The ContainmentTechnology Test Facility (CTTF) and the Surtsey Test Facility at Sandia National Laboratoriesaxe used to perform scaled experiments for the Nuclear Regulatory Commission that simulate high pressure melt ejection (HPME) accidents in a nuclear power plant (NPP). These experimentsare designed to investigate the effects of direct containment heating (DCH) phenomenaon the containmentload. High-temperature, chemicallyreactive melt is ejected by high-pressuresteaminto a scale model of a reactorcavity. Debris is entrainedby the steam blowdown intoa containmentmodel where specific phenomena, such as the effect of subcompartmentstructures,prototypic atmospheres, and hydrogen generation and combustion, can be studied. Four Integral Effects Tests (IETs) have been performed with scale models of the Surry NPP to investigate DCH phenomena. These experiments were conducted for five primary purposes: (1) to measure the pressureload on the containmentcontainingprototypic subcompartmentstructures, (2) to investigate the amount of hydrogen combustion due to a HPME into a prototypic steam/air/H2 atmosphere, (3) to investigate the effect of an annular gap between the reactor pressurevessel (RPV) and the reactor support skirt, (4) to measureposttest debris distribution in a containmentmodel, and (5) to provide data from prototypic,large-scale experimentsfor validation of DCH models. The 1/6thsc_e Integral Effects Tests (IET-9, IET-10, and IET-11) were conductedin CT1T, which is a 1/6" scale model of the Surryreactorcontainmentbuilding (RCB). The 1/I(Yh scale IET test (IET-12) was performed in the Surtseyvessel, which had been configured as a 1/10_ scale SurryRCB. Scale models were constructedin each of the facilities of the Surry structures, including the RPV, reactor support skirt, control rod drive missile shield, biological shield wall, cavity, instrumenttunnel, residual heatremoval platform and heatexchangers, seal table room and seal table, operating deck, and crane wall. The RPV model had a hemisphericalbottom head with a hole that simulated the ablatedhole in the RPV that would be formed by ejection of an instrumentguide tube in a severe NPP accident. A charge of thermite was used in the RPV model to simulatemolten corium that would accumulateon the bottom head of an actual RPV. This chemically reactive melt was ejected by high-pressuresteam from the melt generator into the scaled reactor catty. Debris was then entrained through the incore instrumenttunnel into the subcompartment structuresand then into the upper dome of the containment models, where the fragmented molten debris particles encountered prototypic air/steam/hydrogen atmospheres. This reportdescribes these experimentsand gives the results.