Clinton Engineer Works

The Clinton Engineer Works (CEW) was the production installation of the Manhattan Project that during World War II produced the enriched uranium used in the 1945 bombing of Hiroshima, as well as the first examples of reactor-produced plutonium. It consisted of production facilities arranged at three major sites, various utilities including a power plant, and the town of Oak Ridge. It was in East Tennessee, about 18 miles (29 km) west of Knoxville, and was named after the town of Clinton, eight miles (13 km) to the north. The production facilities were mainly in Roane County, and the northern part of the site was in Anderson County. The Manhattan District Engineer, Kenneth Nichols, moved the Manhattan District headquarters from Manhattan to Oak Ridge in August 1943. During the war, Clinton's advanced research was managed for the government by the University of Chicago.

Construction workers were housed in a community known as Happy Valley. Built by the Army Corps of Engineers in 1943, this temporary community housed 15,000 people. The township of Oak Ridge was established to house the production staff. The operating force peaked at 50,000 workers just after the end of the war. The construction labor force peaked at 75,000 and the combined employment peak was 80,000. The town was developed by the federal government as a segregated community; black residents lived only in an area known as Gamble Valley, in government-built "hutments" (one-room shacks) on the south side of what is now Tuskegee Drive.

Y-12 Shift Change
Workers leaving the Manhattan Project's Y-12 plant on 11 August 1945

Site selection

Oak Ridge area 1942
Projected Site for Atomic Production Plants, 1942

In 1942, the Manhattan Project was attempting to construct the first atomic bombs. This would require production facilities, and by June 1942 the project had reached the stage where their construction could be contemplated. On 25 June, the Office of Scientific Research and Development (OSRD) S-1 Executive Committee deliberated on where they should be located. Brigadier General Wilhelm D. Styer recommended that the different manufacturing facilities be built at the same site in order to simplify security and construction. Such a site would require a substantial tract of land to accommodate both the facilities and housing for the thousands of workers. The plutonium processing plant needed to be two to four miles (3.2 to 6.4 km) from the site boundary and any other installation, in case radioactive fission products escaped. While security and safety concerns suggested a remote site, it still needed to be near sources of labor, and accessible by road and rail transportation. A mild climate that allowed construction to proceed throughout the year was desirable. Terrain separated by ridges would reduce the impact of accidental explosions, but they could not be so steep as to complicate construction. The substratum needed to be firm enough to provide good foundations, but not so rocky that it would hinder excavation work. It was estimated that the proposed plants would need access to 150,000 kW of electrical power and 370,000 US gallons (1,400,000 l) of water per minute.[1][2][3] A War Department policy held that, as a rule, munitions facilities should not be located west of the Sierra or Cascade Ranges, east of the Appalachian Mountains, or within 200 miles (320 km) of the Canadian or Mexican borders.[4]

Several sites were considered in the Tennessee Valley, two in the Chicago area, one near the Shasta Dam in California, and some in Washington state, where the Hanford site was eventually established.[3] An OSRD team had selected the Knoxville area in April 1942,[1] and in May Arthur Compton, the director of the Metallurgical Laboratory, had met with Gordon R. Clapp, the General Manager of the Tennessee Valley Authority (TVA).[5] The Chief Engineer of the Manhattan District (MED), Colonel James C. Marshall, asked Colonel Leslie R. Groves Jr. to undertake a study within the Army's Office of the Chief of Engineers. After receiving assurances that the TVA could supply the required quantity of electric power if given priority for procuring some needed equipment, Groves also concluded that the Knoxville area was suitable.[6] The only voice of dissent at the 25 June meeting was Ernest O. Lawrence, who wanted the electromagnetic separation plant located much nearer to his Radiation Laboratory in California.[1] The Shasta Dam area remained under consideration for the electromagnetic plant until September, by which time Lawrence had dropped his objection.[7]

On 1 July, Marshall and his deputy, Lieutenant Colonel Kenneth Nichols, surveyed sites in the Knoxville area with representatives of the TVA and Stone & Webster, the designated construction contractor. No perfectly suitable site was found, and Marshall even ordered another survey of the Spokane, Washington area.[2] At the time, the proposed nuclear reactor, gas centrifuge and gaseous diffusion technologies were still in the research stage, and the design of the plant was a long way off. The schedules, which called for construction work on the nuclear reactor to commence by 1 October 1942, the electromagnetic plant by 1 November, the centrifugal plant by 1 January 1943 and the gaseous diffusion plant by 1 March, were unrealistic.[8] While work could not commence on the plants, a start could be made on the housing and administrative buildings. Stone & Webster therefore drew up a detailed report on the most promising site, about 12 miles (19 km) west of Knoxville.[2] Stephane Groueff later wrote:

This portion of the quiet rural area was called Black Oak Ridge and was the northernmost of five principal oak- and pine-covered ridges around the meandering Clinch River. It was a verdant, beautiful countryside with rolling hills covered with dogwood and full of partridge and deer. To the east were the Great Smoky Mountains, to the west the peaks of the Cumberland Mountains.[9]

The site was located in Roane County and Anderson County, and lay roughly halfway between the two county seats of Kingston and Clinton.[10] Its greatest drawback was that a major road, Tennessee State Route 61, ran through it. Stone & Webster considered the possibility of re-routing the road.[7] The Ohio River Division (ORD) of the Corps of Engineers estimated that it would cost $4.25 million to purchase the entire 83,000-acre (34,000 ha) site.[7]

Groves became the director of the Manhattan Project on 23 September, with the rank of brigadier general.[11] That afternoon, he took a train to Knoxville, where he met with Marshall.[12] After touring the site, Groves concluded that the site "was an even better choice than I had anticipated".[13] He called Colonel John J. O'Brien of the Corps of Engineers' Real Estate Branch, and told him to proceed with acquiring the land.[10] The site was initially known as the Kingston Demolition Range; it officially became the Clinton Engineer Works (CEW) in January 1943,[14] and was given the codename Site X.[15] After the township was established in mid-1943, the name Oak Ridge was chosen from employee suggestions. It met with the Manhattan District's approval because "its rural connotation held outside curiosity to a minimum".[16] Oak Ridge then became the site's postal address, but the site itself was not officially renamed Oak Ridge until 1947.[17]

