MODELLING REFLOOD HEAT TRANSFER

In the event of a large break loss-of-coolant accident in a PWR the normal coolant would be lost. Cooling would be restored by reflooding the dry overheated reactor core from below. A model of heat transfer in this dry region is presented. It includes a film boiling and a dispersed flow region and explicitly represents the effect of spacer grids. In parallel channel mode it can calculate the effect of partial flow blockage. Predictions of the model are compared with experimental data and show good agreement in both blocked and unblocked configurations.