Uranium hydride
Encyclopedia
Uranium hydride, also called uranium trihydride (UH3) is an inorganic compound
, a hydride
of uranium
.
at 20 °C is 10.95, much lower than that of uranium (19.1). It has a metallic conductivity, is slightly soluble in hydrochloric acid
and decomposes in nitric acid
.
Two crystal modifications of uranium hydride exist, both cubic: an α form that is obtained at low temperatures and a β form that is grown when the formation temperature is above 250 °C. After growth, both forms are metastable at room temperature and below, but the α form slowly converts to the β form upon heating to 100 °C. Both α- and β-UH3 are ferromagnetic
at temperatures below ~180 K. Above 180 K, they are paramagnetic.
. Hydrogen diffuses through metal and forms a network of brittle hydride over the grain boundaries
. Hydrogen can be removed and ductility renewed by annealing
in vacuum
.
Uranium metal heated to 250 to 300 °C
(482 to 572 °F
) reacts with hydrogen
to form uranium hydride. Further heating to about 500 °C will reversibly remove the hydrogen. This property makes uranium hydrides convenient starting materials to create reactive uranium powder along with various uranium carbide
, nitride
, and halide
compounds. The reversible reaction proceeds as follows:
Uranium hydride expands considerably during formation and is therefore not an interstitial compound
. In its lattice
, each uranium atom is surrounded by 6 other uranium atoms and 12 atoms of hydrogen; each hydrogen atom occupies a large tetrahedral hole in the lattice. The density of hydrogen in uranium hydride is approximately the same as in liquid water or in liquid hydrogen
. The U-H-U linkage through a hydrogen atom is present in the structure.
fuel with corroded cladding gets exposed to water; the reaction proceeds as follows:
The formed uranium hydride is pyrophoric; when the metal (e.g. a damaged fuel rod) gets exposed to air afterwards, a lot of heat may be generated and the bulk uranium metal itself can be ignited. Hydride-contaminated uranium can be passivated
by exposition to a gaseous mixture of 98% helium
with 2% oxygen
. Condensed moisture on uranium metal promotes formation of hydrogen and uranium hydride; pyrophoric surface may be formed in absence of oxygen. This poses a problem with underwater storage of spent nuclear fuel
in spent fuel ponds. Depending on the size and distribution on the hydride particles, self-ignition occurs after indeterminate length of exposure to air. Such exposure poses risk of self-ignition of fuel debris in radioactive waste storage vaults.
Uranium metal exposed to steam produces a mixture of uranium hydride and uranium dioxide
.
Uranium hydride exposed to water evolves hydrogen. In contact with strong oxidizers this may cause fire and explosions. Contact with halocarbon
s may cause a violent reaction.
-impregnated uranium hydride powder is non-pyrophoric and can be pressed, however its hydrogen-carbon ratio is unfavorable. Hydrogenated polystyrene was introduced in 1944 instead.
Uranium deuteride is said to be usable for design of some types of neutron initiators.
Uranium hydride enriched to about 5% uranium-235
is proposed as a combined nuclear fuel
/neutron moderator
for the Hydrogen Moderated Self-regulating Nuclear Power Module
. According to the aforementioned patent application, the reactor design in question begins producing power when hydrogen
gas at a sufficient temperature and pressure is admitted to the core (made up of granulated uranium metal) and reacts with the uranium metal to form uranium hydride. Uranium hydride is both a nuclear fuel
and a neutron moderator
; apparently it, like other neutron moderators, will slow neutrons sufficiently to allow for fission reactions to take place; the uranium-235 atoms within the hydride also serve as the nuclear fuel. Once the nuclear reaction has started, it will continue until it reaches a certain temperature, approximately 800 °C, where, due to the chemical properties of uranium hydride, it chemically decomposes and turns into hydrogen gas and uranium metal. The loss of neutron moderation due to the chemical decomposition of the uranium hydride will consequently slow — and eventually halt — the reaction. When temperature returns to an acceptable level, the hydrogen will again combine with the uranium metal, forming uranium hydride, restoring moderation and the nuclear reaction will start again.
Uranium zirconium hydride (UZrH), a combination of uranium hydride and zirconium(II) hydride
, is used as a fuel/moderator in the TRIGA
-class reactors.
On heating with diborane
, uranium hydride produces uranium boride
. With bromine
at 300 °C, uranium(IV) bromide is produced. With chlorine
at 250 °C, uranium(IV) chloride is produced. Hydrogen fluoride
at 20 °C produces uranium(IV) fluoride. Hydrogen chloride
at 300 °C produces uranium(III) chloride
. Hydrogen bromide
at 300 °C produces uranium(III) bromide. Hydrogen iodide
at 300 °C produces uranium(III) iodide. Ammonia
at 250 °C produces uranium(III) nitride. Hydrogen sulfide
at 400 °C produces uranium(IV) sulfide. Oxygen
at 20 °C produces triuranium octoxide. Water at 350 °C produces uranium dioxide
.
