During the Three Mile Island accident , a slow partial meltdown of the reactor core occurred . About of material melted and relocated in about 2 minutes , approximately 224 minutes after the reactor scram . A pool of corium formed at the bottom of the reactor vessel , but the reactor vessel was not breached . The layer of solidified corium ranged in thickness from 5 to 45 cm
Three Mile Island accident
Three Mile Island accident
Corium (nuclear reactor)