IKE University of Stuttgart

Institute of Nuclear Technology and Energy Systems

Department of Energy Conversion and Heat Transfer Dr.-Ing. R. Kulenovic, Dr.-Ing. R. Mertz

Task formulation of the Student Research Project for xxx. cand. mach. Manita Cannell Cassiana, Matr.-Nr.: xxxxxx, Address xxxxxx, in the frame of the main subject “Nuclear Energy Technology”, Prof. Dr.-Ing. E. Laurien.

“Experimental and Numerical Investigations of Debris Beds”

Motivation and Background: During a severe nuclear reactor accident with loss of coolant, the reactor core can melt and form a particle bed (debris) in the lower plenum of the reactor pressure vessel (RPV). Within the reactor safety research, the removal of decay heat from a debris bed (formed from corium and residual water) is of great importance. In order to investigate experimentally the long term coolability of debris beds numerical models are developed at IKE in the framework of reactor safety research. These models have to be validated by means of experimental data. In this context this student research project should contribute to model validation by providing some specific experiments.

Aim of Study: Task 1: Determination of porosity and effective particle diameter of a particulate debris bed In order to investigate the potential of coolability of a debris bed, it is important to know the porosity of the bed and the effective particle diameter. These bed characteristics depend on the size distribution of particles from fragmentation but also on the settling process and may differ from a bed obtained by well mixing a certain size distribution of particles. Therefore, experiments will be carried out in which debris beds are formed in settling process (free falling particles in the water pool). Then, the porosity of this debris bed is to be determined and an effective particle diameter characterizing the bed is to be determined by