105-677: The Salt Wells Pilot Plant was a facility established by the Manhattan Project at the Naval Ordnance Test Station (NOTS) at Inyokern, California , where non-nuclear explosive components of nuclear weapons were manufactured. The first explosives were melted, mixed and poured on 25 July 1945. Between 1945 and 1954, it manufactured explosive components of the Fat Man , Mark 4 , Mark 5 and Mark 12 nuclear bombs . The Salt Wells Pilot Plant also helped design, equip, and train workers for
210-550: 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
315-733: 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
420-607: 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
525-418: A chemical engineer, of technical aspects; and Palmer Sabin was chief architect. The firm of Holmes and Narver were chosen as architect-engineers, and Haddock Engineers as the construction contractor. Complicating the construction program was the fact that Los Alamos had not finalized what processes would be used. Of particular concern was whether they would use casting or hot pressing with the explosives. For
630-707: 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
735-856: 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
840-477: 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
945-399: A mixture of TNT and barium nitrate , with a small quantity (about 1%) of paraffin wax used as a phlegmatizing agent . TNT typically makes up 25% to 33% of the mixture. Because of the high density of barium nitrate, Baratol has a density of at least 2.5 g/cm . Baratol, which has a detonation velocity of only about 4,900 metres per second, was used as the slow-detonating explosive in
1050-572: 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
1155-499: 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
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#17328488515811260-541: A production site, so different methods were required. Special instrumentation was devised by Caltech's Ira Bowen to assess the quality of the explosive blocks. In 1945, 120 prefabricated housing units had been hurriedly erected to provide accommodation for the work force. Rent was $ 15 for a furnished one-bedroom unit, $ 19 for a two-bedroom unit and $ 23 for a three-bedroom unit. Despite their temporary nature, these units were retained, and remained occupied until 1961. The influx of new employees called for more accommodation, and
1365-501: A quarter of the 100 scientists and engineers accepted other jobs at NOTS. Others went to Picatinny Arsenal and the Lawrence Livermore National Laboratory . The plant closed on 30 June 1954. Manhattan Project The Manhattan Project 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
1470-470: 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
1575-462: 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
1680-598: 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
1785-660: 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
1890-575: 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
1995-487: A spherical shape using a combination of both slow and fast high explosives. The design of lenses that detonated with the proper shape and velocity turned out to be slow, difficult and frustrating. Various explosives were tested before settling on composition B as the fast explosive and baratol as the slow explosive. The final design resembled a soccer ball, with 20 hexagonal and 12 pentagonal lenses, each weighing about 80 pounds (36 kg). The explosive lenses required by
2100-481: A time, work proceeded so as to accommodate either process, but ultimately a decision was required. Lauritsen pushed for a decision, and in April it was decided to use the melting and casting method. Work commenced on 80 buildings, 52 of them permanent. To meet the deadline, construction was carried out around the clock. Equipping the plants involved its own challenges. As soon as specifications were drawn up for certain items,
2205-475: 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
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#17328488515812310-913: The Burlington AEC Plant in Iowa and the Pantex Plant in Texas. The Salt Wells Pilot Plant closed on 30 June 1954. In the early 1930s, an emergency landing field was built by the Works Progress Administration in the Mojave Desert near the small town of Inyokern, California . Opened in 1935, it was acquired by the United States Army Air Forces (USAAF) in 1942 after the United States became involved in World War II , and became part of
2415-503: The Atomic Energy Commission (AEC), which took over from the Manhattan Project on 1 January 1947, spent $ 3.252 million on 380 sets of family quarters, streets, electricity, sewers, mains water, and a small school, which was named after Groves, that opened in 1948. Improved techniques and facilities allowed the plant, which operated on a 48-hour week, with the occasional 51- and 54-hour week, to triple its output in 1947. By 1949,
2520-737: 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. ,
2625-627: 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
2730-526: 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
2835-562: 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
2940-570: The Muroc Bombing and Gunnery Range . In 1943, the Office of Scientific Research and Development (OSRD) contracted with the California Institute of Technology (Caltech) for the testing and evaluation of rockets for the Navy. A suitable test area was required for this convenient to Pasadena, California , so the area was transferred from the Army to the Navy in October 1943, and commissioned as
3045-494: The Naval Ordnance Test Station (NOTS), Inyokern , on 8 November 1943, under the command of Captain Sherman E. Burroughs, Jr. Workshops, laboratories and facilities were constructed for over 600 men. During 1944, NOTS worked on the development and testing of the 3.5-inch , 5-inch , HVAR and 11.75-inch (Tiny Tim) rockets. By late 1944, rocket development and testing work began to taper off, and production models started to reach
3150-594: 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
