Utilization of 14-MeV neutron Generator for nondestructive activation assay of uranium samples

Determination of uranium contents in nuclear fuel is one of the most important task in the system of nuclear material control and safeguards. Facilities of neutron activation analysis laboratory at Nuclear physics department were used to estimate the uranium mass and enrichment of U-235. A 14 MeV neutron generator with neutron yield of 1 x 1011 n/sec was used for activation. The neutron yield of the system was measured using Cu-foil and aluminium activation techniques. Uranium samples of different shapes (Pellet, powder) and different compounds of UO2 and U-nitrate were assayed. HPGe detector of 171cm3 active volume was calibrated and used in the detection of gamma-ray spectra of the irradiated samples. The contents of 238U and enrichment of 235U were determined using the photopeak areas corresponding to the gamma-ray lines at 208 keV following the reaction 238U (n, 2 n) 237U and 205 keV of the 235U. Due to the effect of self-absorption of the samples for gamma rays, the attenuation corrections were taken into consideration