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152-443: Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written U) has been increased through the process of isotope separation . Naturally occurring uranium is composed of three major isotopes: uranium-238 (U with 99.2732–99.2752% natural abundance ), uranium-235 (U, 0.7198–0.7210%), and uranium-234 (U, 0.0049–0.0059%). U is the only nuclide existing in nature (in any appreciable amount) that

304-416: A laser enrichment process known as SILEX ( separation of isotopes by laser excitation ), which it intends to pursue through financial investment in a U.S. commercial venture by General Electric, Although SILEX has been granted a license to build a plant, the development is still in its early stages as laser enrichment has yet to be proven to be economically viable, and there is a petition being filed to review

456-431: A nuclear reactor . Another fissile isotope, uranium-233 , can be produced from natural thorium and is studied for future industrial use in nuclear technology. Uranium-238 has a small probability for spontaneous fission or even induced fission with fast neutrons; uranium-235, and to a lesser degree uranium-233, have a much higher fission cross-section for slow neutrons. In sufficient concentration, these isotopes maintain

608-764: A Senate hearing the Yucca Mountain site is no longer viewed as an option for storing reactor waste. In June 2018, the Trump administration and some members of Congress again began proposing using Yucca Mountain, with senators from Nevada raising opposition. In February 2020, U.S. President Donald Trump tweeted about a potential change of policy on plans to use Yucca Mountain in Nevada as a repository for nuclear waste. Trump's previous budgets have included funding for Yucca Mountain but, according to Nuclear Engineering International, two senior administration officials said that

760-773: A blendstock to dilute the unwanted byproducts that may be contained in the HEU feed. Concentrations of these isotopes in the LEU product in some cases could exceed ASTM specifications for nuclear fuel if NU or DU were used. So, the HEU downblending generally cannot contribute to the waste management problem posed by the existing large stockpiles of depleted uranium. Effective management and disposition strategies for depleted uranium are crucial to ensure long-term safety and environmental protection. Innovative approaches such as reprocessing and recycling of depleted uranium could offer sustainable solutions to minimize waste and optimize resource utilization in

912-528: A description of this process of reactor control). As little as 15 lb (6.8 kg) of uranium-235 can be used to make an atomic bomb. The nuclear weapon detonated over Hiroshima , called Little Boy , relied on uranium fission. However, the first nuclear bomb (the Gadget used at Trinity ) and the bomb that was detonated over Nagasaki ( Fat Man ) were both plutonium bombs. Uranium metal has three allotropic forms: The major application of uranium in

1064-479: A distribution of uranium oxidation species in various forms ranging from most oxidized to least oxidized. Particles with short residence times in a calciner will generally be less oxidized than those with long retention times or particles recovered in the stack scrubber. Uranium content is usually referenced to U 3 O 8 , which dates to the days of the Manhattan Project when U 3 O 8

1216-644: A facility in Australia unlikely. Giant Mine has been used as a deep repository for storage of highly toxic arsenic waste in the form of powder. As of 2020 there is ongoing research to reprocess the waste into a frozen block form which is more chemically stable and prevents water contamination. The Onkalo site in Finland based on the KBS-3 technology, is the furthest along the road to becoming operational among repositories worldwide. Posiva started construction of

1368-566: A form of invisible light or rays emitted by uranium had exposed the plate. During World War I when the Central Powers suffered a shortage of molybdenum to make artillery gun barrels and high speed tool steels, they routinely used ferrouranium alloy as a substitute, as it presents many of the same physical characteristics as molybdenum. When this practice became known in 1916 the US government requested several prominent universities to research

1520-745: A higher incidence of cancer . An excess risk of lung cancer among Navajo uranium miners, for example, has been documented and linked to their occupation. The Radiation Exposure Compensation Act , a 1990 law in the US, required $ 100,000 in "compassion payments" to uranium miners diagnosed with cancer or other respiratory ailments. During the Cold War between the Soviet Union and the United States, huge stockpiles of uranium were amassed and tens of thousands of nuclear weapons were created using enriched uranium and plutonium made from uranium. After

1672-799: A licence for the Andrews County CISF in September 2021. A group including the State of Texas petitioned for a court review of the licence. In August 2023, the United States Court of Appeals for the Fifth Circuit ruled that the NRC does not have the authority from Congress to license such a temporary storage facility that is not at a nuclear power station or federal site, nullifying the purported license. The other New Mexico CISF

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1824-603: A license application to the NRC for an autonomous consolidated interim storage facility (CISF) in southeastern New Mexico in March 2017. Similarly, Interim Storage Partners is also planning to build and operate a CISF in Andrews County , Texas . Meanwhile, other companies have indicated that they are prepared to bid on an anticipated procurement from the DOE to design a facility for interim storage of nuclear waste. The NRC issued

1976-428: A lower than 20% concentration of U; for instance, in commercial LWR, the most prevalent power reactors in the world, uranium is enriched to 3 to 5% U. Slightly enriched uranium ( SEU ) has a concentration of under 2% U. High-assay LEU (HALEU) is enriched between 5% and 20% and is called for in many small modular reactor (SMR) designs. Fresh LEU used in research reactors is usually enriched between 12% and 19.75% U;

2128-525: A minimum of 20% could be sufficient (called weapon-usable) although it would require hundreds of kilograms of material and "would not be practical to design"; even lower enrichment is hypothetically possible, but as the enrichment percentage decreases the critical mass for unmoderated fast neutrons rapidly increases, with for example, an infinite mass of 5.4% U being required. For criticality experiments, enrichment of uranium to over 97% has been accomplished. The first uranium bomb, Little Boy , dropped by

2280-409: A mix of ions . France developed its own version of PSP, which it called RCI. Funding for RCI was drastically reduced in 1986, and the program was suspended around 1990, although RCI is still used for stable isotope separation. "Separative work"—the amount of separation done by an enrichment process—is a function of the concentrations of the feedstock, the enriched output, and the depleted tailings; and

2432-448: A much more complicated and far more powerful type of fission/fusion bomb ( thermonuclear weapon ) was built, that uses a plutonium-based device to cause a mixture of tritium and deuterium to undergo nuclear fusion . Such bombs are jacketed in a non-fissile (unenriched) uranium case, and they derive more than half their power from the fission of this material by fast neutrons from the nuclear fusion process. The main use of uranium in

2584-524: A negatively charged plate and collected. Molecular laser isotope separation uses an infrared laser directed at UF 6 , exciting molecules that contain a U atom. A second laser frees a fluorine atom, leaving uranium pentafluoride , which then precipitates out of the gas. Separation of isotopes by laser excitation is an Australian development that also uses UF 6 . After a protracted development process involving U.S. enrichment company USEC acquiring and then relinquishing commercialization rights to

2736-499: A particular vortex tube separator design, and both embodied in industrial plant. A demonstration plant was built in Brazil by NUCLEI, a consortium led by Industrias Nucleares do Brasil that used the separation nozzle process. However, all methods have high energy consumption and substantial requirements for removal of waste heat; none is currently still in use. In the electromagnetic isotope separation process (EMIS), metallic uranium

2888-459: A plutonium-based device (see Trinity test and " Fat Man ") whose plutonium was derived from uranium-238. Little Boy became the first nuclear weapon used in war when it was detonated over Hiroshima , Japan , on 6 August 1945. Exploding with a yield equivalent to 12,500 tonnes of TNT , the blast and thermal wave of the bomb destroyed nearly 50,000 buildings and killed about 75,000 people (see Atomic bombings of Hiroshima and Nagasaki ). Initially it

