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出典:『Wikipedia』 (2010/12/05 04:48 UTC 版)

英語による解説

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A steam explosion (also called a littoral explosion, or fuel-coolant interaction, FCI) is a violent boiling or flashing of water into steam, occurring when water is either superheated, rapidly heated by fine hot debris produced within it, or the interaction of molten metals (e.g., Fuel-Coolant Interaction of molten nuclear-reactor fuel rods with water in a nuclear reactor core following a core-meltdown). Pressure vessels (e.g., Pressurized-Water (nuclear) Reactors) that operate at above atmospheric pressure can also provide the conditions for a rapid boiling event which can be characterized as a steam explosion. The water changes from a liquid to a gas with extreme speed, increasing dramatically in volume. A steam explosion sprays steam and boiling-hot water and the hot medium that heated it in all directions (if not otherwise confined, e.g. by the walls of a container), creating a danger of scalding and burning. Steam explosions are not normally chemical explosions, although a number of substances will react chemically with steam (for example, zirconium and superheated graphite react with steam and air respectively to give off hydrogen, which burns violently in air) so that chemical explosions and fires may follow. Some steam explosions appear to be special kinds of Boiling Liquid Expanding Vapor Explosion, and rely on release of stored superheat. But many large-scale events (e.g., 'Foundry Accidents') show evidence of an energy-release front propagating through the material (see description of FCI below), where the forces created fragment and mix the hot phase into the cold volatile one; the rapid heat transfer at the front sustains the propagation.