An empirical model for natural convection heat transfer for fi lm-boiling conditionhas been developed for volumetrically heated particulate debris beds when fl oodedwith water at the top of the bed. The model has been derived from the quenchingdata generated in the POMECO facility located at KTH, Stockholm. A dryout model isalso developed for countercurrent fl ooding limiting condition when the heatgenerating saturated debris bed is fl ooded with water from the top. The model is ingood agreement with the experimental data over a wide range of particle size andporosity as compared to the existing models. The implication of the models withrespect to quenching of porous debris bed formed during postulated severeaccident condition is discussed.