3040-405: A reaction by piling together 360 tonnes of graphite , 53 tonnes of uranium oxide , and 5.5 tonnes of uranium metal, most of which was supplied by Westinghouse Lamp Plant in a makeshift production process. Two types of atomic bomb were developed by the United States during World War II : a uranium-based device (codenamed " Little Boy ") whose fissile material was highly enriched uranium , and

3192-413: A shielding material. Due to its high density, this material is found in inertial guidance systems and in gyroscopic compasses . Depleted uranium is preferred over similarly dense metals due to its ability to be easily machined and cast as well as its relatively low cost. The main risk of exposure to depleted uranium is chemical poisoning by uranium oxide rather than radioactivity (uranium being only

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3344-525: A shorter half-life and so is an extinct radionuclide , having long since decayed completely to Th. Further uranium-236 was produced by the decay of Pu , accounting for the observed higher-than-expected abundance of thorium and lower-than-expected abundance of uranium. While the natural abundance of uranium has been supplemented by the decay of extinct Pu (half-life 375,000 years) and Cm (half-life 16 million years), producing U and U respectively, this occurred to an almost negligible extent due to

3496-433: A significant contributor to global energy security and environmental sustainability, effectively repurposing material once intended for destructive purposes into a resource for peaceful energy production. The United States Enrichment Corporation has been involved in the disposition of a portion of the 174.3 tonnes of highly enriched uranium (HEU) that the U.S. government declared as surplus military material in 1996. Through

3648-638: A silvery-grey metal in the actinide series of the periodic table . A uranium atom has 92 protons and 92 electrons , of which 6 are valence electrons . Uranium radioactively decays , usually by emitting an alpha particle . The half-life of this decay varies between 159,200 and 4.5 billion years for different isotopes , making them useful for dating the age of the Earth . The most common isotopes in natural uranium are uranium-238 (which has 146 neutrons and accounts for over 99% of uranium on Earth) and uranium-235 (which has 143 neutrons). Uranium has

3800-455: A site selection process. RWM continues to have discussions in a range of places across England with people and organisations who are interested in exploring the benefits of hosting a GDF. More Working Groups are anticipated to form across the country in the next year or two. Any proposal for a GDF will be evaluated against highly rigorous criteria [6] to ensure all safety and security tests are met. The Waste Isolation Pilot Plant (WIPP) in

3952-451: A sphere about 17 centimetres (6.7 in) in diameter. Later U.S. nuclear weapons usually use plutonium-239 in the primary stage, but the jacket or tamper secondary stage, which is compressed by the primary nuclear explosion often uses HEU with enrichment between 40% and 80% along with the fusion fuel lithium deuteride . This multi-stage design enhances the efficiency and effectiveness of nuclear weapons, allowing for greater control over

4104-502: A sustained nuclear chain reaction . This generates the heat in nuclear power reactors and produces the fissile material for nuclear weapons. The primary civilian use for uranium harnesses the heat energy to produce electricity. Depleted uranium ( U) is used in kinetic energy penetrators and armor plating . The 1789 discovery of uranium in the mineral pitchblende is credited to Martin Heinrich Klaproth , who named

4256-412: A weak alpha emitter ). During the later stages of World War II , the entire Cold War , and to a lesser extent afterwards, uranium-235 has been used as the fissile explosive material to produce nuclear weapons. Initially, two major types of fission bombs were built: a relatively simple device that uses uranium-235 and a more complicated mechanism that uses plutonium-239 derived from uranium-238. Later,

4408-535: A world total production of 48,332 tonnes. Most uranium was produced not by conventional underground mining of ores (29% of production), but by in situ leaching (66%). In the late 1960s, UN geologists discovered major uranium deposits and other rare mineral reserves in Somalia . The find was the largest of its kind, with industry experts estimating the deposits at over 25% of the world's then known uranium reserves of 800,000 tons. The ultimate available supply

4560-430: Is fissile with thermal neutrons . Enriched uranium is a critical component for both civil nuclear power generation and military nuclear weapons . There are about 2,000  tonnes of highly enriched uranium in the world, produced mostly for nuclear power , nuclear weapons, naval propulsion , and smaller quantities for research reactors . The U remaining after enrichment is known as depleted uranium (DU), and

4712-552: Is malleable , ductile , slightly paramagnetic , strongly electropositive and a poor electrical conductor . Uranium metal has a very high density of 19.1 g/cm , denser than lead (11.3 g/cm ), but slightly less dense than tungsten and gold (19.3 g/cm ). Uranium metal reacts with almost all non-metallic elements (except noble gases ) and their compounds , with reactivity increasing with temperature. Hydrochloric and nitric acids dissolve uranium, but non-oxidizing acids other than hydrochloric acid attack

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4864-471: Is a naturally occurring element found in low levels in all rock, soil, and water. It is the highest-numbered element found naturally in significant quantities on Earth and is almost always found combined with other elements. Uranium is the 48th most abundant element in the Earth’s crust. The decay of uranium, thorium , and potassium-40 in Earth's mantle is thought to be the main source of heat that keeps

5016-410: Is a minor isotope contained in natural uranium (primarily as a product of alpha decay of U —because the half-life of U is much larger than that of U , it is be produced and destroyed at the same rate in a constant steady state equilibrium, bringing any sample with sufficient U content to a stable ratio of U to U over long enough timescales); during

5168-514: Is a natural deposit of highly concentrated uranium ore located under sandstone and a quartz layer at a depth of 450 m, that is 1 billion years old with no radioactive leaks to the surface. The ability of natural geologic barriers to isolate radioactive waste is demonstrated by the natural nuclear fission reactors at Oklo , Gabon. During their long reaction period about 5.4 tonnes of fission products as well as 1.5 tonnes of plutonium together with other transuranic elements were generated in

5320-532: Is a very effective and cheap method of uranium separation, able to be done in small facilities requiring much less energy and space than previous separation techniques. The cost of uranium enrichment using laser enrichment technologies is approximately $ 30 per SWU which is less than a third of the price of gas centrifuges, the current standard of enrichment. Separation of isotopes by laser excitation could be done in facilities virtually undetectable by satellites. More than 20 countries have worked with laser separation over

5472-530: Is also fissile by thermal neutrons. These discoveries led numerous countries to begin working on the development of nuclear weapons and nuclear power . Despite fission having been discovered in Germany, the Uranverein ("uranium club") Germany's wartime project to research nuclear power and/or weapons was hampered by limited resources, infighting, the exile or non-involvement of several prominent scientists in

5624-438: Is approximately 100 dollars per Separative Work Units (SWU), making it about 40% cheaper than standard gaseous diffusion techniques. The Zippe-type centrifuge is an improvement on the standard gas centrifuge, the primary difference being the use of heat. The bottom of the rotating cylinder is heated, producing convection currents that move the U up the cylinder, where it can be collected by scoops. This improved centrifuge design

5776-402: Is being done that would use nuclear resonance ; however, there is no reliable evidence that any nuclear resonance processes have been scaled up to production. Gaseous diffusion is a technology used to produce enriched uranium by forcing gaseous uranium hexafluoride ( hex ) through semi-permeable membranes . This produces a slight separation between the molecules containing U and U. Throughout

5928-520: Is believed to be sufficient for at least the next 85 years, though some studies indicate underinvestment in the late twentieth century may produce supply problems in the 21st century. Uranium deposits seem to be log-normal distributed. There is a 300-fold increase in the amount of uranium recoverable for each tenfold decrease in ore grade. In other words, there is little high grade ore and proportionately much more low grade ore available. Calcined uranium yellowcake, as produced in many large mills, contains

