Many translated example sentences containing "heavy water" – German-English dictionary and search engine for German translations. processed or used in the aforementioned nuclear installations, in which the heavy water produced in the aforementioned plant is used, shall not be diverted to. Many translated example sentences containing "heavy water plant" – German-English dictionary and search engine for German translations.
Heavy Water Testen Sie Ihren Wortschatz mit unseren lustigen Bild-Quiz.
Schweres Wasser ist chemisch gesehen Wasser mit der Summenformel D₂O. Von „normalem“ Wasser H₂O, das in diesem Zusammenhang auch als „leichtes Wasser“ bezeichnet wird, unterscheidet es sich dadurch, dass die „normalen“. In: Heavy Water Board. Department of Atomic Energy, Government of India, August , abgerufen am August (englisch). ↑ Plants at a Glance. Der packende Dokumentarfilm "Heavy Water" taucht tief ein in die Kultur des Surfens und folgt dem charismatischen Big-Wave-Surfer Nathan Fletcher durch die. Many translated example sentences containing "heavy water" – German-English dictionary and search engine for German translations. Many translated example sentences containing "heavy water plant" – German-English dictionary and search engine for German translations. This article is cited by 40 publications. Gabor Jancso and W. Alexander Van Hook. Condensed phase isotope effects. Chemical Reviews , 74 (6), Übersetzung im Kontext von „heavy water“ in Englisch-Deutsch von Reverso Context: We want pounds of heavy water by Easter next year.
This article is cited by 40 publications. Gabor Jancso and W. Alexander Van Hook. Condensed phase isotope effects. Chemical Reviews , 74 (6), Many translated example sentences containing "heavy water plant" – German-English dictionary and search engine for German translations. processed or used in the aforementioned nuclear installations, in which the heavy water produced in the aforementioned plant is used, shall not be diverted to. Norsk Hydro, which already used electrolytic cells in the early s to make fertilizer, seized the chance to make heavy water Chernobyl an industrial scale. Although many people associate heavy water primarily with its use in nuclear reactors, pure heavy water is Cube Imdb radioactive. The US scientist and Nobel laureate Harold Urey discovered the isotope deuterium in and was later able to concentrate it in water. Burak Yigit Allied air raid prompted the Nazi government to move all available heavy water to Germany for safekeeping. Binary compounds Heavy Water hydrogen. Here's how it works. The Bruce Heavy Water Plant BHWP in Ontario was the world's largest heavy water production plant with Cineparc Ravensburg capacity of tonnes per year at its peak tonnes per year per full plant, two fully operational plants at its peak.
Give Feedback. Let us know if you have suggestions to improve this article requires login. External Websites. The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree See Article History.
Learn More in these related Britannica articles:. Since water and heavy water also can function as coolants, they perform a dual purpose in thermal reactors.
See below Coolants and moderators. A reactor of this kind consists of a tank, or calandria vessel, containing a cold heavy water moderator at atmospheric pressure.
Heavy water is not radioactive. Nevertheless, the various differences in deuterium-containing water especially affecting the biological properties are larger than in any other commonly occurring isotope-substituted compound because deuterium is unique among heavy stable isotopes in being twice as heavy as the lightest isotope.
This difference increases the strength of water's hydrogen-oxygen bonds, and this in turn is enough to cause differences that are important to some biochemical reactions.
The human body naturally contains deuterium equivalent to about five grams of heavy water, which is harmless. Heavy water was first produced in , a few months after the discovery of deuterium.
Since then, heavy water has been an essential component in some types of reactors, both those that generate power and those designed to produce isotopes for nuclear weapons.
These heavy water reactors have the advantage of being able to run on natural uranium without using graphite moderators that pose radiological  and dust explosion  hazards in the decommissioning phase.
Most modern reactors use enriched uranium with ordinary water as the moderator. Semiheavy water , HDO, exists whenever there is water with light hydrogen protium, 1 H and deuterium D or 2 H in the mix.
This is because hydrogen atoms hydrogen-1 and deuterium are rapidly exchanged between water molecules. In normal water, about 1 molecule in 3, is HDO one hydrogen in 6, is in the form of D , and heavy water molecules D 2 O only occur in a proportion of about 1 molecule in 41 million i.
Thus semiheavy water molecules are far more common than "pure" homoisotopic heavy water molecules. Water enriched in the heavier oxygen isotopes 17 O and 18 O is also commercially available, e.
It is "heavy water" as it is denser than normal water H 2 18 O is approximately as dense as D 2 O , H 2 17 O is about halfway between H 2 O and D 2 O —but is rarely called heavy water, since it does not contain the deuterium that gives D 2 O its unusual nuclear and biological properties.
It is more expensive than D 2 O due to the more difficult separation of 17 O and 18 O. Tritiated water contains tritium 3 H in place of protium 1 H or deuterium 2 H , and therefore it is radioactive.
The physical properties of water and heavy water differ in several respects. For heavy water Kw D 2 O The electrode correction for alkaline conditions is 0.
Heavy water is If the water is ice-cold the higher melting temperature of heavy ice can also be observed: it melts at 3.
