Burnout on the external surface of a VVER reactor vessel

For solving the problem of external cooling of the vessel of a VVER (PWR or BWR) reactor when a severe accident with a core melt takes place, an experimental investigation was conducted of the nucleate boiling crisis (burnout) on a model of the bottom of the vessel of a VVER-640 reactor. The hydrodynamic model for burnout and the generalized data obtained from the new experiment and previous ones were used as the basis for deriving a dependence for calculating critical heat fluxes in boiling on a curvilinear surface, including the external surface of the bottom of the reactor vessel that account for the surface orientation and the parameters of the coolant.