6080-443: Is considerably less radioactive than even natural uranium, though still very dense. Depleted uranium is used as a radiation shielding material and for armor-penetrating weapons . Uranium as it is taken directly from the Earth is not suitable as fuel for most nuclear reactors and requires additional processes to make it usable ( CANDU design is a notable exception). Uranium is mined either underground or in an open pit depending on

6232-408: Is crucial for optimizing the economic and operational performance of uranium enrichment facilities. In addition to the separative work units provided by an enrichment facility, the other important parameter to be considered is the mass of natural uranium (NU) that is needed to yield a desired mass of enriched uranium. As with the number of SWUs, the amount of feed material required will also depend on

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6384-785: Is difficult to precipitate uranium as phosphate in the presence of excess carbonate at alkaline pH. A Sphingomonas sp. strain BSAR-1 has been found to express a high activity alkaline phosphatase (PhoK) that has been applied for bioprecipitation of uranium as uranyl phosphate species from alkaline solutions. The precipitation ability was enhanced by overexpressing PhoK protein in E. coli . Plants absorb some uranium from soil. Dry weight concentrations of uranium in plants range from 5 to 60 parts per billion, and ash from burnt wood can have concentrations up to 4 parts per million. Dry weight concentrations of uranium in food plants are typically lower with one to two micrograms per day ingested through

6536-418: Is diluted with uranium-238 and reused as fuel for nuclear reactors. Spent nuclear fuel forms radioactive waste , which mostly consists of uranium-238 and poses a significant health threat and environmental impact . Uranium is a silvery white, weakly radioactive metal . It has a Mohs hardness of 6, sufficient to scratch glass and roughly equal to that of titanium , rhodium , manganese and niobium . It

6688-402: Is diverted to weapon use. There is general agreement that placing spent nuclear fuel in repositories hundreds of meters below the surface would be safer than indefinite storage of spent fuel on the surface [of the earth]. Common elements of repositories include the radioactive waste, the containers enclosing the waste, other engineered barriers or seals around the containers, the tunnels housing

6840-639: Is expressed in units that are so calculated as to be proportional to the total input (energy / machine operation time) and to the mass processed. Separative work is not energy. The same amount of separative work will require different amounts of energy depending on the efficiency of the separation technology. Separative work is measured in Separative work units SWU, kg SW, or kg UTA (from the German Urantrennarbeit – literally uranium separation work ). Efficient utilization of separative work

6992-513: Is first vaporized, and then ionized to positively charged ions. The cations are then accelerated and subsequently deflected by magnetic fields onto their respective collection targets. A production-scale mass spectrometer named the Calutron was developed during World War II that provided some of the U used for the Little Boy nuclear bomb, which was dropped over Hiroshima in 1945. Properly

7144-485: Is found in hundreds of minerals, including uraninite (the most common uranium ore ), carnotite , autunite , uranophane , torbernite , and coffinite . Significant concentrations of uranium occur in some substances such as phosphate rock deposits, and minerals such as lignite , and monazite sands in uranium-rich ores (it is recovered commercially from sources with as little as 0.1% uranium ). Like all elements with atomic weights higher than that of iron , uranium

7296-456: Is further processed to obtain the desired form of uranium suitable for nuclear fuel production. After the milling process is complete, the uranium must next undergo a process of conversion, "to either uranium dioxide , which can be used as the fuel for those types of reactors that do not require enriched uranium, or into uranium hexafluoride , which can be enriched to produce fuel for the majority of types of reactors". Naturally occurring uranium

7448-566: Is little debate in Germany regarding toxic waste, in spite of the fact that unlike nuclear waste, it does not lose toxicity with time. There is a debate about the search for a final repository for radioactive waste, accompanied by protests, especially in the Gorleben village in the Wendland area, which was seen as ideal for the final repository until 1990 because of its location in a remote, economically depressed corner of West Germany, next to

7600-432: Is lost during manufacturing. The opposite of enriching is downblending; surplus HEU can be downblended to LEU to make it suitable for use in commercial nuclear fuel. Downblending is a key process in nuclear non-proliferation efforts, as it reduces the amount of highly enriched uranium available for potential weaponization while repurposing it for peaceful purposes. The HEU feedstock can contain unwanted uranium isotopes: U

7752-650: Is made of a mixture of U and U. The U is fissile , meaning it is easily split with neutrons while the remainder is U, but in nature, more than 99% of the extracted ore is U. Most nuclear reactors require enriched uranium, which is uranium with higher concentrations of U ranging between 3.5% and 4.5% (although a few reactor designs using a graphite or heavy water moderator , such as the RBMK and CANDU , are capable of operating with natural uranium as fuel). There are two commercial enrichment processes: gaseous diffusion and gas centrifugation . Both enrichment processes involve

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7904-605: Is not usable in thermal neutron reactors but can be chemically separated from spent fuel to be disposed of as waste or to be transmutated into Pu (for use in nuclear batteries ) in special reactors. Understanding and managing the isotopic composition of uranium during downblending processes is essential to ensure the quality and safety of the resulting nuclear fuel, as well as to mitigate potential radiological and proliferation risks associated with unwanted isotopes. The blendstock can be NU or DU; however, depending on feedstock quality, SEU at typically 1.5 wt% U may be used as

8056-685: Is only 1.26% lighter than U.) This problem is compounded because uranium is rarely separated in its atomic form, but instead as a compound (UF 6 is only 0.852% lighter than UF 6 ). A cascade of identical stages produces successively higher concentrations of U. Each stage passes a slightly more concentrated product to the next stage and returns a slightly less concentrated residue to the previous stage. There are currently two generic commercial methods employed internationally for enrichment: gaseous diffusion (referred to as first generation) and gas centrifuge ( second generation), which consumes only 2% to 2.5% as much energy as gaseous diffusion. Some work

8208-427: Is only naturally formed by the r-process (rapid neutron capture) in supernovae and neutron star mergers . Primordial thorium and uranium are only produced in the r-process, because the s-process (slow neutron capture) is too slow and cannot pass the gap of instability after bismuth. Besides the two extant primordial uranium isotopes, U and U, the r-process also produced significant quantities of U , which has

8360-407: Is produced through the thermal decomposition of uranium halides on a hot filament. It is estimated that 6.1 million tonnes of uranium exists in ores that are economically viable at US$ 130 per kg of uranium, while 35 million tonnes are classed as mineral resources (reasonable prospects for eventual economic extraction). Australia has 28% of the world's known uranium ore reserves and

8512-558: Is similarly being challenged in the United States Court of Appeals for the Tenth Circuit . Deep Isolation, a corporation based in Berkeley, California, proposed a solution involving horizontal storage of radioactive waste canisters in directional boreholes, using technology developed for oil and gas mining. An 18" borehole can be directed vertically to the depth of several thousand feet in geologically stable formations, and then

8664-448: Is the only naturally occurring fissile isotope , which makes it widely used in nuclear power plants and nuclear weapons . However, because of the low abundance of uranium-235 in natural uranium (which is, overwhelmingly, mostly uranium-238), uranium needs to undergo enrichment so that enough uranium-235 is present. Uranium-238 is fissionable by fast neutrons and is fertile , meaning it can be transmuted to fissile plutonium-239 in

