A method of uranium determination in organic and aqueous solutions has been developed, based on fluorescence L X-ray excitation
with a109Cd source of several mCi activity and counting the excited Lα lines with a proportional counter. To eliminate uranium X-ray absorption by the accompanying elements the intensity of the
source radiation (Ag K) transmitted through the analysed solution is measured. The ratio of these two intensities is independent
of other elements present in the solution over a very broad range of concentration. The analysis time does not exceed 5 minutes.
The precision and accuracy of this method in the range 0.5 to 100 g U/1 are comparable to those of the classical titrimetric