Investigations of natural convection in large pools during the heating up of the secondary side of an emergency condenser

Natural convection is a basic principle for a lot of industrial processes. As an example for the investigation of natural convection phenomena, the paper describes investigations of a passive heat removal system in advanced designs of nuclear power plants. The SWR-1000 concept of Siemens AG includes emergency condensers. In the Research Centre Jülich at the NOKO test facility experiments were performed, to investigate the heat transfer capability under different operation modes. In the last time experiments with detailed instrumentation of thermocouples on the secondary side were performed, to investigate the heating up phenomena in the pool. The paper describes simulations performed in the FZ-Rossendorf using the CFD-code CFX-4 of AEA-Technology and comparisons to the experiments.