Contact

Porträt Prof. Dr. Kvashnina, Kristina; FWOS

Prof. Dr. Kristina Kvashnina

Head of Department "Molecular Structures"
Responsible for the BM20 (ROBL) beamline at ESRF

Phone: +33 476 88 2367

Department of Molecular Structures

Molecular Structures

Research

The Department of Molecular Structures conducts synchrotron-based research, offering a robust toolkit for scientists investigating materials containing actinides and lanthanides.

Experiments take place at the Rossendorf Beamline of The European Synchrotron (ESRF), in Grenoble (France) which is specifically dedicated to the actinide science and research on radioactive waste disposal. The beamline consists of four experimental stations -XAFS, XES, XRD-1, XRD-2:

  • XAFS station with fluorescence and transmission detection for X-ray Absorption Fine-Structure (XAFS) spectroscopy, including (conventional) X-ray Absorption Near-Edge Structure (XANES) and Extended X-ray absorption fine-structure (EXAFS) spectroscopies
  • XES with a 5-crystal Johann-type spectrometer for high-energy-resolution fluorescence-detection X-ray absorption near-edge spectroscopy (HERFD-XANES), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS) measurements.
  • XRD-1 station with a heavy-duty, Eulerian cradle, 6-circle goniometer for (high-resolution) powder X-ray diffraction (PXRD), surface-sensitive crystal truncation rod (CTR) and resonant anomalous X-ray reflectivity (RAXR) measurements
  • XRD-2 station with a Pilatus3 x2M detector stage for single crystal X-ray diffraction (SCXRD) and in situ/in-operando PXRD measurements.

Our research provides detailed insights into the structural and electronic properties of actinide and lanthanide-containing materials across various scientific disciplines, including physics, chemistry, environmental science, and geoscience. We study fundamental electron interactions, bonding properties, probing the local structures and oxidation states of complex systems. Data analysis is performed with the help of electronic structure calculations. 

EXAFS, HERFD-XANES, XES and RIXS is not restricted to crystalline solids, but can be applied to a wide range of samples, to derive information on e.g. aqueous speciation, complexation with dissolved inorganic ligands like chloride, sulfate or nitrate, complexation with organic ligands like acetate or humic acid, interaction with bacteria and plants, sorption to mineral and rock surfaces for actinides an other metals and metalloids. Due to the high penetration depth of the employed hard X-rays, the methods are suited to study chemical reactions in-situ/in-operando, for instance at very low or high temperatures, under special atmospheres, or under electrochemical potentials.

More about Rossendorf Beamline

Latest publication

State-of-the-Art report on the understanding of radionuclide retention and transport in clay and crystalline rocks

Maes, N.; Churakov, S.; Glaus, M.; Baeyens, B.; Fernandez Marques, M.; Dähn, R.; Grangeon, S.; Tournassat, C.; Geckeis, H.; Brandt, F.; Poonoosamy, J.; Hoving, A.; Havlova, V.; Scheinost, A.; Fischer, C.; Noseck, U.; Britz, S.; Siitari-Kauppi, M.; Fabritius, O.; Missana, T.; Charlet, L.

Abstract

After isolation of radioactive waste in deep geological formations, radionuclides can enter to the biosphere by slow migration through engineered barriers and host rocks. This process typically takes many thousands to hundreds of thousands of years. The rate of transfer to the biosphere depends on the distance from the repository, dominant transport mechanism (diffusion vs advection), and the interaction of the dissolved radionuclides with minerals present in the host rock and engineered barrier systems.
Within the framework of the European Union’s Horizon 2020 EURAD project (https://www.ejp-eurad.eu/), a series of state of the art reports have been drafted which form the basis of a series of papers. This state-of-the-art paper aims at providing a comprehensive overview of the current understanding of the underlying processes contributing to the radionuclide retention and migration in clay and crystalline host rocks. For each process, a brief theoretical background is provided together with current methodologies used to study these processes as well as references to key data.
Thanks to the innovative research on retention and migration and the extensive knowledge collected for some decades, the process understanding and insights are continuously improving, prompting to adapt and refine conceptual descriptions towards safety assessments. Nevertheless there remain important research questions to be investigated in the future which are enlisted at the end of the manuscript.

Keywords: Nuclear Waste; Geological disposal; radionuclide migration; diffusion; retention; sorption; redox chemistry; clay host rock; crystalline host rock

Involved research facilities

Related publications

Permalink: https://www.hzdr.de/publications/Publ-38978

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Team

Head

NameBld./Office+49 351 260Email
Prof. Dr. Kristina KvashninaROBL/21.6.04+33 476 88 2367

Employees

NameBld./Office+49 351 260Email
Dr. Lucia AmidaniROBL/14.1.04+33 476 88 1982
Dr. Nils BaumannROBL/21.6.03+33 476 88 2849
Dr. Elena BazarkinaROBL/14.1.01+33 476 88 4578
Clara Lisa E SilvaROBL/14.1.04+33 476 88 2044
Jörg ExnerROBL/BM20+33 476 88 2372
Dr. Christoph HennigROBL/21.6.02a+33 476 88 2005
Dr. Eleanor Sophia Lawrence Bright+33 476 88 2462
Dr. Damien PrieurROBL/21.6.03+33 476 88 2463
Dr. André Roßberg801/P3162758
Anne Thielena.thielenAthzdr.de