Three Mile Island Unit 2 Core Geometry

The Three Mile Island Unit 2 core geometry at the end of the core damage phase of the accident on March 28, 1979, is described. The information was derived from in situ measurements, observations during defueling of the reactor vessel, and sample examinations. The combined information indicates that a consolidated region formed inside the core boundaries before molten material began to escape in large quantity and that the core materials were transported outside the core primarily by gravity flow of liquefied core material to the core bypass region, the lower core support assembly, and the reactor vessel lower head.