Determination of uranium content in Th, U mixed oxides using EDXRF

An energy dispersive X-ray fluorescence (EDXRF) technique has been developed for the determination of U content in the range 2–80% in mixed oxides of thorium and uranium. The experimental parameters for XRF measurements were optimized using 1 cm diameter pellets made from 1:1 mixture of thorium–uranium mixed oxide standards and cellulose. Calibration plots were established using both Lα as well as Lβ peaks of uranium. The reproducibility of the determination was evaluated to be better than 3% for Lα peak, while for Lβ peak, it was better than 4%. The measured values of the uranium concentration in the synthetic samples were found to be in good agreement with the added values. Simultaneously Th was also determined using its Lα peak. The present method will be useful for fast routine measurements of mixed oxide samples of Th and U, without the need for dissolution.