Research projects
| Funding: | Deutsche Forschungsgemeinschaft (DFG) |
| Grant No.: | HA 3088/25-1 |
| Partner: | Brandenburgische Technische Universität Cottbus-Senftenberg |
| Duration: | 2022 – 2023 |
| Contact: | Prof. Uwe Hampel () |
Aerosol particles play an essential role in the transmission of respiratory viruses such as SARS-CoV-2, which is why masks, ventilation and air purification methods are effective protective measures. Investigating the effectiveness of such measures requires flow dynamic studies, either with experimental or numerical methods, as the flow conditions largely influence their effectiveness. In the project, a sensor is being developed for this purpose, which will be used in connection with exposure experiments with helium-filled micro soap bubbles.
Sub-Project:
Development of measurement technology for recording flow parameters in large-scale nuclear safety research test facilities
In the joint research project, new robust imaging techniques are being developed that will make it possible in the future to instrument large-scale test facilities in reactor safety research in such a way that thermal-hydraulic data can be recorded in CFD quality. In the sub-project, a new sensor technology for the spatially resolved measurement of gas content and flow velocity according to the principle of thermal anemometry will be developed.
Sub-Project:
Development of measurement methods for concrete porosity and moisture as well as software modules for the visualisation of findings data
In the joint project, new measurement and analysis methods as well as concepts for the electronic documentation of data from decommissioning projects are being developed. In the sub-project, an in-situ analysis technique for the determination of moisture and porosity in the wall of a borehole will be developed by means of a tubular probe. Furthermore, a software for the visualisation of findings data will be developed.
| Funding: | Deutsche Forschungsgemeinschaft (DFG) |
| Grant No.: | HA 3088/18-1 |
| Duration: | 2020 – 2024 |
| Contact: | Sara Marchini (M. Eng.) () |
In the project, the methodology of measuring axial dispersion coefficients using volumetric flow modulation, which has already been demonstrated in a feasibility study, will be further developed and comprehensively applied for bubble columns.
Sub-Project:
Radiation based imaging
Until the commissioning of a final waste repository for highly-radioactive waste in Germany, intermediate storage of spent fuel in dry storage casks is required. Thereby, prolonged intermediate storage times of more than 50 years have to be taken into consideration. For such long durations it is not yet possible to fully exclude the potential loss of integrity of fuel elements due to structural changes. The research project is dedicated to the development and testing of methods for non-invasive long-term monitoring of the container inventory based on the detection of cosmic muons and measurement of the gamma and neutron radiation field.
The research project targets the development and implementation of methods and algorithms for the tracking of structures in process spaces such as particles or gas bubbles, e.g. in bubble columns. For this purpose, we develop algorithms for pattern recognition, which can extract certain flow structures in real-time using massively parallel computing approaches.
Sub-Project:
Laboratory experiments to model the crystallization and deposition behavior as well as heat transfer properties of zinc borates
The main goal of the project was to provide data and correlations on the solubility and crystallization behavior as well as on parameter dependent deposition rates of zinc borates on hot zircaloy surfaces and in heated coolant as mobile particles. Based on the results, the project partner GRS developed a tool to simulate thermal-hydraulic consequences of zinc borate depositions in the reactor core during a loss of cooling accident by extensions of the ATHLET code. The purpose of these developments was to evaluate different loss-of-coolant accident (LOCA) scenarios in PWR power plants.
Sub-Project:
Characterization of fluid dynamics in sandwich packings
| Funding: | Deutsche Forschungsgemeinschaft (DFG) |
| Grant No.: | HA 3088/10-3 |
| Partners: | Paderborn University, Chair of Fluid Process Engineering |
| Duration: | 2016 - 2025 |
| Contact: | Iman Shabanilemraski () |
Because of the energy demand of thermal separation processes improvements in process control and devices are of major interest. In this project, investigations on the innovative concept of column internals called sandwich packings are carried out. Sandwich packings consist of two layers of structured packings with different specific surface areas. The combination of these layers causes flow configurations with excellent gas-liquid interactions which improve mass transfer and hence column separation efficiency. Pressure measurements as well as ultrafast X-ray tomography are applied to investigate the fluid dynamics in sandwich packings in a wide range of operation parameters.
The project targets the development of reliable thermal-hydraulic models for the primary circuit of a pressurized water reactor in accident conditions. The focus is on the modelling of the steam generator. There, we find complex thermal hydraulic states, such as two-phase flow, reverse flows, counter-current flow limitation and potentially inert gases. For the numerical calculation, we use the simulation code Modelica and validate the models by comparison with experimental data. Some phenomena of interest will be assessed in a more detailed manner with CFD simulations.
Sub-project:
Experimental studies on the hydrodynamics, mass-transfer and reaction in bubble swarms with ultrafast X-ray tomography and local probes
| Funding: | Deutsche Forschungsgemeinschaft (DFG) – SPP1740 Reaktive Blasenströmungen |
| Grant No.: | HA 3088/8-1 |
| Partners: | TU Hamburg Harburg, Universität der Bundeswehr München, LMU München, TU Berlin, TU Darmstadt, Uni Stuttgart, Uni Bremen, JLU Gießen, TU Dortmund, MLU Halle-Wittenberg, Karlsruher Institut für Technologie |
| Duration: | 2014 – 2021 |
| Contact: |
Due to their simple construction and good heat and mass-transfer characteristics, bubble column reactors are a favored reactor type in chemical industries. However, the understanding of the coupled heat and mass-transfer processes is still very limited. The priority program 1740 “Reactive Bubbly Flows” deals with the experimental and numerical investigation of transport processes with coupled reaction in bubbly flows. The focus of the presented sub-project lies in the experimental investigation of the interrelation of bubble swarm dynamics, mass transfer and chemical reaction.