8816-441: Is then calcined to remove impurities from the milling process before refining and conversion. Commercial-grade uranium can be produced through the reduction of uranium halides with alkali or alkaline earth metals . Uranium metal can also be prepared through electrolysis of KUF 5 or UF 4 , dissolved in molten calcium chloride ( CaCl 2 ) and sodium chloride ( Na Cl) solution. Very pure uranium

8968-491: Is under way in several countries, with the first expected to be commissioned some time after 2010. There was a proposal in the early 2000s for an international high level waste repository in Australia and Russia . Since the proposal for a global repository in Australia, which has never produced nuclear power, and has one research reactor, was raised, domestic political objections have been loud and sustained, making such

9120-487: Is used commercially by Urenco to produce nuclear fuel and was used by Pakistan in their nuclear weapons program. Laser processes promise lower energy inputs, lower capital costs and lower tails assays, hence significant economic advantages. Several laser processes have been investigated or are under development. Separation of isotopes by laser excitation (SILEX) is well developed and is licensed for commercial operation as of 2012. Separation of isotopes by laser excitation

9272-600: Is used for X-ray targets in the making of high-energy X-rays. The use of pitchblende , uranium in its natural oxide form, dates back to at least the year 79 AD, when it was used in the Roman Empire to add a yellow color to ceramic glazes. Yellow glass with 1% uranium oxide was found in a Roman villa on Cape Posillipo in the Bay of Naples , Italy, by R. T. Gunther of the University of Oxford in 1912. Starting in

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9424-566: The American Physical Society filed a petition with the NRC, asking that before any laser excitation plants are built that they undergo a formal review of proliferation risks. The APS even went as far as calling the technology a "game changer" due to the ability for it to be hidden from any type of detection. Aerodynamic enrichment processes include the Becker jet nozzle techniques developed by E. W. Becker and associates using

9576-498: The Cold War , gaseous diffusion played a major role as a uranium enrichment technique, and as of 2008 accounted for about 33% of enriched uranium production, but in 2011 was deemed an obsolete technology that is steadily being replaced by the later generations of technology as the diffusion plants reach their ends of life. In 2013, the Paducah facility in the U.S. ceased operating, it was the last commercial U gaseous diffusion plant in

9728-472: The LIGA process and the vortex tube separation process. These aerodynamic separation processes depend upon diffusion driven by pressure gradients, as does the gas centrifuge. They in general have the disadvantage of requiring complex systems of cascading of individual separating elements to minimize energy consumption. In effect, aerodynamic processes can be considered as non-rotating centrifuges. Enhancement of

9880-402: The Manhattan Project , another team led by Enrico Fermi was able to initiate the first artificial self-sustained nuclear chain reaction , Chicago Pile-1 . An initial plan using enriched uranium-235 was abandoned as it was as yet unavailable in sufficient quantities. Working in a lab below the stands of Stagg Field at the University of Chicago , the team created the conditions needed for such

10032-497: The Megatons to Megawatts Program . An additional 4.6 billion tonnes of uranium are estimated to be dissolved in sea water ( Japanese scientists in the 1980s showed that extraction of uranium from sea water using ion exchangers was technically feasible). There have been experiments to extract uranium from sea water, but the yield has been low due to the carbonate present in the water. In 2012, ORNL researchers announced

10184-475: The Oklo Fossil Reactors . The ore deposit is 1.7 billion years old; then, uranium-235 constituted about 3% of uranium on Earth. This is high enough to permit a sustained chain reaction, if other supporting conditions exist. The capacity of the surrounding sediment to contain the health-threatening nuclear waste products has been cited by the U.S. federal government as supporting evidence for

10336-721: The Shippingport Atomic Power Station in Pennsylvania , which began on 26 May 1958. Nuclear power was used for the first time for propulsion by a submarine , the USS Nautilus , in 1954. In 1972, French physicist Francis Perrin discovered fifteen ancient and no longer active natural nuclear fission reactors in three separate ore deposits at the Oklo mine in Gabon , Africa, collectively known as

10488-527: The United States (2.5%), Argentina (2.1%) and Ukraine (1.9%). In 2008, Kazakhstan was forecast to increase production and become the world's largest supplier of uranium by 2009; Kazakhstan has dominated the world's uranium market since 2010. In 2021, its share was 45.1%, followed by Namibia (11.9%), Canada (9.7%), Australia (8.7%), Uzbekistan (7.2%), Niger (4.7%), Russia (5.5%), China (3.9%), India (1.3%), Ukraine (0.9%), and South Africa (0.8%), with

10640-474: The United States on Hiroshima in 1945, used 64 kilograms (141 lb) of 80% enriched uranium. Wrapping the weapon's fissile core in a neutron reflector (which is standard on all nuclear explosives) can dramatically reduce the critical mass. Because the core was surrounded by a good neutron reflector, at explosion it comprised almost 2.5 critical masses. Neutron reflectors, compressing the fissile core via implosion, fusion boosting , and "tamping", which slows

10792-672: The United States went into service in 1999 by putting the first cubic metres of transuranic radioactive waste in a deep layer of salt near Carlsbad, New Mexico . In 1978, the U.S. Department of Energy (DOE) began studying Yucca Mountain , within the secure boundaries of the Nevada Test Site in Nye County, Nevada , to determine whether it would be suitable for a long-term geologic repository for spent nuclear fuel and high-level radioactive waste. This project faced significant opposition and suffered delays due to litigation by

10944-604: The break-up of the Soviet Union in 1991, an estimated 600 short tons (540 metric tons) of highly enriched weapons grade uranium (enough to make 40,000 nuclear warheads) had been stored in often inadequately guarded facilities in the Russian Federation and several other former Soviet states. Police in Asia , Europe , and South America on at least 16 occasions from 1993 to 2005 have intercepted shipments of smuggled bomb-grade uranium or plutonium, most of which

11096-505: The first nuclear weapon used in war . An ensuing arms race during the Cold War between the United States and the Soviet Union produced tens of thousands of nuclear weapons that used uranium metal and uranium-derived plutonium-239 . Dismantling of these weapons and related nuclear facilities is carried out within various nuclear disarmament programs and costs billions of dollars. Weapon-grade uranium obtained from nuclear weapons

11248-432: The oceans may contain 10  kg (2 × 10  lb). The concentration of uranium in soil ranges from 0.7 to 11 parts per million (up to 15 parts per million in farmland soil due to use of phosphate fertilizers ), and its concentration in sea water is 3 parts per billion. Uranium is more plentiful than antimony , tin , cadmium , mercury , or silver, and it is about as abundant as arsenic or molybdenum . Uranium

11400-629: The Agency for Nuclear Projects for the State of Nevada (Nuclear Waste Project Office) and others. The Obama administration rejected use of the site in the 2009 United States Federal Budget proposal, which eliminated all funding except that needed to answer inquiries from the U.S. Nuclear Regulatory Commission (NRC), "while the Administration devises a new strategy toward nuclear waste disposal." In March 2009, Energy Secretary Steven Chu told

11552-640: The Dean of the Sapienza University of Rome , Orso Mario Corbino , named ausenium and hesperium , respectively. The experiments leading to the discovery of uranium's ability to fission (break apart) into lighter elements and release binding energy were conducted by Otto Hahn and Fritz Strassmann in Hahn's laboratory in Berlin. Lise Meitner and her nephew, physicist Otto Robert Frisch , published

11704-408: The Earth's outer core in the liquid state and drives mantle convection , which in turn drives plate tectonics . Uranium's concentration in the Earth's crust is (depending on the reference) 2 to 4 parts per million, or about 40 times as abundant as silver . The Earth's crust from the surface to 25 km (15 mi) down is calculated to contain 10  kg (2 × 10  lb) of uranium while

