Chemist, Argonne National LaboratoryUnion Carbide Corporation, ArgonneSouth Charleston, ILWV
Pages: 6 Published: Jan 1998
A 20 kg uranium metal ingot was prepared from two isotopically distinct feedstocks, and drillings from various ingot sections were dissolved in a mixture of HCl, HNO3, and HF. Uranium isotope ratios in each solution were determined by inductively coupled plasma-mass spectrometry (ICP-MS); total dissolved solid content was 20 μg/L for determination of 238U/235U, and 2 mg/L for determination of 236U/235U and 234U/235U. Between-sample coefficients of variation (n=35) for 238U/235U, 236U/235U, and 234U/235U were 0.70%, 0.90%, and 1.4%, respectively. Linear regression indicated that 236U/235U versus 238U/235U and 234 234 234U/235U versus 238U/235U were significantly correlated at the 90% confidence interval; 234U/235U versus 236U/235U was significantly correlated at the 98% confidence interval. These data show that the samples were not isotopically homogeneous, and demonstrate that ICP-MS can be used to assess isotopic homogeneity, even in cases where aggregate variations in isotopic composition are on the order of 1%.
uranium, isotopic composition, ICP mass spectrometry
Paper ID: STP15722S