Determination of uranium and plutonium in mixed oxide samples by X-ray methods and their comparison with potentiometry

Uranium and plutonium in nuclear fuels are generally determined by conventional potentiometric methods which generates large quantities of radioactive waste. In the present study, K-edge densitometry (KED) and Energy dispersive X-ray fluorescence (EDXRF) have been examined for the determination of uranium and plutonium in solutions as an alternative to potentiometric methods. In the present study, uranium plutonium mixed oxide (MOX) pellets were dissolved in nitric acid medium containing small quantities of HF. Uranium and plutonium in MOX solutions were determined by KED and EDXRF methods and the results are compared with the one obtained by conventional potentiometric methods. The relative standard deviation (RSD) of the analytical results for U and Pu using KED were found to be better than ±1% and ± 0.9% respectively. Similarly, RSD for U and Pu by EDXRF were found to be better than ±1.6% and ± 0.8%, respectively. The absolute difference between KED and EDXRF with respect to potentiometric data for uranium and plutonium were calculated and it was found to be marginal indicating that KED and EDXRF methods can be employed for the routine analysis of U and Pu in solutions. X-ray methods employed in the present study are non-consumptive, direct and offer precise determination of U and Pu and generate no waste.