Developments of models for boiling and dryout in LWR debris beds

The coolability of solid self-heated fuel debris in water is a topic of interest in probabilistic safety analyses of light water reactors. Many experiments have been undertaken, using simulant heating methods and simulant materials for the particulate, to investigate the dependence of the dryout heat flux. In most cases the observed dryout power is consistent with a semitheoretical model developed by Lipinski, and another by Turland and Moore. This paper considers further developments and applications of these models. In particular, it discusses the transient approach to dryout for deep beds, the effect of a gradation in particulate size, and the inclusion of a driedout layer in a one-dimensional model