Current Projects

TRANS-LARA

Project TRANS-LARA (Transport and transfer behavior of long-lived radionuclides along the causal chain Groundwater - soil surface - plant, taking into account long-term climatic changes)

 

Persons in charge:
Thorsten Schäfer, Dirk Merten, Arno Märten, Thomas Lange, Marcus Böhm, Daniel Jara

Description:
For long-term safety detection of potential repositories, the current radioecologic models in accident scenarios proceed from a radionuclide entry into the biosphere via the water path. In addition to the path over rainfall and irrigation, the entry is particularly interesting in the soil via fluctuating groundwater level changes. The aim is to provide a deeper understanding of the complex mechanisms of radionuclide transport from the groundwater zone to the plants, including climatic changes, which should lead to improved risk assessments for the exposure of the population over long periods. A significant step forward is the elucidation of the host mechanisms of radionuclides in crop plants at the molecular level, a concept which allows for far-reaching explanatory power beyond previous transfer factors.

This results in the following tasks: experimental investigations on the migration and accumulation of radionuclides in soil near the surface and their transfer into plants via the root path; modeling both the transport of radionuclides from contaminated groundwaters into the upper soil layers (via the unsaturated zone), as well as sorption and speciation of radionuclides in different soils, including climatic changes and different management scenarios; clarification of the largely incomplete transport of radionuclides in crops over the root path on the molecular level.

Funding: The TRANSLARA joint project is financially supported by the Federal Ministry of Education and Research (BMBF) under the funding code 02NUK051A-E.

Funding period: 9/2017 – 8/2020

Extended lysimeter setup for the transport experiments on different reference soilsöden.
(Photos © Arno Märten 2017)
Additional equipment with a VisiSens TD system (PreSens) for the spatially resolved time resolved measurement of pO2, pH and pCO2 in the lysimeters.
(Photo © PreSens 2017)

USER

Implementation of heavy metal landfarming for sustainable landscaping and for exploitation of renewable energies on radionuclide contaminated areas (translated from German)


Project leadership:
Dr. Dirk Merten, Prof. Dr. Georg Büchel

Funding period:
01.12.2014 bis 30.11.2018 

Summary:
The current project funded by the R&D program "Decommissioning and dismantling of nuclear facilities" focusses on radiation protection by establishing bioremediation methods for substrates contaminated by heavy metals and radionuclides. This goal is combined with the exploitation of bioenergy. Microbial methods are applied to improve phytoremediation using soil and microbial amendments (mycorrhiza, streptomyces).  In the USER-project field scale investigations are applied to areas of moderate heavy metal and radionuclides (HM/R) contaminated substrates at the testsites Gessenwiese and Kanigsberg, near Ronneburg, to investigate phytoremediation strategies. Here, the main focuses lie on designing sustainable landscapes by reducing the bioavailability of contaminants with carbonatic soil material (rendzina) and microbial amendments, as well as the production of renewable energy with metal tolerant plants within a short-rotation-coppice (SRC, landfarming). In this connection, production of woody biomass with fast growing plants in SRC provides a positive effect on biodiversity and erosion protection. Furthermore, quantification of biomass productivity and HM/R-transfer within the soil-plant-water system by using soil and microbial amendments (mycorrhiza, streptomyces) are scopes of this project, and should lead to reduction in leaching of HM/R and soil erosion as well. Therefore, soil hydrological measurement stations and a lysimeter station are installed to get information about distribution, changes, transfer and output of HM/R in the water phase. Additionally, biomass productivity, plant vitality and erosion processes should be monitored with a multispectral camera and a high resolution camera system (accuracy 5 mm) installed on a microdrone (project TerraSensE, FKZ 13007-715).

 

 

Funding Code:
15S9194

 
 

CONCERT

Project CONCERT (Rheology of reactive, multiscale, multiphase construction materials)

Persons in charge:
Thorsten Schäfer, Frank Heberling, Johannes Lützenkirchen (both KIT-INE) & Teba Gil Diaz

Description:
The collaborative project "Component additive approach to predict cement paste rheology considering mineral and particle heterogeneity on different scales; CONCERT" within the SPP 2005 is a joint venture between the Bauhaus University Weimar (Prof. Professor Dr.-Ing. Horst-Michael Ludwig), the Karlsruhe Institute of Technology (KIT; Dr.-Ing. Michael Haist) and the Friedrich Schiller University Jena (Prof. Dr. habil. Thorsten Schäfer). Close cooperation within CONCERT and the multi- and interdisciplinary SPP 2005 consortium with researchers from Physics, Chemistry, Materials Science, Civil Engineering and Mineralogy offers unique prerequisites for transferring the findings from basic research into applications.

The Surface complexation models (SCoMs) for the different mineral phases in cementitious systems and combination thereof will be established based on adsorption studies (including superplasticizers; SPs), zeta potential and AFM force-distance measurements. The rheological behavior of corresponding colloidal suspensions will be studied and serve to calibrate the link between SCoMs / DLVO theory and rheological modelling. Stability of organo-mineral phases subject to shear will be investigated using radiotracer labelling of SPs as well as sulfate carriers. Model description will include a component additive model, allowing to quantify the mechanical interaction behaviour as a function of particle composition, granulometry, composition of carrier liquid, temperature and progress of hydration (surface roughness). Within the CONCERT consortium it is planned to use this model as a basis for the probabilistic formulation of the Eigenstress-state to be used in a homogenized rheology model setup that describes the sum of all particle interactions.