Uranium hydride ion may interfere with some mass spectrometry
measurements, appearing as a peak at mass 239, creating false increase of signal for plutonium-239.
of uranium.
Uranium hydride and uranium deuteride
were suggested as a fissile material for an uranium hydride bomb
. The tests with uranium hydride and uranium deuteride during the Operation Upshot-Knothole
were however disappointing. During early phases of Manhattan Project
, in 1943, uranium hydride was investigated as a promising bomb material; it was however abandoned by spring 1944 as it turned out such design would be inefficient.
, and tritium
can be purified by reacting with uranium, then thermally decomposing the resulting hydride/deuteride/tritide. Extremely pure hydrogen has been prepared from beds of uranium hydride for decades. Heating uranium hydride is a convenient way to introduce hydrogen into a vacuum system.
The swelling and pulverization at uranium hydride synthesis can be used for preparation of very fine uranium metal if the powdered hydride is thermally decomposed.
Uranium hydride can be used for isotope separation
of hydrogen
, preparing uranium metal powder, and as a reducing agent
.
Inorganic compound
Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...
, a hydride
Transition metal hydride
Transition metal hydrides are chemical compounds containing a transition metal bonded to hydrogen. Most transition metals form hydride complexes and some are significant in various catalytic and synthetic reactions...
of uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
.
Properties
Uranium hydride is a highly toxic, brownish gray to brownish black pyrophoric powder or brittle solid. Its specific gravitySpecific gravity
Specific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water for...
at 20 °C is 10.95, much lower than that of uranium (19.1). It has a metallic conductivity, is slightly soluble in hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....
and decomposes in nitric acid
Nitric acid
Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...
.
Two crystal modifications of uranium hydride exist, both cubic: an α form that is obtained at low temperatures and a β form that is grown when the formation temperature is above 250 °C. After growth, both forms are metastable at room temperature and below, but the α form slowly converts to the β form upon heating to 100 °C. Both α- and β-UH3 are ferromagnetic
Ferromagnetism
Ferromagnetism is the basic mechanism by which certain materials form permanent magnets, or are attracted to magnets. In physics, several different types of magnetism are distinguished...
at temperatures below ~180 K. Above 180 K, they are paramagnetic.
Hydrogen gas reaction
Exposition of uranium metal to hydrogen leads to hydrogen embrittlementHydrogen embrittlement
Hydrogen embrittlement is the process by which various metals, most importantly high-strength steel, become brittle and fracture following exposure to hydrogen...
. Hydrogen diffuses through metal and forms a network of brittle hydride over the grain boundaries
Grain boundary
A grain boundary is the interface between two grains, or crystallites, in a polycrystalline material. Grain boundaries are defects in the crystal structure, and tend to decrease the electrical and thermal conductivity of the material...
. Hydrogen can be removed and ductility renewed by annealing
Annealing (metallurgy)
Annealing, in metallurgy and materials science, is a heat treatment wherein a material is altered, causing changes in its properties such as strength and hardness. It is a process that produces conditions by heating to above the recrystallization temperature, maintaining a suitable temperature, and...
in vacuum
Vacuum
In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...
.
Uranium metal heated to 250 to 300 °C
Celsius
Celsius is a scale and unit of measurement for temperature. It is named after the Swedish astronomer Anders Celsius , who developed a similar temperature scale two years before his death...
(482 to 572 °F
Fahrenheit
Fahrenheit is the temperature scale proposed in 1724 by, and named after, the German physicist Daniel Gabriel Fahrenheit . Within this scale, the freezing of water into ice is defined at 32 degrees, while the boiling point of water is defined to be 212 degrees...
) reacts with hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
to form uranium hydride. Further heating to about 500 °C will reversibly remove the hydrogen. This property makes uranium hydrides convenient starting materials to create reactive uranium powder along with various uranium carbide
Carbide
In chemistry, a carbide is a compound composed of carbon and a less electronegative element. Carbides can be generally classified by chemical bonding type as follows: salt-like, covalent compounds, interstitial compounds, and "intermediate" transition metal carbides...
, nitride
Nitride
In chemistry, a nitride is a compound of nitrogen where nitrogen has a formal oxidation state of −3. Nitrides are a large class of compounds with a wide range of properties and applications....
