SAMOP 2023 – scientific programme

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MS: Fachverband Massenspektrometrie

MS 8: Accelerator Mass Spectrometry III

MS 8.1: Invited Talk

Friday, March 10, 2023, 11:00–11:30, F128

What Single Hot Particles Tell Us: From Nuclear Forensics to Bioavailability — •Clemens Walther — Institute of Radioecology and Radiation Protection, Leibniz University Hannover, 30419 Hannover, Germany

Micrometer-sized radioactive particles are of highest concern in environmental and life sciences, cosmochemistry and forensics. From their composition, detailed information on the origin is obtained (for instance, did it originate from Tschernobyl of from Saporischschja ?) and potential risks to human health is assesed. We combine secondary-ion mass spectrometry with resonant laser ionization to selectively examine elemental and isotopic composition of individual particles at sub-micrometer spatial resolution. Identification of actinide elements and fission products including ^242mAm and Cm at ultra-trace levels is possible. Isobaric interferences, particularly ²³⁸U/²³⁸Pu and ²⁴¹Pu/²⁴¹Am, are suppressed by up to five orders of magnitude. In contrast to most mass-spectrometric techniques, only negligible mass is consumed, leaving the particle intact for further studies, e.g. chemical leaching: Selected individual particles were sequentially leached in order to assess stability in the environment and availability of radionuclides for uptake into the human food chain. The solutions are then analyzed by gamma spectrometry and ICP-MS. Fuel particles from the Chernobyl accident are usually classified according to their appearance, dissolution rates and oxidation state: the further oxidized and brittle UO_2+Z, non-oxidized UO₂ and zirconium merged bearing U_X-Zr_Y-O_Z particles, of which we investigated several particles each.