Heavy Water

Definition: Heavy Water

Heavy Water

Noun

1. Water containing a substantial proportion of deuterium atoms, used in nuclear reactors.

Specialty Definitions: Heavy Water

Domain	Definitions
Energy	Water containing significantly more than the natural proportions (one in 6,500) of heavy hydrogen (deuterium, D) atoms to ordinary hydrogen atoms. Heavy water is used as a moderator in some reactors because it slows down neutrons effectively and also has a low probability of absorption of neutrons. (D20). (references)
	A type of hydrogen atom that may be used as fuel for fusionpower plants. Also called DEUTERIUM, it is found in abundance in the seas. (references)
Mining	Deuterium oxide, D2 O , in which D is the symbol for deuterium (heavy hydrogen or hydrogen 2). Water in which ordinary hydrogen atoms have been replaced by deuterium atoms. Natural water contains 1 heavy-water molecule per 6,500 ordinary water molecules. Deuterium oxide has a low neutron absorption cross section; hence, it is used as amoderator in some nuclear reactors. (references)
Nuclear Energy & Physics	Water in which the hydrogen is replaced by'heavy hydrogen'or deuterium. Because of the very low neutron absorption cross-section of deuterium, heavy water makes an excellent moderator and is used in, e. g. , CANDU and SGHWR nuclear reactors. It is present in ordinary water at one part in about 5000. Source: European Union. (references)
Source: compiled by the editor from various references; see credits.

Top

Specialty Definition: Heavy water

(From Wikipedia, the free Encyclopedia)

Heavy water is dideuterium oxide, or D₂O or ²H₂O. 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.

Production

Semiheavy water, HDO, is more common than heavy water. Heavy water occurs naturally in regular water as a lot less than 115 parts per million, that is a lot less than about one part in 7,000. It may be separated from regular water by distillation or by electrolysis. In each case the slight difference in molecular weight produces a slight difference in the speed at which the reaction proceeds. To produce pure heavy water a large cascade of stills or electrolysis chambers is required, and large amounts of electric power are consumed.

India is the world's second largest producer of heavy water through its Heavy Water Board [1].

Use

Neutron Moderator

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 otherwise criticality is impossible. 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 sufficiently powerful heavy water reactor can use it to turn uranium into bomb-usable plutonium without requiring enrichment facilities. Heavy water reactors have been used for this purpose by India, Israel, Pakistan and North Korea. North Korea also possesses graphite-moderated reactors, as used by the USA, UK, USSR and France for their bomb programs (in fact it was stated in British Parliament that one of these had been built to the declassified blueprints for Calder Hall). A major part of the negotiations involving North Korean nuclear reactors have been to attempt to shut down all of these reactors.

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).

Neutrino Detector

The Sudbury Neutrino Observatory (SNO) in Sudbury, Ontario uses 1000 tonnes of heavy water on loan from Atomic Energy of Canada Limited. The neutrino detector is 6800 feet underground in an old mine to shield it from cosmic rays. SNO detects the Cherenkov radiation as neutrinos pass through the heavy water.

Toxicity

Heavy water is mildly toxic. Experiments with mice showed that the main effect of the slightly different reaction rate is to inhibit mitosis, causing progressive damage of tissues that need rapid regeneration. After several days of ingesting only heavy water, the body fluids contain about 50% heavy water, and at this point symptoms begin owing to the decrease in cell division rates of rapidly dividing tissues, such as hair roots and stomach linings. Aggressive cancers might also go into remission, but the effect is not predicted to be great enough to make this a useful therapy.

Poisoning is doubtful except in unusual industrial and scientific situations. It depends on the patient taking only heavy water. An intake of, say, 25% heavy water in ordinary water would produce no symptoms. So it is not so much that heavy water is damaging to health, but rather that light water is necessary for it.

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

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Heavy water."

Top

Synonym: Heavy Water

Synonym: deuterium oxide (n). (additional references)

Top

Crosswords: Heavy Water

English words defined with "heavy water": atomic number 17, atomic number 35 ♦ Br, bromine ♦ Carbonic acid, chlorine, cl, Cornish engine ♦ Hushing ♦ Land spout ♦ Quick match ♦ Water buck, Water-logged. (references)

Specialty definitions using "heavy water": air table, animal shelter supervisor ♦ barge-crane operator, box sluice ♦ cable-tool drilling, cement slurry, Chance sand-flotation process, coal-tar oil, Combined Sewers, Convertol process ♦ D20, deck-engine operator, dense medium, dense-media separation, derrick-barge operator, DERRICK-BOAT OPERATOR, DOG BATHER, down flooding, dust-laying oil ♦ end-bump table ♦ floating-derrick operator, frame dam ♦ general utility worker, Gully erosion ♦ Heavy water moderated reactor, heavy-machinery assembler, heavy-water-moderated reactor, Holme mud sampler, hydraulic conveying, HYDROELECTRIC-PLANT MAINTAINER ♦ influx of water ♦ Jeffrey diaphragm jig, jig bed ♦ Karl Fischer reagent ♦ lead oxide, Light water ♦ MACHINERY ERECTOR, MARINE-CARGO SURVEYOR ♦ Oxford Stroke ♦ PAINT SPRAYER, SANDBLASTER, PROOF TECHNICIAN, prospecting dish ♦ RUBBER-GOODS TESTER ♦ safety-equipment tester, SANITARY LANDFILL OPERATOR, scow-derrick operator, sluicebox, solid waste facility operator, steam-generating heavy-water reactor, Stripa process, SUPERVISOR, KENNEL, Sutton, Steele, and Steele dry table ♦ tandem hydroseparator, Tar sand, turtle deck, turtleback ♦ Vooys process ♦ wash rod, water inrush, whaleback. (references)