, and halide
Halide
A halide is a binary compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative than the halogen, to make a fluoride, chloride, bromide, iodide, or astatide compound. Many salts are halides...
compounds. The reversible reaction proceeds as follows:
- 2 U + 3 H2 ↔ 2 UH3
Uranium hydride expands considerably during formation and is therefore not an interstitial compound
Interstitial compound
An interstitial compound or interstitial alloy is a compound that is formed when an atom of sufficiently small radius sits in an interstitial “hole” in a metal lattice. Examples of small atoms are hydrogen, boron, carbon and nitrogen...
. In its lattice
Crystal structure
In mineralogy and crystallography, crystal structure is a unique arrangement of atoms or molecules in a crystalline liquid or solid. A crystal structure is composed of a pattern, a set of atoms arranged in a particular way, and a lattice exhibiting long-range order and symmetry...
, each uranium atom is surrounded by 6 other uranium atoms and 12 atoms of hydrogen; each hydrogen atom occupies a large tetrahedral hole in the lattice. The density of hydrogen in uranium hydride is approximately the same as in liquid water or in liquid hydrogen
Liquid hydrogen
Liquid hydrogen is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form.To exist as a liquid, H2 must be pressurized above and cooled below hydrogen's Critical point. However, for hydrogen to be in a full liquid state without boiling off, it needs to be...
. The U-H-U linkage through a hydrogen atom is present in the structure.
Water reaction
Uranium hydride forms when uranium metal in e.g. MagnoxMagnox
Magnox is a now obsolete type of nuclear power reactor which was designed and is still in use in the United Kingdom, and was exported to other countries, both as a power plant, and, when operated accordingly, as a producer of plutonium for nuclear weapons...
fuel with corroded cladding gets exposed to water; the reaction proceeds as follows:
- 7 U + 6 H2O → 3 UO2 + 4 UH3
The formed uranium hydride is pyrophoric; when the metal (e.g. a damaged fuel rod) gets exposed to air afterwards, a lot of heat may be generated and the bulk uranium metal itself can be ignited. Hydride-contaminated uranium can be passivated
Passivation
Passivation is the process of making a material "passive", and thus less reactive with surrounding air, water, or other gases or liquids. The goal is to inhibit corrosion, whether for structural or cosmetic reasons. Passivation of metals is usually achieved by the deposition of a layer of oxide...
by exposition to a gaseous mixture of 98% helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
with 2% oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
. Condensed moisture on uranium metal promotes formation of hydrogen and uranium hydride; pyrophoric surface may be formed in absence of oxygen. This poses a problem with underwater storage of spent nuclear fuel
Spent nuclear fuel
Spent nuclear fuel, occasionally called used nuclear fuel, is nuclear fuel that has been irradiated in a nuclear reactor...
in spent fuel ponds. Depending on the size and distribution on the hydride particles, self-ignition occurs after indeterminate length of exposure to air. Such exposure poses risk of self-ignition of fuel debris in radioactive waste storage vaults.
Uranium metal exposed to steam produces a mixture of uranium hydride and uranium dioxide
Uranium dioxide
Uranium dioxide or uranium oxide , also known as urania or uranous oxide, is an oxide of uranium, and is a black, radioactive, crystalline powder that naturally occurs in the mineral uraninite. It is used in nuclear fuel rods in nuclear reactors. A mixture of uranium and plutonium dioxides is used...
.
Uranium hydride exposed to water evolves hydrogen. In contact with strong oxidizers this may cause fire and explosions. Contact with halocarbon
Halocarbon
Halocarbon compounds are chemicals in which one or more carbon atoms are linked by covalent bonds with one or more halogen atoms resulting in the formation of organofluorine compounds, organochlorine compounds, organobromine compounds, and organoiodine compounds...
s may cause a violent reaction.
Other chemical reactions
PolystyrenePolystyrene
Polystyrene ) also known as Thermocole, abbreviated following ISO Standard PS, is an aromatic polymer made from the monomer styrene, a liquid hydrocarbon that is manufactured from petroleum by the chemical industry...
-impregnated uranium hydride powder is non-pyrophoric and can be pressed, however its hydrogen-carbon ratio is unfavorable. Hydrogenated polystyrene was introduced in 1944 instead.
Uranium deuteride is said to be usable for design of some types of neutron initiators.
Uranium hydride enriched to about 5% uranium-235
Uranium-235
- References :* .* DOE Fundamentals handbook: Nuclear Physics and Reactor theory , .* A piece of U-235 the size of a grain of rice can produce energy equal to that contained in three tons of coal or fourteen barrels of oil. -External links:* * * one of the earliest articles on U-235 for the...
is proposed as a combined nuclear fuel
Nuclear fuel
Nuclear fuel is a material that can be 'consumed' by fission or fusion to derive nuclear energy. Nuclear fuels are the most dense sources of energy available...
