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Revision as of 04:35, 16 January 2003 by Roadrunner (talk | contribs)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)] Heavy water is dideuterium oxide, or D2O. It is chemically the same as normal water, H2O, but the hydrogen atoms are of the heavy isotope deuterium, in which the nucleus contains a neutron in addition to the proton found in the nucleus of any hydrogen atom. Heavy water is generated from regular water by distilation.
Heavy water is used in certain types of nuclear reactors where it acts as a neutron moderator to slow down neutrons so that they can react with the uranium in the reactor. Light water also acts as a moderator but because light water absorbs neutrons, reactors using light water must use enriched uranium rather than natural uranium. The CANDU reactor uses this design.
Because heavy water reactors can use natural uranium, it is of concern in efforts to prevent nuclear proliferation. A nation with a heavy water reactor can use it to turn uranium into plutonium which can be reprocessed to form material for nuclear weapons. Heavy water reactors have been used for this purpose by India, Israel, and North Korea, and a major part of the negotiations involving North Korean nuclear reactors have been to attempt to shut down North Korean reactors using heavy water. Due to its usefulness in nuclear weapons programs, heavy water is subject to government control in several countries. (In Australia, the Nuclear Non-Proliferation (Safeguards) Act 1987).
India is the world's second largest producer of heavy water through its Heavy Water Board .
Heavy water is toxic, since it inhibits cell division, but only in very large quantities: approximately 50% of the water in one's body must be replaced with heavy water for poisoning to occur. The symptoms of deuterium poisoning are similar to those of radiation poisoning or chemotherapy.
Data
- boiling point: 101.42° C (214.56°F) at standard pressure.
- freezing point: 3.81° C (38.86° F).
- relative density: 1.1079 at standard temperature and pressure