Land acquisition

Although War Department policy maintained that land should be acquired by direct purchase, as time was short it was decided to proceed immediately with condemnation.[18] This allowed access to the site for construction crews, provided faster compensation to the owners, and expedited the handling of property with defective titles. On 28 September 1942, the ORD Real Estate Branch opened a project office in Harriman with a staff of 54 surveyors, appraisers, lawyers and office workers. The ORD Real Estate Branch was quite busy at this time, as it was also acquiring land for the Dale Hollow Reservoir, so some staff were borrowed from the Federal Land Bank and the TVA.[19] The next day, Under Secretary of War Robert P. Patterson authorized the acquisition of 56,000 acres (23,000 ha) at an estimated cost of $3.5 million.[10] At the request of the ORD Real Estate Branch attorneys, the District Court for the Eastern District of Tennessee issued an order of possession on 6 October, effective the next day.[19] Recognizing the hardship that it would cause to the landowners, it restricted immediate exclusive possession to properties "essential to full and complete development of the project".[20]

HD.30.242 (10424306573)
A. L. Robinette, one of the farmers dispossessed by the compulsory acquisition of his land[21]

Over 1,000 families lived on the site on farms or in the hamlets of Elza, Robertsville, and Scarboro.[10][22] The first that most heard about the acquisition was when a representative from the ORD visited to inform them that their land was being acquired. Some returned home from work one day to find an eviction notice nailed to their door or to a tree in the yard. Most were given six weeks to leave, but some were given just two.[23] The government took possession of 13 tracts for immediate construction work on 20 November 1942. By May 1943, 742 declarations had been filed covering 53,334 acres (21,584 ha). Most residents were told to prepare to leave between 1 December and 15 January. In cases where this would cause undue hardship, the MED allowed residents to stay beyond this date.[20] For some it was the third time that they had been evicted by the government, having previously been evicted for the Great Smoky Mountains National Park in the 1920s and the TVA's Norris Dam in the 1930s. Many expected that, like the TVA, the Army would provide assistance to help them relocate; but unlike the TVA, the Army had no mission to improve the area or the lot of the local people, and no funds for the purpose.[24][25] Tires were in short supply in wartime America,[24] and moving vehicles were hard to find.[25] Some residents had to leave behind possessions that they were unable to take with them.[23]

A delegation of landowners presented the ORD Real Estate Branch with a petition protesting the acquisition of their property on 23 November 1942, and that night over 200 landowners held a meeting at which they agreed to hire lawyers and appraisers to challenge the Federal government. Local newspapers and politicians were sympathetic to their cause. By the end of May 1943, agreements were reached covering 416 tracts totaling 21,742 acres (8,799 ha), but some landowners rejected the government's offers. The ORD Real Estate Branch invoked a procedure under Tennessee law that allowed for a jury of five citizens appointed by the Federal District Court to review the compensation offered. They handled five cases in which they proposed higher values than those of the ORD appraisers, but the landowners rejected them as well, so the Army discontinued the use of this method. In response to rising public criticism, O'Brien commissioned a review by the Department of Agriculture. It found that the appraisals had been fair and just, and that farmers had overestimated the size and productivity of their land.[26]

The landowners turned to their local Congressman, John Jennings, Jr., On 1 February 1943, Jennings introduced a resolution in the House of Representatives calling for a committee to investigate the values offered to the landowners. He also complained to Patterson about how buildings and facilities were being demolished by the MED. On 9 July, Andrew J. May, the chairman of the House Committee on Military Affairs, appointed an investigating subcommittee chaired by Tennessee Representative Clifford Davis, who selected Dewey Short of Missouri and John Sparkman of Alabama as its other members. Public hearings were held in Clinton on 11 August, and in Kingston the following day. The Committee report, presented in December 1943, made a number of specific recommendations concerning the Corps of Engineers' land acquisition process, but neither Congress nor the War Department moved to provide any additional compensation for the landowners.[27]

Civil Action No. 429
A notice to landowners that their land was now in the possession of the federal government and that they had to vacate the premises

In July 1943, Groves prepared to issue Public Proclamation No. 2, declaring the site a military exclusion area. He asked Marshall to present it to the Governor of Tennessee, Prentice Cooper. Marshall, in turn, delegated the task to the area engineer, Major Thomas T. Crenshaw, who sent a junior officer, Captain George B. Leonard.[28][29][30] Cooper was unimpressed; he told Leonard that he had not been informed about the purpose of the CEW, and that the Army had kicked the farmers off their land and had not compensated the counties for the roads and bridges, which would now be closed. In his opinion it was "an experiment in socialism",[29] a New Deal project being undertaken in the name of the war effort. Instead of reading the proclamation, he tore it up and threw it in a waste paper basket.[29] Marshall went to Nashville to apologize to Cooper, who refused to talk to him. Nichols, who succeeded Marshall as chief engineer of the Manhattan District, met Cooper on 31 July,[31] and offered compensation in the form of Federal financing for road improvements.[30] Cooper accepted an offer from Nichols to visit the CEW, which he did on 3 November.[32]

Nichols and Cooper came to an agreement about the Solway Bridge. Although it was in Knox County, Anderson County had contributed $27,000 towards its construction. It was still paying off the bonds, but now the bridge was usable only by CEW workers. Nichols negotiated a deal in which Knox County was paid $25,000 annually for the bridge, of which $6,000 was to be used to maintain the access road. Judge Thomas L. Seeber then threatened to close the Edgemoor Bridge unless Anderson County was similarly compensated. An agreement was reached under which Anderson County received $10,000 for the bridge and $200 per month. Knox County did not keep its side of the bargain to maintain the road, which was damaged by heavy traffic and became impassable after torrential rains in 1944. The Army was forced to spend $5,000 per month on road works in Knox County.[32][33]

Additional parcels of land were acquired during 1943 and 1944 for access roads, a railway spur, and for security purposes, bringing the total to about 58,900 acres (23,800 ha).[19] The Harriman office closed on 10 June 1944, but reopened on 1 September to deal with the additional parcels. The last acquisition was not complete until 1 March 1945.[34] The final cost of the land acquired was around $2.6 million, about $47 an acre.[35]


Clinton Engineer Works
Oak Ridge. The Y-12 electromagnetic separation plant is in the upper right. The K-25 and K-27 gaseous diffusion plants are in the lower left, near the S-50 thermal diffusion plant. The X-10 is in the lower center.

