Studies of Intensified Small-scale Processes for Liquid-Liquid Separations in Spent Nuclear Fuel Reprocessing

The present work focuses on the development of intensified small-scale extraction units for spent nuclear fuel reprocessing using advanced process engineering with combined experimental and modelling methodologies. It discusses a number of novel elements, such as the intensification of spent fuel reprocessing and the use of ionic liquids as green alternatives to organic solvents. The use of ionic liquids in two-phase liquid-liquid separation is new to the Multiphase Flow community, and has proved to be challenging, especially in small channels, because of the surface and interfacial properties involved, which are very different to those of common organic solvents. Numerical studies have been also performed to couple the hydrodynamics at small scale with the mass transfer. The numerical results, taken together with scale-up studies, are used to evaluate the applicability of the small-scale units in reprocessing large volumes of nuclear waste.

Nominated as an outstanding PhD thesis by the University College London, UK Provides insight into the fundamentals of ionic liquid-based extractions for the intensification of liquid-liquid separations in the spent nuclear fuel reprocessing cycle Presents the characterization of important hydrodynamic characteristics using advanced optical techniques (µ-PIV) and scale-up studies Outlines the development of numerical and empirical models for the rapid analysis of two-phase systems Includes supplementary material: sn.pub/extras

Auteur
Dimitrios Tsaoulidis is a chemical engineer with expertise on intensified two-phase processes particularly relevant to spent nuclear fuel reprocessing. The main aim of his research, which combines sophisticated experimental and modelling methodologies, is to provide insight into the fundamentals of two-phase flows, study the interaction with mass transfer, as well as develop models for accurate prediction of the process' performance. The research is facilitated by state of the art devices, equipment, and techniques, which include among others small scale setups, laser based instruments (PIV, shadowgraphy), high speed cameras, conductivity probes, etc.

Contenu
Introduction & Background.- Literature review.- Experimental details.- Liquid-liquid flows in micro and small channels: Hydrodynamics and pressure drop.- Circulation patterns and mixing characteristics of liquid-liquid flows in small channels.- Liquid-liquid mass transfer using ionic liquids.- Modelling of a micro-extractor.- Conclusions & future developments.