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S-1 Executive Committee

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194-714: The S-1 Executive Committee laid the groundwork for the Manhattan Project by initiating and coordinating the early research efforts in the United States, and liaising with the Tube Alloys Project in Britain. In the wake of the discovery of nuclear fission in December 1938, the possibility that Nazi Germany might develop nuclear weapons prompted Leo Szilard and Eugene Wigner to draft

388-494: A German atomic bomb project would develop one first, especially among scientists who were refugees from Nazi Germany and other fascist countries. In August 1939, Hungarian-born physicists Leo Szilard and Eugene Wigner drafted the Einstein–Szilard letter , which warned of the potential development of "extremely powerful bombs of a new type". It urged the United States to acquire stockpiles of uranium ore and accelerate

582-456: A mass spectrometer . These were ready in February 1940, and Dunning, Eugene T. Booth and Aristid von Grosse then carried out a series of experiments. They demonstrated that uranium-235 was indeed primarily responsible for fission with slow neutrons, but were unable to determine precise neutron capture cross sections because their samples were not sufficiently enriched. Pegram forwarded

776-755: A neutron moderator . The S-1 Committee recommended pursuing all five technologies. This was approved by Bush, Conant, and Brigadier General Wilhelm D. Styer , who had been designated the Army's representative on nuclear matters. Bush and Conant then took the recommendation to the Top Policy Group with a budget proposal for $ 54 million for construction by the United States Army Corps of Engineers , $ 31 million for research and development by OSRD and $ 5 million for contingencies in fiscal year 1943. They sent it on 17 June 1942, to

970-619: A AAA rating whenever it was required. Nelson initially balked but quickly caved in when Groves threatened to go to the President. Groves promised not to use the AAA rating unless it was necessary. It soon transpired that for the routine requirements of the project the AAA rating was too high but the AA-3 rating was too low. After a long campaign, Groves finally received AA-1 authority on 1 July 1944. According to Groves, "In Washington you became aware of

1164-528: 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

1358-412: 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

1552-539: 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 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

1746-660: A fission bomb was theoretically possible. The properties of pure uranium-235 were relatively unknown, as were those of plutonium, which had only been isolated by Glenn Seaborg and his team in February 1941. The scientists at the July 1942 conference envisioned creating plutonium in nuclear reactors where uranium-238 atoms absorbed neutrons that had been emitted from fissioning uranium-235. At this point no reactor had been built, and only tiny quantities of plutonium were available from cyclotrons . Even by December 1943, only two milligrams had been produced. There were many ways of arranging

1940-566: 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

2134-741: A fuel in the nuclear power industry and in Little Boy , 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

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2328-627: 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

2522-497: A lesser degree uranium-233, have a much higher fission cross-section for slow neutrons. In sufficient concentration, these isotopes maintain 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

2716-884: A liaison office in Washington, D.C., but established his temporary headquarters at 270 Broadway in New York, where he could draw on administrative support from the Corps of Engineers' North Atlantic Division . It was close to the Manhattan office of Stone & Webster , the principal project contractor, and to Columbia University. He had permission to draw on his former command, the Syracuse District, for staff, and he started with Lieutenant Colonel Kenneth Nichols , who became his deputy. Because most of his task involved construction, Marshall worked in cooperation with

2910-486: A meeting called by Stimson, which established a Military Policy Committee, responsible to the Top Policy Group, consisting of Bush (with Conant as an alternate), Styer and Rear Admiral William R. Purnell . Tolman and Conant were later appointed as Groves' scientific advisers. On 19 September, Groves went to Donald Nelson , the chairman of the War Production Board, and asked for broad authority to issue

3104-448: 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

3298-578: A plant, much less four of them for $ 90 million." A single TNT plant that Nichols had recently built in Pennsylvania had cost $ 128 million. Nor were they impressed with estimates to the nearest order of magnitude, which Groves compared with telling a caterer to prepare for between ten and a thousand guests. A survey team from Stone & Webster had already scouted a site for the production plants. The War Production Board recommended sites around Knoxville, Tennessee , an isolated area where

3492-459: 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

3686-504: A possible source of bombs with a destructiveness vastly greater than anything now known." In February 1940, the U.S. Navy awarded Columbia University $ 6,000, most of which Fermi and Szilard spent on graphite . A team of Columbia professors including Fermi, Szilard, Eugene T. Booth and John Dunning created the first nuclear fission reaction in the Americas, verifying the work of Hahn and Strassmann. The same team subsequently built

3880-480: A ranch. On 16 November 1942, Oppenheimer, Groves, Dudley and others toured the vicinity of the Los Alamos Ranch School . Oppenheimer expressed a strong preference for the site, citing its natural beauty, which, it was hoped, would inspire those working on the project. The engineers were concerned about the poor access road, and whether the water supply would be adequate, but otherwise felt that it

4074-469: A reaction becomes self-sustaining became known as "going critical". Compton reported the success to Conant in Washington, D.C., by a coded phone call, saying, "The Italian navigator [Fermi] has just landed in the new world." In January 1943, Grafton's successor, Major Arthur V. Peterson , ordered Chicago Pile-1 dismantled and reassembled at the Argonne Forest site, as he regarded the operation of

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4268-405: 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

4462-619: A reactor as too hazardous for a densely populated area. The new site, still operated by the Metallurgical Laboratory, became known as ' Site A '. Chicago Pile-3 , the first heavy water reactor, also went critical at this site, on 15 May 1944. After the war, operations at Site A were moved about 6 miles (9.7 km) to DuPage County , the current location of the Argonne National Laboratory . By December 1942 there were concerns that even Oak Ridge

4656-540: A review of the uranium project by the National Academy of Sciences . The review committee was chaired by Arthur Compton , with physicists Ernest O. Lawrence , John C. Slater , and John H. Van Vleck and chemist William D. Coolidge as its other members. It issued a favorable report on May 17, 1941, recommending an intensified effort, but Bush was troubled by the emphasis on nuclear power instead of nuclear weapons, and had two engineers, Oliver E. Buckley from

4850-684: A series of prototype nuclear reactors (or "piles" as Fermi called them) in Pupin Hall at Columbia but were not yet able to achieve a chain reaction. The Advisory Committee on Uranium became the National Defense Research Committee (NDRC) on Uranium when that organization was formed on 27 June 1940. On 28 June 1941, Roosevelt signed Executive Order 8807, which created the Office of Scientific Research and Development (OSRD), under director Vannevar Bush . The office