An early experiment reported not the "slightest difference" in taste between ordinary and heavy water.
No physical properties are listed for "pure" semi-heavy water, because it is unstable as a bulk liquid.
In the liquid state, a few water molecules are always in an ionised state , which means the hydrogen atoms can exchange among different oxygen atoms.
However, if it were made in the gas phase and directly deposited into a solid, semi heavy water in the form of ice could be stable.
This is due to collisions between water vapour molecules being almost completely negligible in the gas phase at standard temperatures, and once crystallized, collisions between the molecules cease altogether due to the rigid lattice structure of solid ice.
The US scientist and Nobel laureate Harold Urey discovered the isotope deuterium in and was later able to concentrate it in water.
Different isotopes of chemical elements have slightly different chemical behaviors, but for most elements the differences are far too small to have a biological effect.
In the case of hydrogen, larger differences in chemical properties among protium light hydrogen , deuterium, and tritium occur, because chemical bond energy depends on the reduced mass of the nucleus—electron system; this is altered in heavy-hydrogen compounds hydrogen-deuterium oxide is the most common species more than for heavy-isotope substitution involving other chemical elements.
The isotope effects are especially relevant in biological systems, which are very sensitive to even the smaller changes, due to isotopically-influenced properties of water when it acts as a solvent.
Heavy water affects the period of circadian oscillations , consistently increasing the length of each cycle. The effect has been demonstrated in unicellular organisms, green plants, isopods, insects, birds, mice, and hamsters.
The mechanism is unknown. To perform their tasks, enzymes rely on their finely-tuned networks of hydrogen bonds , both in the active center with their substrates, and outside the active center, to stabilize their tertiary structures.
As a hydrogen bond with deuterium is slightly stronger  than one involving ordinary hydrogen, in a highly deuterated environment, some normal reactions in cells are disrupted.
Particularly hard-hit by heavy water are the delicate assemblies of mitotic spindle formations necessary for cell division in eukaryotes.
Plants stop growing and seeds do not germinate when given only heavy water, because heavy water stops eukaryotic cell division.
In it was demonstrated that an increase in the percentage content of deuterium in water reduces plant growth.
It is more toxic to malignant cells than normal cells but the concentrations needed are too high for regular use. Despite the problems of plants and animals in living with too much deuterium, prokaryotic organisms such as bacteria, which do not have the mitotic problems induced by deuterium, may be grown and propagated in fully deuterated conditions, resulting in replacement of all hydrogen atoms in the bacterial proteins and DNA with the deuterium isotope.
In higher organisms, full replacement with heavy isotopes can be accomplished with other non-radioactive heavy isotopes such as carbon, nitrogen, and oxygen , but this cannot be done for deuterium.
This is a consequence of the ratio of nuclear masses between the isotopes of hydrogen, which is much greater than for any other element.
Deuterium oxide is used to enhance boron neutron capture therapy , but this effect does not rely on the biological or chemical effects of deuterium, but instead on deuterium's ability to moderate slow neutrons without capturing them.
Poisoning would require that the victim ingest large amounts of heavy water without significant normal water intake for many days to produce any noticeable toxic effects.
Oral doses of heavy water in the range of several grams, as well as heavy oxygen 18 O, are routinely used in human metabolic experiments.
See doubly labeled water testing. A loss of blood pressure may partially explain the reported incidence of dizziness upon ingestion of heavy water.
However, it is more likely that this symptom can be attributed to altered vestibular function. Although many people associate heavy water primarily with its use in nuclear reactors, pure heavy water is not radioactive.
Commercial-grade heavy water is slightly radioactive due to the presence of minute traces of natural tritium, but the same is true of ordinary water.
Heavy water that has been used as a coolant in nuclear power plants contains substantially more tritium as a result of neutron bombardment of the deuterium in the heavy water tritium is a health risk when ingested in large quantities.
In , a disgruntled employee at the Point Lepreau Nuclear Generating Station in Canada obtained a sample estimated as about a "half cup" of heavy water from the primary heat transport loop of the nuclear reactor , and loaded it into a cafeteria drink dispenser.
Eight employees drank some of the contaminated water. The incident was discovered when employees began leaving bioassay urine samples with elevated tritium levels.
The quantity of heavy water involved was far below levels that could induce heavy water toxicity, but several employees received elevated radiation doses from tritium and neutron-activated chemicals in the water.
Some news services were not careful to distinguish these points, and some of the public were left with the impression that heavy water is normally radioactive and more severely toxic than it actually is.
On Earth , deuterated water, HDO, occurs naturally in normal water at a proportion of about 1 molecule in 3, This means that 1 in 6, hydrogen atoms is deuterium, which is 1 part in 3, by weight hydrogen weight.
The HDO may be separated from normal water by distillation or electrolysis and also by various chemical exchange processes, all of which exploit a kinetic isotope effect.
With the partial enrichment also occurring in natural bodies of water under particular evaporation conditions. In theory, deuterium for heavy water could be created in a nuclear reactor, but separation from ordinary water is the cheapest bulk production process.