X-10 graphite reactor

Girl Scouts at Oak Ridge
Girl scouts visit X-10. When the Girl Scout troop was formed in wartime Oak Ridge, girls were listed as coming from the Knoxville Girl Scout office, and were registered by their first names only to safeguard their fathers' identities.[36]

On 2 February 1943, DuPont began construction of the plutonium semiworks,[37] on an isolated 112-acre (0.5 km2) site in the Bethel Valley about 10 miles (16 km) southwest of Oak Ridge. Intended as a pilot plant for the larger production facilities at the Hanford Site, it included the air-cooled graphite-moderated X-10 Graphite Reactor. There was also a chemical separation plant, research laboratories, waste storage area, training facility for Hanford staff, and administrative and support facilities that included a laundry, cafeteria, first aid center and fire station. Because of the subsequent decision to construct water-cooled reactors at Hanford, only the chemical separation plant operated as a true pilot.[38][39] The facility was known as the Clinton Laboratories, and was operated by the University of Chicago as part of the Metallurgical Laboratory project.[40]

The X-10 Graphite Reactor was the world's second artificial nuclear reactor after Enrico Fermi's Chicago Pile-1, and was the first reactor designed and built for continuous operation.[41] It consisted of a block, 24 feet (7.3 m) long on each side, of nuclear graphite cubes, weighing around 1,500 short tons (1,400 t), surrounded by seven feet (2.1 m) of high-density concrete as a radiation shield.[38] There were 36 horizontal rows of 35 holes. Behind each was a metal channel into which uranium fuel slugs could be inserted.[42] The cooling system was driven by three large electric fans.[43]

Construction work on the reactor had to wait until DuPont had completed the design. Excavation commenced on 27 April 1943, but a large pocket of soft clay was soon discovered, necessitating additional foundations.[44] Further delays occurred due to wartime difficulties in procuring building materials. There was also an acute shortage of common and skilled labor: the contractor had only three-quarters of the required workforce, and less after high turnover and absenteeism, mainly the result of poor accommodations and difficulties in commuting. The township of Oak Ridge was still under construction, and barracks were built to house workers. Special arrangements with individual workers increased their morale and reduced turnover. Finally, there was unusually heavy rainfall, with 9.3 inches (240 mm) falling in July 1943, more than twice the average of 4.3 inches (110 mm).[38][45]

700 short tons (640 t) of graphite blocks were purchased from National Carbon, and the construction crews began stacking it in September 1943. Cast uranium billets came from Metal Hydrides, Mallinckrodt and other suppliers. These were extruded into cylindrical slugs, and canned by Alcoa, which started production on 14 June 1943. General Electric and the Metallurgical Laboratory developed a new welding technique; the new equipment was installed in the production line at Alcoa in October 1943.[46] Supervised by Compton, Martin D. Whitaker and Fermi, the reactor went critical on 4 November with about 30 short tons (27 t) of uranium. A week later the load was increased to 36 short tons (33 t), raising its power generation to 500 kW, and by the end of the month the first 500 mg of plutonium was created.[47] Modifications over time raised the power to 4,000 kW in July 1944.[48]

Construction commenced on the pilot separation plant before a chemical process for separating plutonium from uranium had been selected. In May 1943, DuPont managers decided to use the bismuth-phosphate process.[49] The plant consisted of six cells, separated from each other and the control room by thick concrete walls. The equipment was operated remotely from the control room.[40] Construction work was completed on 26 November,[50] but the plant could not operate until the reactor started producing irradiated uranium slugs.[38] The first batch was received on 20 December, allowing the first plutonium to be produced in early 1944.[51] By February, the reactor was irradiating a ton of uranium every three days. Over the next five months, the efficiency of the separation process was improved, with the percentage of plutonium recovered increasing from 40 to 90 percent. X-10 operated as a plutonium production plant until January 1945, when it was turned over to research activities. By this time, 299 batches of irradiated slugs had been processed.[48]

In September 1942, Compton asked Whitaker to form a skeleton operating staff for X-10.[48] Whitaker became director of the Clinton Laboratories,[44] and the first permanent operating staff arrived at X-10 from the Metallurgical Laboratory in Chicago in April 1944, by which time DuPont began transferring its technicians to the site. They were augmented by one hundred technicians in uniform from the Army's Special Engineer Detachment. By March 1944, there were 1,500 people working at X-10.[48]

A radioisotope building, a steam plant, and other structures were added in April 1946 to support the laboratory's peacetime educational and research missions. All work was completed by December, adding another $1,009,000 to the cost of construction at X-10, and bringing the total cost to $13,041,000.[40] Operational costs added another $22,250,000.[42]

Y-12 electromagnetic separation plant

Electromagnetic isotope separation was developed by Lawrence at the University of California Radiation Laboratory. This method employed devices known as calutrons, a hybrid of the standard laboratory mass spectrometer and cyclotron. The name was derived from the words "California", "university" and "cyclotron".[52] In the electromagnetic separation process, a magnetic field deflected charged uranium particles according to mass.[53] The process was neither scientifically elegant nor industrially efficient.[54] Compared with a gaseous diffusion plant or a nuclear reactor, an electromagnetic separation plant would consume more scarce materials, require more manpower to operate, and cost more to build. The process was approved because it was based on proven technology and therefore represented less risk. It could be built in stages, and rapidly reach industrial capacity.[52]

Y12 Calutron Operators
Operators at their calutron control panels at Y-12. Gladys Owens, the woman seated in the foreground, did not know what she had been involved with until seeing this photo in a public tour of the facility fifty years later.[55]

Responsibility for the design and construction of the electromagnetic separation plant, which came to be called Y-12, was assigned to Stone & Webster by the S-1 Committee in June 1942. The design called for five first-stage processing units, known as Alpha racetracks, and two units for final processing, known as Beta racetracks. In September, Groves authorized construction of four more racetracks, known as Alpha II. Construction began in February 1943.[56]