3255-478: 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
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3360-853: 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
3465-565: 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 a simpler gun-type design called Little Boy
3570-655: 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
3675-671: 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
3780-612: 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
3885-736: 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
3990-609: 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
4095-590: The Fat Man had to be fabricated. A small explosive plant was established at Los Alamos known as Site S, as it was a former sawmill. Groves was appalled at the work practices and safety at Site S, and considered it only a matter of time before it blew up. Graves expressed his concerns about Site S to Captain William S. (Deak) Parsons , a Navy officer who was in charge of O (for ordnance) Division at Los Alamos. Parsons recommended establishing another explosives plant. While Site S had
4200-596: 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
4305-801: 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
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4410-513: 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,
4515-403: 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
4620-521: The Navy and USAAF in quantity. The director of the OSRD, Vannevar Bush , saw an opportunity to use some of the expertise at Caltech on another secret wartime project he was involved with, the Manhattan Project . Bush arranged for Charles C. Lauritsen , the head of the rocket team at Caltech, to visit the Los Alamos Laboratory , and meet with the project director, Major General Leslie R. Groves, Jr. ,
4725-480: The Navy might err too far on the side of workplace safety when time was of the utmost importance. On 1 January 1945, Groves and Parsons flew to Pasadena, California , where they met with Lauritsen and Bruce Sage, who had built the China Lake Pilot Plant where the rockets were made, and it was agreed that Caltech would build and operate the pilot plant for the manufacture of the non-nuclear explosives used in
4830-464: 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
4935-713: 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
5040-573: 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 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
5145-475: 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
5250-564: The assembly line. The molds, which needed to be surrounded by cooling water coils, proved difficult to fabricate, and went through several design changes. The melting kettles required stainless steel mixing blades, cooling jackets and tilting supports. Since each held enough high explosive to level a building, they were operated remotely, behind thick concrete walls. Groves felt that his fears about excessive safety were realized; reinforced concrete structures, barricades, blast proof doors, deluge systems and electrical shielding all drove up costs. In
5355-476: The atomic bomb. Groves wanted the plant working within 100 days to meet the expected demand in the months to come. A site was chosen in the Salt Wells Valley. The cost of the plant and its equipment were estimated at $ 13 million. Sage was in overall charge, with particular responsibility for planning, administration and the approval of special equipment. William Lacey was in charge of safety; Paul A. Longwell,
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#17328488515815460-670: 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
5565-683: 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
5670-405: The capacity to produce enough explosive lenses for one or two bombs per month, more might be required. Parsons suggested that NOTS might be a suitable location. It was remote and easy to secure, and Caltech had experience with pilot plants, such as the ones at Eaton Canyon and China Lake, where rocket propellants were manufactured. Groves had some misgivings about this, because he thought that
5775-402: 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:
5880-437: The design group would place orders for them. Some facilities had to be fabricated for the purpose. Some items were hard to locate, while others were in short supply in the wartime economy. The Manhattan Project's overriding priority overcame this problem. In some cases, the Army had representatives at the factories where items were made who designated them for use by the Manhattan Project and took possession of them as they came off
5985-471: 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
6090-433: 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,
6195-482: 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
6300-429: 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
6405-437: The end, the Salt wells Pilot Plant was completed and equipped for $ 16,500,000. The first explosives were melted, mixed and poured on 25 July 1945, missing the 100-day deadline by 15 days. The end of the war in August 1945 did not immediately affect operations at the Salt Wells Pilot Plant. Indeed, the process chosen for manufacturing the explosives, that of melting and casting, more or less mandated that operations continue, as it
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#17328488515816510-418: 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 was for building and operating the plants that produced
6615-418: 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
6720-415: 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. Baratol Baratol is an explosive made of
6825-422: 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
6930-464: 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
7035-401: 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
7140-411: 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
7245-476: 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
7350-437: 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
7455-425: 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
