Synchrotron-induced EDXRF determination of uranium and thorium in mixed uranium-thorium oxide pellets.

Uranium and thorium in their mixed oxides were determined by synchrotron-induced energy dispersive X-ray fluorescence (EDXRF) spectrometry. Mixed oxide calibration mixtures containing uranium and thorium in different relative amounts and approximately fixed amount of yttrium were prepared in the form of pellets. The EDXRF spectra of the pellets were measured at the microfocus XRF (BL-16) beam line of Indus-2 synchrotron radiation facility (Raja Ramanna Centre of Advanced Technology, Indore, India). Characteristic X-ray lines U Lα, Th Lα, and Y Kα were used as analyte lines. Calibration plot for the determination of uranium was prepared by plotting amount ratios of U and Y against the intensity ratios of U Lα and Y Kα. Similarly, a calibration plot for thorium analysis was also made. The amounts of uranium and thorium in the sample mixtures prepared in similar way as the calibration mixtures were determined using the aforementioned calibration plots. The precision values obtained for uranium and thorium determinations were found to be 0.3 and 0.2% (relative standard deviation, 1 σ), respectively. The EDXRF results deviated from the expected values by 1% for uranium and 0.9% for thorium determinations. These analytical features are much superior compared with laboratory-based analysis results. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]