/neutron moderator
Neutron moderator
In nuclear engineering, a neutron moderator is a medium that reduces the speed of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction involving uranium-235....
for the Hydrogen Moderated Self-regulating Nuclear Power Module
Hydrogen Moderated Self-regulating Nuclear Power Module
The Hydrogen Moderated Self-Regulating Nuclear Power Module , also referred to as the Compact Self-regulating Transportable Reactor , is a new type of nuclear power reactor using hydride as a neutron moderator. The design is inherently safe, as the fuel and the neutron moderator are uranium hydride...
. According to the aforementioned patent application, the reactor design in question begins producing power when hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
gas at a sufficient temperature and pressure is admitted to the core (made up of granulated uranium metal) and reacts with the uranium metal to form uranium hydride. Uranium hydride is both a nuclear fuel
Nuclear fuel
Nuclear fuel is a material that can be 'consumed' by fission or fusion to derive nuclear energy. Nuclear fuels are the most dense sources of energy available...
and a neutron moderator
Neutron moderator
In nuclear engineering, a neutron moderator is a medium that reduces the speed of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction involving uranium-235....
; apparently it, like other neutron moderators, will slow neutrons sufficiently to allow for fission reactions to take place; the uranium-235 atoms within the hydride also serve as the nuclear fuel. Once the nuclear reaction has started, it will continue until it reaches a certain temperature, approximately 800 °C, where, due to the chemical properties of uranium hydride, it chemically decomposes and turns into hydrogen gas and uranium metal. The loss of neutron moderation due to the chemical decomposition of the uranium hydride will consequently slow — and eventually halt — the reaction. When temperature returns to an acceptable level, the hydrogen will again combine with the uranium metal, forming uranium hydride, restoring moderation and the nuclear reaction will start again.
Uranium zirconium hydride (UZrH), a combination of uranium hydride and zirconium(II) hydride
Zirconium(II) hydride
Zirconium hydride is a chemical compound, a hydride of zirconium. The commercial form is usually a flammable, gray-black powder.It is used in powder metallurgy, as a hydrogenation catalyst, and as a reducing agent, vacuum tube getter, and a foaming agent in production of metal foams...
, is used as a fuel/moderator in the TRIGA
TRIGA
TRIGA is a class of small nuclear reactor designed and manufactured by General Atomics. The design team for TRIGA was led by the physicist Freeman Dyson.TRIGA is the acronym of Training, Research, Isotopes, General Atomics.-Design:...
-class reactors.
On heating with diborane
Diborane
Diborane is the chemical compound consisting of boron and hydrogen with the formula B2H6. It is a colorless gas at room temperature with a repulsively sweet odor. Diborane mixes well with air, easily forming explosive mixtures. Diborane will ignite spontaneously in moist air at room temperature...
, uranium hydride produces uranium boride
Uranium boride
Uranium boride , a compound of uranium and boron, is a very stable glassy boride material that is insoluble in water.It is being explored as a method of immobilising uranium based radioactive waste, and rendering it safe for long term storage...
. With bromine
Bromine
Bromine ") is a chemical element with the symbol Br, an atomic number of 35, and an atomic mass of 79.904. It is in the halogen element group. The element was isolated independently by two chemists, Carl Jacob Löwig and Antoine Jerome Balard, in 1825–1826...
at 300 °C, uranium(IV) bromide is produced. With chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
at 250 °C, uranium(IV) chloride is produced. Hydrogen fluoride
Hydrogen fluoride
Hydrogen fluoride is a chemical compound with the formula HF. This colorless gas is the principal industrial source of fluorine, often in the aqueous form as hydrofluoric acid, and thus is the precursor to many important compounds including pharmaceuticals and polymers . HF is widely used in the...
at 20 °C produces uranium(IV) fluoride. Hydrogen chloride
Hydrogen chloride
The compound hydrogen chloride has the formula HCl. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric humidity. Hydrogen chloride gas and hydrochloric acid are important in technology and industry...
at 300 °C produces uranium(III) chloride
Uranium(III) chloride
Uranium chloride , UCl3, is a chemical compound that contains the earth metal uranium and chlorine. UCl3 is used mostly to reprocess spent nuclear fuel. Uranium chloride is synthesized various ways from uranium chloride; however, UCl3 is less stable than UCl4.-Preparation:There are two ways to...
