Analysis of isotopic ratios of uranium in uranium oxide using the inductively coupled plasma mass spectrometry technique for nuclear forensics purposes

The ICP-MS was used to measure the isotopic ratios of uranium in uranium oxide samples. The typical within-run precision measurement was less than 0.02%. Verification measurements on reference standard as a sample were performed successfully and showed good agreement with the reference values. To avoid mass biased results, mass fractionation corrections were performed using lead NIST 981 certificate reference standards traceable to NIST. The uranium isotopic ratio showed unique signatures for South Africa compared to literature. The signatures showed that origin location reflect significant variation with other uranium plants thus provided valuable information about the geochemical formation and origin. Overall, the characterization and measurements implied that the isotopic ratios of uranium samples are a powerful geographical signature in uranium oxide for uranium attribution and a powerful approach for nuclear forensics studies. The results obtained can be added into a national nuclear forensics library for reference purposes; since South Africa is embarking on developing and establishing a national nuclear forensic library, these results support and strengthen the initiatives.