Optimization of plutonium extraction with methyltrioctylammonium chloride preceding its determination by liquid scintillation spectrometry

Optimization of selective extraction conditions for separating plutonium from uranium and thorium standard solutions using methytrioctylammonium chloride (Aliquat 336) as extracting agent is presented. Influence of such parameters as concentration of extracting agent and nitric acid, and kind of reducing agent on the efficiency of extraction were studied. The method was developed for standard solutions of Pu, Th and U. A Quantulus liquid scintillation spectrometer was used for determination of alpha activity of these isotopes. It was found that using HDEHP in the first stage of the elaborated procedure and Aliquat 336 in the next, it is possible to separate Pu from the mixture of U and Th. Optimal values of measuring parameters such as a PSA value and a scintillation cocktail volume were established as well.