Uranium enrichment measurements using the intensity ratios of self-fluorescence X-rays to 92* keV gamma ray in UXKα spectral region

In this paper, the known multigroup gamma-ray analysis method for uranium (MGAU) as one of the non-destructive gamma-ray spectrometry methods has been applied to certified reference nuclear materials (depleted, natural and enriched uranium) containing U-235 isotope in the range of 0.32-4.51% atom U-235. Its analysis gives incorrect results for the low component U-235 in depleted and natural uranium samples where the build-up of the decay products begins to interfere with the analysis. The results reveal that the build-up of decay products seems to be significant and thus the algorithms for the presence of decay products should be improved to resulting in the correct enrichment value. For instance, for the case of U-235 analysis in depleted uranium or natural ore samples, self-induced X-rays such as 94.6 keV and 98.4 keV lying in UXK alpha spectral region used by MGAU can be excluded from the calculation. Because the significant increases have been observed in the intensities of uranium self-induced X-rays due to gamma-ray emissions with above 100 keV energy arising from decay products of U-238 and U-235 and these parents. Instead. the use of calibration curve to be made between the intensity ratios of self-fluorescence X-rays to 92(*) keV gamma-ray and the certified U-235 abundances is suggested for the determination of U-235 when higher amounts of decay products are detected in the gamma-ray spectrum acquired for the MGAU analysis. (c) 2008 Elsevier B.V. All rights reserved.