X-ray fluorescence analysis has been used for some years at two Institutes of the Karlsruhe Nuclear Research Center to determine routinely thorium, uranium, and plutonium in unirradiated and irradiated nuclear fuels. It has "been used in addition to assay neptunium, americium and curium contained in irradiated samples. The method excels because it is versatile, rapid, tamperproof, and efficient. As a rule, fission products, pollutions, and foreign activities do not interfere with the determination which can be made in a direct way without chemical separation. In practice, the nuclear fuels are dissolved prior to the analysis and a given amount of an appropriate element as an “internal standard” is added. The accuracies attainable (1 σ RSD better than 1 %) are comparable with the mass spectrometric isotope dilution analysis so that in the input analysis of reprocessing plants X-ray fluorescence analysis constitutes a true alternative to the mass spectrometric isotope dilution analysis.

Within the efforts to automate the method the prototype of the fully automated system is presently tested with non-active material. A first, not yet fully automated, development stage is being installed in the Karlsruhe Reprocessing Plant. It is anticipated that it will be tested soon under operating conditions. Complete automation of the system is scheduled to be completed at a later date.