[en] When the (US) Reactor Safety Study on the assessment of accident risks in light water reactors (LWR) was performed, it was noted that much of the basic data required to realistically evaluate the probability of occurrence of containment breaching steam explosions did not exist. Consequently, the U. S. Nuclear Regulatory Commission (Fuel Behavior Research Branch, Division of Reactor Safety Research) initiated a program at Sandia Laboratories to provide relevant data on the interaction of molten LWR core materials with water. Two different sub-tasks were established to achieve this goal. The first was the performance of laboratory-scale experiments to investigate the ability to trigger steam explosions for realistic LWR core melt simulants under a wide range of initial conditions. The second was the performance of field-scale experiments to investigate the efficiency of converting the thermal energy of the melt into mechanical work in much larger steam explosions. Both types of experiments and their conclusions are reviewed