7560-491: 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
7665-415: The laboratory director, Robert Oppenheimer , and senior scientists. Oppenheimer and Lauritsen knew each other well, as Oppenheimer had worked at Caltech before the war. In addition to its scientists, Caltech also possessed an experienced procurement team, headed by Trevor Gardner . This group worked closely with its counterpart at Los Alamos, which was headed by Lieutenant Colonel Robert W. Lockridge. All
7770-519: 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
7875-484: 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
7980-551: 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
8085-505: 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
8190-403: 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
8295-464: The new plant, which became operational in 1949. Negotiations began for land, and plans and designs were made, for a new, larger still, plant at Chillicothe, Ohio , but it was decided not to proceed with building it. Another facility was established at the Pantex Plant near Amarillo, Texas , which became operational in 1953. Once again, the staff at the Salt Wells Pilot Plant helped establish
8400-573: The new plant. While the introduction of the Mark 4 nuclear bomb to replace the Fat Man (the Mark 3) in 1949 caused few problems, that of the Mark 5 nuclear bomb in 1951 required extensive re-tooling. The Los Alamos Scientific Laboratory and Salt Wells Pilot Plant staffs agreed to adopt direct machining of the explosive components. While this was known to generate additional heat, tests at both sites had been conducted without an explosive accident. Further re-tooling
8505-457: The pilot plant employed over 700 people. The lenses were initially shipped by rail, but this was inconvenient because their high security classification required armed guards. This was therefore replaced by an air transport route, with the lenses being flown in C-54 aircraft based at Fairfield-Suisun Army Air Base . On two occasions, C-54s loaded with explosives were struck by lightning, but no damage to
8610-611: The plane, the crew or the explosives resulted. As production increased, the advantages of additional plants became obvious. Brigadier General James McCormack , the AEC Director of Military Application, had his staff investigate World War II ordnance installations, looking for ones that could be converted to use as an additional plants. One was selected at Burlington, Iowa , which became the Burlington AEC Plant . The Salt Wells Pilot Plant helped design, equip, and train workers for
8715-544: 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
8820-567: 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
8925-528: 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
9030-598: 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,
9135-528: 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
9240-438: 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
9345-434: The work done at NOTS on behalf of the Manhattan Project came under the codename Project Camel . The name is said to have come from a remark by a Los Alamos scientist that once a camel (meaning Caltech) gets its nose under a tent flap it is hard to dislodge. The Los Alamos Laboratory was engaged in the development of an implosion-type nuclear weapon , codenamed Fat Man . This used explosive lenses to focus an explosion onto
9450-569: 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
9555-573: 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
9660-471: 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 the University of Chicago , the project designed
9765-515: 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
9870-547: 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
9975-443: 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
10080-408: 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
10185-556: Was required for the Mark 12 nuclear bomb explosives, which the Salt Wells Pilot Plant began manufacturing in 1953. It also began tooling up for the Mark 13 nuclear bomb . In January 1954, the AEC informed the Salt Well Pilot Plant staff that the plant would be closed. The Salt Wells Pilot Plant had a higher unit cost than Burlington or Pantex, largely because its isolation required more expenditure on overhead and community costs. About
10290-421: 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
10395-505: Was that all civilian staff were transferred from Caltech to the United States federal civil service in October 1945. All employees of the Salt Wells Pilot Plant, whether military or civilian, had to hold Q clearances . Production at Site S ceased in late 1945 due to the cold weather. By the time it became warmer, the Los Alamos Laboratory had lost so many staff that routine manufacture of explosive lenses would have unacceptably hindered casting of explosives for experimental purposes. All work
10500-426: Was then done at Salt Wells. The last construction work was completed in January 1946, and all equipment was installed and working by May 1946, by which time the plant had been in operation for several months. Work was initially dogged by an unacceptably large number of defects in the form of cracks or imperfections in the explosive blocks. The core of the problem was that the techniques used at Los Alamos did not scale to
10605-417: 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
10710-469: 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
10815-410: 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
10920-476: Was undesirable to allow a full kettle of high explosive to freeze solid. There were administrative changes, however. On 6 August 1945, Sage proposed that Salt Wells and China Lake Pilot Plants be placed under a single administration. Sage was the only candidate for the administrator position, and this change was implemented with the concurrence of both the Manhattan Project and the Bureau of Ordnance . Another major change
11025-520: 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
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