Nuclear reactor accidents in the United States ordered during the late 1960s raised new safety questions and created fears of a severe reactor accident that would send large quantities of radiation into the environment. In the early 1970s, a highly contentious debate over the performance of emergency core cooling systems in nuclear plants, designed to prevent a core meltdown that could lead to the "China syndrome", received coverage in the popular media and technical journals. In 1976, four nuclear engineers —three from GE and one from the Nuclear Regulatory Commission— resigned, stating that nuclear power was not as safe as their superiors were claiming. They testified to
Corium (nuclear reactor) ejected as a molten stream by the pressure inside the reactor vessel. The reactor vessel failure may be caused by heating of its vessel bottom by the corium melt, resulting first in creep failure and then in breach of the vessel. Cooling water from above the corium layer, in sufficient quantity, may obtain a thermal equilibrium below the metal creep temperature, without reactor vessel failure. If the vessel is sufficiently cooled, a crust between the melt and the reactor wall can form. The layer of molten steel at the top of the oxide may create a zone of increased heat