The difference in mass between the two hydrogen isotopes translates into a difference in the zero-point energy and thus into a slight difference in the speed of the reaction.
Once HDO becomes a significant fraction of the water, heavy water becomes more prevalent as water molecules trade hydrogen atoms very frequently.
Production of pure heavy water by distillation or electrolysis requires a large cascade of stills or electrolysis chambers and consumes large amounts of power, so the chemical methods are generally preferred.
The most cost-effective process for producing heavy water is the dual temperature exchange sulfide process known as the Girdler sulfide process developed in parallel by Karl-Hermann Geib and Jerome S.
Spevack in An alternative process,  patented by Graham M. Keyser, uses lasers to selectively dissociate deuterated hydrofluorocarbons to form deuterium fluoride , which can then be separated by physical means.
Although the energy consumption for this process is much less than for the Girdler sulfide process, this method is currently uneconomical due to the expense of procuring the necessary hydrofluorocarbons.
As noted, modern commercial heavy water is almost universally referred to, and sold as, deuterium oxide. It is also a major exporter to Canada, Germany, the US and other countries.
The heavy water production facility located in Arroyito is the world's largest heavy water production facility. Argentina produces short tons tonnes of heavy water per year [ timeframe?
In October , Soviet physicists Yakov Borisovich Zel'dovich and Yulii Borisovich Khariton concluded that heavy water and carbon were the only feasible moderators for a natural uranium reactor, and in August , along with Georgy Flyorov , submitted a plan to the Russian Academy of Sciences calculating that 15 tons of heavy water were needed for a reactor.
With the Soviet Union having no uranium mines at the time, young Academy workers were sent to Leningrad photographic shops to buy uranium nitrate, but the entire heavy water project was halted in when German forces invaded during Operation Barbarossa.
In late , the Soviet purchasing commission in the U. The Chicago Pile-3 experimental reactor used heavy water as a moderator and went critical in The three domestic production plants were shut down in after producing around 20 metric tons 20, litres of product.
In , the United States began using heavy water in plutonium production reactors at the Savannah River Site. The first of the five heavy water reactors came online in , and the last was placed in cold shutdown in The SRS reactors were heavy water reactors so that they could produce both plutonium and tritium for the US nuclear weapons program.
The U. India is one of the world's largest producers of heavy water through its Heavy Water Board and also exports to countries like Republic of Korea and the US.
Development of heavy water process in India happened in three phases: The first phase late s to mids was a period of technology development, the second phase was of deployment of technology and process stabilisation mids to early s and third phase saw consolidation and a shift towards improvement in production and energy conservation.
In the s, it was suspected by the United States and Soviet Union that Austrian chemist Fritz Johann Hansgirg built a pilot plant for the Empire of Japan in Japanese ruled northern Korea to produce heavy water by using a new process he had invented.
In , Norsk Hydro built the first commercial heavy water plant at Vemork , Tinn , with a capacity of 12 tonnes per year.
In late , a planned raid called Operation Freshman by British airborne troops failed, both gliders crashing.
The raiders were killed in the crash or subsequently executed by the Germans. On the night of 27 February Operation Gunnerside succeeded.
Norwegian commandos and local resistance managed to demolish small, but key parts of the electrolytic cells, dumping the accumulated heavy water down the factory drains.
On 16 November , the Allied air forces dropped more than bombs on the site. The Allied air raid prompted the Nazi government to move all available heavy water to Germany for safekeeping.
A few of the barrels were only half full, and therefore could float, and may have been salvaged and transported to Germany.
The Germans would have needed a total of about 5 tons of heavy water to get a nuclear reactor running. The manifest clearly indicated that there was only half a ton of heavy water being transported to Germany.
Hydro was carrying far too little heavy water for one reactor, let alone the 10 or more tons needed to make enough plutonium for a nuclear weapon.
Is it safe? Heavy water has the same chemical formula as any other water—H 2 O—with the exception that one or both of the hydrogen atoms are the deuterium isotope of hydrogen rather than the regular protium isotope which is why heavy water is also known as deuterated water or D 2 O.
While the nucleus of a protium atom consists of a solitary proton, the nucleus of deuterium atom contains both a proton and a neutron.
This makes deuterium about twice as heavy as protium, however, since it's not radioactive , heavy water is not radioactive either. So, if you drank heavy water, you wouldn't need to worry about radiation poisoning.
Just because heavy water isn't radioactive doesn't mean it's completely safe to drink. While it's unlikely you could drink enough heavy water to really harm yourself, the hydrogen bonds formed by deuterium are stronger than those formed by protium.
One critical system affected by this change is mitosis, the cellular division used by the body to repair and multiply cells.
Too much heavy water in cells disrupts the ability of mitotic spindles to equally separate dividing cells. Other species tolerate heavy water better.
Since only about one water molecule in 20 million naturally contains deuterium—which adds up to about five grams of natural heavy water in your body and is harmless—you don't really need to worry about heavy water poisoning.
Even if you did drink some heavy water, you'd still be getting regular water from food.