Solving isobaric interferences in Secondary Ion Mass Spectrometry: The case of Am and Pu in irradiated thorium-based fuel

Secondary Ion Mass Spectrometry (SIMS) is routinely used to provide radial isotopic distribution of actinides in irradiated nuclear fuel samples but the measurements are mainly qualitative because many isobaric interferences remain. A simple method to solve the isobaric interferences between Am and Pu for mass 241 and 242 is proposed in this work. The method is based on isotope ratio measurements currently gained by SIMS. The discussion of the results includes the evaluation of the limit of utilization of this approach as well as the enhancement possibility. The method is applied on thorium-based fuels, which represent a sustainable alternative to the classical uranium-based fuels commonly used in most of power plants around the world.

► Resolution of the 241Am/241Pu isobaric interference in SIMS, in (Th/Pu)O2 fuel.
► Enhanced isotopic distribution of plutonium along a pellet cross section.
► Good agreement with MC-ICP-MS results (on bulk).