Feasibility study of isotope ratio analysis of individual uranium-plutonium mixed oxide particles with SIMS and ICP-MS

Esaka, Fumitaka  ; Magara, Masaaki  ; Suzuki, Daisuke   ; Miyamoto, Yutaka   ; Lee, C. G.; Kimura, Takaumi 

In this study, we applied secondary ion mass spectrometry (SIMS) and inductively coupled plasma mass spectrometry (ICP-MS) to the isotope ratio analysis of individual U-Pu mixed oxide particles. In the analysis of individual U-Pu particles prepared from mixed solution of uranium and plutonium standard reference materials, accurate U/U, Pu/Pu and Pu/Pu isotope ratios were obtained with both methods. However, accurate analysis of Pu/Pu isotope ratio was impossible, due to the interference of the Am peak to the Pu peak. In addition, it was indicated that the interference of the UH peak to the Pu peak has a possibility to prevent accurate analysis of plutonium isotope ratios. These problems would be avoided by a combination of ICP-MS and chemical separation of uranium, plutonium and americium in individual U-Pu particles.