Determination of uranium in plutonium solutions by laser induced fluorescence

A highly sensitive method for determining uranium in plutonium solutions has been developed at the Savannah River Plant. It uses a pulsed nitrogen laser as an excitation source for a time resolved fluorimetric measurement. Since the sample matrix contains large quantities of fluorescence quenchers, sample purification is necessary to achieve 1 part per billion sensitivity. Liquid-liquid solvent extraction is used to separate uranium from the sample matrix into a fluorescence enhancing solution. The method has been successfully applied to PUREX process streams with a precision of +-13% (95% C.I.) with volumetric transfers