SIMS characterisation of actinide isotopes in irradiated nuclear fuel

Numerical codes are used to calculate the inventory of plutonium and minor actinides produced during irradiation in industrial power reactors. Secondary ion mass spectrometry (SIMS) is a useful method for validating theses inventory calculations especially with regards to isotopic characterisation. Isotopic ratios measured by SIMS on the radius of an UO2 irradiated fuel pellet are presented and compared with calculated values in this paper. The SIMS results tally well with the calculations, as both show an increase in the actinide concentration on the pellet periphery due to the rim effect.