[en] A best-estimate postaccident analysis of the TMI-2 reactor system was made with the TRAC code. Based on these results, an assessment of the extent of damage to the TMI-2 reactor core was made; and several alternative event sequences and their consequences were investigated. Results indicate that although no significant fuel melting occurred, large regions of cladding were severely oxidized and clad melting and relocation took place in the central region of the core, above the midplane elevation. In the alternative event sequences, the timeliness of the initiation of HPI flow in preventing large scale fuel melting is examined