When the plant was started up for testing on schedule in November, the 14-ton vacuum tanks crept out of alignment because of the power of the magnets and had to be fastened more securely. A more serious problem arose when the magnetic coils started shorting out. In December, Groves ordered a magnet broken open, and handfuls of rust were found inside. Groves then ordered the racetracks to be torn down and the magnets sent back to the factory to be cleaned. A pickling plant was established on-site to clean the pipes and fittings.[54] The second Alpha I was not operational until the end of January 1944; the first Beta and first and third Alpha I's came online in March, and the fourth Alpha I became operational in April. The four Alpha II racetracks were completed between July and October 1944.[57]

Tennessee Eastman was hired to manage Y-12 on the usual cost plus fixed fee basis, with a fee of $22,500 per month plus $7,500 per racetrack for the first seven racetracks and $4,000 per additional racetrack.[58] The calutrons were initially operated by scientists from Berkeley to remove bugs and achieve a reasonable operating rate. They were then turned over to trained Tennessee Eastman operators who had only a high school education. Nichols compared unit production data, and pointed out to Lawrence that the young "hillbilly" girl operators were outperforming his PhDs. They agreed to a production race and Lawrence lost, a morale boost for the Tennessee Eastman workers and supervisors. The girls were "trained like soldiers not to reason why", while "the scientists could not refrain from time-consuming investigation of the cause of even minor fluctuations of the dials".[59]

Y-12 initially enriched the uranium-235 content to between 13 and 15 percent, and shipped the first few hundred grams of this to the Manhattan Project's weapons design laboratory, the Los Alamos Laboratory, in March 1944. Only 1 part in 5,825 of the uranium feed emerged as final product; much of the rest was splattered over equipment in the process. Strenuous recovery efforts helped raise production to 10 percent of the uranium-235 feed by January 1945. In February the Alpha racetracks began receiving slightly enriched (1.4 percent) feed from the new S-50 thermal diffusion plant, and the next month it received enhanced (5 percent) feed from the K-25 gaseous diffusion plant. By August K-25 was producing uranium sufficiently enriched to feed directly into the Beta tracks.[60]

The Alpha tracks began to suspend operations on 4 September 1945, and ceased operation completely on 22 September. The last two Beta tracks went into full operation in November and December, processing feed from K-25 and the new K-27.[61] By May 1946, studies suggested that the gaseous plants could fully enrich the uranium by themselves without accidentally creating a critical mass.[62] After a trial showed this was the case, Groves ordered all but one Beta track at Y-12 shut down in December 1946.[63] Y-12 remained in use for nuclear weapons processing and materials storage. A production facility for the hydrogen bomb used in Operation Castle in 1954 was hastily installed in 1952.[64]

K-25 gaseous diffusion plant

K-25 under construction with one of original houses Oak Ridge Tennessee1942
One of the original houses overlooking the construction of K-25

The most promising but also the most challenging method of isotope separation was gaseous diffusion. Graham's law states that the rate of effusion of a gas is inversely proportional to the square root of its molecular mass, so in a box containing a semi-permeable membrane and a mixture of two gases, the lighter molecules will pass out of the container more rapidly than the heavier molecules. The gas leaving the container is somewhat enriched in the lighter molecules, while the residual gas is somewhat depleted. The idea was that such boxes could be formed into a cascade of pumps and membranes, with each successive stage containing a slightly more enriched mixture. Research into the process was carried out at Columbia University by a group that included Harold Urey, Karl P. Cohen and John R. Dunning.[65]

In November 1942 the Military Policy Committee approved the construction of a 600-stage gaseous diffusion plant.[66] On 14 December, M. W. Kellogg accepted an offer to construct the plant, which was codenamed K-25. A cost plus fixed fee contract was negotiated, eventually totaling $2.5 million. A separate corporate entity called Kellex was created for the project, headed by Percival C. Keith, one of Kellogg's vice presidents.[67] The process faced formidable technical difficulties. The highly corrosive gas uranium hexafluoride had to be used, as no substitute could be found, and the motors and pumps would have to be vacuum tight and enclosed in inert gas. The biggest problem was the design of the barrier, which would have to be strong, porous and resistant to corrosion by uranium hexafluoride. The best choice for this seemed to be nickel, and Edward Adler and Edward Norris created a mesh barrier from electroplated nickel. A six-stage pilot plant was built at Columbia to test the process, but the Norris-Adler prototype proved to be too brittle. A rival barrier was developed from powdered nickel by Kellex, the Bell Telephone Laboratories and the Bakelite Corporation. In January 1944, Groves ordered the Kellex barrier into production.[68][69]

HD.30.379. (10427311974)
Welder at K-25

Kellex's design for K-25 called for a four-story U-shaped structure 0.5 miles (0.80 km) long containing 54 contiguous buildings. These were divided into nine sections. Within these were cells of six stages. The cells could be operated independently, or consecutively within a section. Similarly, the sections could be operated separately or as part of a single cascade. A survey party began construction by marking out the 500-acre (2.0 km2) site in May 1943. Work on the main building began in October, and the six-stage pilot plant was ready for operation on 17 April 1944. In 1945 Groves canceled the upper stages of the plant, directing Kellex to instead design and build a 540-stage side feed unit, which became known as K-27. Kellex transferred the last unit to the operating contractor, Union Carbide and Carbon, on 11 September 1945. The total cost, including the K-27 plant completed after the war, came to $480 million.[70]

The production plant commenced operation in February 1945, and as cascade after cascade came online, the quality of the product increased. By April, K-25 had attained a 1.1 percent enrichment and the output of the S-50 thermal diffusion plant began being used as feed. Some product produced the next month reached nearly 7 percent enrichment. In August, the last of the 2,892 stages commenced operation. K-25 and K-27 achieved their full potential in the early postwar period, when they eclipsed the other production plants and became the prototypes for a new generation of plants.[71] Uranium was enriched by the K-25 gaseous diffusion process until 1985; the plants were then decommissioned and decontaminated. A 235 MW coal-fired power station was included for reliability and to provide variable frequency, although most electric power came from the TVA.[72]

S-50 liquid thermal diffusion plant

The thermal diffusion process was based on Sydney Chapman and David Enskog's theory, which explained that when a mixed gas passes through a temperature gradient, the heavier one tends to concentrate at the cold end and the lighter one at the warm end. Since hot gases tend to rise and cool ones tend to fall, this can be used as a means of isotope separation. This process was first demonstrated by H. Clusius and G. Dickel in Germany in 1938.[73] It was developed by US Navy scientists, but was not one of the enrichment technologies initially selected for use in the Manhattan Project. This was primarily due to doubts about its technical feasibility, but the inter-service rivalry between the Army and Navy also played a part.[74]

