Rachel C. Connick
Uranium centrifuge enrichment poses a challenge to the nonproliferation regime due to the dual-use nature of the technology: enriched uranium is necessary for both nuclear energy and nuclear weapons. Radiation damage to materials containing uranium leaves signatures that may contain enough information to verify that uranium suitable for nuclear weapons has not been produced. However, the low doses expected from the natural decay of uranium can be difficult to detect if relatively small changes are induced in the material. The technique differential scanning calorimetry (DSC) is chosen to measure changes in the thermal properties of the candidate material, polytetrafluoroethylene (PTFE), from helium ion irradiation. The results show that, even for the extremely low doses, the changes to the melting temperature and enthalpy of fusion are significant and repeatable. Characterizing this sensitivity of both the material and the measurement to radiation is the first step towards the ability to verify the peaceful use of uranium centrifuges based on forensic analysis of the components.