Preliminary development of a radiochemical separation method to determine Cs-135 and Cs-135/Cs-137 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. Cs-135 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 Cs-135 by measuring Cs-135/Cs-137 isotopic ratio. To exploit this powerful tool, the removal of matrix contaminants, especially Ba-135,Ba-137 isobaric interferences, remains paramount and challenging. The combined effect of co-precipitation followed by chromatographic separations is being explored in this work.