5044-413: 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

5238-525: 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

5432-550: A simpler gun-type design called Little Boy was developed that used uranium-235 . Three methods were employed for uranium enrichment : electromagnetic , gaseous , and thermal . In parallel with the work on uranium was an effort to produce plutonium. After the feasibility of the world's first artificial nuclear reactor, the Chicago Pile-1 , was demonstrated in 1942 at the Metallurgical Laboratory in

5626-592: A special account not subject to the usual auditing and controls was used to hold Trust monies. Between 1944 and his resignation from the Trust in 1947, Groves deposited a total of $ 37.5 million. Groves appreciated the early British atomic research and the British scientists' contributions to the Manhattan Project but stated that the United States would have succeeded without them, although not in time for

5820-412: 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,

6014-535: 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

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6208-552: 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

6402-523: 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

6596-530: 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

6790-520: 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

6984-785: 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

7178-418: 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

7372-485: 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

7566-479: Is likely to be started." In Serber's account, Oppenheimer mentioned the possibility of this scenario to Arthur Compton , who "didn't have enough sense to shut up about it. It somehow got into a document that went to Washington" and was "never laid to rest". The Chief of Engineers , Major General Eugene Reybold , selected Colonel James C. Marshall to head the Army's part of the project in June 1942. Marshall created

7760-427: 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

7954-424: Is present. Uranium-238 is fissionable by fast neutrons and is fertile , meaning it can be transmuted to fissile plutonium-239 in 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

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8148-407: 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

8342-441: 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

8536-600: 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

8730-777: The Belgian Government in Exile was in London. Britain agreed to give the United States most of the Belgian ore, as it could not use most of the supply without restricted American research. In 1944, the Trust purchased 3,440,000 pounds (1,560,000 kg) of uranium oxide ore from companies operating mines in the Belgian Congo. To avoid briefing US Secretary of the Treasury Henry Morgenthau Jr. ,

8924-493: The Bell Telephone Laboratories and L. Warrington Chubb from Westinghouse added to produce a second report with an emphasis on estimating how soon practical benefits could be expected. On June 28, 1941, Roosevelt issued Executive Order 8807, creating the Office of Scientific Research and Development (OSRD), with Bush as its director personally responsible to the president. The new organisation subsumed

9118-581: The Carnegie Institution of Washington and later the Naval Research Laboratory . Murphree also headed an unsuccessful separation project using gas centrifuges . Meanwhile, there were two lines of investigation into nuclear reactor technology : Harold Urey researched heavy water at Columbia, while Arthur Compton organized the Metallurgical Laboratory in early 1942 to study plutonium and reactors using graphite as

9312-476: The Carnegie Institution of Washington , and Szilárd, Wigner and Edward Teller . Einstein was invited but declined to attend. Adamson was skeptical about the prospect of building an atomic bomb, but was willing to authorize $ 6,000 (equivalent to $ 130,000 in 2023 current dollars) for the purchase of uranium and graphite for Szilárd and Fermi's experiments into producing a nuclear chain reaction at Columbia University. The Advisory Committee on Uranium reported to

9506-534: The Chief of Staff of the Army , General George C. Marshall . Roosevelt chose the Army to run the project rather than the Navy, because the Army had more experience with managing large-scale construction. He agreed to coordinate the effort with the British and on 11 October sent a message to Prime Minister Winston Churchill , suggesting that they correspond on atomic matters. The S-1 Committee meeting on 18 December 1941

9700-576: The Clinton Engineer Works (CEW) in early 1943. While Stone & Webster concentrated on the production facilities, the architectural and engineering firm Skidmore, Owings & Merrill developed a residential community for 13,000. The community was located on the slopes of Black Oak Ridge, from which the new town of Oak Ridge got its name. The Army presence at Oak Ridge increased in August 1943 when Nichols replaced Marshall as head of

9894-670: The Einstein–Szilárd letter to the President of the United States , Franklin D. Roosevelt , in August 1939. In response, the Advisory Committee on Uranium was created at the National Bureau of Standards under the chairmanship of Lyman J. Briggs to determine the feasibility of nuclear weapons . In June 1940, the National Defense Research Committee (NDRC) was created to coordinate defense-related research, and

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10088-402: 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

10282-497: 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

10476-475: 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

10670-721: 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

10864-605: The Tennessee Valley Authority could supply ample electric power and the rivers could provide cooling water for the reactors. After examining several sites, the survey team selected one near Elza, Tennessee . Conant advised that it be acquired at once and Styer agreed but Marshall temporized, awaiting the results of Conant's reactor experiments. Of the prospective processes, only Lawrence's electromagnetic separation appeared sufficiently advanced for construction to commence. Marshall and Nichols began assembling

11058-465: 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

11252-426: The University of Birmingham had made a breakthrough investigating the critical mass of uranium-235 in June 1939. Their calculations indicated that it was within an order of magnitude of 10 kilograms (22 lb), small enough to be carried by contemporary bombers. Their March 1940 Frisch–Peierls memorandum initiated the British atomic bomb project and its MAUD Committee , which unanimously recommended pursuing

11446-600: The University of Birmingham in England, who ironically had been assigned to investigate nuclear weapons by Mark Oliphant because, as enemy aliens in Britain, they were ineligible to participate in secret war work, issued the Frisch–Peierls memorandum in March 1940. The memorandum contradicted the common thinking of the time that many tons of uranium would be needed to make a bomb, requiring delivery by ship. The calculation in

11640-935: The University of Chicago , the project designed the X-10 Graphite Reactor and the production reactors at the Hanford Site , in which uranium was irradiated and transmuted into plutonium. The Fat Man plutonium implosion-type weapon was developed in a concerted design and development effort by the Los Alamos Laboratory. The project was also charged with gathering intelligence on the German nuclear weapon project . Through Operation Alsos , Manhattan Project personnel served in Europe, sometimes behind enemy lines, where they gathered nuclear materials and documents, and rounded up German scientists. Despite

11834-545: The University of Chicago . Another $ 500,000 was earmarked for raw materials. His proposed schedule was no less breathtaking: to produce a nuclear chain reaction by July 1942, and an atomic bomb by January 1945. In January 1942, he created the Metallurgical Laboratory , centralizing the work at the University of Chicago. The March 9, 1942, meeting of the S-1 Section was attended by Brigadier General Wilhelm D. Styer ,

