China syndrome (nuclear meltdown)

For the 1979 film, see The China Syndrome. For The King of Queens episode, see China Syndrome (The King of Queens).

The China Syndrome is a term that describes one possible result of a severe nuclear meltdown in which molten reactor core components penetrate their containment vessel and building. The term is misleading, since molten material from such an event could not melt through the crust of the Earth and reach China, nor could such an event melt through the bottom of most reactor containment structures.

History and usage

Nuclear power plants ordered during the late 1960s raised safety questions and created fears that a severe reactor accident could release large quantities of radioactive material into the environment. In the early 1970s, a controversy arose regarding the ability of emergency cooling systems to prevent a core meltdown, which might lead to the so-called China Syndrome. This issue was discussed in the popular media and technical journals.

In 1971, nuclear physicist Ralph Lapp used the term China syndrome to describe a possible burn-through, following a loss of coolant accident of the reactor containment structures and the subsequent escape of radioactive material into the environment. His statements were based on the report of a task force of nuclear physicists headed by W. K. Ergen, published in 1967. The dangers of such a hypothetical accident were popularized by the 1979 film, The China Syndrome.

The name itself comes from the idea that, to many Americans, "the other side of the world" is China.

Possible effects of a catastrophic meltdown

The "China Syndrome" refers to a possible result of the catastrophic meltdown of a nuclear reactor. Also called a loss of coolant accident, the scenario begins when something causes the coolant level in a reactor vessel to drop, uncovering part—or all—of the fuel rod assemblies. Even if the nuclear chain reaction has been stopped through use of control rods or other devices, the fuel continues to produce significant residual heat for some time due to further decay of fission products. If not properly cooled, the fuel assemblies may soften and melt, falling to the bottom of the reactor vessel. There, without neutron-absorbing control rods to prevent it, nuclear fission could resume but, in the absence of a neutron moderator, might not. Although many feel the radioactive slag would stop at or before the subterranean aquifer, such a series of events could release large quantities of radioactive material into the atmosphere, potentially causing damage to the local environment's plant and animal life.

There was no China Syndrome at Three Mile Island

The nuclear incident at Three Mile Island did not involve molten "corium" escaping the containment. The heating power of the nuclear fuel was only sufficient to melt the fuel itself and penetrated only a short distance into the containing steel shell. Calculation on that situation reveals that the melted fuel could not have penetrated the containment.