Rapid measurement of U, Np, and Pu in feces using ICP-MS/MS and alpha spectrometry

Internal contamination with alpha-particle emitting actinides, such as 238U, 237Np, 239Pu, 240Pu, is likely to result in high internal exposure risk even if the intake amount is small. To provide valuable information apart from urinary bioassay for internal dose estimation, we developed a simple and rapid method for fecal bioassay to determine ultra-trace U, 237Np, and Pu isotopes in synthetic feces using ICP-MS/MS and alpha spectrometry, respectively. After rapid ashing by microwave muffle furnace and acid digestion by opening and microwave digestions, the sample was separated for analyses by ICP-MS/MS and alpha spectrometry, respectively. Conventional alpha spectrometry was used for the analysis of short-lived 238Pu (t1/2 = 87.74 y) for dose estimation, the ICP-MS/MS was used to obtain the atom ratio of 240Pu/239Pu for source identification. The sensitivities of ICP-MS/MS were improved and compared by introducing different reaction/collision gases to allow us to measure these isotopes with low background signal intensities.日本放射化学会第65回討論会(2021