AbstractData on the heat transfer and the pressure drop in sodium under forced convection boiling are presented. It is shown that in annular-dispersed flow, a difference between wall and saturation temperatures is small, being within 1 to 5°C. It is also shown that in two-phase alkali-metal flow with heat input friction losses are smaller than in adiabatic flow. This is associated with a“push aside”effect on the main stream of the vapor flowing from the interface.The heat transfer and friction loss data indicate that the phase change takes place by evaporation from a liquid film surface, without vapor bubble generation at the wall. The experiments showed that, even in the presence of artificial cavities, the incipient super-heat is statistical in nature. The efficiency of the double-reentrant-angle-type cavities and of inert gas injection as a means of stabilizing forced convection boiling of the alkali metal was proven.