Funding: 1/2018 – 12/2021

Funded by the German Research Foundation (DFG).

Figure 1: a) Normalized force versus separation curves upon approach of the silica colloid probe and clinker surface, b) corresponding curves upon retraction of the silica colloid probe from the surface, c) SEM micrograph of a cement particle modified AFM cantilever. The es-timated contact area is highlighted in red.

KOLLORADO-e2

KOLLORADO-e2 (Integrity of the bentonite barrier for the retention of radionuclides in crystalline host rock - experiments and modeling)

Persons in charge: Thorsten Schäfer (FSU) & Francesca Quinto, Madeleine Stoll, Franz Rinderknecht (all KIT-INE)

Description:
The knowledge on the colloid/nanoparticle problem, in particular on the prediction of the colloid/nanoparticle source term, colloid/nanoparticle stability and nanoparticle/colloid-mineral-surface interaction, including the surface roughness, has made great progress in recent years. In addition to the description of colloid/nanoparticle stability by means of electrostatic approaches, quantitative data on the erosion of the bentonite barrier have been generated in laboratory tests. All data on the colloid/nanoparticle -supported radionuclide transport indicate a strong dependence of the colloid/nanoparticle mobility on the fracture geometry / surface roughness, the complete dissociation of tetravalent actinides from the clay colloid surface being still an open question. The main objective of the project is to improve the mechanistic understanding of the erosion of the compacted bentonite and the radionuclide-colloid interactions under near-natural conditions by means of in-situ experiments and the relevance of the nanoparticle/colloid-borne radionuclide transport with regard to the long-term safety of a repository in crystalline rock formations. In addition, generic statements on colloid relevance and the mobility of radionuclides are developed.

Funding: 3/2016 – 2/2019

The BEACON project is funded under the Euratom research and training programme 2014-2018 Grant Agreement No 745 942.

Figure 1: Mobility of the actinides americium (Am-243) and plutonium (Pu-242) associated with clay nanoparticles, together with the nonreactive fluorescence tracer Amino-G over a transport distance of approx. 6m. Breakthrough curves were calculated with COFRAME. (© KOLLORADO-e2 Consortium).

BEACON

Project BEACON (Bentonite Mechanical Evolution)


Persons in charge:
Thorsten Schäfer & Franz Rinderknecht (KIT-INE)

Description:
The overall objective of the project is to develop and test the tools necessary for the assessment of the mechanical evolution of an installed bentonite barrier and the resulting performance of the barrier. This will be achieved by cooperation between design and engineering, science and performance assessment. The evolution from an installed engineered system to a fully functioning barrier will be assessed. This will require a more detailed understanding of material properties, of the fundamental processes that lead to homogenization via water saturation, of the role of scale effects and improved capabilities for numerical modelling.  The goal is to verify the performance of current designs for buffers, backfills, seals and plugs. For some repository designs mainly in crystalline host rock, the results can also be used for the assessment of consequences of mass loss from a bentonite barrier in long-term perspective.

Funding: 6/2017 – 5/2021

The BEACON project is funded under the Euratom research and training programme 2014-2018 Grant Agreement No 745 942.

Figure 1: Schematic diagram of the CFM LIT (Long-Term In Situ) Test running over 1100 days with different swelling pressures in the upper (1400-1850 kPa) and lower regions (850-950 kPa) of the packer and spontaneous pressure release (homogenization?) of ca. 300 kPa after approx. 500 days in the upper packer area (Photos © CFM Consortium 2017).

FluviMag: Fluviatile Transport of magnetominerals

Person in charge:
Michael Pirrung

Description:
The physical property magnetic susceptiblity is measured in host rocks and sediments of creeks and rivers in order to provide a better understanding of the dynamics of material transport, and – preferably in combination with geochemical data - to detect anthropogenic contaminations e.g. from historical mining sites. 

Contributions in German or French language can be downloaded here.

Grainsize-dependency of magnetic susceptiblity and Fe content in recent sediments of the Thuringian Saale at Jena, with host rock and transport length effects; after data from a project report of D. Beyer, 2008, and from the B.Sc. thesis of S. Möller, 2009.

Scientific Project Saale Clarke: Geogenic background values in the Thuringian Saale catchment

Person in charge:
Michael Pirrung

Description:
For an evaluation of geochemical anomalies regional geogenic background values are essential. The latter are compiled from an extensive literature study and new geochemical data. They can be compared with element contents of recent fluviatile sediments in a catchment in order to highlight anthropogenic influences. Host rock chemistry also indicates environmental conditions during sediment deposition.

Selected element ratios (2700 analyses) from host rocks in the catchment of river Thuringian Saale characterize the depositional milieu within the central and eastern Thuringian Syncline and in surrounding mountain areas.

Anthropogenic and geogenic sources of dust in urban areas in central Germany

Persons in charge:
Neele van Laaten, Dirk Merten, Michael Pirrung

Description:
Dust is collected via spider webs, moss bags and passive samplers in central Germany (focus on the city of Jena), taking samples in city centers as well as suburban areas and some more remote areas. The samples are characterized geochemically and statistical methods are applied to find out to which extent specific sources contribute to the chemical characteristics of deposited dust.

Funding:

Project of International Max Planck Research School for Global biogeochemical Cycles (IMPRS-gBGC), joint funding from Friedrich Schiller University and Max Planck Institute for Biogeochemistry

[Translate to Englisch:] Auf der Leiter mit Moss Bag
[Translate to Englisch:] Einsammeln von Spinnweben an der Brücke am Arbeitsamt