Top

Commercial Usage: Heavy Water

Domain	Title
Books	Assurances of long-term supply of technology, fuel and heavy water and services in the interest of national needs consistent with non-proliferation (reference) Fuel and heavy water availability (reference) Heavy Water and Other Stories (reference) Heavy Water and the Wartime Race for Nuclear Energy (reference) Heavy water handbook : evaluation of presently available thermophysical properties of heavy water (Db2sO) liquid and vapour (reference) (more book examples)

Music	Heavy Water Music (reference) (more classical music examples; more popular music examples)
Source: compiled by the editor from various references; see credits.

Top

Photo Album: Heavy Water

Thumbnail	Description & Credit
	Egyptian women carrying their heavy water jars from the Nile, Cairo, Egypt.Credit: Library of Congress.
Source: compiled by the editor from various references; see credits.

Top

Non-Fiction Usage: Heavy Water

Subject	Topic	Quote
Business		Romania has its own uranium deposits as well as enriched uranium and heavy water producing facilities. (references)
Trade	China	Products subject to strict licensing controls include dual-use chemicals, chemical precursors, heavy water, and exports of fish, fresh vegetables and fruits to Hong Kong and Macao. (references)
Source: compiled by the editor from ICON Group International, Inc.; see credits.

Top

Frequency of Internet Keywords: Heavy Water

The following statistics estimate the number of searches per day across the major English-language search engines as identified by various trade publications. Hyperlinks lead to commercial use of the expression at Amazon.com.

Expression	Frequency per Day
heavy water	96
deuterium heavy water	2
Source: compiled by the editor from various references; see credits.

Top

Modern Translations: Heavy Water

Language		Translations for "heavy water"; alternative meanings/domain in parentheses.
Albanian		ujë i rëndë. (various references)

Danish		tungt vand (deuterium oxide), deuteriumoxid (deuterium oxide). (various references)

Dutch		zwaar water (deuterium oxide), deuteriumoxyde (deuterium oxide), deuteriumoxide (deuterium oxide), D2O (deuterium oxide). (various references)

French		protoxyde de deutérium, oxyde de deutérium, eau lourde. (various references)

German		schweres Wasser (D20, deuterium oxide). (various references)

Greek		βαρύ ύδωρ (D20, deuterium oxide), βαρύ νερό (deuterium oxide), πρωτοξείδιο του δευτερίου (deuterium oxide), διοξείδιο του δευτερίου (D20, deuterium oxide). (various references)

Hungarian		nehézvíz (deuterium oxide). (various references)

Italian		protossido di deuterio (deuterium oxide), Ossido di deuterio (D20, deuterium oxide), acqua pesante (D20, deuterium oxide). (various references)

Japanese Kanji		重水 . (various references)

Japanese Katakana		じゅうすい. (various references)

Pig Latin		eavyhay aterway

Portuguese		D2O (D20, deuterium oxide), óxido de deutério (D20, deuterium oxide), água pesada (D20, deuterium oxide). (various references)

Russian		тяжелая вода. (various references)

Serbo-Croatian		teška voda. (various references)

Spanish		protóxido de deuterio (deuterium oxide), agua pesada (D20, deuterium oxide), óxido de deuterio (D20, deuterium oxide). (various references)
Source: compiled by the editor from various translation references.

Top

Anagrams: Heavy Water

Scrabble® Enable2K-Verified Anagrams
	Words within the letters "a-a-e-e-h-r-t-v-w-y"
	-2 letters: aweather, hereaway, whatever, wheatear.
	-3 letters: hetaera, teaware, weather, whereat, wreathe, wreathy.
	-4 letters: aerate, aether, aweary, earthy, eatery, hearty, heater, heaver, hereat, reheat, thawer, thrave, watery, wavery, weaver, wether, wharve, wherve, wrathy, wreath.
	-5 letters: areae, arete, arhat, avert, aware, earth, eater, ether, evert, every, hater, haver, hayer, heart, heave, heavy, hewer, rathe, rayah, reata, reave, revet, rewet, rhyta, tawer, teary, there, thewy, thraw, three, threw, trave, twyer, veery, warty, water, waver, wavey, weary, weave, wheat, where, wrath.
Source: compiled by the editor from various references; see credits. SCRABBLE® is a registered trademark. All intellectual property rights in and to the game are owned in the U.S.A and Canada by Hasbro Inc., and throughout the rest of the world by J.W. Spear & Sons Limited of Maidenhead, Berkshire, England, a subsidiary of Mattel Inc. Mattel and Spear are not affiliated with Hasbro.