Experimental study of stratification behavior of the steady two-liquid corium pool.

• The prototypic materials have been conducted to investigate the stratification behavior of the steady molten pool. • The synergistic effect of M Fe /M ∑ and Cn on redistribution of the corium components. • The reason for layer inversion of the molten pool occurred is studied. The prototypic materials have been used to investigate the stratification behavior of the steady molten pool at 3100 K in the context of the IVR condition. Induction heating in a cold crucible was used for melting of the 2 kg-scale UO 2 -ZrO 2 -Zr-Fe. A post-test examination of SEM, EDS, and XRD has been performed to investigate the metallic and oxide layers for all ingots. The effects of M Fe /M ∑ (initial iron to corium ratio) and Cn (initial degree of zirconium oxidation) on the configuration of the molten pool were studied. The results indicate that structure of the molten pools consists of the top light metallic layer and oxide layer. Nevertheless, a layer inversion may occur when the density of the metallic layer increased. The synergistic effect of M Fe /M ∑ and Cn on redistribution of the corium components leads to a significant increase of the uranium concentration for the metallic phase, which can explain why the layer inversion of the molten pool occurred. [ABSTRACT FROM AUTHOR]