[en] It is possible to encounter molten fuel pools in the course of events during a hypothetical Liquid Metal Fast Breeder Reactor accident. In such cases it may be important to estimate correctly the rate of melting of the pool walls and bottom, which are governed by the rate of heat transfer to those materials. The heat transfer characteristics of internally heated two-phase pools are thus of interest. Heat transfer measurements were made in the horizontal and downward directions both in transient and in steady state. The transient study involved slow cooling or heating of the pool liquid, while in the steady state case heat was provided by electrical immersion heaters. A permanent gas was injected from a distributed hypodermic tubing network with two hole sizes. Void fraction measurements were also made by static pressure probes. The data is reported as plots of Nusselts number versus Reynolds number and surface evaporation and entrainment effects for a boiling pool were estimated for comparison purposes