China Syndrome

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For the 1979 movie see The China Syndrome.

China syndrome refers to a possible extreme result of a nuclear meltdown in which molten reactor core products breach the barriers below them and flow downwards out of containment.

The phrase arose from the humorously exaggerated and incorrect notion that molten reactor material would burrow from the United States through the Earth and emerge in China, as popularized by the 1979 film, The China Syndrome. This has usually been meant jokingly (including in the film): to bore through the Earth to China, the molten fissile material would have to go both with gravity and then against gravity and a line drawn from the United States through the center of the Earth would emerge in the south Indian Ocean and not China.

In reality, a melting reactor could sink at most tens of meters. If radioactive slag reached the water table beneath the reactor building, the resulting steam could throw radioactive material into the air, producing fallout. Despite several meltdowns in both civilian and military reactors, such an extreme meltdown has never taken place. Almost all current reactor designs do not allow such a meltdown to occur, either by preventing any meltdown (such as in a TRIGA reactor) or by dispersing any molten material so that it cools and soldifies.