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12028-649: The Whiskey Rebellion . Most are short-lived, terminating after a couple of years, with their membership changing when a new president takes office. The committee consisted of Briggs, Adamson and Hoover. Its first meeting was held on October 21, 1939, at the National Bureau of Standards in Washington, D.C. In addition to the committee members, it was attended by physicists Fred L. Mohler from the National Bureau of Standards and Richard B. Roberts from

12222-439: 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 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

12416-604: 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

12610-432: 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

12804-407: The program to produce heavy water . The September 1942 meeting was held at Bohemian Grove . Nichols and Major Thomas T. Crenshaw, Jr., attended, along with physicist Robert Oppenheimer . This meeting resolved most of the outstanding issues confronting the project, but Bush and Conant felt that the time had now come for the Army to take over the project, something that had already been approved by

12998-416: The symbol U and atomic number 92. It is 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

13192-764: The 18th floor of 270 Broadway in New York City. He chose the name Development of Substitute Materials (DSM), but this would not stick. Colonel Leslie R. Groves, Jr. , the head of the Construction Branch in the Office of the Chief of Engineers thought it would attract undue attention. Instead, the new district was given the innocuous name of the Manhattan Engineer District , following the usual practice of naming engineer districts after

13386-453: The 1930s, but had encountered technical difficulties. The process required high rotational speeds, but at certain speeds harmonic vibrations developed that threatened to tear the machinery apart. It was therefore necessary to accelerate quickly through these speeds. In 1941 he began working with uranium hexafluoride , the only known gaseous compound of uranium, and was able to separate uranium-235. At Columbia, Urey had Karl P. Cohen investigate

13580-503: The 1930s. Two of them, Leo Szilard and Eugene Wigner drafted the Einstein–Szilárd letter to the President of the United States , Franklin D. Roosevelt . It advised Roosevelt of the existence of the German nuclear weapon project , warned that it was likely the Germans were working on an atomic bomb using uranium , and urged that the United States secure sources of uranium and conduct research into nuclear weapon technology. The letter

13774-770: The Advisory Committee on Uranium became the Uranium Committee of the NDRC. In June 1941, Roosevelt created the Office of Scientific Research and Development under the leadership of Vannevar Bush (OSRD), at it incorporated the NDRC, now under James B. Conant . The Uranium Committee became the Uranium Section of the OSRD, which was soon renamed the S-1 Section for security reasons. By May 1942, it

13968-656: The Army allowed the crops to be harvested, but this was not always possible. The land acquisition process dragged on and was not completed before the end of the Manhattan Project in December 1946. The dispute did not delay work. Although progress on the reactor design at Metallurgical Laboratory and DuPont was not sufficiently advanced to accurately predict the scope of the project, a start was made in April 1943 on facilities for an estimated 25,000 workers, half of whom were expected to live on-site. By July 1944, some 1,200 buildings had been erected and nearly 51,000 people were living in

14162-690: The Army's component the Manhattan District; Reybold officially created this district on 13 August. Informally, it was known as the Manhattan Engineer District, or MED. Unlike other districts, it had no geographic boundaries, and Marshall had the authority of a division engineer. Development of Substitute Materials remained as the official codename of the project as a whole but was supplanted over time by "Manhattan". Marshall later conceded that, "I had never heard of atomic fission but I did know that you could not build much of

14356-625: The August 1945 bombing of Hiroshima. The British wartime participation was crucial to the success of the United Kingdom's independent nuclear weapons program after the war when the McMahon Act of 1946 temporarily ended American nuclear cooperation. The day after he took over the project, Groves went to Tennessee with Colonel Marshall to inspect the proposed site there, and Groves was impressed. On 29 September 1942, United States Under Secretary of War Robert P. Patterson authorized

14550-757: The Australian physicist Mark Oliphant , flew to the US in late August 1941 and discovered that data provided by the MAUD Committee had not reached key American physicists. Oliphant set out to find out why the committee's findings were apparently being ignored. He met with the Uranium Committee and visited Berkeley, California , where he spoke persuasively to Ernest O. Lawrence . Lawrence was sufficiently impressed to commence his own research into uranium. He in turn spoke to James B. Conant , Arthur H. Compton and George B. Pegram . Oliphant's mission

14744-772: The British Tube Alloys project. The United States Army created the Manhattan District in June 1942, and took over responsibility for the development of nuclear weapons from the S-1 Executive Committee in September 1942. The OSRD's research and development contracts were terminated as they lapsed, and production contracts were terminated and transferred to the Army. Although the S-1 Executive Committee remained as an advisory body, it became inactive. The OSRD and NDRC continued to influence

14938-452: The British, and possibly the Germans too. On April 15, 1941, Briggs received a note from Rudolf Ladenburg , a physicist at Princeton University , stating: It may interest you that a colleague of mine who arrived from Berlin via Lisbon a few days ago, brought the following message: a reliable colleague who is working at a technical research laboratory asked him to let us know that a large number of German physicists are working intensively on

15132-560: The Budget , gave Bush assurances that should OSRD resources prove insufficient, additional funding would be made available from monies controlled by the president. Oliphant flew to the United States from England in August 1941 to find out why Briggs and his committee were apparently ignoring the MAUD Report. Oliphant discovered to his dismay that the reports and other documents sent directly to Briggs had not been shared with all members of

15326-609: The Corps of Engineers to acquire 56,000 acres (23,000 ha) of land by eminent domain at a cost of $ 3.5 million. An additional 3,000 acres (1,200 ha) was subsequently acquired. About 1,000 families were affected by the order, which came into effect on 7 October. Protests, legal appeals, and a 1943 Congressional inquiry were to no avail. By mid-November U.S. Marshals were posting notices to vacate on farmhouse doors, and construction contractors were moving in. Some families were given two weeks' notice to vacate farms that had been their homes for generations. The ultimate cost of

15520-640: 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

15714-408: 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

15908-606: The Manhattan Engineer District. One of his first tasks was to move the district headquarters to Oak Ridge, although the name of the district did not change. In September 1943 the administration of community facilities was outsourced to Turner Construction Company through a subsidiary, the Roane-Anderson Company. Chemical engineers were part of "frantic efforts" to make 10% to 12% enriched uranium 235, with tight security and fast approvals for supplies and materials. The population of Oak Ridge soon expanded well beyond

