The state-of-the art tools for analysing the complex processes of nuclear reactors are the multi-physics codes. The “traditional” approach for investigating transient phenomena was the application of reactor physics/kinetics, thermal-hydraulics and thermal-mechanics code separately. However, neglecting the coupling between the various phenomena may result in significant inaccuracies. The above mentioned multi-physics codes handle these problems in a different way: a single code can model all the relevant groups of phenomena. Most of the available codes, such as the commercial ANSYS system and the open-source GenFoam apply a single finite-volume discretization mesh for solving all of the groups of partial differential equations of reactor physics, thermal-hydraulics and thermal-mechanics.
The validation of such multi-physics codes is difficult and problematic in many cases. One of the reasons for the problems is that there is only a narrow group of reactor systems which can be applied for validation purposes. Reactors of too low power, such as critical assemblies cannot be used since there are no detectable thermal effects which are essential for the validation. On the other hand, in reactors of too high power it is not normally allowed to perform certain measurements. Quite luckily, the Training Reactor of BME (TR) has many good properties which make this device an almost ideal tool for Multiphysics code validation. Since the international nuclear community is strongly lacking measurements, the results would be of great value.
The PhD student would perform the following tasks:
- Study the literature on reactor transient analysis
- Study the features of different Multiphysics software
- Study the ability of available Multiphysics software to model different transients of the Training Reactor
- Investigate the option of using a self-developed Multiphysics code based on the open-source solver OpenFoam for modelling the TR
- Set up models and perform calculations for various transients of the TR
- Compare partial results, such as static reactor physics modelling data with those obtained from reference codes (eg. MCNP)
- Design measuring tools and perform related safety analysis to perform new measurements, such as temperature field, in the reactor core of the TR
- Study the effect of technological uncertainties occurring in TR on the validation process
- Design measurements, such as thermal conductivity of the fuel, in order to decrease the effect of uncertainties
- Analyse the applicability of the validated code system for modelling more complex power reactor systems
There will be opportunities for the PhD student to participate in international collaboration, particularly with EPFL Lausanne.
Adequate knowledge of reactor physics and thermal hydraulics
Fundamental knowledge of nuclear measurement techniques
Affinity for using computational modelling tools, applying experimental methods
Good level of English