Department of Surface Processes
The why? The how? The what?
The ultimate goal of our research, driven by scientific curiosity, is to gain fundamental and independent knowledge of the (geo)chemistry and environmental fate of long-lived radionuclides (RNs). One prominent and socially important application is the safe disposal of radioactive waste, to aid future generations in the responsibility of dealing with “our” legacy from energy production in nuclear reactors.
For this purpose we provide the radiochemical knowledge, namely structural and mechanistic data of important mobilizing and immobilizing reactions of RNs in solution, at interfaces, and in solids.
Our particular focus is using a variety of established and advanced microscopic and spectroscopic techniques, to accurately describe complex formation reactions and complex structures that govern RN interactions in the geosphere. In addition, we investigate the creation and chemical speciation of activation products in materials from nuclear power plants in the context of their safe decommissioning.
As part of a value chain, the derived structural information forms a sound basis for a reliable thermodynamic description of the investigated systems, which can be integrated in thermodynamic databases. The thermodynamic work is done in close collaboration with the department of Actinide thermodynamics.
Our core competencies
- Chemistry of long-lived RNs – Expertise in handling RNs, ranging from fission- and activation products to transuranium elements, and access to radiation safety labs.
- Structural characterization – Expertise in applying and coupling spectroscopic and microscopic as well as diffraction techniques for accessing molecular information.
- Thermodynamic description of RN complexes – Using macroscopic, spectroscopic, and calorimetric information of reactant-water-surface phenomena as basis for the derivation of surface complexation models and their thermodynamic parameters.
Research fields
- Coordination chemistry of RNs in aqueous solution and in human artificial biofluids, e.g. RADEKOR project.
- Molecular characterization of RN reactions at natural and engineered mineral-water interfaces, e.g. REDOX project.
- Incorporation of actinides and lanthanides in solid phases, e.g. AcE project.
- Environmental technetium chemistry., e.g. Young Investigator Group TecRad.
- Experimental support for calculations of neutron fields and the resulting activities close to nuclear reactors, e.g. EBENE project.
Latest Publication
Self-healing ThSiO4-ZrSiO4 system under conditions relevant to underground nuclear waste repositories
Svitlyk, V.; Weiß, S.; Garbarino, G.; Shams Aldin Azzam, S.; Hübner, R.; Worbs, A.; Huittinen, N. M.; Hennig, C.
Abstract
Two series of Th1-xZrxSiO4 phases were synthesized hydrothermally under weakly basic (pH = 8) and strongly acidic (pH = 1) conditions. Changes in pH were found to have a significant effect on experimental phase diagrams. Synthesis at pH = 8 favors the formation of Th-rich phases with resulting Th1-xZrxSiO4 solid solution for x = 0 – 0.5. Contrary, synthesis at pH = 1 results in the formation of pure end-members of the ThSiO4-ZrSiO4 pseudo-binary system separated by multiple miscibility gaps. Phases formed both under basic and acidic conditions were found to retain water, which can be discharged from the structure upon heating. A different high-pressure (HP) behaviour was found for Th-rich and Zr-rich solid solutions. While Th-rich Th0.9Zr0.1SiO4 and Th0.6Zr0.4SiO4 phases retain their stoichiometry and crystal structure upon compression at HP, a significant reduction of the Th occupancy related to a decrease of the Th-O distances is observed for the Th-poor Th0.26Zr0.74SiO4 phase at P > 8 GPa, with the subsequent formation of a Th-rich amorphous phase. The Th diffusion between the crystalline and amorphous phases was found to be fully reversible. This unique self-healing property makes these phases promising candidates for nuclear applications under extreme pressure and temperature conditions, in particular those found in underground repositories.
Involved research facilities
- Rossendorf Beamline at ESRF DOI: 10.1107/S1600577520014265
Related publications
- DOI: 10.1107/S1600577520014265 is cited by this (Id 39571) publication
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Acta Materialia 281(2024), 120357
DOI: 10.1016/j.actamat.2024.120357
Permalink: https://www.hzdr.de/publications/Publ-39571
A list of publications can be found here.
Research groups
Currently running third-party funded projects
- Experimentally supported calculations of neutron fields and the resulting activities in spaces far from the reactor (EBENE) started: 04/2024, BMBF
- Interactions of technetium with microorganisms, metabolites and at the mineral-water interface – Radioecological considerations (TecRad) started: 07/2022, BMBF
- Redox reactivity of selenium in environmental geomedia (REDOX) started: 06/2022, ANDRA
An overview of finished projects can be found here.
Team
"Surface processes" department
Head | |||||
Name | Bld./Office | +49 351 260 | |||
---|---|---|---|---|---|
Dr. Katharina Müller | 801/P248 | 2439 | k.mueller![]() | ||
Employees | |||||
Name | Bld./Office | +49 351 260 | |||
Dr. Astrid Barkleit | 801/P207 | 3136 2512 2518 | a.barkleit![]() | ||
Aline Chlupka | 801/P203 | 3198 2518 2523 | a.chlupka![]() | ||
Dr. Norbert Jordan | 801/P218 | 2148 | n.jordan![]() | ||
Stephan Weiß | 801/P316 | 2758 2523 | s.weiss![]() | ||
Maud Emilie Zilbermann | m.zilbermann![]() | ||||
"TecRad" Wechselwirkung von Technetium mit Mikroorganismen, Metaboliten und an Mineral-Wasser-Grenzflächen - Radioökologische Betrachtungen | |||||
Name | Bld./Office | +49 351 260 | |||
Dr. Natalia Mayordomo Herranz | 801/P252 | 2076 | n.mayordomo-herranz![]() | ||
Caroline Börner | 801/P254 | 2251 | c.boerner![]() | ||
Arkadz Bureika | 801/P201 | 2434 | a.bureika![]() | ||
Irene Cardaio | 801/P254 | 2251 | i.cardaio![]() | ||
Vijay Kumar Saini | 801/P352 | 3328 | v.saini![]() | ||
Other employees | |||||
Name | Bld./Office | +49 351 260 | |||
Dr. Marcos Felipe Martinez Moreno | 801/P352 | 3154 | m.martinez-moreno![]() |
Alumni
Name | at HZDR |
---|---|
Heidrun Neubert | Lab assistant |
Sara E. Gilson | PostDoc |
Christa Müller | Lab assistant |
Quirina Isabella Roode-Gutzmer | Ph.D. student |
Isabelle Jessat | Ph.D. student, gratuated 2023 |
Maximilian Demnitz | Ph.D. student, graduated 2022 |
Diana Marcela Rodriguez Hernandez | Ph.D. student, graduated 2021 |
Henry Lösch | Ph.D. student, graduated 2021 |
Manuel Eibl | Ph.D. student, graduated 2020 |
Susanne Lehmann | Ph.D. student, graduated 2020 |