Abstract The uranium isotope characterization for nuclear safeguards and security purposes was conducted using both passive and active non-destructive techniques. The interrogated samples were natural uranium (NU), low-enriched uranium (LEU), and depleted uranium (DU) all in the form of uranium dioxide. The obtained spectra using both techniques were accumulated using a high-efficiency HPGe detector. Improving detector efficiency was developed using the neural network (NN) method based on the obtained intrinsic calibration data. The obtained enrichment results of passive measurements showed good agreement with certified samples to within 1.12% in the case of LEU, 1.03% in the case of NU, and 1.04% in the case of DU.
Active interrogation of the samples was done using the neutron spectrum of a 5 Ci 241Am-Be neutron source. Seven short-lived fission products (FPs) (101Tc, 97Nb, 105Ru, 92Y, 91Sr, 92Sr, and 88Kr) were chosen as indicators to provide a complete characterization of isotopic mass determination, uranium content, and enrichment. Isotopic masses of the samples were calculated using thermal and fast interrogations. A comparison of the obtained results of 238U mass was found to agree within 0.2% with certified value based on fast interrogation, and within 0.3% of 235U mass based on thermal interrogation.
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