Definition of light water in US English:

light water


  • 1Water containing the normal proportion (or less) of deuterium oxide, i.e., about 0.02 percent, especially to distinguish it from heavy water.

    • ‘The role of uranium metal in Iran's declared nuclear fuel cycle still needs to be fully understood, since neither its light water reactors nor its planned heavy water reactors require uranium metal for fuel.’
    • ‘However, eddying mixing motion can overturn this density profile, momentarily lifting heavy water above light water.’
    • ‘Because of their heavier weight, heavy water molecules evaporate less readily than light water molecules.’
    • ‘To date Kim Jong-il's rogue state has been kept in check by a 1994 treaty that provided for the construction of light water nuclear reactors and the granting of economic aid.’
    • ‘The Chernobyl reactor used graphite as moderator and boiling light water as coolant, while the Koodankulam reactor uses light water as moderator and coolant.’
    • ‘Why from a non-proliferation point of view, are light water reactors preferable to the graphite moderator reactors that the North Koreans have built?’
    • ‘During interglacial periods the ice caps melt and return the isotopically light water to the oceans, where it mixes rapidly.’
    • ‘The Israeli air strike on the Osirak light water nuclear reactor in Iraq in the early 1980s signaled to countries like Iran that they should not put everything in one place.’
  • 2Foam formed by water and a fluorocarbon surfactant, which floats on flammable liquids lighter than water and is used in firefighting.


light water

/laɪt ˈwɔdər/