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
Nuclear reactor coolant successful. Nuclear reactor coolant A nuclear reactor coolant is a coolant in a nuclear reactor used to remove heat from the nuclear reactor core and transfer it to electrical generators and the environment. Frequently, a chain of two coolant loops are used because the primary coolant loop takes on short-term radioactivity from the reactor. Almost all currently operating nuclear power plants are light water reactors using ordinary water under high pressure as coolant and neutron moderator. About 1/3 are boiling water reactors where the primary coolant undergoes phase transition to steam inside the reactor. About 2/3 are pressurized water reactors