16102-821: The Manhattan Project conducted weapons testing at Bikini Atoll as part of Operation Crossroads , developed new weapons, promoted the development of the network of national laboratories , supported medical research into radiology and laid the foundations for the nuclear navy . It maintained control over American atomic weapons research and production until the formation of the United States Atomic Energy Commission (AEC) in January 1947. The discovery of nuclear fission by Otto Hahn and Fritz Strassmann in 1938, and its theoretical explanation by Lise Meitner and Otto Frisch , made an atomic bomb theoretically possible. There were fears that

16296-581: The Manhattan Project through the participation of Bush and Conant in the Military Policy Committee that controlled what became the Manhattan Project . The discovery of nuclear fission in December 1938, reported in the January 6, 1939 issue of Die Naturwissenschaften by Otto Hahn , and Fritz Strassmann , and its correct identification as nuclear fission by Lise Meitner in the February 11, 1939 issue of Nature , generated intense interest among physicists. Even before publication,

16490-524: The Manhattan Project's emphasis on security, Soviet atomic spies penetrated the program. The first nuclear device ever detonated was an implosion-type bomb during the Trinity test , conducted at White Sands Proving Ground in New Mexico on 16 July 1945. Little Boy and Fat Man bombs were used a month later in the atomic bombings of Hiroshima and Nagasaki , respectively. In the immediate postwar years,

16684-403: The Metallurgical Laboratory, was assigned to assist Oppenheimer by coordinating experimental physics groups scattered across the country. Oppenheimer and Robert Serber of the University of Illinois examined the problems of neutron diffusion—how neutrons moved in a nuclear chain reaction—and hydrodynamics —how the explosion produced by a chain reaction might behave. To review this work and

16878-501: The NDRC Committee on Uranium, reporting directly to him. Briggs remained chairman, but Hoover and Adamson were dropped from its membership, while Tuve, Pegram, Beams, Gunn, and Urey were added. For security reasons, no foreign-born scientists were appointed to the Uranium Committee. Publication of research into uranium, fission and isotope separation was now banned. Meanwhile, Otto Frisch and Rudolf Peierls , two researchers at

17072-426: The NDRC, now chaired by James B. Conant . The Uranium Committee became the Uranium Section of the OSRD, which was soon renamed the S-1 Section for security reasons. To the S-1 Section, Bush added Samuel K. Allison , Breit, Edward U. Condon , Lloyd P. Smith and Henry D. Smyth ; Gunn was dropped in line with an NDRC policy not to have Army or Navy personnel in the sections. Briggs remained the chairman, with Pegram as

17266-518: The National Bureau of Standards. It reviewed the work thus far and recommended increased support for research into both nuclear chain reactions and isotope separation. The German invasion of Belgium in May 1940 generated concern over the fate of uranium ore from the Belgian Congo , the world's largest source; the subsequent Battle of France created alarm in the administration over the direction

17460-405: The OSRD work, mainly the technical and contractual aspects of the project, while the Army handled engineering, construction and site selection. Procurement was an OSRD responsibility, but it could turn to the Army for help in case of difficulties. Bush obtained the president's approval for this, and on June 19, 1942, he abolished the S-1 Section and replaced it with the S-1 Executive Committee. Conant

17654-470: The OSRD's research and development contracts as they lapsed. Production contracts were terminated and transferred to the Army, mostly on March 31, 1943. While the S-1 Executive Committee remained as an advisory body, it became inactive, although not formally dissolved. Bush and Conant continued to influence the Manhattan Project through participation in the MPC. Manhattan Project The Manhattan Project

17848-632: The President on November 1, 1939. While acknowledging that the science was unproven and that nuclear chain reaction was no more than a theoretical possibility, it foresaw that nuclear energy might be used as propulsion for submarines, and that an atomic bomb "would provide a possible source of bombs with a destructiveness vastly greater than anything now known." The committee recommended that the government purchase 50 short tons (45 t) of uranium oxide and 4 short tons (3.6 t) of graphite for chain reaction experiments. It also recommended that Einstein, Karl Compton , George B. Pegram , and Sachs be added to

18042-411: The President, who approved it by writing "OK FDR" on the document. Compton asked theoretical physicist J. Robert Oppenheimer of the University of California to take over research into fast neutron calculations —key to calculations of critical mass and weapon detonation—from Gregory Breit , who had quit on 18 May 1942 because of concerns over lax operational security. John H. Manley , a physicist at

18236-726: The Quebec Agreement, the Americans' progress and expenditures amazed the British. Chadwick pressed for British involvement in the Manhattan Project to the fullest extent and abandoned hopes of an independent British project during the war. With Churchill's backing, he attempted to ensure that every request from Groves for assistance was honored. The British Mission that arrived in the United States in December 1943 included Niels Bohr , Otto Frisch, Klaus Fuchs , Rudolf Peierls, and Ernest Titterton . More scientists arrived in early 1944. While those assigned to gaseous diffusion left by

18430-691: 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

18624-489: The S-1 Section's progress. He personally delivered a third report from Arthur Compton, dated November 1, to Roosevelt on November 19, 1941. On December 6, 1941, Bush held a meeting to organize an accelerated research project managed by Compton, with Urey researching gaseous diffusion for uranium enrichment and Lawrence researching electromagnetic enrichment techniques. The next day, the Japanese attack on Pearl Harbor led to

18818-404: The United States entry into the war. With the United States at war, funding was now available in amounts undreamt of the year before. When, at the S-1 Section meeting on December 18, 1941, Lawrence asked for $ 400,000 for electromagnetic separation, the section immediately recommended granting it. Compton was allocated $ 340,000 for nuclear reactor research at Columbia and Princeton, and $ 278,000 at

19012-486: The academic scientists working on the project. Groves' orders placed him directly under Somervell rather than Reybold, with Colonel Marshall now answerable to Groves. Groves established his headquarters in Washington, D.C., in the New War Department Building , where Colonel Marshall had his liaison office. He assumed command of the Manhattan Project on 23 September 1942. Later that day, he attended

19206-705: The bomb design team at Los Alamos needed them, despite the risk of revealing weapon design secrets. In August 1943 Churchill and Roosevelt negotiated the Quebec Agreement , which established the Combined Policy Committee to coordinate the efforts of the US and UK; Canada was not a signatory, but the Agreement provided for a Canadian representative on the Combined Policy Committee in view of Canada's contribution to

