Nuclear forensic analysis of uranium oxide powders interdicted in Victoria, Australia

Nuclear forensic analysis was conducted on two uranium samples confiscated during a police investigation in Victoria, Australia. The first sample, designated NSR-F-270409-1, was a depleted uranium powder of moderate purity (similar to 1000 mu g/g total elemental impurities). The chemical form of the uranium was a compound similar to K-2(UO2)(3)O-4 center dot 4H(2)O. While aliquoting NSR-F-270409-1 for analysis, the body and head of a Tineid moth was discovered in the sample. The second sample, designated NSRF-270409-2, was also a depleted uranium powder. It was of reasonably high purity (similar to 380 mu g/g total elemental impurities). The chemical form of the uranium was primarily UO3 center dot 2H(2)O, with minor phases of U3O8 and UO2. While aliquoting NSR-F-270409-2 for analysis, a metal staple of unknown origin was discovered in the sample. The presence of U-236 and U-232 in both samples indicates that the uranium feed stocks for these samples experienced a neutron flux at some point in their history. The reactor burn-up calculated from the isotopic composition of the uranium is consistent with that of spent fuel from natural uranium (NU) fueled Pu production. These nuclear forensic conclusions allow us to categorically exclude Australia as the origin of the material and greatly reduce the number of candidate sources.