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Microanalysis (Micro-XRF, Micro-XANES, and Micro-XRD) of a Tertiary Sediment Using Microfocused Synchrotron Radiation

  • Melissa A. Denecke (a1), Andrea Somogyi (a2), Koen Janssens (a3), Rolf Simon (a2), Kathy Dardenne (a1) and Ulrich Noseck (a4)...

Abstract

Micro-focused synchrotron radiation techniques to investigate actinide elements in geological samples are becoming an increasingly used tool in nuclear waste disposal research. In this article, results using μ-focus techniques are presented from a bore core section of a U-rich tertiary sediment collected from Ruprechtov, Czech Republic, a natural analog to nuclear waste repository scenarios in deep geological formations. Different methods are applied to obtain various, complementary information. Elemental and element chemical state distributions are obtained from μ-XRF measurements, oxidation states of As determined from μ-XANES, and the crystalline structure of selected regions are studied by means of μ-XRD. We find that preparation of the thin section created an As oxidation state artifact; it apparently changed the As valence in some regions of the sample. Results support our previously proposed hypothesis of the mechanism for U-enrichment in the sediment. AsFeS coating on framboid Fe nodules in the sediment reduced mobile groundwater-dissolved U(VI) to less-soluble U(IV), thereby immobilizing the uranium in the sediment.

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Corresponding author. E-mail melissa@ine.fzk.de

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Keywords

Microanalysis (Micro-XRF, Micro-XANES, and Micro-XRD) of a Tertiary Sediment Using Microfocused Synchrotron Radiation

  • Melissa A. Denecke (a1), Andrea Somogyi (a2), Koen Janssens (a3), Rolf Simon (a2), Kathy Dardenne (a1) and Ulrich Noseck (a4)...

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