19400-686: The bombs. The Army program was designated the Manhattan District , as its first headquarters were in Manhattan ; the name gradually superseded the official codename, Development of Substitute Materials , for the entire project. The project absorbed its earlier British counterpart, Tube Alloys , and subsumed the program from the American civilian Office of Scientific Research and Development . The Manhattan Project employed nearly 130,000 people at its peak and cost nearly US$ 2 billion (equivalent to about $ 27 billion in 2023), over 80 percent of which

19594-713: The branch office in Santa Fe, where she met new arrivals and issue them with passes. An Army-OSRD council on 25 June 1942 decided to build a pilot plant for plutonium production in the Argonne Forest preserve , southwest of Chicago. In July, Nichols arranged for a lease of 1,025 acres (415 ha) from the Cook County Forest Preserve District , and Captain James F. Grafton was appointed Chicago area engineer. It soon became apparent that

19788-566: 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

19982-460: The chief of staff of the newly created United States Army Services of Supply . OSRD contracts were due to expire at the end of June, and with the country at war, there was intense competition for raw materials. It was agreed that in 1942–43, the Army would fund $ 53 million of the $ 85 million program. On June 18, 1942, Colonel James C. Marshall was ordered to organize the Army component of the project. Marshall established his district headquarters on

20176-428: The city in which their headquarters was located. The name of the project soon followed suit. It was formally established by the Chief of Engineers , Major General Eugene Reybold on August 16, 1942. By May 1942, Conant felt that the S-1 Section had become too unwieldy. It had not met since the March meeting. When he needed expert advice in May, he had called upon a smaller group, and he recommended that this supervise

20370-409: 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

20564-620: The committee. When he read the report, Sachs felt that it was too academic and failed to make its points forcefully. Experiments with the fission of uranium were already proceeding at universities and research institutes in the United States. Alfred Lee Loomis was supporting Ernest Lawrence at the Berkeley Radiation Laboratory . Vannevar Bush was also doing similar research at the Carnegie Institution. At Columbia, while Fermi and Szilard investigated

20758-445: The committee; Briggs had locked them in a safe. Oliphant then met with Allison, Coolidge, Conant and Fermi to explain the urgency. In these meetings Oliphant spoke of an atomic bomb with forcefulness and certainty, and explained that Britain did not have the resources to undertake the project alone, so it was up to the United States. Bush met with Roosevelt and his vice president , Henry Wallace , on October 9, 1941, and briefed them on

20952-402: The construction camp. As area engineer, Matthias exercised overall control of the site. At its peak, the construction camp was the third most populous town in Washington state. Hanford operated a fleet of over 900 buses, more than the city of Chicago. Like Los Alamos and Oak Ridge, Richland was a gated community with restricted access, but it looked more like a typical wartime American boomtown:

21146-549: 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

21340-496: The conversation as: "Alex, what you are after is to see that the Nazis don't blow us up." He told Watson: "This requires action." As a result of the letter Roosevelt asked scientist Lyman J. Briggs , the director of the National Bureau of Standards , to organize an Advisory Committee on Uranium. Federal advisory committees had been a feature of the federal government since 1794, when George Washington had appointed one to investigate

21534-471: The deuterium concentration in the water from 2.3% to 99.8%. For this process, Hugh Taylor of Princeton developed a platinum-on-carbon catalyst for the first three stages while Urey developed a nickel- chromia one for the fourth stage tower. The final cost was $ 2.8 million. The Canadian Government did not officially learn of the project until August 1942. Trail's heavy water production started in January 1944 and continued until 1956. Heavy water from Trail

21728-505: The development of an atomic bomb as a matter of urgency, although it recognised that the resources required might be beyond those available to Britain. The MAUD Committee completed the MAUD report on July 15, 1941, and disbanded. The report had two parts; the first concluded that a uranium-235 bomb could be feasible in as little as two years using 25 pounds (11 kg) of uranium-235 with a yield equivalent to 1,800 tonnes of TNT (7,500 GJ);

21922-496: The development of an atomic bomb. In July 1940, Britain had offered to give the United States access to its research, and the Tizard Mission 's John Cockcroft briefed American scientists on British developments. He discovered that the American project was smaller than the British, and not as advanced. As part of the scientific exchange, the MAUD Committee's findings were conveyed to the United States. One of its members,

22116-442: 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

22310-399: The director of the Naval Research Laboratory (NRL), along with Sachs, Pegram, Fermi, Szilard, and Wigner. Once again, Einstein, although invited, declined to attend. The meeting highlighted differences between the optimistic Szilard and Sachs, and the more cautious Fermi. The committee agreed to proceed with the work at Columbia, which it hoped would demonstrate whether or not a chain reaction

22504-482: The efficiency of the bomb as it exploded. As the idea of the fission bomb was theoretically settled—at least until more experimental data was available—Edward Teller pushed for discussion of a more powerful bomb: the "super", now usually referred to as a " hydrogen bomb ", which would use the force of a detonating fission bomb to ignite a nuclear fusion reaction in deuterium and tritium . Teller proposed scheme after scheme, but Bethe refused each one. The fusion idea

22698-503: The effort. An agreement between Roosevelt and Churchill known as the Hyde Park Aide-Mémoire , signed in late September 1944, extended the Quebec Agreement to the postwar period and suggested that "when a 'bomb' is finally available, it might perhaps, after mature consideration, be used against the Japanese, who should be warned that this bombardment will be repeated until they surrender". When cooperation resumed after

22892-465: 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

23086-418: The fall of 1944, the thirty-five working under Oliphant with Lawrence at Berkeley were assigned to existing laboratory groups and most stayed until the end of the war. The nineteen sent to Los Alamos also joined existing groups, primarily related to implosion and bomb assembly, but not the plutonium-related ones. The Quebec Agreement specified that nuclear weapons would not be used against another country without

23280-493: 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

23474-446: 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

23668-418: The first Canadian reactor, and the first to be completed outside the United States, when it went critical in September 1945; ZEEP remained in use by researchers until 1970. A larger 10 MW NRX reactor, which was designed during the war, was completed and went critical in July 1947. The Eldorado Mine at Port Radium was a source of uranium ore. Uranium Uranium is a chemical element with

