Heavy water producing

The relative amount of heavy water produced by each primary concentration process up to 1975 was reported [M7] to have been... 

The minimum consumption of steam per mole of heavy water produced is secured when an infinite number of plates is used, so that the outgoing steam depleted in deuterium may be in equilibrium with incoming feed. 

Costs for tower volume and power. The contribution of tower volume and availability loss to the cost of heavy water produced by the distillation of water in an ideal cascade may be evaluated when values are assigned to... 

Acquiring a suitable moderator looked more difficult. The German scientists favored heavy water, but Germany had no extraction plant of its own. Harteck calculated at the beginning of the year that a coal-fired installation would require 100,000 tons of coal for each ton of heavy water produced, an impossibility in wartime. The only source of heavy water in quantity in the world was an electrochemical plant built into a sheer 1,500-foot granite bluff beside a powerful waterfall at Vemork, near Rjukan, ninety miles west of Oslo in southern Norway. Norsk Hydro-Elektrisk Kvaelstofaktieselskab produced the rare liquid as a byproduct of hydrogen electrolysis for synthetic ammonia production. 

Despite its intrinsic limitations and difficulties, the G-S process was commercialized in the United States and subsequently on a larger scale in Canada and elsewhere. It had provided the preponderance of the 20,000 tons of heavy water produced worldwide to 2007. Production in Canada peaked aroimd 1980 at around 1200 tonne/a from four plants. Since then, G-S production has been phased-out in Canada because ample stockpiles exist and more ACR designs require less heavy water. G-S production does continue in Romania and India. 

The rapid fission of a mass of or another heavy nucleus is the principle of the atomic bomb, the energy liberated being the destructive power. For useful energy the reaction has to be moderated this is done in a reactor where moderators such as water, heavy water, graphite, beryllium, etc., reduce the number of neutrons and slow those present to the most useful energies. The heat produced in a reactor is removed by normal heat-exchange methods. The neutrons in a reactor may be used for the formation of new isotopes, e.g. the transuranic elements, further fissile materials ( °Pu from or of the... 

In the spring of 1989, it was announced that electrochemists at the University of Utah had produced a sustained nuclear fusion reaction at room temperature, using simple equipment available in any high school laboratory. The process, referred to as cold fusion, consists of loading deuterium into pieces of palladium metal by electrolysis of heavy water, E)20, thereby developing a sufficiently large density of deuterium nuclei in the metal lattice to cause fusion between these nuclei to occur. These results have proven extremely difficult to confirm (20,21). Neutrons usually have not been detected in cold fusion experiments, so that the D-D fusion reaction familiar to nuclear physicists does not seem to be the explanation for the experimental results, which typically involve the release of heat and sometimes gamma rays. 

Tritium is produced in heavy-water-moderated reactors and sometimes must be separated isotopicaHy from hydrogen and deuterium for disposal. Ultimately, the tritium could be used as fuel in thermonuclear reactors (see Fusionenergy). Nuclear fusion reactions that involve tritium occur at the lowest known temperatures for such reactions. One possible reaction using deuterium produces neutrons that can be used to react with a lithium blanket to breed more tritium. 

The homogeneous reactor experiment-2 (HRE-2) was tested as a power-breeder in the late 1950s. The core contained highly enriched uranyl sulfate in heavy water and the reflector contained a slurry of thorium oxide [1314-20-1J, Th02, in D2O. The reactor thus produced fissile uranium-233 by absorption of neutrons in thorium-232 [7440-29-1J, the essentially stable single isotope of thorium. Local deposits of uranium caused reactivity excursions and intense sources of heat that melted holes in the container (18), and the project was terrninated. 

In the heavy-water plants constmcted at Savannah River and at Dana, these considerations led to designs in which the relatively economical GS process was used to concentrate the deuterium content of natural water to about 15 mol %. Vacuum distillation of water was selected (because there is Httle likelihood of product loss) for the additional concentration of the GS product from 15 to 90% D2O, and an electrolytic process was used to produce the final reactor-grade concentrate of 99.75% D2O. 

Production in Target Elements. Tritium is produced on a large scale by neutron irradiation of Li. The principal U.S. site of production is the Savaimah River plant near Aiken, South Carolina where tritium is produced in large heavy-water moderated, uranium-fueled reactors. The tritium may be produced either as a primary product by placing target elements of Li—A1 alloy in the reactor, or as a secondary product by using Li—A1 elements as an absorber for control of the neutron flux. 

Production in Heavy Water Moderator. A small quantity of tritium is produced through neutron capture by deuterium in the heavy water used as moderator in the reactors. The thermal neutron capture cross section for deuterium is extremely small (about 6 x 10 consequendy the... 

Heavy water [11105-15-0] 1 2 produced by a combination of electrolysis and catalytic exchange reactions. Some nuclear reactors (qv) require heavy water as a moderator of neutrons. Plants for the production of heavy water were built by the U.S. government during World War II. These plants, located at Trad, British Columbia, Morgantown, West Virginia, and Savaimah River, South Carolina, have been shut down except for a portion of the Savaimah River plant, which produces heavy water by a three-stage process (see Deuterium and tritium) an H2S/H2O exchange process produces 15% D2O a vacuum distillation increases the concentration to 90% D2O an electrolysis system produces 99.75% D2O (58). 

Shankar and De Souza have also recently investigated the effect of the additions of various anions to this system in both water and heavy water solvent. Fluoride was found to have very little influence on the exchange rate while acetate, nitrate and sulphate ions produced an increase. For the addition of sulphate ions an estimate of the rate coefficient kj of 20 l.mole . sec (at 14 °C and = 2.0 M) was made. For the addition of nitrate and acetate, values of the coefficients k and kj (where k = k K and kj = k K ), viz. 

A process involving water electrolysis is the production of heavy water. During cathodic polarization the relative rates of deuterium discharge and evolution are lower than those of the normal hydrogen isotope. Hence, during electrolysis the solution is enriched in heavy water. When the process is performed repeatedly, water with a D2O content of up to 99.7% can be produced. Electrochemical methods are also used widely in the manufacture of a variety of other inorganic and organic substances. 

Some nuclear reactors use heavy water to slow down neutrons produced during nuclear fission. Heavy water contains deuterium, an isotope of hydrogen. What is the mass number of deuterium ... 

Electrolysis continued to be used for primary enrichment in countries with abundant electric power, such as Iceland and Norway, where the H2 is used in ammonia manufacture [9]. Molecular deuterium, D2, is produced in Norway by the electrolysis of DzO. For heavy water production, the method has, for the most part, been replaced by steam-H2S exchange columns for heavy water enrichment ... 

Colorless gas with a strong odor of rotten eggs detectable at 0.005 ppm. However, it can cause olfactory fatigue and the sense of smell is not reliable. Used industrially to produce elemental sulfur, sulfuric acid, and heavy water for nuclear reactors. 

A feature common to both ir complex mechanisms is the nature of the second reagent in the exchange reaction [Eqs. (11), (12a), (12b)], namely heavy water or deuterium gas. Water is generally preferred in exchange reactions as it does not produce hydrogenated by-products. The important aspect concerning water and deuterium gas is the rapid exchange between these compounds on transition metal catalysts, which has been explained by dissociative chemisorption. 

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