Estimation of ²³⁵U concentration in some depleted uranium samples by high resolution gamma-ray spectrometry using 185 keV and 1001 keV gamma-energies of ²³⁵U and ^234mPa

Abstract

The identification of isotopic composition of depleted uranium obtained after the reprocessing of spent fuel is very much important as far as their further applications are concerned. The concentration of ²³⁵U in the reprocessed uranium will be lower and their depletion depends mainly on the type of the reactor and burn up. The depleted uranium has a variety of applications in nuclear fuel cycle operations and industries warranting quick assessment of its isotopic composition. This paper describes the methodology developed and used for the estimation of ²³⁵U concentration in reprocessed uranium in the form of uranyl nitrate solution. A non destructive technique by high resolution gamma-ray spectrometry with HPGe detector has been used for the analysis. The activity ratio of ²³⁸U/²³⁵U, obtained from the absolute activity measurement on the 185 keV gamma-line of ²³⁵U and 1001 keV gamma-line of ^234mPa, has been used for the estimation of ²³⁵U isotopic content in the sample using a mathematical formula. This method offers rapid and reliable estimate of the ²³⁵U concentration in samples comparable with that of mass spectrometry measurements. The results show that ²³⁵U concentration in the sample can be determined within 5% error for 10000 seconds counting.