11856-637: The Netherlands, North Korea, Pakistan, Russia, the United Kingdom, and the United States. Belgium, Iran, Italy, and Spain hold an investment interest in the French Eurodif enrichment plant, with Iran's holding entitling it to 10% of the enriched uranium output. Countries that had enrichment programs in the past include Libya and South Africa, although Libya's facility was never operational. The Australian company Silex Systems has developed

12008-691: The Russian government approved a federal program for nuclear and radiation safety for 2016 to 2030 with a budget of 562 billion rubles (ca. 8 billion USD ). Its key issue is "the deferred liabilities accumulated during the 70 years of the nuclear industry, particularly during the time of the Soviet Union". About 73% of the budget will be spent on decommissioning aged and obsolete nuclear reactors and nuclear facilities, especially those involved in state defense programs; 20% will go in processing and disposal of nuclear fuel and radioactive waste, and 5% into monitoring and ensuring of nuclear and radiation safety. Uranium

12160-633: The U.S. HEU Downblending Program, this HEU material, taken primarily from dismantled U.S. nuclear warheads, was recycled into low-enriched uranium (LEU) fuel, used by nuclear power plants to generate electricity.This innovative program not only facilitated the safe and secure elimination of excess weapons-grade uranium but also contributed to the sustainable operation of civilian nuclear power plants, reducing reliance on newly enriched uranium and promoting non-proliferation efforts globally The following countries are known to operate enrichment facilities: Argentina, Brazil, China, France, Germany, India, Iran, Japan,

12312-467: The amount of NU required and the number of SWUs required during enrichment change in opposite directions, if NU is cheap and enrichment services are more expensive, then the operators will typically choose to allow more U to be left in the DU stream whereas if NU is more expensive and enrichment is less so, then they would choose the opposite. When converting uranium ( hexafluoride , hex for short) to metal, 0.3%

12464-413: The blended LEU product. U is a neutron poison ; therefore the actual U concentration in the LEU product must be raised accordingly to compensate for the presence of U. While U also absorbs neutrons, it is a fertile material that is turned into fissile U upon neutron absorption . If U absorbs a neutron, the resulting short-lived U beta decays to Np , which

12616-566: The bulk of the use, including common bathroom and kitchen tiles which can be produced in green, yellow, mauve , black, blue, red and other colors. Uranium was also used in photographic chemicals (especially uranium nitrate as a toner ), in lamp filaments for stage lighting bulbs, to improve the appearance of dentures , and in the leather and wood industries for stains and dyes. Uranium salts are mordants of silk or wool. Uranyl acetate and uranyl formate are used as electron-dense "stains" in transmission electron microscopy , to increase

12768-489: The centrifugal forces is achieved by dilution of UF 6 with hydrogen or helium as a carrier gas achieving a much higher flow velocity for the gas than could be obtained using pure uranium hexafluoride. The Uranium Enrichment Corporation of South Africa (UCOR) developed and deployed the continuous Helikon vortex separation cascade for high production rate low-enrichment and the substantially different semi-batch Pelsakon low production rate high enrichment cascade both using

12920-409: The civilian sector is to fuel nuclear power plants . One kilogram of uranium-235 can theoretically produce about 20  terajoules of energy (2 × 10   joules ), assuming complete fission; as much energy as 1.5 million kilograms (1,500 tonnes ) of coal . Commercial nuclear power plants use fuel that is typically enriched to around 3% uranium-235. The CANDU and Magnox designs are

13072-566: The closed border to the former East Germany . After reunification, the village is now close to the center of Germany, and is now used for temporary storage of nuclear waste. The pit Asse II is a former salt mine in the mountain range of Asse in Lower Saxony / Germany , that was allegedly used as a research mine since 1965. Between 1967 and 1978, radioactive waste was placed in storage. Research indicated that brine contaminated with radioactive caesium-137 , plutonium and strontium

13224-611: The containers, and the geologic makeup of the surrounding area. A storage space hundreds of metres below the ground needs to withstand the effects of one or more future glaciations , with thick ice sheets resting on top of the rock. The presence of ice sheets affects the hydrostatic pressure at repository depth, groundwater flow and chemistry, and the potential for earthquakes. This is being taken into consideration by organizations preparing for long-term waste repositories in Sweden, Finland, Canada and some other countries that have to assess

13376-549: The contrast of biological specimens in ultrathin sections and in negative staining of viruses , isolated cell organelles and macromolecules . The discovery of the radioactivity of uranium ushered in additional scientific and practical uses of the element. The long half-life of uranium-238 (4.47 × 10 years) makes it well-suited for use in estimating the age of the earliest igneous rocks and for other types of radiometric dating , including uranium–thorium dating , uranium–lead dating and uranium–uranium dating . Uranium metal

13528-409: The depth at which it is found. After the uranium ore is mined, it must go through a milling process to extract the uranium from the ore. This is accomplished by a combination of chemical processes with the end product being concentrated uranium oxide, which is known as " yellowcake ", contains roughly 80% uranium whereas the original ore typically contains as little as 0.1% uranium. This yellowcake

13680-442: The development of uranium mining to extract the radium, which was used to make glow-in-the-dark paints for clock and aircraft dials. This left a prodigious quantity of uranium as a waste product, since it takes three tonnes of uranium to extract one gram of radium. This waste product was diverted to the glazing industry, making uranium glazes very inexpensive and abundant. Besides the pottery glazes, uranium tile glazes accounted for

13832-477: The effects of future glaciations. Despite a long-standing agreement among many experts that geological disposal can be safe, technologically feasible and environmentally sound, a large part of the general public in many countries remains skeptical as a result of anti-nuclear campaigns . One of the challenges facing the supporters of these efforts is to demonstrate confidently that a repository will contain wastes for so long that any releases that might take place in

13984-465: The element very slowly. When finely divided, it can react with cold water; in air, uranium metal becomes coated with a dark layer of uranium oxide . Uranium in ores is extracted chemically and converted into uranium dioxide or other chemical forms usable in industry. Uranium-235 was the first isotope that was found to be fissile . Other naturally occurring isotopes are fissionable, but not fissile. On bombardment with slow neutrons, uranium-235 most of

14136-464: The enriched stream to contain 3.6% U (as compared to 0.7% in NU) while the depleted stream contains 0.2% to 0.3% U. In order to produce one kilogram of this LEU it would require approximately 8 kilograms of NU and 4.5 SWU if the DU stream was allowed to have 0.3% U. On the other hand, if the depleted stream had only 0.2% U, then it would require just 6.7 kilograms of NU, but nearly 5.7 SWU of enrichment. Because

14288-618: The enrichment process, its concentration increases but remains well below 1%. High concentrations of U are a byproduct from irradiation in a reactor and may be contained in the HEU, depending on its manufacturing history. U is produced primarily when U absorbs a neutron and does not fission. The production of U is thus unavoidable in any thermal neutron reactor with U fuel. HEU reprocessed from nuclear weapons material production reactors (with an U assay of approximately 50%) may contain U concentrations as high as 25%, resulting in concentrations of approximately 1.5% in

14440-440: The exact figure is classified. In August, 2011 Global Laser Enrichment, a subsidiary of GEH, applied to the U.S. Nuclear Regulatory Commission (NRC) for a permit to build a commercial plant. In September 2012, the NRC issued a license for GEH to build and operate a commercial SILEX enrichment plant, although the company had not yet decided whether the project would be profitable enough to begin construction, and despite concerns that

