The Determination of Impurities in Plutonium Nitrate Solutions by Amine Extraction and ICP Analysis

Abstract

With the reactivation of the Purex Fuel Reprocessing Facility at Hanford, a method for the determination of metal impurities in plutonium nitrate solutions is needed. The need was met by the use of amine extraction for the separation of plutonium and optical emission spectrometry for the analysis. Some 10 impurity metals are listed in the specifications (see Table I). Optical emission spectrometry with its simultaneous, multielement capability is a good candidate technique. Inductively coupled plasma (ICP) emission spectrometry is even better. The extremely high temperature of the plasma minimizes chemical and ionization interferences. The plasma, furthermore, is more stable than the arc or spark and leads to better precision. Analytical wavelengths were selected from the EPA document of Winge et al. In order to check for interferences, scans were run across the selected wavelengths with each of the specification elements; scans were also made with more common interferences listed in an atlas of spectral interferences. The lines listed in Table II were found to be free of interferences and are recommended for the analysis.