Estimation of trace impurities in reactor-grade uranium using ICP-AES

Estimation of impurities in reactor grade uranium is important from the poi nt of view of neutron economy. For chemical separation, ion exchange and so lvent extraction techniques have been employed although the latter is gener ally preferred. Amongst various extractants TBP (tri-n-butyl phosphate), TB P-TOPO (tri-n-octyl phosphine oxide), or TOPO only (in CCl4, xylene, dodeca ne) is most often used. New reagents like Cyanex-923 (mixture of 4 tri-alky l phosphine oxides)/TEHP (tri-ethylhexyl phosphoric acid) are also being us ed. This communication reports chemical separation of uranium by precipitat ion using 1,2-diaminocyclohexane NNN'N'-tetra acetic acid (CyDTA)/ ammonium hydroxide in presence of 1,10-phenanthroline and estimation of impurities in the filtrate by ICP-AES. Quantitative separation of U, a high spectral i nterferent in plasma and recovery of impurities have been achieved. Recover y of Cd has been improved by using 1,10-phenanthroline. The method is accur ate and precise, offering a relative standard deviation ranging from less t han 4% (3.8% for Eu at the 10 mu g g(-1) level) to 12.9% (for Ce at the 2.5 mu g g(-1) level) for all the elements studied. (C) 1999 Elsevier Science B.V. All rights reserved.