In this document, we present a simplified geometrical model (0D model) for the in-core corium propagation transient. A degraded core with a formed corium pool is used as an initial state. This state can be obtained from a simulation computed with an integral code. | A simplified geometrical model for transient corium propagation in core for LWR with heavy reflector EPJ Nuclear Sci. Technol. 3 20 2017 Nuclear Sciences L. Saas et al. published by EDP Sciences 2017 amp Technologies DOI epjn 2016007 Available online at http REGULAR ARTICLE A simplified geometrical model for transient corium propagation in core for LWR with heavy reflector Laurent Saas Romain Le Tellier and Sophie Bajard CEA DEN CAD DTN SMTA LPMA CEA Cadarache 13108 Saint-Paul-lez-Durance Cedex France Received 6 May 2015 Received in final form 16 December 2015 Accepted 28 January 2016 Abstract. In the context of the simulation of the Severe Accidents SA in Light Water Reactors LWR we are interested on the in-core corium pool propagation transient in order to evaluate the corium relocation in the vessel lower head. The goal is to characterize the corium and debris flows from the core to accurately evaluate the corium pool propagation transient in the lower head and so the associated risk of vessel failure. In the case of LWR with heavy reflector to evaluate the corium relocation into the lower head we have to study the risk associated with focusing effect and the possibility to stabilize laterally the corium in core with a flooded down-comer. It is necessary to characterize the core degradation and the stratification of the corium pool that is formed in core. We assume that the core degradation until the corium pool formation and the corium pool propagation could be modeled separately. In this document we present a simplified geometrical model 0D model for the in-core corium propagation transient. A degraded core with a formed corium pool is used as an initial state. This state can be obtained from a simulation computed with an integral code. This model does not use a grid for the core as integral codes do. Geometrical shapes and 0D models are associated with the corium pool and the other components of the degraded core debris heavy reflector core plate
