Age determination analysis of a single uranium particle for safeguards

An analytical technique was developed to determine the age of uranium particles. After the chemical separation of uranium and thorium, the ²³⁰Th/²³⁴U ratio was measured using single-collector inductively coupled plasma mass spectrometry and a ²³³U-based reference material comprising a certain amount of ²²⁹Th as a progeny nuclide of ²³³U. The results allowed us to determine the purification age of two certified materials, i.e., U-850 and U-100, which was in good agreement with the reference purification age (61 y). Moreover, the age of a single U-850 particle was determined with a difference of - 28 to 2 years from the reference date. (author)