14592-416: The expansion of the fissioning core with inertia, allow nuclear weapon designs that use less than what would be one bare-sphere critical mass at normal density. The presence of too much of the U isotope inhibits the runaway nuclear chain reaction that is responsible for the weapon's power. The critical mass for 85% highly enriched uranium is about 50 kilograms (110 lb), which at normal density would be

14744-493: The feasibility to store spent nuclear fuel at the Yucca Mountain nuclear waste repository . Above-ground nuclear tests by the Soviet Union and the United States in the 1950s and early 1960s and by France into the 1970s and 1980s spread a significant amount of fallout from uranium daughter isotopes around the world. Additional fallout and pollution occurred from several nuclear accidents . Uranium miners have

14896-503: The field and several crucial mistakes such as failing to account for impurities in available graphite samples which made it appear less suitable as a neutron moderator than it is in reality. Germany's attempts to build a natural uranium / heavy water reactor had not come close to reaching criticality by the time the Americans reached Haigerloch , the site of the last German wartime reactor experiment. On 2 December 1942, as part of

15048-468: The first sample of uranium metal by heating uranium tetrachloride with potassium . Henri Becquerel discovered radioactivity by using uranium in 1896. Becquerel made the discovery in Paris by leaving a sample of a uranium salt, K 2 UO 2 (SO 4 ) 2 (potassium uranyl sulfate), on top of an unexposed photographic plate in a drawer and noting that the plate had become "fogged". He determined that

15200-506: The fissile component, and on 29 February 1940, Nier used an instrument he built at the University of Minnesota to separate the world's first uranium-235 sample in the Tate Laboratory. Using Columbia University 's cyclotron , John Dunning confirmed the sample to be the isolated fissile material on 1 March. Further work found that the far more common uranium-238 isotope can be transmuted into plutonium, which, like uranium-235,

15352-611: The food people eat. Worldwide production of uranium in 2021 was 48,332 tonnes , of which 21,819 t (45%) was mined in Kazakhstan . Other important uranium mining countries are Namibia (5,753 t), Canada (4,693 t), Australia (4,192 t), Uzbekistan (3,500 t), and Russia (2,635 t). Uranium ore is mined in several ways: open pit , underground , in-situ leaching , and borehole mining . Low-grade uranium ore mined typically contains 0.01 to 0.25% uranium oxides. Extensive measures must be employed to extract

15504-486: The future will pose no significant health or environmental risk. Nuclear reprocessing does not eliminate the need for a repository, but reduces the volume, the long-term radiation hazard, and long-term heat dissipation capacity needed. Reprocessing does not eliminate the political and community challenges to repository siting. Natural uranium ore deposits serve as proof of concept for stability of radioactive elements in geological formations— Cigar Lake Mine for example

15656-448: The highest atomic weight of the primordially occurring elements. Its density is about 70% higher than that of lead and slightly lower than that of gold or tungsten . It occurs naturally in low concentrations of a few parts per million in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite . Many contemporary uses of uranium exploit its unique nuclear properties. Uranium-235

15808-732: The late Middle Ages , pitchblende was extracted from the Habsburg silver mines in Joachimsthal , Bohemia (now Jáchymov in the Czech Republic) in the Ore Mountains , and was used as a coloring agent in the local glassmaking industry. In the early 19th century, the world's only known sources of uranium ore were these mines. The discovery of the element is credited to the German chemist Martin Heinrich Klaproth . While he

15960-470: The latest spending blueprint will not include any money for licensing the project. On February 7, Energy Secretary Dan Brouillette echoed Trump's sentiment and stated that the U.S. administration may investigate other types of [nuclear] storage, such as interim or temporary sites in other parts of the country. Though no formal plan had solidified from the federal government, the private sector moved forward with their own plans. Holtec International submitted

16112-410: The latter concentration is used to replace HEU fuels when converting to LEU. Highly enriched uranium (HEU) has a 20% or higher concentration of U. This high enrichment level is essential for nuclear weapons and certain specialized reactor designs. The fissile uranium in nuclear weapon primaries usually contains 85% or more of U known as weapons grade , though theoretically for an implosion design ,

16264-405: The level of enrichment desired and upon the amount of U that ends up in the depleted uranium. However, unlike the number of SWUs required during enrichment, which increases with decreasing levels of U in the depleted stream, the amount of NU needed will decrease with decreasing levels of U that end up in the DU. For example, in the enrichment of LEU for use in a light water reactor it is typical for

16416-531: The license given to SILEX over nuclear proliferation concerns. It has also been claimed that Israel has a uranium enrichment program housed at the Negev Nuclear Research Center site near Dimona . During the Manhattan Project , weapons-grade highly enriched uranium was given the codename oralloy , a shortened version of Oak Ridge alloy, after the location of the plants where the uranium was enriched. This covert terminology underscores

16568-515: The long term and ensuring a GDF supports local interests and priorities. The policy is emphatic in requiring the consent of the people who would be living alongside a GDF and giving them influence over the pace at which discussions progress. The first Working Groups were established in Copeland [4] and Allerdale [5] in Cumbria during late 2020 and early 2021. These Working Groups have started

16720-601: The metal from its ore. High-grade ores found in Athabasca Basin deposits in Saskatchewan , Canada can contain up to 23% uranium oxides on average. Uranium ore is crushed and rendered into a fine powder and then leached with either an acid or alkali . The leachate is subjected to one of several sequences of precipitation, solvent extraction, and ion exchange. The resulting mixture, called yellowcake , contains at least 75% uranium oxides U 3 O 8 . Yellowcake

16872-491: The military sector is in high-density penetrators. This ammunition consists of depleted uranium (DU) alloyed with 1–2% other elements, such as titanium or molybdenum . At high impact speed, the density, hardness, and pyrophoricity of the projectile enable the destruction of heavily armored targets. Tank armor and other removable vehicle armor can also be hardened with depleted uranium plates. The use of depleted uranium became politically and environmentally contentious after

17024-462: The new element after the recently discovered planet Uranus . Eugène-Melchior Péligot was the first person to isolate the metal, and its radioactive properties were discovered in 1896 by Henri Becquerel . Research by Otto Hahn , Lise Meitner , Enrico Fermi and others, such as J. Robert Oppenheimer starting in 1934 led to its use as a fuel in the nuclear power industry and in Little Boy ,

17176-584: The newly discovered metal itself (in fact, that powder was an oxide of uranium ). He named the newly discovered element after the planet Uranus (named after the primordial Greek god of the sky ), which had been discovered eight years earlier by William Herschel . In 1841, Eugène-Melchior Péligot , Professor of Analytical Chemistry at the Conservatoire National des Arts et Métiers (Central School of Arts and Manufactures) in Paris , isolated

17328-599: The nuclear fuel cycle. A major downblending undertaking called the Megatons to Megawatts Program converts ex-Soviet weapons-grade HEU to fuel for U.S. commercial power reactors. From 1995 through mid-2005, 250 tonnes of high-enriched uranium (enough for 10,000 warheads) was recycled into low-enriched uranium. The goal is to recycle 500 tonnes by 2013. The decommissioning programme of Russian nuclear warheads accounted for about 13% of total world requirement for enriched uranium leading up to 2008.This ambitious initiative not only addresses nuclear disarmament goals but also serves as

