Measured63Ni contents in Savannah River Site high level waste and Defense Waste Processing Facility glass product by Ni-selective ion exchange purification and β-decay counting

Abstract

We describe tests of EiChrom Industries' Ni-selective ion exchange resin for use in analysis of63Ni in Savannah River Site high level waste. We report measurement of63Ni content in two sets of Savannah River Site glass product from the Defense Waste Processing Facility. The63Ni β-decay activity was chemically separated in quintuplicate from fission product and plutonium α-β activities of up to 103 times the observed63Ni content. The separation used a Ni-dimethlyglyoxime precipitation followed by radiochemical purification using the Ni-selective extraction chromatography resin. Further removal of interfering activity was based on diagnosis of observed radioactivity in each successive product phase. We analyzed eleven plant glass product samples using seven spiked standard addition duplicates to measure63Ni recovery in the separations. Selected liquid scintillation β-decay spectra are shown to validate the method. Interpretation of accuracy is based upon three distinct comparisions to predicted63Ni content.