Preliminary development of a radiochemical separation method to determine 135Cs and 135Cs/137Cs isotopic ratio by a non-radiometric technique

The completion of the radiological inventory of a nuclear facility is hindered by some radionuclides that cannot be easily detected because of hardly measurable gamma lines or low abundance. 135Cs is a long-lived hard-to-measure radionuclide that needs chemical and radiochemical treatments to be measured. A preliminary separation approach to be combined with a non-radiometric assay is being proposed to quantify 135Cs by measuring 135Cs/137Cs isotopic ratio. To exploit this powerful tool, the removal of matrix contaminants, especially 135,137Ba isobaric interferences, remains paramount and challenging. The combined effect of co-precipitation followed by chromatographic separations is being explored in this work.