Extraction behavior of actinides and lanthanides in a molten fluoride/liquid aluminum system

• Published in: Journal of nuclear materials 2005-09, Vol.344 (1), p.136-141
• Main Authors: Conocar, Olivier, Douyere, Nicolas, Lacquement, Jérôme
• Format: Article
• Language: English
• Subjects: Applied sciences; Controled nuclear fusion plants; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fission nuclear power plants; Fuels; Installations for energy generation and conversion: thermal and electrical energy; Nuclear fuels
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2005.04.031

As one of the basic investigations on the group partitioning of actinides and lanthanides by a pyrochemical reductive extraction process, the distribution ratios of Pu, Am, Ce and Sm have been experimentally determined in the binary liquid LiF–AlF 3/Al–Cu system at the temperature of 830 °C. The distribution ratios of Pu and Am are much larger than those of Ce and Sm. They would allow a high recovery yield of the actinides and good separation factors with lanthanides. The influence of the salt composition (LiF/AlF 3 ratio) on the distribution coefficients has been investigated. Coupling the obtained experimental results and literature data, a thermodynamic model that describes the extraction in terms of Gibbs enthalpies of formation and the fluorobasicity of the melt (p F) has been developed. The activity coefficients of Sm(+II) et Ce(+III) versus the p F have been infered: they clearly reveal the difference in solvation behavior between divalent and trivalent species.