23862-468: 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

24056-506: 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,

24250-422: The fissile material into a critical mass. The simplest was shooting a "cylindrical plug" into a sphere of "active material" with a "tamper"—dense material to focus neutrons inward and keep the reacting mass together to increase its efficiency. They also explored designs involving spheroids , a primitive form of " implosion " suggested by Richard C. Tolman , and the possibility of autocatalytic methods to increase

24444-611: 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

24638-520: The general theory of fission reactions, Oppenheimer and Fermi convened meetings at the University of Chicago in June and at the University of California in July 1942 with theoretical physicists Hans Bethe , John Van Vleck , Edward Teller, Emil Konopinski , Robert Serber, Stan Frankel , and Eldred C. (Carlyle) Nelson, and experimental physicists Emilio Segrè , Felix Bloch , Franco Rasetti , Manley, and Edwin McMillan . They tentatively confirmed that

24832-401: The head of the Corps of Engineers Construction Division, Major General Thomas M. Robbins , and his deputy, Colonel Leslie Groves . Reybold, Somervell, and Styer decided to call the project "Development of Substitute Materials", but Groves felt that this would draw attention. Since engineer districts normally carried the name of the city where they were located, Marshall and Groves agreed to name

25026-411: The highest rating he could assign was AA-3, although he was willing to provide a AAA rating on request for critical materials if the need arose. Nichols and Marshall were disappointed; AA-3 was the same priority as Nichols' TNT plant in Pennsylvania. Vannevar Bush became dissatisfied with Colonel Marshall's failure to get the project moving forward expeditiously and felt that more aggressive leadership

25220-533: The importance of top priority. Most everything proposed in the Roosevelt administration would have top priority. That would last for about a week or two and then something else would get top priority". One of Groves' early problems was to find a director for Project Y , the group that would design and build the bomb. The obvious choice was one of the three laboratory heads, Urey, Lawrence, or Compton, but they could not be spared. Compton recommended Oppenheimer, who

25414-498: The industrial manufacturing area of Ontario and Quebec, and proximity to a rail head adjacent to a large military base, Camp Petawawa . Located on the Ottawa River, it had access to abundant water. The first director of the new laboratory was Hans von Halban . He was replaced by John Cockcroft in May 1944, who was succeeded by Bennett Lewis in September 1946. A pilot reactor known as ZEEP (zero-energy experimental pile) became

25608-500: The initial plans, and peaked at 75,000 in May 1945, by which time 82,000 people were employed at the Clinton Engineer Works, and 10,000 by Roane-Anderson. The idea of locating Project Y at Oak Ridge was considered, but it was decided that it should be in a remote location. On Oppenheimer's recommendation, the search for a suitable site was narrowed to the vicinity of Albuquerque, New Mexico , where Oppenheimer owned

25802-491: The issues involved in setting up a laboratory in a remote area and should be appointed as its director. Groves personally waived the security requirements and issued Oppenheimer's clearance on 20 July 1943. The British and Americans exchanged nuclear information but did not initially combine their efforts; during 1940-41 the British project ( Tube Alloys ) was larger and more advanced. Britain rebuffed attempts by Bush and Conant in August 1941 to strengthen cooperation because it

25996-535: The land acquisition, which was not completed until March 1945, was only about $ 2.6 million—around $ 47 an acre. When presented with a proclamation declaring Oak Ridge a total exclusion area that no one could enter without military permission, the Governor of Tennessee , Prentice Cooper , angrily tore it up. Initially known as the Kingston Demolition Range, the site was officially renamed

26190-800: 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

26384-530: The memorandum showed that a bomb might be possible using as little as 1 to 10 kilograms (2.2 to 22.0 lb) of pure uranium-235, which would be quite practical for aircraft to carry. Oliphant took the memorandum on to Henry Tizard , and the MAUD Committee was established to investigate further. It concluded that an atomic bomb was not only technically feasible, but could be produced in as little as two years. The Committee unanimously recommended pursuing

26578-601: 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

26772-488: The military necessity continues". Wartime land purchases eventually came to 49,383 acres (19,985 ha), but only $ 414,971 was spent. Work commenced in December 1942. Groves initially allocated $ 300,000 for construction, three times Oppenheimer's estimate, but by the time Sundt finished on 30 November 1943, over $ 7 million had been spent. During the war, Los Alamos was referred to as "Site Y" or "the Hill". Initially it

26966-551: The military profile was lower, and physical security elements like high fences and guard dogs were less evident. Canada provided research, extraction and production of uranium and plutonium, and Canadian scientists worked at Los Alamos. Cominco had produced electrolytic hydrogen at Trail, British Columbia , since 1930. Urey suggested in 1941 that it could produce heavy water. To the existing $ 10 million plant consisting of 3,215 cells consuming 75 MW of hydroelectric power, secondary electrolysis cells were added to increase

27160-491: 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

27354-422: The mineral pitchblende is credited to Martin Heinrich Klaproth , who named 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

27548-516: The mutual consent of the US and UK. In June 1945, Wilson agreed that the nuclear bombing of Japan would be recorded as a decision of the Combined Policy Committee. The Combined Policy Committee created the Combined Development Trust in June 1944, with Groves as its chairman, to procure uranium and thorium ores on international markets. The Belgian Congo and Canada held much of the world's uranium outside Eastern Europe, and

27742-403: The necessary resources. The first step was to obtain a high priority rating for the project. The top ratings were AA-1 through AA-4 in descending order, although there was a special AAA rating reserved for emergencies. Ratings AA-1 and AA-2 were for essential weapons and equipment, so Colonel Lucius D. Clay , the deputy chief of staff at Services and Supply for requirements and resources, felt that

27936-584: 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

28130-588: The news was brought to the United States by Danish physicist Niels Bohr , who opened the Fifth Washington Conference on Theoretical Physics with Enrico Fermi on January 26, 1939. The results were quickly corroborated by experimental physicists, most notably Fermi and John R. Dunning at Columbia University . The possibility that Nazi Germany might develop nuclear weapons was particularly alarming to refugee scientists from Germany and other fascist countries, many of whom had left Europe in

28324-656: 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

28518-431: 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

28712-411: The possibility of creating a nuclear chain reaction, Dunning considered the possibility, advanced by Niels Bohr and John A. Wheeler but discounted by Fermi, that it was the rare uranium-235 isotope of uranium that was primarily responsible for fission. He had Alfred O. C. Nier from the University of Minnesota prepare samples of uranium enriched in uranium-234 , uranium-235 and uranium-238 using

