Experimental comparison of uranium enrichment measurement methods

Uranium enrichment (the weight fraction of the fissile material, 235 U, in the uranium sample) can be determined with passive or active methods. In the present work, the characteristics of uranium enrichment measurement methods were measured and compared. Especially, the applicability of a low-intensity neutron generator to the uranium enrichment measurement was investigated. The γ - ray energy spectra from uranium samples (enrichment from 1.5% to 4.5%) were measured passively. The delayed γ -ray spectra from the uranium were measured by interrogating with a continuous neutron beam or a pulsed neutron beam. The relation between the γ -ray count rate and the uranium enrichment was obtained for each measurement. The background contribution to the total count rate could be minimized and the sensitivity of the count rate to the uranium enrichment was larger when the γ -ray spectrum was measured with a pulsed neutron beam.