This International Standard specifies an analytical method for determining the uranium concentration between 0,1 g/l and 400 g/l in nitric acid solutions of irradiated fuel from light-water reactors, gas-cooled reactors and fast-breeder reactors. It specifies how interference by nitrite and plutonium ions is prevented. The other constituents of fuel solutions do not interfere. This method is suitable for process control, but not for accountancy purposes.