28906-557: 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

29100-415: The president on June 17, 1942. After some discussion, it was decided that Groves, who would be promoted to the rank of brigadier general, would become the director of the Manhattan Project on September 23, 1942. He would be answerable to the Military Policy Committee (MPC), which would consist of Styer, Bush (with Conant as his alternate) and Rear Admiral William R. Purnell . The Army took full control over

29294-416: The problem of the uranium bomb under direction of Heisenberg , that Heisenberg himself tries to delay the work as much as possible, fearing catastrophic results of a success. But he cannot help fulfilling the orders given to him, and if the problem can be solved, it will be solved probably in the near future. So he gave the advice to us to hurry up if U.S.A. will not come too late. Bush therefore commissioned

29488-412: The process, and he produced a body of mathematical theory making it possible to design a centrifugal separation unit, which Westinghouse undertook to construct. Another possibility was gaseous diffusion , which George B. Kistiakowsky suggested at a lunch on May 21, 1940. The September 1940 Tizard Mission shared the British results with the Americans, but this only made them aware that they were behind

29682-547: The research of Enrico Fermi and others into nuclear chain reactions . They had it signed by Albert Einstein and delivered to President Franklin D. Roosevelt . Roosevelt called on Lyman Briggs of the National Bureau of Standards to head an Advisory Committee on Uranium ; Briggs met with Szilard, Wigner and Edward Teller in October 1939. The committee reported back to Roosevelt in November that uranium "would provide

29876-574: The results to Briggs on March 11, 1940; they were subsequently published to the Physical Review ' s March 15 and April 15, 1940 issues. Briggs reported to Watson on April 9 that it was doubtful that a chain reaction could be initiated in uranium without uranium enrichment , and therefore urged that research be undertaken into isotope separation technology. Nier, Booth, Dunning and von Grosse's results were discussed by Jesse Beams , Ross Gunn , Fermi, Nier, Merle Tuve and Harold Urey at

30070-572: The scale of operations was too great for the area, and it was decided to build the pilot plant at Oak Ridge and keep a research and testing facility in Chicago. Delays in establishing the plant at Argonne led Arthur Compton to authorize the Metallurgical Laboratory to construct the first nuclear reactor beneath the bleachers of Stagg Field at the University of Chicago. The reactor required an enormous amount of highly purified graphite blocks and uranium in both metallic and powdered oxide forms. At

30264-431: The second concluded that the controlled fission be a source of energy for powering machines and a source of radio-isotopes. As a result of the MAUD Committee report, the British started an atomic bomb program under the codename Tube Alloys . Urey began considering isotope separation methods. The centrifuge process was regarded as the most promising. Beams had developed such a process at the University of Virginia during

30458-550: 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

30652-540: The site be located far from the existing uranium production facility at Oak Ridge. In December 1942, Groves dispatched Colonel Franklin Matthias and DuPont engineers to scout potential sites. Matthias reported that Hanford Site near Richland, Washington , was "ideal in virtually all respects". It was isolated and near the Columbia River , which could supply sufficient water to cool the reactors. Groves visited

30846-613: The site in January and established the Hanford Engineer Works (HEW), codenamed "Site W". Under Secretary Patterson gave his approval on 9 February, allocating $ 5 million for the acquisition of 430,000 acres (170,000 ha). The federal government relocated some 1,500 residents of nearby settlements, as well as the Wanapum and other tribes using the area. A dispute arose with farmers over compensation for crops, which had already been planted. Where schedules allowed,

31040-509: 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

31234-514: The spring meeting of the American Physical Society in Washington, D.C., in the last week of April 1940. The New York Times reported that conferees argued "the probability of some scientist blowing up a sizable portion of the earth with a tiny bit of uranium." The Advisory Committee on Uranium met again at the National Bureau of Standards on April 27, 1940. This time they were joined by Rear Admiral Harold G. Bowen, Sr. ,

31428-509: 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,

31622-515: 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%),

31816-513: 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

32010-528: The time, there was a limited source of pure uranium metal; Frank Spedding of Iowa State University was able to produce only two short tons . Three short tons was supplied by Westinghouse Lamp Plant , produced in a rush with makeshift process. A large square balloon was constructed by Goodyear Tire to encase the reactor. On 2 December 1942, a team led by Enrico Fermi initiated the first artificial self-sustaining nuclear chain reaction in an experimental reactor known as Chicago Pile-1 . The point at which

32204-438: The two countries were reversed, and in January 1943 Conant notified the British that they would no longer receive atomic information except in certain areas. The British investigated the possibility of an independent nuclear program but determined that it could not be ready in time to impact the war in Europe . By March 1943 Conant decided that James Chadwick and one or two other British scientists were important enough that

32398-727: 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

32592-528: 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

32786-451: The vice chairman. In line with the president's wishes, matters of policy were restricted to the president, Wallace, Bush, Conant, Secretary of War Henry Stimson and the Chief of Staff of the Army , General George C. Marshall . To implement this, the S-1 Section was placed outside NDRC, directly under Bush, who could authorize purchases. Harold D. Smith , the director of the Bureau of

32980-435: The war was taking. On June 12, 1940, Bush and Harry Hopkins went to the president with a proposal to create a National Defense Research Committee (NDRC) to coordinate defense-related research. The NDRC was formally created on June 27, 1940, with Bush as its chairman. It immediately absorbed the Advisory Committee on Uranium, which was indeed one of its purposes. Bush immediately reorganised the Advisory Committee on Uranium as

33174-487: 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

33368-680: 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

33562-514: Was "pervaded by an atmosphere of enthusiasm and urgency" in the wake of the attack on Pearl Harbor and the United States declaration of war on Japan and on Germany . Work was proceeding on three techniques for isotope separation : Lawrence and his team at the University of California investigated electromagnetic separation , Eger Murphree and Jesse Wakefield Beams 's team looked into gaseous diffusion at Columbia University , and Philip Abelson directed research into thermal diffusion at

33756-488: Was a research and development program undertaken during World War II to produce the first nuclear weapons . It was led by the United States in collaboration with the United Kingdom and Canada. From 1942 to 1946, the project was directed by Major General Leslie Groves of the U.S. Army Corps of Engineers . Nuclear physicist J. Robert Oppenheimer was the director of the Los Alamos Laboratory that designed

