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  • 1 Bhabha Atomic Research Centre Nuclear Materials Accounting Cell Trombay 400 085 Bombay (India)
  • 2 Bhabha Atomic Research Centre Radiochemistry Division Trombay 400 085 Bombay (India)
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Abstract  

Quantitative determination of uranium in (U, Pu)O2 fuels is usually done by the DAVIES-GRAY method. High concentrations of phosphoric acid in the analytical waste generated by this method make the revocery of plutonium rather complex. Studies on the recovery of plutonium from nitric acid medium containing different concentrations of H3PO4 by conventional anion-exchange procedure reveal that more than 90% of the plutonium can be easily recovered when the phosphoric acid concentration is less than 0.5 M in the solution. A method was developed for the determination of uranium in the presence of plutonium, which involves the reduction of U(VI) to U(IV) by Fe(II) in a medium of 3.5M H3PO4 +4.5M H2SO4 instead of 10–11M H3PO4 so as to have the H3PO4 concentration 0.6M in the waste. A number of determinations of uranium in UO2(NO3)2 working standard solutions and (U, Pu) synthetic solutions with uranium at the 3–7 mg level were carried out by this method. The precision obtained was better than ±0.2% and the accuracy was also within the precision limits. The resulting analytical waste generated was directly subjected to anion exchange separation for the recovery of plutonium which was found to be more than 90%.