ISO 24459:2021

This document specifies a method for the determination of uranium concentrations in nitric acid or TBP-DILUANT (for example TBP-kerosene) solutions coming from the nuclear fuel cycle. The method is applicable —    for process control of solutions, free of suspension, which contain between 10 g/l to 300 g/l uranium, and —    for high accuracy purposes (Safeguards) to nitric acid solutions, free of suspension, which contain between 100 g/l and 220 g/l uranium. Having —    the content of neptunium and plutonium impurities in the solution less than 1 % of the uranium content. —    the content of neutron poisons (gadolinium, erbium) less than 1 % of the uranium content to ensure the absence of significant interferences at the level of required precision, for high accuracy purposes. The method is applicable to solid samples as well, provided that they can be fully dissolved in nitric acid.