Numerical simulation of the emergency condenser of the SWR1000

The SWR1000 is a new innovative boiling water reader concept, which is deve loped by Siemens AG. This concept is characterized in particular by passive safety systems (e.g. Sour emergency condensers, four building condensers, eight passive pressure pulse transmitters, six gravity-driven core flooding lines). In the framework of BWR Physics and Thermohydraulic Complementary Action (BWR-CA) to the EU BWR R&D Cluster emergency condenser tests were pe rformed by Forschnugszentrum Julich at the NOKO test facility. In this pape r post test calculations with ATHLET are presented, which aim at the determ ination of the removable power of the emergency condenser and its operation mode. The ID thermal-hydraulic code ATHLET was extended by the module KONW AR for the calculation of the heat transfer coefficient during condensation in horizontal tubes. In addition, results of CFD-calculations using the co de CFX-4 are presented which investigate the natural convection during the heat rep process at the secondary side of the NOKO test facility.