. Hydrogen bromide
Hydrogen bromide
Hydrogen bromide is the diatomic molecule HBr. HBr is a gas at standard conditions. Hydrobromic acid forms upon dissolving HBr in water. Conversely, HBr can be liberated from hydrobromic acid solutions with the addition of a dehydration agent, but not by distillation. Hydrogen bromide and...
at 300 °C produces uranium(III) bromide. Hydrogen iodide
Hydrogen iodide
Hydrogen iodide is a diatomic molecule. Aqueous solutions of HI are known as iohydroic acid or hydroiodic acid, a strong acid. Gas and aqueous solution are interconvertible...
at 300 °C produces uranium(III) iodide. Ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
at 250 °C produces uranium(III) nitride. Hydrogen sulfide
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
at 400 °C produces uranium(IV) sulfide. Oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
at 20 °C produces triuranium octoxide. Water at 350 °C produces uranium dioxide
Uranium dioxide
Uranium dioxide or uranium oxide , also known as urania or uranous oxide, is an oxide of uranium, and is a black, radioactive, crystalline powder that naturally occurs in the mineral uraninite. It is used in nuclear fuel rods in nuclear reactors. A mixture of uranium and plutonium dioxides is used...
.
Uranium hydride ion may interfere with some mass spectrometry
Mass spectrometry
Mass spectrometry is an analytical technique that measures the mass-to-charge ratio of charged particles.It is used for determining masses of particles, for determining the elemental composition of a sample or molecule, and for elucidating the chemical structures of molecules, such as peptides and...
measurements, appearing as a peak at mass 239, creating false increase of signal for plutonium-239.
History
Uranium hydride slugs were used in the Tickling the Dragons Tail series of experiments to determine the critical massCritical mass
A critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction. The critical mass of a fissionable material depends upon its nuclear properties A critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction. The...
of uranium.
Uranium hydride and uranium deuteride
Deuterium
Deuterium, also called heavy hydrogen, is one of two stable isotopes of hydrogen. It has a natural abundance in Earth's oceans of about one atom in of hydrogen . Deuterium accounts for approximately 0.0156% of all naturally occurring hydrogen in Earth's oceans, while the most common isotope ...
were suggested as a fissile material for an uranium hydride bomb
Uranium hydride bomb
The uranium hydride bomb was a variant design of the atomic bomb, that was first suggested by Robert Oppenheimer in 1939 and advocated and tested by Edward Teller. It used deuterium, an isotope of hydrogen, as a neutron moderator in a U235-deuterium compound. The chain reaction is a slow nuclear...
. The tests with uranium hydride and uranium deuteride during the Operation Upshot-Knothole
Operation Upshot-Knothole
Operation Upshot-Knothole was a series of eleven nuclear test shots conducted in 1953 at the Nevada Test Site.Over twenty-one thousand soldiers took part in the ground exercise Desert Rock V in conjunction with the Grable shot...
were however disappointing. During early phases of Manhattan Project
Manhattan Project
The Manhattan Project was a research and development program, led by the United States with participation from the United Kingdom and Canada, that produced the first atomic bomb during World War II. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the US Army...
, in 1943, uranium hydride was investigated as a promising bomb material; it was however abandoned by spring 1944 as it turned out such design would be inefficient.
Applications
Hydrogen, deuteriumDeuterium
Deuterium, also called heavy hydrogen, is one of two stable isotopes of hydrogen. It has a natural abundance in Earth's oceans of about one atom in of hydrogen . Deuterium accounts for approximately 0.0156% of all naturally occurring hydrogen in Earth's oceans, while the most common isotope ...
, and tritium
Tritium
Tritium is a radioactive isotope of hydrogen. The nucleus of tritium contains one proton and two neutrons, whereas the nucleus of protium contains one proton and no neutrons...
can be purified by reacting with uranium, then thermally decomposing the resulting hydride/deuteride/tritide. Extremely pure hydrogen has been prepared from beds of uranium hydride for decades. Heating uranium hydride is a convenient way to introduce hydrogen into a vacuum system.
The swelling and pulverization at uranium hydride synthesis can be used for preparation of very fine uranium metal if the powdered hydride is thermally decomposed.
Uranium hydride can be used for isotope separation
Isotope separation
Isotope separation is the process of concentrating specific isotopes of a chemical element by removing other isotopes, for example separating natural uranium into enriched uranium and depleted uranium. This is a crucial process in the manufacture of uranium fuel for nuclear power stations, and is...
of hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
, preparing uranium metal powder, and as a reducing agent
Reducing agent
A reducing agent is the element or compound in a reduction-oxidation reaction that donates an electron to another species; however, since the reducer loses an electron we say it is "oxidized"...
.