Film boiling and vapor explosion phenomena

An initial period of film boiling has been identified as a key element in the chain of events leading to a large-scale vapor explosion. From theoretical considerations, the conditions required for molten UO/sub 2/ particles (assumed spherical) to undergo-film boiling in water and sodium coolants are assessed. In addition, it is shown that experimental vapor explosion results that have been interpreted in terms of spontaneous nucleation theory may likewise be viewed in terms of film boiling destabilization. 32 refs