Uranium enrichment measurement by X- and γ-ray spectrometry with the “URADOS” process

The methods used for the uranium enrichment measurement require in general prior instrument calibration with several standards. Thus, it is possible to avoid the constraints involved in calibration by considering the complex spectral region called XKα. This spectral region is sufficiently limited so that the variation of the detector efficiency response is small enough to facilitate a self-calibration. Processing this region is critical and requires taking into account 3 elemental images, one corresponding to 235U, one to 238U and one to the X-ray fluorescence induced in the sample by radiation above 100 keV. A process called “URADOS” based on this principle has been developed. Six uranium oxide standards with different enrichments and infinite thicknesses were counted several times to test this process; other samples, some highly enriched, were also used. The results obtained are compared to the declared values. From these measurements, it has been possible to improve the photon emission probability values.