STUDY OF CAVITATION IN LIQUID SODIUM AND SIMULATION OF DYNAMIC CORE DEFORMATIONS

¹ *DES - Service d’études des réacteurs et de mathématiques appliquées (SERMA)
² DES - Service de thermohydraulique et de mécanique des fluides (STMF)
CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France

sofiane.houbar@cea.fr
antoine.gerschenfeld@cea.fr
cyril.patricot@cea.fr

Published online: 22 February 2021

Abstract

Due to the high confinement of the closed fuel assemblies in Sodium-cooled Fast Reactors (SFR), the liquid sodium filling the space between these assemblies may vaporize in case of an important mechanical excitation (cavitation process). That phenomenon would therefore induce a specific force feedback to the assemblies leading to a specific neutronic response of the core. Neutronic of SFR is indeed sensible to mechanical deformation. Hence the necessity to have a good prediction of the displacement of these mechanical structures in the framework of Fluid-Structure Interaction (FSI).

To study this kind of transient at a reactor scale, we propose in this paper a coupling procedure between the fluid and the structures. The fluid behaviour is investigated by Merkle’s three-equations model and simulated within a coarse mesh. The structures are modelled by a mass-spring system subjected to the fluid forces. In order to stabilize the numerical code coupling, a relaxation process is added and some results of this computational work are presented.