The Bundesanstalt für Materialforschung und -prüfung (BAM) is a senior scientific and technical federal institute with responsibility to the Federal Ministry for Economic Affairs and Climate Action. It tests, researches, and advises to protect people, the environment and material goods.
The Safety of Transport Containers division is engaged with research, testing and assessment of transport containers for radioactive materials. This includes mechanical and thermal safety verifications and the development of experimental and computational test methods for the analysis of transport containers.
As part of the experimental work, we perform a variety of load tests at our BAM Test Site for Technical Safety (BAM-TTS) close to Berlin. We offer good and close supervision of the work in a scientific environment.
Topic of the Thesis
At the Federal Institute for Materials Research and Testing (BAM), the department 3.3 "Safety of Transport Containers" deals, among other things, with the topic of heat input and heat dissipation in containers for radioactive waste. The transport processes that take place inside and on the free surface of the containers are diverse and very complex. Heat generation as a phenomenon is generally described by the heat conduction equation and corresponding DIRICHLET, NEUMANN and ROBIN boundary conditions on the free surface. The inner process in an isotropic structure is physically described by conduction and the outer boundary of the transport container is described by two different physical phenomena - thermal radiation and convection. While thermal radiation is clearly defined physically by the STEFAN-BOLTZMANN law, free convection is described empirically in the literature for a wide variety of constellations.
Transport containers must comply with a number of boundary conditions as part of their approval process, see IAEA regulations. The IAEA regulations specifies boundary conditions to which a transport container with radioactive waste may be exposed and must be able to withstand. Three scenarios are usually examined, routine, normal and accident conditions of transport. In the present task, an accident condition of transport from the IAEA regulations is to be investigated. In this scenario it is assumed that the transport container is exposed to a flame temperature of 800°C for 30 minutes.
Accident conditions of transport containers with radioactive waste are usually analysed in experimental and numerical investigations. Since experimental tests often require elaborate preparation and are very cost-intensive, numerical FEM simulations are usually designated as a preliminary investigation to determine the worst damaging case for the experiment. FEM simulations have the advantage that they can be performed quickly and at low cost compared to experiments. In addition, a large number of scenarios (various external boundary conditions, material variations, etc.) can be investigated, which can only be carried out in the experiment with great effort and many costs. Regardless of the advantages and disadvantages, the synergy of experiment and simulation is indispensable and must be congruence.
For in-depth investigations for the above-mentioned accident scenario, the department 3.3 has created a transport container and would like to study different parameters with the help of experiments and simulations.
Task of the Thesis
In this thesis, the transport container from the experiment is to be investigated with the aid of the FEM-Software Ansys®. For this purpose, a corresponding model is to be created with the aid of CAD plans. In addition, the sensors of the test setup must be analysed and, if necessary, taken into account in the model. With the help of a literature research, the corresponding external influences are to be analysed from the experiment and adopted with adequate boundary conditions. Corresponding weather data and imposed influences are available as raw data from the experiment and needs to be considered. Corresponding characteristic values of all components to be considered can be taken from data sheets or must be collected by literature research. Since the manufacturing process of all components of a transport container is also subject to certain material uncertainties, the range of material properties and their influence on the temperature distribution will be investigated. In addition to the various dependencies of material properties, boundary conditions and other influences, the comparison with the experiment is an essential part of the thesis. The measurement results are to be evaluated in a suitable manner and compared with the simulation results.
Agenda
- The thesis can be written in English or German
- Literature research for materials, boundary conditions, modelling, validation
- Creation of a suitable generic model and boundary conditions for validation with experimental test results
- Convergence studies
- Evaluation of the experimental data and comparison with the simulation results
Qualifications:
- Experience in the field of thermodynamics
- Essential: Application of the simulation software Ansys®
Contact:
Dr. Tobias Gleim
Safety of Transport Containers division
Phone: +49 30 8104-3168
Email: Tobias.Gleim@bam.de