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2018
Conference Paper
Titel
Application of a coupled CFD/LP code approach for containment simulations of a konvoi type PWR plant
Abstract
The reliable simulation of all relevant phenomena occurring during design basis and severe accidents in the containment of a nuclear power plant (NPP) is an ongoing challenge for the development of computer codes in order to assess potential consequences of accidents also with regard to possible counter measures and to assess new design features of modern plant types. This proved to be important for the analyses of the Fukushima Daiichi accidents which highlighted the relevance of a correct and detailed simulation of possible temperature stratification inside large water pools e.g. in the torus shaped wetwell of the BWR. For a detailed simulation of flow conditions and thermal behavior inside water pools in NPP containments a specialized Containment Pool Simulation Tool (CoPool) - a fast running CFD tool - has been developed at ITWM. The work was done in close cooperation with GRS with the intention to extend its Lumped-Parameter (LP) type Containment Code System (COCOS YS). The motivation for coupling the two codes comes from the fact that COCOSYS works with average values in the water pools, and in this way the thermal gradients in zone parts occupied by liquid are not accounted for. Based on a postulated accident in a PWR plant of a German KONVOI type, results of coupled COCOSYS - CoPool calculations will be presented and compared with a stand-alone COCOSYS calculation. Especially for new NPP plants with larger water reservoirs inside the containment and/or using passive systems these type of code coupling is of high interest.