The results of the bulk material examinations performed on samples from the Three Mile Island Unit 2 (TMI-2) reactor pressure vessel (RPV) are summarized and the materials chemistry that resulted in the observed behavior is reviewed. As part of the TMI-2 core examination program, core material samples from all regions within the RPV were examined, from lead screws in the top head to previously molten material relocated to the lower plenum of the RPV during the accident. These results indicate that >99% of the core materials were retained within the RPV; however, the constituents of the various core components were redistributed within the original core volume and RPV. The data suggest redistribution of the core materials based mostly on the thermodynamic properties of the metallic constituents and oxides.