Development of an optimized method for faster and more reliable automated U/Pu/Np separations

Modern chemical separation techniques enable high selectivity and high recovery. The development of an automated, rapid and robust procedure for U/Pu separation was the focus of the present work. In this respect, using a column extraction chromatographic separation based on TOPO (tri n-octylphosphine oxide), a novel and efficient way of striping the plutonium was developed. Using ascorbic acid (AA) in formic acid (FA) a stable reagent for Pu reduction and fast stripping was identified, tested and validated. Optimizing steps lead to fraction concentrations high enough for direct filament loading in order to perform mass spectrometry measurements. Even better mass spectrometric results were achieved using FA acid solution than using nitric acid solutions. Lower tailing in alpha spectrometry has been achieved through the new procedure. The downscaling capabilities were demonstrated successfully. Additionally, a new method has been developed to separate Np, Pu and U on a single column. (orig.)