17480-544: The ones produced during D–T fusion . HEU is also used in fast neutron reactors , whose cores require about 20% or more of fissile material, as well as in naval reactors , where it often contains at least 50% U, but typically does not exceed 90%. These specialized reactor systems rely on highly enriched uranium for their unique operational requirements, including high neutron flux and precise control over reactor dynamics. The Fermi-1 commercial fast reactor prototype used HEU with 26.5% U. Significant quantities of HEU are used in

17632-656: The only commercial reactors capable of using unenriched uranium fuel. Fuel used for United States Navy reactors is typically highly enriched in uranium-235 (the exact values are classified ). In a breeder reactor , uranium-238 can also be converted into plutonium-239 through the following reaction: Before (and, occasionally, after) the discovery of radioactivity, uranium was primarily used in small amounts for yellow glass and pottery glazes, such as uranium glass and in Fiestaware . The discovery and isolation of radium in uranium ore (pitchblende) by Marie Curie sparked

17784-452: The past two decades, the most notable of these countries being Iran and North Korea, though all countries have had very limited success up to this point. Atomic vapor laser isotope separation employs specially tuned lasers to separate isotopes of uranium using selective ionization of hyperfine transitions . The technique uses lasers tuned to frequencies that ionize U atoms and no others. The positively charged U ions are then attracted to

17936-487: The physical explanation in February 1939 and named the process " nuclear fission ". Soon after, Fermi hypothesized that fission of uranium might release enough neutrons to sustain a fission reaction. Confirmation of this hypothesis came in 1939, and later work found that on average about 2.5 neutrons are released by each fission of uranium-235. Fermi urged Alfred O. C. Nier to separate uranium isotopes for determination of

18088-557: The possibility that these organisms could be used in bioremediation to decontaminate uranium-polluted water. The proteobacterium Geobacter has also been shown to bioremediate uranium in ground water. The mycorrhizal fungus Glomus intraradices increases uranium content in the roots of its symbiotic plant. In nature, uranium(VI) forms highly soluble carbonate complexes at alkaline pH. This leads to an increase in mobility and availability of uranium to groundwater and soil from nuclear wastes which leads to health hazards. However, it

18240-431: The process of obtaining consent for hosting a GDF in their areas. These Working Groups are believed to be a critical step in the process to find a willing community and a suitable, feasible and acceptable site for a GDF. Allerdale withdrew from the process to select a deep waste repository site in 2023. NWS explained this decision in terms of there being insufficient extent of potentially suitable geology in which to undertake

18392-492: The production of medical isotopes , for example molybdenum-99 for technetium-99m generators .The medical industry benefits from the unique properties of highly enriched uranium, which enable the efficient production of critical isotopes essential for diagnostic imaging and therapeutic applications Isotope separation is difficult because two isotopes of the same element have nearly identical chemical properties, and can only be separated gradually using small mass differences. (U

18544-429: The release of energy during detonation. For the secondary of a large nuclear weapon, the higher critical mass of less-enriched uranium can be an advantage as it allows the core at explosion time to contain a larger amount of fuel. This design strategy optimizes the explosive yield and performance of advanced nuclear weapons systems. The U is not said to be fissile but still is fissionable by fast neutrons (>2 MeV) such as

18696-431: The same separation than the older gaseous diffusion process, which it has largely replaced and so is the current method of choice and is termed second generation . It has a separation factor per stage of 1.3 relative to gaseous diffusion of 1.005, which translates to about one-fiftieth of the energy requirements. Gas centrifuge techniques produce close to 100% of the world's enriched uranium. The cost per separative work unit

18848-467: The secrecy and sensitivity surrounding the production of highly enriched uranium during World War II, highlighting the strategic importance of the Manhattan Project and its role in the development of nuclear weapons. The term oralloy is still occasionally used to refer to enriched uranium. Uranium Uranium is a chemical element with the symbol U and atomic number 92. It is

19000-550: The shorter half-lives of these parents and their lower production than U and Pu, the parents of thorium: the Cm/ U ratio at the formation of the Solar System was (7.0 ± 1.6) × 10 . Some bacteria, such as Shewanella putrefaciens , Geobacter metallireducens and some strains of Burkholderia fungorum , use uranium for their growth and convert U(VI) to U(IV). Recent research suggests that this pathway includes reduction of

19152-531: The site in 2004. The Finnish government issued the company a licence for constructing the final disposal facility in November 2015. As of June 2019 , continuous delays mean that Posiva expects operations to begin in 2023. A number of repositories including potash mines in Herfa-Neurode and Zielitz have been used for years for the storage of highly toxic mercury , cyanide and arsenic waste. There

19304-509: The soluble U(VI) via an intermediate U(V) pentavalent state. Other organisms, such as the lichen Trapelia involuta or microorganisms such as the bacterium Citrobacter , can absorb concentrations of uranium that are up to 300 times the level of their environment. Citrobacter species absorb uranyl ions when given glycerol phosphate (or other similar organic phosphates). After one day, one gram of bacteria can encrust themselves with nine grams of uranyl phosphate crystals; this creates

19456-509: The stabilization of political and economical turmoil of the early 1990s. For example, in 1993 there were 29 incidents ranking above level 1 on the International Nuclear Event Scale , and this number dropped under four per year in 1995–2003. The number of employees receiving annual radiation doses above 20 mSv , which is equivalent to a single full-body CT scan , saw a strong decline around 2000. In November 2015,

19608-515: The successful development of a new absorbent material dubbed HiCap which performs surface retention of solid or gas molecules, atoms or ions and also effectively removes toxic metals from water, according to results verified by researchers at Pacific Northwest National Laboratory . In 2005, ten countries accounted for the majority of the world's concentrated uranium oxides: Canada (27.9%), Australia (22.8%), Kazakhstan (10.5%), Russia (8.0%), Namibia (7.5%), Niger (7.4%), Uzbekistan (5.5%),

19760-455: The technology could contribute to nuclear proliferation . The fear of nuclear proliferation arose in part due to laser separation technology requiring less than 25% of the space of typical separation techniques, as well as requiring only the energy that would power 12 typical houses, putting a laser separation plant that works by means of laser excitation well below the detection threshold of existing surveillance technologies. Due to these concerns

19912-484: The technology, GE Hitachi Nuclear Energy (GEH) signed a commercialization agreement with Silex Systems in 2006. GEH has since built a demonstration test loop and announced plans to build an initial commercial facility. Details of the process are classified and restricted by intergovernmental agreements between United States, Australia, and the commercial entities. SILEX has been projected to be an order of magnitude more efficient than existing production techniques but again,

20064-510: The term 'Calutron' applies to a multistage device arranged in a large oval around a powerful electromagnet. Electromagnetic isotope separation has been largely abandoned in favour of more effective methods. One chemical process has been demonstrated to pilot plant stage but not used for production. The French CHEMEX process exploited a very slight difference in the two isotopes' propensity to change valency in oxidation/reduction , using immiscible aqueous and organic phases. An ion-exchange process

20216-513: The time splits into two smaller nuclei , releasing nuclear binding energy and more neutrons. If too many of these neutrons are absorbed by other uranium-235 nuclei, a nuclear chain reaction occurs that results in a burst of heat or (in some circumstances) an explosion. In a nuclear reactor, such a chain reaction is slowed and controlled by a neutron poison , absorbing some of the free neutrons. Such neutron absorbent materials are often part of reactor control rods (see nuclear reactor physics for