Guards at the Solway Gate in 1946

The Naval Research Laboratory continued the research under Philip Abelson's direction, but there was little contact with the Manhattan Project until April 1944, when Captain William S. Parsons, the naval officer who was in charge of ordnance development at Los Alamos, brought Robert Oppenheimer, the director there, news of encouraging progress in the Navy's experiments on thermal diffusion. Oppenheimer wrote to Groves suggesting that the output of a thermal diffusion plant could be fed into Y-12. Groves set up a committee consisting of Warren K. Lewis, Eger Murphree and Richard Tolman to investigate the idea, and they estimated that a thermal diffusion plant costing $3.5 million could enrich 110 pounds (50 kg) of uranium per week to nearly 0.9 percent uranium-235. Groves approved its construction on 24 June 1944.[75]

Groves contracted with the H. K. Ferguson Company of Cleveland to build the thermal diffusion plant, which was designated S-50. Groves' advisers, Karl Cohen and W. I. Thompson from Standard Oil,[76] estimated that it would take six months to build; Groves gave Ferguson just four. Plans called for the installation of 2,142 forty-eight-foot-tall (15 m) diffusion columns arranged in 21 racks. Inside each column were three concentric tubes. Steam, obtained from the nearby K-25 powerhouse at a pressure of 100 pounds per square inch (690 kPa) and temperature of 545 °F (285 °C), flowed downward through the innermost 1.25-inch (32 mm) nickel pipe, while water at 155 °F (68 °C) flowed upward through the outermost iron pipe. Isotope separation occurred in the uranium hexafluoride gas between the nickel and copper pipes.[77]

Work commenced on 9 July 1944, and S-50 began partial operation in September. Ferguson operated the plant through a subsidiary known as Fercleve. The plant produced just 10.5 pounds (4.8 kg) of 0.852 percent uranium-235 in October. Leaks limited production and forced shutdowns over the next few months, but in June 1945 it produced 12,730 pounds (5,770 kg).[78] By March 1945, all 21 production racks were operating. Initially the output of S-50 was fed into Y-12, but starting in March all three enrichment processes were run in series. S-50 became the first stage, enriching from 0.71 percent to 0.89 percent. This material was fed into the gaseous diffusion process in the K-25 plant, which produced a product enriched to about 23 percent. This was, in turn, fed into Y-12.[79]

In early September Nichols appointed a production control committee, headed by Major A.V. (Pete) Peterson. Peterson's staff tried various combinations, using mechanical calculating machines, and decided that the S-50 production should be fed to K-25 rather than Y-12, which was done in April 1945. The charts also showed that the proposed top stages for K-25 should be abandoned, as should Lawrence's recommendation to add more alpha stages to the Y-12 plant. Groves accepted their proposal to add more base units to the K-27 gaseous-diffusion plant and one more Beta stage track for Y-12. These additions were estimated to cost $100 million, with completion in February 1946.[80] Soon after Japan surrendered in August 1945, Peterson recommended that S-50 be shut down. The Manhattan District ordered this on 4 September. The last uranium hexafluoride was sent to K-25, and the plant had ceased operation by 9 September.[81] S-50 was completely demolished in 1946.[82]

Electric power

Despite protests from TVA that it was unnecessary, the Manhattan District built a coal-fired power plant at K-25 with eight 25,000 KW generators.[83] Steam generated from the K-25 power plant was subsequently used by S-50. Additional power lines were laid from the TVA hydroelectric plants at Norris Dam and Watts Bar Dam, and the Clinton Engineer Works was given its own electrical substations at K-25 and K-27. By 1945, power sources were capable of supplying Oak Ridge with up to 310,000 KW, of which 200,000 KW was earmarked for Y-12, 80,000 KW for K-25, 23,000 KW for the township, 6,000 KW for S-50 and 1,000 KW for X-10. Peak demand occurred in August 1945, when all the facilities were running. The peak load was 298,800 KW on 1 September.[84] The 235,000 KVA steam plant was required for reliability; in 1953-55 a rat shorting out a transformer at CEW resulted in a complete loss of load and of several weeks of production. The plant could supply up to five different frequencies, although it was found that variable frequency was not necessary. J. A. Jones built the plant and the gaseous diffusion plant. The site was cleared in June 1943, steam was available from one boiler in March 1944 and in April 15,000 KVA was available from the first turbine generator. The plant was the largest single block of steam power built at one time, and with completion in January 1945 in record time.[85]


HD.30.336. (10426941936)
A hutment at Oak Ridge. Each of these 16-by-16-foot (4.9 by 4.9 m) temporary structures provided accommodation for five workers.

Planning for a "Government village" to house the workers at the Clinton Engineer Works began in June 1942. Because the site was remote, it was believed more convenient and secure for the workers to live on the site.[86] The gentle slopes of Black Oak Ridge, from which the new town of Oak Ridge got its name, were selected as a suitable location.[87] Brigadier General Lucius D. Clay, the deputy chief of staff of the Army Services of Supply, reminded Marshall of a wartime limit of $7,500 per capita for individual quarters. Groves argued for "economy" with small and simple houses; but Marshall, who had argued for an exemption from the limit, saw no prospect that the kind of workers they needed would be willing to live with their family in substandard accommodation (and du Pont at HEW agreed). The houses at CEW and HEW were basic but of a higher standard (as specified by Marshall and Nichols) than the houses at Los Alamos (as specified by Groves; and the quality of housing there suffered).[88]

The first plan, submitted by Stone & Webster on 26 October 1942, was for a residential community of 13,000 people.[89] As Stone & Webster began work on the production facilities, it became clear that building the township as well would be beyond its capacity. The Army therefore engaged the architectural and engineering firm Skidmore, Owings & Merrill to design and build the township. The John B. Pierce Foundation were brought in as a consultant. In turn, Skidmore, Owings & Merrill brought in numerous subcontractors.[87][90] This first phase of construction became known as the East Town. It included some 3,000 family dwellings, an administrative center, three shopping centers, three grade schools for 500 children each and a high school for 500, recreation buildings, men's and women's dormitories, cafeterias, a medical services building and a 50-bed hospital. The emphasis was on speed of construction and getting around wartime shortages of materials. Where possible, fiberboard and gypsum board were used instead of wood, and foundations were made from concrete blocks rather than poured concrete. The work was completed in early 1944.[90][91]

