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Migration of Actinide-Analogues visualized by Positron Emission Tomography GeoPET
Schymura, S.; Karimzadeh, L.; Mansel, A.; Franke, K.; Eichelbaum, S.; Frühwirt, T.; Zakhnini, A.; Jankovsky, F.; Zuna, M.; Molodtsov, K.; Kulenkampff, J.; Schmidt, M.ORC; Lippmann-Pipke, J.; Fischer, C.
The search of a final repository for nuclear wastes from energy and weapon production calls for knowledge of actinide migration from molecular to kilometer scales. The migration behaviour on the mm to centimetre scale bridges a crucial step for the up- scaling of molecular knowledge and the validation of models based thereupon. Using the positron-emitting analogue for trivalent actinides 86Y we visualized its migration behaviour in a fractured granite core using positron emission tomography.
A granite drill core was obtained from the Bukov underground research facility in the Czech Republic. An artificial fracture was induced into the core by a geomechanical shear test and the core was subsequently encased in a plexiglas column. Radiotracers 18F and 86Y were produced at the in-house cyclotron at the HZDR Research Site Leipzig. 18F was produced by proton irradiation of 18O enriched water via 18O(p,n)18F. 86Y was obtained by proton irradiation of 86Sr enriched SrCO3 via 86Sr(p,n)86Y. Positon emission tomography was performed using the GeoPET setup at the HZDR Research Site Leipzig.
A transport experiment consisting of two steps was performed. First, aqueous [18F]KF solution was injected into the core to establish the conservative flow path through the fracture. Second, an aqueous 10-5 M [86Y]Y(NO3)3 solution in 0.1 M NaCl at pH 7.5 was flown through the fracture, followed by the eluent. The transport behaviour of the actinide analogue was monitored for a throughput of several pore volumes. After the conclusion of the experiment the core was opened and the sorption pattern on the fracture surface was additionally imaged by autoradiography.
Under the chosen conditions most of the 86Y got sorbed in the area close to the inlet and only 1% got eluted. The sorption pattern follows the conservative flow path. More detailed investigations of the sorbed species by μTRLFS (using Eu as a luminescent probe) and a modelling of the experiment based on the extracted flow path from the GeoPET data are planned.
Keywords: Positronenemissionstomographie, Positron Emission Tomography Aktinide, Actinides
  • Poster
    GDCh Fachgruppentagung Nuklearchemie, 25.-27.09.2019, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-29700
Publ.-Id: 29700