Determination of trace impurities in uranium, thorium and plutonium matrices by solvent extraction and inductively coupled plasma atomic emission spectrometry

Studies on the determination of trace metallic impurities in nuclear materials such as uranium, thorium and plutonium are described. The bulk of the matrix is separated by batch extraction from their nitric acid solutions using 2-ethylhexyl hydrogen 2-ethylhexyl phosphonate (KSM-17, equivalent to PC88-A). The final aqueous phase containing the metallic impurities is fed to a high-temperature source inductively coupled plasma and the analysis is carried out employing a computer-controlled multichannel direct-reading spectrometer. The studies also included the recovery of impurities at various acidities and spectral interferences of the above matrices over the analyte elements. Based on the above studies, methods were standardized for the determination of 19 elements, viz. Al, B, Be, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Si, Zn, Ce, Dy, Eu, Gd and Sm, in U/Th/Pu solutions. The relative standard deviation for various elements is in the range 1-5%.