In addition to the East Town, a self-contained community known as the East Village, with 50 family units, its own church, dormitories and a cafeteria, was built near the Elza gate. This was intended as a segregated community for Black people, but by the time it was completed, it was required by white people. Black people were instead housed in "hutments" (one-room shacks) in segregated areas, some in "family hutments" created by joining two regular hutments together.[90][92]

White and Colored privies X-10 plant
White and colored privies at the X-10 plant

The Army presence at Oak Ridge increased in August 1943 when Nichols replaced Marshall as head of 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.[93] In September 1943 the administration of community facilities was outsourced to Turner Construction Company through a subsidiary, the Roane-Anderson Company. The company was paid a fee of $25,000 per month on a cost-plus contract, about 1 percent of the $2.8 million monthly cost of running the town facilities.[94] Roane-Anderson did not take over everything at once, and a phased takeover started with Laundry No. 1 on 17 October 1943; transportation and garbage collection soon followed. It assumed responsibility for water and sewage in November, and electricity in January 1944. The number of Roane-Anderson workers peaked at around 10,500 in February 1945, including concessionaires and subcontractors. Thereafter, numbers declined to 2,905 direct employees and 3,663 concessionaires and subcontractors when the Manhattan Project ended on 31 December 1946.[95]

By mid-1943, it had become clear that the initial estimates of the size of the town had been too low, and a second phase of construction was required. Plans now called for a town of 42,000 people. Work began in the fall of 1943, and continued into the late summer of 1944. Hospitals were expanded, as were the police and fire services, and the telephone system. Only 4,793 of a planned total of 6,000 family houses were built, mostly on the East Town area and the undeveloped stretch along State Route 61. They were supplemented by 55 new dormitories, 2,089 trailers, 391 hutments, a cantonment area of 84 hutments and 42 barracks. Some 2,823 of the family units were prefabricated off-site. The high school was expanded to cater for 1,000 students. Two additional primary schools were built, and existing ones were expanded so that they could accommodate 7,000 students.[96][91]

Lie detector test
Security screening at the Clinton Engineer Works. Lie detector test.

Although expected to accommodate the needs of the entire workforce, by late 1944 expansion of both the electromagnetic and gaseous diffusion plants led to forecasts of a population of 62,000. This prompted another round of construction that saw an additional 1,300 family units and 20 dormitories built. More shopping and recreational facilities were added, the schools were expanded to accommodate 9,000 students, and a 50-bed annex was added to the hospital.[96][91] The number of school children reached 8,223 in 1945. Few issues resonated more with the scientists and highly skilled workers than the quality of the education system. Although school staff were nominally employees of the Anderson County Education Board, the school system was run autonomously, with federal funding under the supervision of administrators appointed by the Army. Teachers enjoyed salaries that were considerably higher than those of Anderson County.[97] The population of Oak Ridge peaked at 75,000 in May 1945, by which time 82,000 people were employed at the Clinton Engineer Works,[98] and 10,000 by Roane-Anderson.[94]

In addition to the township, there were a number of temporary camps established for construction workers. It was initially intended that the construction workers should live off-site, but the poor condition of the roads and a shortage of accommodations in the area made commuting long and difficult, and in turn made it difficult to find and retain workers. Construction workers therefore came to be housed in large hutment and trailer camps. The largest, the trailer camp at Gamble Valley, had four thousand units. Another, at Happy Valley, held 15,000 people. The population of the construction camps declined as the construction effort tapered off, but they continued to be occupied in 1946.[99]

The main shopping area was Jackson Square, with about 20 shops. The Army attempted to keep prices down by encouraging competition, but this met with limited success due to the captive nature of the population, and the requirements of security, which meant that firms and goods could not freely move in and out. The Army could give prospective concessionaires only vague information about how many people were in or would be in the town, and concessions were only for the duration of the war. Concessions were therefore charged a percentage of their profits in rental rather than a fixed fee. The Army avoided imposing draconian price controls, but limited prices to those of similar goods in Knoxville.[87] By 1945, community amenities included 6 recreation halls, 36 bowling alleys, 23 tennis courts, 18 ball parks, 12 playgrounds, a swimming pool, a 9,400-volume library, and a newspaper.[97]


From 1 April 1943, access to the Clinton Engineer Works was strictly controlled, with wire fences, guarded gates, and guards patrolling the perimeter.[100] All employees had to sign a security declaration, the purpose of which was to make them aware of possible penalties under the Espionage Act of 1917. Noting the distillation facilities and their high energy consumption, "I thought they were making sour mash to drop on the Germans, get them all drunk," engineer Benjamin Bederson recalled, before realizing that the facilities were enriching nuclear isotopes.[101] Mail was censored, and lie detectors were employed in security checks.[102] Everyone was issued with a color-coded badge that restricted where they could go.[103] Despite the security, the Clinton Engineer Works was penetrated by atomic spies George Koval and David Greenglass, who passed secrets to the Soviet Union.[104]

Occupational health and safety presented a challenge, because workers were handling a variety of toxic chemicals, using hazardous liquids and gases under high pressures, and working with high voltages, not to mention the largely unknown dangers presented by radioactivity and handling fissile materials. Accidents represented unacceptable numbers of work days lost, and a vigorous safety program was instituted.[105] Since it did not matter where accidents occurred, this included safety off the job, in homes and in the schools.[106] Safety indoctrination was included in job training, and safety training courses were held. Safety posters, manuals and films were distributed.[107] In December 1945, the National Safety Council presented the Manhattan Project with the Award of Honor for Distinguished Service to Safety in recognition of its safety record.[106] The Clinton Engineer Works also received an award of merit in the National Traffic Safety Contest.[108] Many workers had to drive long distances over poorly built and inadequately maintained roads.[106] There were 21 deaths from motor vehicles at the Clinton Engineer Works: two in 1943, nine in 1944, eight in 1945 and two in 1946.[109] This represented a better road safety record than other towns of comparable size.[106]