20368-572: The underground storage. Engineered barriers include bentonite clay and cement. In 2011, the International Panel on Fissile Materials said: It is widely accepted that spent nuclear fuel and high-level reprocessing and plutonium wastes require well-designed storage for periods ranging from tens of thousands to a million years, to minimize releases of the contained radioactivity into the environment. Safeguards are also required to ensure that neither plutonium nor highly enriched uranium

20520-506: The undesirable isotope uranium-236 , which undergoes neutron capture , wasting neutrons (and requiring higher U enrichment) and creating neptunium-237 , which would be one of the more mobile and troublesome radionuclides in deep geological repository disposal of nuclear waste. Reprocessed uranium often carries traces of other transuranic elements and fission products, necessitating careful monitoring and management during fuel fabrication and reactor operation. Low-enriched uranium (LEU) has

20672-560: The upper levels. Approval was granted in January 2022 for the construction of a direct disposal facility using KBS-3 technology, on the site of the Forsmark nuclear power plant . The UK Government, in common with many other countries and supported by scientific advice, has identified permanent deep underground disposal as the most appropriate means of disposing of higher activity radioactive waste. Radioactive Waste Management (RWM) [1]

20824-698: The uranium ore body. This plutonium and the other transuranics remained immobile until the present day, a span of almost 2 billion years. This is remarkable as ground water had ready access to the deposits and they were not in a chemically inert form, such as glass. Deep geologic disposal has been studied for several decades, including laboratory tests, exploratory boreholes , and the construction and operation of underground research laboratories where large-scale in-situ tests are being conducted. Major underground test facilities are listed below. Cigéo ( Centre Industriel de Stockage Géologique ) Bure, Meuse The process of selecting appropriate deep final repositories

20976-727: The use of such munitions by the US, UK and other countries during wars in the Persian Gulf and the Balkans raised questions concerning uranium compounds left in the soil (see Gulf War syndrome ). Depleted uranium is also used as a shielding material in some containers used to store and transport radioactive materials. While the metal itself is radioactive, its high density makes it more effective than lead in halting radiation from strong sources such as radium . Other uses of depleted uranium include counterweights for aircraft control surfaces, as ballast for missile re-entry vehicles and as

21128-547: The use of uranium hexafluoride and produce enriched uranium oxide. Reprocessed uranium (RepU) undergoes a series of chemical and physical treatments to extract usable uranium from spent nuclear fuel. RepU is a product of nuclear fuel cycles involving nuclear reprocessing of spent fuel . RepU recovered from light water reactor (LWR) spent fuel typically contains slightly more U than natural uranium , and therefore could be used to fuel reactors that customarily use natural uranium as fuel, such as CANDU reactors . It also contains

21280-528: The use of uranium in manufacturing and metalwork. Tools made with these formulas remained in use for several decades, until the Manhattan Project and the Cold War placed a large demand on uranium for fission research and weapon development. A team led by Enrico Fermi in 1934 found that bombarding uranium with neutrons produces beta rays ( electrons or positrons from the elements produced; see beta particle ). The fission products were at first mistaken for new elements with atomic numbers 93 and 94, which

21432-542: The whole facility (later, the town of Arco became the first in the world to have all its electricity come from nuclear power generated by BORAX-III , another reactor designed and operated by Argonne National Laboratory ). The world's first commercial scale nuclear power station, Obninsk in the Soviet Union , began generation with its reactor AM-1 on 27 June 1954. Other early nuclear power plants were Calder Hall in England, which began generation on 17 October 1956, and

21584-680: The world's largest single uranium deposit is located at the Olympic Dam Mine in South Australia . There is a significant reserve of uranium in Bakouma , a sub-prefecture in the prefecture of Mbomou in the Central African Republic . Some uranium also originates from dismantled nuclear weapons. For example, in 1993–2013 Russia supplied the United States with 15,000 tonnes of low-enriched uranium within

21736-545: The world. Thermal diffusion uses the transfer of heat across a thin liquid or gas to accomplish isotope separation. The process exploits the fact that the lighter U gas molecules will diffuse toward a hot surface, and the heavier U gas molecules will diffuse toward a cold surface. The S-50 plant at Oak Ridge, Tennessee , was used during World War II to prepare feed material for the Electromagnetic isotope separation (EMIS) process, explained later in this article. It

21888-422: Was abandoned in favor of gaseous diffusion. The gas centrifuge process uses a large number of rotating cylinders in series and parallel formations. Each cylinder's rotation creates a strong centripetal force so that the heavier gas molecules containing U move tangentially toward the outside of the cylinder and the lighter gas molecules rich in U collect closer to the center. It requires much less energy to achieve

22040-588: Was believed that uranium was relatively rare, and that nuclear proliferation could be avoided by simply buying up all known uranium stocks, but within a decade large deposits of it were discovered in many places around the world. The X-10 Graphite Reactor at Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee, formerly known as the Clinton Pile and X-10 Pile, was the world's second artificial nuclear reactor (after Enrico Fermi's Chicago Pile) and

22192-534: Was developed by the Asahi Chemical Company in Japan that applies similar chemistry but effects separation on a proprietary resin ion-exchange column. Plasma separation process (PSP) describes a technique that makes use of superconducting magnets and plasma physics . In this process, the principle of ion cyclotron resonance is used to selectively energize the U isotope in a plasma containing

22344-690: Was established in 2014 to deliver a Geological Disposal Facility (GDF) and is a subsidiary of the Nuclear Decommissioning Authority (NDA) [2] which is responsible for clean-up of the UK's historical nuclear sites. In 2022, Nuclear Waste Services (NWS) formed from the merger of RWM with the Low Level Waste Repository in Cumbria. A GDF will be delivered through a community consent-based process [3] , working in close partnership with communities, building trust for

22496-556: Was from ex-Soviet sources. From 1993 to 2005 the Material Protection, Control, and Accounting Program , operated by the federal government of the United States , spent about US$ 550 million to help safeguard uranium and plutonium stockpiles in Russia. This money was used for improvements and security enhancements at research and storage facilities. Safety of nuclear facilities in Russia has been significantly improved since

22648-541: Was leaking from the mine since 1988 but was not reported until June 2008. The repository for radioactive waste Morsleben is a deep geological repository for radioactive waste in the rock salt mine Bartensleben in Morsleben , in Saxony-Anhalt / Germany , that was used from 1972 to 1998. Since 2003, 480,000 m (630,000 cu yd) of salt-concrete has been pumped into the pit to temporarily stabilize

22800-491: Was the first reactor designed and built for continuous operation. Argonne National Laboratory 's Experimental Breeder Reactor I , located at the Atomic Energy Commission's National Reactor Testing Station near Arco, Idaho , became the first nuclear reactor to create electricity on 20 December 1951. Initially, four 150-watt light bulbs were lit by the reactor, but improvements eventually enabled it to power

22952-566: Was used as an analytical chemistry reporting standard. Deep geological repository Highly toxic waste that cannot be further recycled must be stored in isolation, to avoid contamination of air, ground and underground water. Deep geological repository is a type of long-term storage that isolates waste in geological structures that are expected to be stable for millions of years, with a number of natural and engineered barriers. Natural barriers include water-impermeable (e.g. clay) and gas-impermeable (e.g. salt) layers of rock above and surrounding

23104-454: Was working in his experimental laboratory in Berlin in 1789, Klaproth was able to precipitate a yellow compound (likely sodium diuranate ) by dissolving pitchblende in nitric acid and neutralizing the solution with sodium hydroxide . Klaproth assumed the yellow substance was the oxide of a yet-undiscovered element and heated it with charcoal to obtain a black powder, which he thought was

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