S. Martinson, J. Garcia, I. Haynes, S. Saini, E. Wagner, G. Long, C. III, S. Chirayath, “Nondestructive and destructive assay for forensics characterization of weapons-grade plutonium produced in LEU irradiated in a thermal neutron spectrum”, Annals of Nuclear Energy, 183 (2023).
A post-irradiation examination (PIE) of an enriched uranium sample was performed to advance a nuclear forensics methodology, based on intra-elemental nuclide ratios. The PIE was carried out on a few milligrams of low enriched uranium dioxide (LEUO2) sample, irradiated to a burnup of 1 GWd/MTU. The PIE of the LEUO2 sample provided the concentration of selected plutonium and fission product nuclides. The PIE supported validation of the MCNP (Monte Carlo N-Particle neutronics simulation code) predicted concentration of these nuclides in the irradiated LEUO2 sample. This study showed that most of the MCNP predicted nuclide concentrations were within 15% and several within 10% compared to the PIE results. Gamma and mass spectrometry of nuclides in irradiated LEUO2 enabled the determination of uranium burnup and time since irradiation.