CFD primary loop analysis of the ELSY reactor with focus on decay heat removal

Commercial CFD tools - such as ANSYS CFX - in connection with the present computational power - mainly by parallel computations - provide the possibility to obtain detailed 3D simulations even for cases with a complex geometry. In this work a detailed model of the ELSY (European Lead cooled System) reactor concept is presented which takes all parts of the reactor vessel into account. As it is not possible to represent all relevant parts in detail, loss coefficients and source terms for momentum and energy - as for the pumps, steam generators and the core- are used in combination with porous media approaches which are obtained from standalone high detailed CFD simulations or from system tools. The intention of this work is to investigate decay heat removal scenarios as consequence of a reactor shutdown. The investigation of the several cooling systems has shown that in case of decay heat removal by IC (Isolation Condenser) systems lead freezing in the lower part of the SG's (Steam Generators) may occur. (orig.)