Thermal Behavior of Molten Corium During the Three Mile Island Unit 2 Core Relocation Event

During the Three Mile Island Unit 2 accident, a pool of molten corium formed in the central region of the core and was contained by solidified crusts. Failure of the crust surrounding the molten material at 224 min resulted in a relocation of an estimated 29 tonnes of molten corium through peripheral fuel assemblies in the east side of the vessel, as well as through the core barrel assembly (CBA) at the periphery of the core. The results of analyses carried out to investigate the heatup and ablation interactions of molten corium with the CBA structures during the relocation event are presented.