Determination of 237Np and Pu isotopes in large soil samples by inductively coupled plasma mass spectrometry

Abstract A new method for the determination of 237 Np and Pu isotopes in large soil samples has been developed that provides enhanced uranium removal to facilitate assay by inductively coupled plasma mass spectrometry (ICP-MS). This method allows rapid preconcentration and separation of plutonium and neptunium in large soil samples for the measurement of 237 Np and Pu isotopes by ICP-MS. 238 U can interfere with 239 Pu measurement by ICP-MS as 238 UH + mass overlap and 237 Np via 238 U peak tailing. The method provides enhanced removal of uranium by separating Pu and Np initially on TEVA Resin, then transferring Pu to DGA resin for additional purification. The decontamination factor for removal of uranium from plutonium for this method is greater than 1 × 10 6 . Alpha spectrometry can also be applied so that the shorter-lived 238 Pu isotope can be measured successfully. 239 Pu, 242 Pu and 237 Np were measured by ICP-MS, while 236 Pu and 238 Pu were measured by alpha spectrometry.