HD.4H.052 (10410067273)
Shopping at the PX in Oak Ridge

The citizens of Oak Ridge were not allowed to have any form of local government, but the state of Tennessee, concerned over the potential loss of tax revenue, did not cede sovereignty over the land. The residents of Oak Ridge therefore did not live on a federal reservation, and were entitled to vote in state and county elections.[100] Notice of the Clinton City elections was withheld by local authorities until a week after the deadline to pay the poll tax. On the day of a 1945 referendum on whether Anderson should remain a dry county, the Edgemoor Bridge was suddenly closed for repairs, and the "dry" vote carried. A subsequent vote in 1947 reversed this result, with 4,653 "dry" votes compared to 5,888 "wet"; 5,369 of the "wet" votes came from Oak Ridge.[110]

This was but one point of difference between Oak Ridge residents and the rest of Anderson County. While most Oak Ridge residents had high school diplomas, and many had college degrees, the average education level of adults in Anderson County was only 6.8 years.[111] Oak Ridge residents demanded, and Groves insisted on, schools with fine teachers and first-rate facilities. To achieve this, the Manhattan District paid teachers nearly twice as much as Anderson County. The consequent drain of qualified teachers from surrounding areas aroused considerable resentment.[112]

The Manhattan District accepted that wages and salaries had to be high enough to allow contractors to hire and retain good workers. It generally allowed wages and salaries to be paid by contractors as they saw fit, subject to limits imposed by wartime national wage and price controls intended to limit inflation. Salaries above $9,000 had to be approved by Patterson and Groves.[113]

The War Production Board was asked to keep stores in Oak Ridge well-stocked in order to reduce absenteeism among the workers. When shortages occurred, the relatively well-paid Oak Ridge residents bought up scarce goods in surrounding areas. In both cases, they attracted the ire of their residents.[112] Personnel employed by the Manhattan District were not exempted from being drafted under the Selective Service System. Efforts were made to employ draft-exempt personnel, and deferments were requested only for critical personnel, mainly young scientists and technicians.[114]

The war ends

V-J Day celebrations-in Jackson Square, Oak Ridge
V-J Day celebrations-in Jackson Square, Oak Ridge

On 10 May 1945, Women's Army Corps typists at Manhattan District headquarters began preparing press kits on the Manhattan Project for use after an atomic bomb had been dropped. Fourteen press releases were prepared, and thousands of copies made by mimeograph.[115] The final wartime shipment of uranium-235 left the Clinton Engineer Works on 25 July.[116] Shipments reached Tinian on C-54 aircraft on 28 and 29 July. They were incorporated into the Little Boy bomb dropped on Hiroshima on 6 August.[117] The news was greeted with wild celebration in Oak Ridge.[118] Patterson issued a letter to the men and women of the Clinton Engineer Works:

Today the whole world knows the secret which you have helped us keep for many months. I am pleased to be able to add that the warlords of Japan now know its effects better, even than we ourselves. The atomic bomb which you have helped to develop with high devotion to patriotic duty is the most devastating military weapon that any country has ever been able to turn against its enemy. No one of you has worked on the entire project or knows the whole story. Each of you has done his own job and kept his own secret, and so today I speak for a grateful nation when I say congratulations, and thank you all. I hope you will continue to keep the secrets you have kept so well. The need for security and for continued effort is fully as great now as it ever was. We are proud of every one of you.[119]

Postwar years

By 1945, Roane-Anderson was divesting itself of many of its tasks. American Industrial Transit took over the transport system, and Southern Bell the telephone system. Tri-State Homes began managing housing. In 1946, tenants were permitted to paint their houses in different colors from the wartime olive drab. Comprehensive medical insurance, originally instituted for security reasons, was replaced with policies from the Provident Life and Accident Insurance Company.[120] Health care had been provided by the Army. As Army doctors were separated from the service they were replaced with civilian doctors employed by Roane-Anderson. The dental service was transferred to civilians in February 1946, and private medical practices were permitted at Oak Ridge from 1 March 1946 on.[121]

The hospital remained an Army hospital until 1 March 1949, when it was transferred to Roane-Anderson.[122] Monsanto took over the operation of the Clinton Laboratories on 1 July 1945.[123] Control of the entire site passed to the Atomic Energy Commission (AEC) on 1 January 1947.[120] The Clinton Laboratories became the Clinton National Laboratory in late 1947,[124] and the Oak Ridge National Laboratory in January 1948.[125] Union Carbide took over its management in December 1947, bringing all of Oak Ridge's operations under its control.[126]

While the war was in progress, the Manhattan District resisted allowing labor unions access to its facilities. In 1946, they were permitted to operate at the Clinton Engineer Works. Elections were held at K-25, Y-12 and X-10 in August and September 1946, and the United Chemical Workers became their representative. A contract was negotiated with Union Carbide on 10 December. The Atomic Trades and Labor Council became the representative of the Clinton Laboratories, signing a contract with Monsanto on 18 December.[127]

Gate opening celebration Elza Gate, Oak Ridge, Tennessee 1949
Gate opening ceremony at Elza Gate on 19 March 1949

At its peak in May 1945, 82,000 people were employed at the Clinton Engineer Works, and 75,000 people lived in the township. By January 1946, these figures had fallen to 43,000 and 48,000 respectively. By the time the Manhattan Project concluded at the end of 1946, the corresponding figures were 34,000 and 43,000. The departure of large numbers of construction workers meant that 47 percent of those remaining were family members of workers. Eight dormitories were closed in October 1945. Most of those who remained in dorms now had their own rooms. The white hutments began to be removed. Trailers were returned to the Federal Public Housing Authority.[128]

The end of the war brought national attention to Oak Ridge, and there was bad publicity about the conditions that the Black residents were living in. Roane-Anderson dusted off plans for a village for them.[128] The new village, called Scarboro, was built where the Gamble Valley Trailer Camp had once stood. Construction commenced in 1948, and the first residents moved in two years later. It housed the entire Black community of Oak Ridge until the early 1960s.[129]

