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 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 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 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 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 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, 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. [1]
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 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 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. [2] 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 the conversation as: "Alex, what you are after is to see that the Nazis don't blow us up." [3] He told Watson: "This requires action." [3]
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. [4] Federal advisory committees had been a feature of the federal government since 1794, when George Washington had appointed one to investigate the Whiskey Rebellion. [5] Most are short-lived, terminating after a couple of years, with their membership changing when a new president takes office. [6] 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 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 $130,000in 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. [7]
The Advisory Committee on Uranium reported to 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." [8] 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 the committee. When he read the report, Sachs felt that it was too academic and failed to make its points forcefully. [9]
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. [10] At Columbia, while Fermi and Szilard investigated 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. [1] 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 a mass spectrometer. [11]
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, [11] but were unable to determine precise neutron capture cross sections because their samples were not sufficiently enriched. [12] Pegram forwarded the results to Briggs on March 11, 1940; they were subsequently published to the Physical Review 's March 15 and April 15, 1940 issues. [13] [14] 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. [12] Nier, Booth, Dunning and von Grosse's results were discussed by Jesse Beams, Ross Gunn, Fermi, Nier, Merle Tuve and Harold Urey at the spring meeting of the American Physical Society in Washington, D.C., in the last week of April 1940. [12] 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." [15] [16]
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., 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 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 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. [17]
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; [17] the subsequent Battle of France created alarm in the administration over the direction 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. [18] The NDRC was formally created on June 27, 1940, with Bush as its chairman. [19] It immediately absorbed the Advisory Committee on Uranium, which was indeed one of its purposes. [18] Bush immediately reorganised the Advisory Committee on Uranium as 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. [20]
Meanwhile, Otto Frisch and Rudolf Peierls, two researchers at 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 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. [21] [22] [23]
Oliphant took the memorandum on to Henry Tizard, and the MAUD Committee was established to investigate further. [24] 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 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); 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. [25]
Urey began considering isotope separation methods. The centrifuge process was regarded as the most promising. [26] Beams had developed such a process at the University of Virginia during 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 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. [27]
The September 1940 Tizard Mission shared the British results with the Americans, but this only made them aware that they were behind the British, and possibly the Germans too. [28] 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 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. [29]
Bush therefore commissioned 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 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. [30]
On June 28, 1941, Roosevelt issued Executive Order 8807, creating the Office of Scientific Research and Development (OSRD), [31] with Bush as its director personally responsible to the president. The new organisation subsumed the NDRC, now chaired by James B. Conant. [19] The Uranium Committee became the Uranium Section of the OSRD, which was soon renamed the S-1 Section for security reasons. [32] [33] 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 the vice chairman. [34]
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 the Budget, gave Bush assurances that should OSRD resources prove insufficient, additional funding would be made available from monies controlled by the president. [35]
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 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. [36]
Bush met with Roosevelt and his vice president, Henry Wallace, on October 9, 1941, and briefed them on the S-1 Section's progress. [37] He personally delivered a third report from Arthur Compton, dated November 1, to Roosevelt on November 19, 1941. [38] 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. [39]
The next day, the Japanese attack on Pearl Harbor led to the United States entry into the war. [40] 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 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. [41]
The March 9, 1942, meeting of the S-1 Section was attended by Brigadier General Wilhelm D. Styer, 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. [42] [43]
Marshall established his district headquarters on 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 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. [43]
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 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 was appointed as its chairman, and Briggs, Compton, Lawrence, Eger Murphree, and Urey as its other members. [42] [43] [44]
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. [45] Its first meeting on June 25, 1942 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. [46] The August 26, 1942, meeting considered Lawrence's electromagnetic separation project, and expansion of the program to produce heavy water. [44]
The September 1942 meeting was held at Bohemian Grove. Nichols and Major Thomas T. Crenshaw, Jr., attended, along with physicist Robert Oppenheimer. [47] This meeting resolved most of the outstanding issues confronting the project, [47] 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 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. [47]
The Army took full control over the OSRD's research and development contracts as they lapsed. Production contracts were terminated and transferred to the Army, mostly on March 31, 1943. [45] 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. [48] [49]
Organization | Date | Expenditure |
---|---|---|
NDRC (of CND) | June 27, 1940 – June 28, 1941 | $468,000.00 |
NDRC (of OSRD) | June 28, 1941 – December 1941 | $452,650.00 |
S-1 Section | January–June 1942 | $1,952,168.00 |
Planning Board of OSRD | January–June 1942 | $2,224,392.77 |
S-1 Executive Committee | June 1942 – September 1943 | $13,041,037.57 |
The Manhattan Project was a program of research and development 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 under the direction of 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 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. The Manhattan Project employed nearly 130,000 people at its peak and cost nearly US$2 billion, over 80 percent of which 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.
Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioactive decay.
Vannevar Bush was an American engineer, inventor and science administrator, who during World War II headed the U.S. Office of Scientific Research and Development (OSRD), through which almost all wartime military R&D was carried out, including important developments in radar and the initiation and early administration of the Manhattan Project. He emphasized the importance of scientific research to national security and economic well-being, and was chiefly responsible for the movement that led to the creation of the National Science Foundation.
Leo Szilard was a Hungarian born physicist and inventor. He conceived the nuclear chain reaction in 1933, patented the idea in 1936, and in late 1939 wrote the letter for Albert Einstein's signature that resulted in the Manhattan Project that built the atomic bomb. According to György Marx, he was one of the Hungarian scientists known as The Martians.
Tube Alloys was the research and development programme authorised by the United Kingdom, with participation from Canada, to develop nuclear weapons during the Second World War. Starting before the Manhattan Project in the United States, the British efforts were kept classified, and as such had to be referred to by code even within the highest circles of government.
George Braxton Pegram was an American physicist who played a key role in the technical administration of the Manhattan Project. He graduated from Trinity College in 1895, and taught high school before becoming a teaching assistant in physics at Columbia University in 1900. He was to spend the rest of his working life at Columbia, taking his doctorate there in 1903 and becoming a full professor in 1918. His administrative career began as early as 1913 when he became the department's executive officer. By 1918, he was Dean of the Faculty of Applied Sciences but he resigned in 1930 to relaunch his research activities, performing many meticulous measurements on the properties of neutrons with John R. Dunning. He was also chairman of Columbia's physics department from 1913 to 1945.
Chicago Pile-1 (CP-1) was the world's first artificial nuclear reactor. On 2 December 1942, the first human-made self-sustaining nuclear chain reaction was initiated in CP-1 during an experiment led by Enrico Fermi. The secret development of the reactor was the first major technical achievement for the Manhattan Project, the Allied effort to create nuclear weapons during World War II. Developed by the Metallurgical Laboratory at the University of Chicago, CP-1 was built under the west viewing stands of the original Stagg Field. Although the project's civilian and military leaders had misgivings about the possibility of a disastrous runaway reaction, they trusted Fermi's safety calculations and decided they could carry out the experiment in a densely populated area. Fermi described the reactor as "a crude pile of black bricks and wooden timbers".
The Quebec Agreement was a secret agreement between the United Kingdom and the United States outlining the terms for the coordinated development of the science and engineering related to nuclear energy and specifically nuclear weapons. It was signed by Winston Churchill and Franklin D. Roosevelt on 19 August 1943, during World War II, at the First Quebec Conference in Quebec City, Quebec, Canada.
K-25 was the codename given by the Manhattan Project to the program to produce enriched uranium for atomic bombs using the gaseous diffusion method. Originally the codename for the product, over time it came to refer to the project, the production facility located at the Clinton Engineer Works in Oak Ridge, Tennessee, the main gaseous diffusion building, and ultimately the site. When it was built in 1944, the four-story K-25 gaseous diffusion plant was the world's largest building, comprising over 5,264,000 square feet (489,000 m2) of floor space and a volume of 97,500,000 cubic feet (2,760,000 m3).
The National Defense Research Committee (NDRC) was an organization created "to coordinate, supervise, and conduct scientific research on the problems underlying the development, production, and use of mechanisms and devices of warfare" in the United States from June 27, 1940, until June 28, 1941. Most of its work was done with the strictest secrecy, and it began research of what would become some of the most important technology during World War II, including radar and the atomic bomb. It was superseded by the Office of Scientific Research and Development in 1941, and reduced to merely an advisory organization until it was eventually terminated during 1947.
