RELOCATION OF MOLTEN MATERIAL TO THE TMI-2 LOWER HEAD

This article presents one possible scenario describing the relocation of debris to the lower head of the Three Mile Island Nuclear Station U nit 2 (TMI-2) reactor vessel and is based on available plant instrumen tation records and postaccident examination results. The scenario pres ented here is not the only potential debris relocation scenario, bur i t is consistent with information obtained from plant data, Vessel Inve stigation Project examinations, analysis efforts, and other TMI-2 prog rams. This scenario addresses debris relocation events chronologically and assesses factors that may have contributed to the end-state condi tion of the lower head, the damage to the structures in the lower part of the reactor vessel, and the debris on the lower head. Included is the initial movement of molten material from the core, through the rea ctor vessel core support assembly to the lower internals, and finally onto the lower head.