[2C07-09] Aqueous Reprocessing and Fuel Cycle Evaluation

[2C08] Exploration of predominant factors determining U(VI) precipitation in advanced spent fuel reprocessing

*Makito Nojima¹, Satoru Tsushima^1,2, Koichiro Takao¹ (1. Tokyo Tech, 2. HZDR)

Keywords:Spent fuel reprocessing, Precipitation, Diamide linker, Uranyl nitrate complex, Crystal structure

Solvent extraction and precipitation methods using amide ligands have been proposed as advanced technologies for spent fuel reprocessing. Precipitation must be avoided for process feasibility of the solvent extraction. On the other hand, it has to be promoted for efficient recovery of nuclear fuel materials in the latter concept. Despite these conflicting requirements, it is not fully understood what kind of ligand structure decides precipitation formation. In this study, we investigated effects of molecular structures of diamide linker ligands on precipitation behavior of U(VI) from HNO₃(aq). As a result, it was suggested that packing efficiency of a diamide complex of uranyl nitrate in its crystal structure affects the precipitation efficiency of U(VI).