Actinide thermodynamics department

Research

The department of “Thermodynamics of Actinides” is hosting a significant part of the analytical backbone of the institutes, e.g. mass spectrometry, atomic emission spectrometry, elemental analyses, powder diffraction, vibrational and nuclear magnetic resonance spectroscopy. This allows us to work on several steps in the thermodynamics value chain.

From a chemical point of view, the focus is set on heavy metal contaminants, namely long-lived radionuclides. The derivation of parameters describing hydrolysis, aqueous complexation, surface reactions or solubilities are combined with structural investigations to validate the species set forming reactions, enabling mechanistic models. Such parameters are fed into respective databases after verification. Gaps still remaining can be closed by applying different estimation methods, from mineral analogies to Linear Free Energy Relationships.

Combined with field data (mineralogical composition, porosity, pH, redox potential, ionic strength, temperature, or CO₂ partial pressure), geochemical speciation patterns and radionuclide retardation can then be computed for complex systems on different scales. To name just a few, we worked on cementitious barriers with organic additives, with real-world crystalline samples or with Chornobyl soils. There, also, geostatistics helps to map the heterogeneities observed, and sensitivity / uncertainty analysis not only increases confidence in computational results but supports also the identification of critical parameters and submodels.

Quite recently, these approaches were complemented by machine learning methods, this will eventually lead to digital twins for nuclear waste repositories. Eventually, this shall bridge the distance between atomistic investigations and the large-scale prognostics required e.g. in performance assessment covering distances of several km over up to one million years.

The actual major research topics of our department can be summarized as follows:

• Spectroscopic characterization of heavy metal species in aqueous solutions and at mineral surfaces.

• Development and parameterization of models describing surface complexation phenomena in complex systems (e.g. natural clays).

• (Radio)chemical analyses of contaminant elements as well as matrix compounds down to the ultratracer level.

• Set-up of thermodynamic data bases for prospective deep nuclear waste repositories.

Latest publication

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Team

Head
Name	Bld./Office	+49 351 260	Email
Prof. Dr. Vinzenz Brendler	801/P250	2430	v.brendler@hzdr.de
Employees
Name	Bld./Office	+49 351 260	Email
Dr. Frank Bok	801/P202	3551	f.bok@hzdr.de
Rodrigo Castro Biondo			r.castro-biondohzdr.de
Alexandra Duckstein	801/P153	2774	a.ducksteinhzdr.de
Dr. Stephan Hilpmann	801/P306	2860	s.hilpmannhzdr.de
Dr. Jerome Kretzschmar	801/P207	3136	j.kretzschmarhzdr.de
Dr. Elmar Plischke			e.plischkehzdr.de
Dr. Solveig Pospiech	801/P205	2128	s.pospiechhzdr.de
Dr. Anke Richter	801/P202	2426	anke.richterhzdr.de
Raj Sarkar	801/P103	2720	r.sarkarhzdr.de
Dr. Katja Schmeide	801/P208	2436 2513	k.schmeidehzdr.de
Salim Shams Aldin Azzam	801/P103	2720	s.shamshzdr.de
Susanne Zechel	801/P352	3328	s.zechelhzdr.de

Analytics

Head
Name	Bld./Office	+49 351 260	Email
Dr. Harald Foerstendorf	801/P251	3664 2504	h.foerstendorfhzdr.de
Employees
Name	Bld./Office	+49 351 260	Email
Sabrina Beutner	801/P203	2429 2528	s.beutnerhzdr.de
Tim Gitzel	801/P316	2025 2517	t.gitzelhzdr.de
Dominik Goldbach	801/P203	3198	d.goldbachhzdr.de
Karsten Heim	801/P201	2434 2504	k.heimhzdr.de
Sylvia Schöne	850/102.1	2526 3198	s.schoene@hzdr.de, s.guertlerhzdr.de