ABSTRACT
The TMI-2 accident and core examination have provided unique and important information on LWR severe-accident behavior, particularly for the late stage of accidents that involve fuel melting and relocation. This accident was successfully terminated by reflooding the core even though the accident had progressed into substantial fuel melting. The phenomenology of the early stage of the TMI-2 accident for which few measurements are available is largely understood from the results of the PBF tests and other past research. The information on late-stage phenomenology that involves substantial fuel melting and relocation has nearly all come from the TMI-2 core examination. Phenomenological modeling has generally accounted for the TMI-2 accident behavior except for the absence of lower head failure under melt attack where relevant experimental data have not yet been obtained.