Sub-Project:
Thermographic and radiographic measurement methods
Until the commissioning of a final waste repository for highly-radioactive waste in Germany, intermediate storage of spent fuel in dry storage casks is required. Thereby, prolonged intermediate storage times of more than 50 years have to be taken into consideration. For such long durations it is not yet possible to fully exclude the potential loss of integrity of fuel elements due to structural changes. Hence, the research project is dedicated to the question if and how a non-invasive condition monitoring is possible by thermography, radiography and acoustic spectroscopy methods.
In case of a loss-of-coolant accident (LOCA), the corrosion of hot-dip galvanized steel containment internals may lead to the formation of aqueous solutions of zinc borates, which have the potential to precipitate at local hot spots like the cladding tubes of PWR fuel rods. So it cannot be ruled out that in the later phase of a LOCA (sump recirculation), such formed particle layers will cause problems regarding the residual heat removal from reactor core internals.
In this project, laboratory experiments are planned to simulate the possible zinc corrosion process and subsequent formation of zinc borate layers at hot spots in the reactor core.
Precise estimations of the boundary conditions for such LOCA scenarios by different project partners via model calculations help to find realistic physical and chemical parameters for those assumed accidents. Laboratory experiments use this data like temperature profiles, flow conditions or changes in the coolant chemistry to simulate the relevant processes of zinc corrosion and zinc borate precipitation during the sump recirculation.
The obtained results support the planning and realization of more realistic LOCA simulation experiments in a semi-technical scale by the project partner HSZG.
They also contribute to generate more reliable evaluations, if formed zinc borate layers in hot spots of the reactor core could lead to relevant problems in the late stage of a LOCA.
Sub-project:
Spatially resolved temperature and gas-phase velocity measurements for the analysis of flow conditions in a spent fuel pool during dry-out
The objective of the joint project SINABEL is the experimental investigation and an improved modeling of the heat transfer in a spent fuel pool during the dry-out phase. Key parameters are the temperature and the velocity of the gas-phase in the subchannels of the fuel element mock-up. The applicability of conventional measurement techniques is limited due to the restricted mechanical and optical accessibility to the subchannels. Within the project the thermal anemometry grid sensor for the investigation of the gas-phase temperature and velocity was developed.
| Funding: | AREVA |
| Duration: | 2015 - 2018 |
| Contact: | Sebastian Unger () |
Passive cooling systems are one of the key future technologies to enhance the safety of nuclear power plants. Such passive thermal hydraulic systems should transfer high amounts of heat from the reactor or the spent fuel pool to the ambient air, e.g. in case of a breakdown of power supply (station black out). This works only through the energy provided by the heat source, e.g. by creating and maintaining a natural convection. For the cooling of spent fuel pools the overall temperature differences are small and since the heat resistance is high compared to active systems, special care is needed to design such a system. The project deals with unconventional methods and designs to reduce the heat resistance of the condenser, which is cooled outside via natural air convection.
Sub-Project:
Instrumentation of the Test Facility, Development and Validation of Nuclear Evaluation Tools
| Funding: | Bundesministerium für Wirtschaft und Energie (BMWi) |
| Partners: | AREVA, RWTH Aachen, GRS, TH Deggendorf |
| Duration: | 2015 - 2018 |
| Contact: | Prof. Uwe Hampel () |
Due to the development of new safety concepts (here especially the use of passive safety systems) the operational and accidental behavior of new nuclear power plants will substantially differ from the current operating reactors. Passive systems have a great potential for accident management, to prevent core damage or to mitigate the consequences of core damage in severe accident sequences. The operation of passive systems is directly based on physical laws related to gravitation, (natural) convection, condensation or evaporation.
| Funding: | Bundesministerium für Wirtschaft und Energie (BMWi) |
| Programme: | Kompetenzerhalt in der Kerntechnik |
| Duration: | 2014 - 2017 |
| Contact: | Dipl.-Ing. Martin Neumann () |
The development and validation of CFD models for the simulation of three-dimensional flow phenomena, in particular turbulence modeling and two-phase flows, requires further research. The experimental validation with appropriate investigations is therefore needed for both system codes as well as CFD tools. This project is dedicated to this field of research.
Sub-projekt:
Calculation of Gamma Radiation Fields of the Reactor Core
| Funding: | Bundesministerium für Wirtschaft und Energie (BMWi) |
| Partners: |
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| Duration: | 2014 - 2018 |
| Contact: |
The project has the objective to identify transient effects which lead to the occurrence of the boiling crisis and to model such effects adequately within the frame of computational fluid dynamics simulations. By the help of dedicated experiments empirical assumptions shall be replaced by physical models.
Sub-project:
Calculation of Gamma Radiation Fields of the Reactor Core
In the case of a severe accident in a nuclear power plant the operational reactor instrumentation is very likely to fail. The research project is dedicated to the question, if and if so, which additional instrumentation could be foreseen to detect and monitor changes inside the reactor pressure vessel, in particular of the coolant filling level and on-setting core melt. Therefore a noninvasive method for detecting core states by the help of the analysis of the external gamma radiation field was developed and assessed.
Work package: X-ray Imaging for Intensified Multiphase Reactors
The chemical industry is one of the largest industrial energy consumers. Therefore, there is a high interest to intensify the chemical processes in order to save energy and resources. Within the frame of the Energy Alliance funded by the Helmholtz-Association, packings as reactor internals were investigated, which are able to significantly increase the mass transfer in the chemical reactor and with that its efficiency. Ultrafast X-ray tomography provided the hydrodynamic characterization of these packings.