33950-573: Was already intimately familiar with the bomb design concepts. However, Oppenheimer had little administrative experience, and, unlike Urey, Lawrence, and Compton, had not won a Nobel Prize, which many scientists felt that the head of such an important laboratory should have. There were also concerns about Oppenheimer's security status, as many of his associates were communists , including his wife, Kitty ; his girlfriend, Jean Tatlock ; and his brother, Frank . A long conversation in October 1942 convinced Groves and Nichols that Oppenheimer thoroughly understood

34144-402: Was appointed as its chairman, and Briggs, Compton, Lawrence, Eger Murphree , and Urey as its other members. S-1 Executive Committee meetings were held on June 25, July 9, July 30, August 26, September 13–14, September 26, October 23–24, November 14, December 9, and December 19, 1942, and January 14, February 10–11, March 18, April 29, and September 10–11, 1943. Its first meeting on June 25, 1942

34338-601: Was attended by Bush, Styer and Colonels Marshall and Kenneth Nichols . It discussed the acquisition of land for the project's production facilities, which the Army recommended be in the vicinity of Knoxville, Tennessee , with the Boston firm of Stone & Webster as the project's principal contractor. The meeting on July 30, 1942, was devoted to reviewing progress on isotope separation by the centrifugal and gaseous diffusion methods. The August 26, 1942, meeting considered Lawrence's electromagnetic separation project, and expansion of

34532-588: 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

34726-461: Was empowered to engage in research and large engineering projects. The NDRC Committee on Uranium became the S-1 Section of the OSRD; the word "uranium" was dropped for security reasons. In July 1941, Briggs proposed spending $ 167,000 on researching uranium, particularly the uranium-235 isotope, and plutonium , which had been isolated for the first time at the University of California in February 1941. In Britain, Frisch and Rudolf Peierls at

34920-477: Was felt that the S-1 Section had become too unwieldy, and in June 1942, was replaced by the smaller S-1 Executive Committee . The feasibility of nuclear weapons was demonstrated by the British MAUD Committee , and its results were shared with the Advisory Committee on Uranium by the Tizard Mission . The S-1 Section coordinated research into nuclear weapons in United States, in cooperation with

35114-537: Was for building and operating the plants that produced the fissile material . Research and production took place at more than 30 sites across the US, the UK, and Canada. The project resulted in two types of atomic bombs, developed concurrently during the war: a relatively simple gun-type fission weapon and a more complex implosion-type nuclear weapon . The Thin Man gun-type design proved impractical to use with plutonium , so

35308-433: 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

35502-430: Was ideal. Patterson approved the acquisition of the site on 25 November 1942, authorizing $ 440,000 for the purchase of pre-calculated 54,000 acres (22,000 ha), all but 8,900 acres (3,600 ha) of which were already owned by the Federal Government. Secretary of Agriculture Claude R. Wickard granted about 45,000 acres (18,000 ha) of United States Forest Service land to the War Department "for so long as

35696-401: Was possible. Bowen and Gunn suggested the creation of a scientific subcommittee to advise the Advisory Committee on Uranium. Tuve and Vannevar Bush at the Carnegie Institution, expressed interest in this, and Briggs created it. Chaired by Briggs, its membership consisted of Urey, Pegram, Tuve, Beams, Gunn, and Gregory Breit . The scientific subcommittee met for the first time on June 13, 1940, at

35890-443: Was put aside to concentrate on producing fission bombs. Teller raised the speculative possibility that an atomic bomb might "ignite" the atmosphere because of a hypothetical fusion reaction of nitrogen nuclei. Bethe calculated that it was "extremely unlikely". A postwar report co-authored by Teller concluded that "whatever the temperature to which a section of the atmosphere may be heated, no self-propagating chain of nuclear reactions

36084-408: Was reluctant to share its technological lead and help the United States develop its own atomic bomb. But the British, who had made significant advances in research early in the war, did not have the resources to carry through such a research program into development while a large portion of their economy was engaged in fighting the war; Tube Alloys soon fell behind its American counterpart. The roles of

36278-421: Was required. He spoke to Harvey Bundy and Generals Marshall, Somervell, and Styer about his concerns, advocating that the project be placed under a senior policy committee, with a prestigious officer, preferably Styer, as director. Somervell and Styer selected Groves for the post; General Marshall ordered that he be promoted to brigadier general, as it was felt that the title "general" would hold more sway with

36472-536: Was signed by Albert Einstein on August 2, 1939, but its delivery was delayed because of the outbreak of World War II in Europe with the German invasion of Poland in September 1939. The letter was eventually hand-delivered to Roosevelt by the economist Alexander Sachs on October 11, 1939. On that date he met with the President, the President's secretary, Brigadier General Edwin "Pa" Watson , and two ordnance experts, Army Lieutenant Colonel Keith F. Adamson and Navy Commander Gilbert C. Hoover . Roosevelt summed up

36666-414: 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

36860-417: Was therefore a success; key American physicists were now aware of the potential power of an atomic bomb. On 9 October 1941, President Roosevelt approved the atomic program after he convened a meeting with Vannevar Bush and Vice President Henry A. Wallace . He created a Top Policy Group consisting of himself—although he never attended a meeting—Wallace, Bush, Conant, Secretary of War Henry L. Stimson , and

37054-412: Was to have been a military laboratory with Oppenheimer and other researchers commissioned into the Army, but Robert Bacher and Isidor Rabi balked at the idea and convinced Oppenheimer that other scientists would object. Conant, Groves, and Oppenheimer then devised a compromise whereby the laboratory was operated by the University of California under contract to the War Department. Dorothy McKibbin ran

37248-410: Was too close to a major population center (Knoxville) in the unlikely event of a major nuclear accident. Groves recruited DuPont in November 1942 to be the prime contractor for the construction of the plutonium production complex. The President of the company, Walter S. Carpenter Jr. , wanted no profit of any kind; for legal reasons a nominal fee of one dollar was agreed upon. DuPont recommended that

37442-410: Was used for Chicago Pile 3 , the first reactor using heavy water and natural uranium, which went critical on 15 May 1944. The Chalk River, Ontario , site was established to rehouse the Allied effort at the Montreal Laboratory away from an urban area. A new community was built at Deep River, Ontario , to provide residences and facilities for the team members. The site was chosen for its proximity to

37636-402: 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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