In the field of severe accident, the description of corium progression events is mainly carried out by using integral calculation codes. However, these tools are usually based on bounding assumptions because of high complexity of phenomena. | Possible in-vessel corium progression way in the Unit 1 of Fukushima Dai-ichi nuclear power plant using a phenomenological analysis EPJ Nuclear Sci. Technol. 1 7 2015 Nuclear Sciences F. Payot and . Seiler published by EDP Sciences 2015 amp Technologies DOI epjn e2015-50001-5 Available online at http REGULAR ARTICLE Possible in-vessel corium progression way in the Unit 1 of Fukushima Dai-ichi nuclear power plant using a phenomenological analysis Frédéric Payot1 and Jean-Marie Seiler2 1 CEA Cadarache DTN SMTA LPMA 13108 Saint-Paul-lez-Durance cedex France 2 CEA Grenoble DTN STCP LTDA 17 rue des Martyrs 38054 Grenoble cedex 9 France Received 28 April 2015 Received in final form 7 July 2015 Accepted 15 September 2015 Published online 05 December 2015 Abstract. In the field of severe accident the description of corium progression events is mainly carried out by using integral calculation codes. However these tools are usually based on bounding assumptions because of high complexity of phenomena. The limitations associated with bounding situations . Seiler B. Tourniaire A phenomenological analysis of melt progression in the lower head of a pressurized water reactor Nucl. Eng. Des. 268 87 2014 . steady state situations and instantaneous whole core relocation in the lower head led CEA to develop an alternative approach in order to improve the phenomenological description of melt progression. The methodology used to describe the corium progression was designed to cover the accidental situations from the core meltdown to the molten core concrete interaction. This phenomenological approach is based on available data including learnings from TMI2 on physical models and knowledge about the corium behavior. It provides emerging trends and best estimated intermediate situations. As different phenomena are unknown but strongly coupled uncertainties at large scale for the reactor application must be taken into account. Furthermore the analysis is .
