industry, i.e.: - first, the need to design a facility requiring as little maintenance as possible, - in a second time, the difficulty in mastering the physical-chemical phenomena whose knowledge is paramount for the design of the installations and the modeling of the process. (author)