The Metallurgical Laboratory was a scientific laboratory at the University of Chicago that was established in February 1942 to study and use the newly discovered chemical element plutonium. It researched plutonium's chemistry and metallurgy, designed the world's first nuclear reactors to produce it, and developed chemical processes to separate it from other elements. In August 1942 the lab's chemical section was the first to chemically separate a weighable sample of plutonium, and on 2 December 1942, the Met Lab produced the first controlled nuclear chain reaction, in the reactor Chicago Pile-1, which was constructed under the stands of the university's old football stadium, Stagg Field.
The Manhattan Project was a research and development project that produced the first atomic bombs during World War II. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the US Army Corps of Engineers. The Army component of the project was designated the Manhattan District; "Manhattan" gradually became the codename for the entire project. Along the way, the project absorbed its earlier British counterpart, Tube Alloys. The Manhattan Project began modestly in 1939, but grew to employ more than 130,000 people and cost nearly US$2 billion. Over 90% of the cost was for building factories and producing the fissionable materials, with less than 10% for development and production of the weapons.
The MAUD Committee was a British scientific working group formed during the Second World War. It was established to perform the research required to determine if an atomic bomb was feasible. The name MAUD came from a strange line in a telegram from Danish physicist Niels Bohr referring to his housekeeper, Maud Ray.
The Einstein–Szilard letter was a letter written by Leo Szilard and signed by Albert Einstein on August 2, 1939, that was sent to President of the United States Franklin D. Roosevelt. Written by Szilard in consultation with fellow Hungarian physicists Edward Teller and Eugene Wigner, the letter warned that Germany might develop atomic bombs and suggested that the United States should start its own nuclear program. It prompted action by Roosevelt, which eventually resulted in the Manhattan Project, the development of the first atomic bombs, and the use of these bombs on the cities of Hiroshima and Nagasaki.
The S-50 Project was the Manhattan Project's effort to produce enriched uranium by liquid thermal diffusion during World War II. It was one of three technologies for uranium enrichment pursued by the Manhattan Project.
The X-10 Graphite Reactor is a decommissioned nuclear reactor at Oak Ridge National Laboratory in Oak Ridge, Tennessee. Formerly known as the Clinton Pile and X-10 Pile, it was the world's second artificial nuclear reactor, and the first designed and built for continuous operation. It was built during World War II as part of the Manhattan Project.
Walter Henry Zinn was a Canadian-born American nuclear physicist who was the first director of the Argonne National Laboratory from 1946 to 1956. He worked at the Manhattan Project's Metallurgical Laboratory during World War II, and supervised the construction of Chicago Pile-1, the world's first nuclear reactor, which went critical on December 2, 1942, at the University of Chicago. At Argonne he designed and built several new reactors, including Experimental Breeder Reactor I, the first nuclear reactor to produce electric power, which went live on December 20, 1951.
The Montreal Laboratory was a program established by the National Research Council of Canada during World War II to undertake nuclear research in collaboration with the United Kingdom, and to absorb some of the scientists and work of the Tube Alloys nuclear project in Britain. It became part of the Manhattan Project, and designed and built some of the world's first nuclear reactors.
Britain initiated the first research project to design an atomic bomb in 1941. Building on this work, Britain prompted the United States to recognise how important this type of research was, helped the U.S. to start the Manhattan Project in 1942, and supplied crucial expertise and materials that contributed to the project's successful completion in time to influence the end of the Second World War.
The P-9 Project was the codename given during World War II to the Manhattan Project's heavy water production program. The Cominco operation at Trail, British Columbia, was upgraded to produce heavy water. DuPont built three plants in the United States: at the Morgantown Ordnance Works, near Morgantown, West Virginia; at the Wabash River Ordnance Works, near Dana and Newport, Indiana; and at the Alabama Ordnance Works, near Childersburg and Sylacauga, Alabama. The American plants operated from 1943 until 1945. The Canadian plant at Trail continued in operation until 1956. Three nuclear reactors were built using the heavy water produced by the P-9 Project: Chicago Pile 3 at Argonne, and ZEEP and NRX at the Chalk River Laboratories in Canada.