The Nuclear Engineering Laboratory LKT

Prof. George Yadigaroglu

LKT provides instruction and conducts research in Nuclear Engineering and related areas; main research activities have traditionally been centred on the applications of fundamental knowledge on multiphase flows and heat transfer with phase change to nuclear and conventional power plant technology and safety. The work includes experimentation, modelling, analysis and numerical simulations. During the 80’s, LKT research was addressing thermal-hydraulic issues related to the Safety of Light Water Reactors (LWR). In the 90’s, the main research moved towards the safety of innovative passive LWRs in relation to the very large scale experiments (PANDA and LINX) built at PSI to simulate the dynamics of passive containment systems. The most recent LKT research centres on the extension and application of Computational Fluid Dynamics (CFD) techniques to multidimensional, multiphase flows: CMFD.

Teaching in LKT includes, beyond the Nuclear Engineering courses (Reactor Physics and Thermal Hydraulics, Reactor Safety), more general courses on Power Plant Engineering (Kraftwerkstechnik), as well as Thermal-Sciences courses of general interest to Mechanical Engineering students.

The laboratory has close ties to the Thermal-Hydraulics Laboratory of the Nuclear Energy and Safety Division of the Paul Scherrer Institute (PSI).

Computational Multi-Fluid Dynamics (CMFD) and multi-scale approach. An illustration for a thermal-hydraulics problem of importance to reactor safety. Certain phenomena in nuclear systems can be best addressed at a multiplicity of time/space scales. In the example of condensation of a steam/air mixture from a downward facing vent illustrated here (of importance to a passive Boiling Water Reactor), the shape of the large bubble produced at the vent is obtained from Volume of Fluid (VOF) computations, while Direct Numerical Simulation (DNS) of turbulence provides heat and mass transfer laws at the interface. The cross-scale interactions (fee-forward and feedback between scales) require merging of the solutions.