In 1947, Oak Ridge was still part of "an island of socialism in the midst of a free enterprise economy".[130] The AEC pressed forward with plans to withdraw from running the community, but it could never be too fast for some members of Congress. AEC officials repeatedly explained how Roane-Anderson provided far more than regular municipal services. For the residents, the benefits of a free enterprise economy were slight. They enjoyed low rents and no property taxes, but high standards of services and an excellent school system.[131] Oak Ridge City Historian William J. Wilcox, Jr. noted that the townspeople "thoroughly enjoyed their much protected existence and the benevolence the Army had provided".[132] A straw poll of the residents on opening the gates showed them opposed, 10 to 1.[132]

Nonetheless, on 19 March 1949 the residential and commercial portion of Oak Ridge was ceremoniously opened to public access. Vice President Alben W. Barkley, Governor Gordon Browning, Atomic Energy Commission Chairman David E. Lilienthal, and movie star Marie McDonald were on hand to watch the guards take down the barriers.[133][132] Access to the nuclear facilities was controlled by three Oak Ridge gatehouses.[134] On 6 June 1951, the Senate Appropriations Committee called on the Atomic Energy Commission to discontinue "the present undemocratic method" of operating the community,[135] and it initiated steps to coerce Oak Ridge residents to establish democratic institutions and adopt a free enterprise system.[136]


  1. ^ a b c Jones 1985, pp. 46–47.
  2. ^ a b c Jones 1985, p. 69.
  3. ^ a b Manhattan District 1947d, p. S3.
  4. ^ Fine & Remington 1972, pp. 134–135.
  5. ^ Compton 1956, p. 155.
  6. ^ Groves 1962, pp. 13–14.
  7. ^ a b c Jones 1985, p. 70.
  8. ^ Groves 1962, p. 16.
  9. ^ Groueff 1967, p. 16.
  10. ^ a b c d Jones 1985, p. 78.
  11. ^ Groves 1962, p. 23.
  12. ^ Groueff 1967, pp. 15–16.
  13. ^ Groves 1962, p. 25.
  14. ^ Jones 1985, pp. 318–319.
  15. ^ Rhodes 1986, p. 427.
  16. ^ Jones 1985, p. 443.
  17. ^ Groves 1962, pp. 25–26.
  18. ^ Manhattan District 1947b, pp. S1-S3.
  19. ^ a b c Jones 1985, pp. 320–321.
  20. ^ a b Jones 1985, p. 321.
  21. ^ Johnson & Jackson 1981, p. 42.
  22. ^ Johnson & Jackson 1981, p. 47.
  23. ^ a b Johnson & Jackson 1981, p. 41.
  24. ^ a b Johnson & Jackson 1981, pp. 43–45.
  25. ^ a b Jones 1985, p. 323.
  26. ^ Jones 1985, pp. 321–324.
  27. ^ Jones 1985, pp. 323–327.
  28. ^ Groves 1962, pp. 26–27.
  29. ^ a b c Johnson & Jackson 1981, p. 49.
  30. ^ a b Hales 1997, p. 122.
  31. ^ Nichols 1987, pp. 100–101.
  32. ^ a b Nichols 1987, pp. 116–120.
  33. ^ Johnson & Jackson 1981, pp. 61–62.
  34. ^ Manhattan District 1947b, pp. S4-S5.
  35. ^ Jones 1985, pp. 327–328.
  36. ^ Allured 1995, pp. 73–74.
  37. ^ Hewlett & Anderson 1962, p. 207.
  38. ^ a b c d Jones 1985, pp. 204–206.
  39. ^ Manhattan District 1947e, pp. 2.4–2.6.
  40. ^ a b c Manhattan District 1947e, p. S3.
  41. ^ "ORNL Metals and Ceramics Division History, 1946–1996" (PDF). Oak Ridge National Laboratory. ORNL/M-6589. Archived from the original (PDF) on 28 January 2015. Retrieved 25 January 2015.
  42. ^ a b Manhattan District 1947e, p. S4.
  43. ^ Manhattan District 1947e, p. S5.
  44. ^ a b Hewlett & Anderson 1962, pp. 207–208.
  45. ^ Manhattan District 1947e, pp. 2.7–2.8.
  46. ^ Hewlett & Anderson 1962, pp. 209–210.
  47. ^ Hewlett & Anderson 1962, p. 211.
  48. ^ a b c d Jones 1985, p. 209.
  49. ^ Jones 1985, p. 194.
  50. ^ Manhattan District 1947e, p. S2.
  51. ^ Manhattan District 1947e, p. S7.
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  53. ^ Smyth 1945, pp. 164–165.
  54. ^ a b Fine & Remington 1972, p. 684.
  55. ^ "The Calutron Girls". SmithDRay. Retrieved 22 June 2011.
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  59. ^ Nichols 1987, p. 131.
  60. ^ Jones 1985, pp. 143–148.
  61. ^ Hewlett & Anderson 1962, pp. 624–625.
  62. ^ Hewlett & Anderson 1962, p. 630.
  63. ^ Hewlett & Anderson 1962, p. 646.
  64. ^ Nichols 1987, p. 333.
  65. ^ Hewlett & Anderson 1962, pp. 30–32, 96–98.
  66. ^ Hewlett & Anderson 1962, p. 108.
  67. ^ Jones 1985, pp. 150–151.
  68. ^ Jones 1985, pp. 154–157.
  69. ^ Hewlett & Anderson 1962, pp. 126–127.
  70. ^ Jones 1985, pp. 158–165.
  71. ^ Jones 1985, pp. 167–171.
  72. ^ Nichols 1987, pp. 93–94.
  73. ^ Smyth 1945, pp. 161–162.
  74. ^ Jones 1985, p. 172.
  75. ^ Jones 1985, pp. 175–177.
  76. ^ Hewlett & Anderson 1962, pp. 170–172.
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  78. ^ Jones 1985, pp. 180–183.
  79. ^ Hewlett & Anderson 1962, pp. 300–302.
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  81. ^ Hewlett & Anderson 1962, p. 624.
  82. ^ "K-25 and S-50 Uranium and Fluoride Releases" (PDF). Agency for Toxic Substances and Disease Registry. Retrieved 7 February 2015.
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  86. ^ Jones 1985, p. 433.
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  88. ^ Nichols 1987, pp. 59,175.
  89. ^ Jones 1985, p. 434.
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  91. ^ a b c Manhattan District 1947d, pp. 4.2–4.4.
  92. ^ Johnson & Jackson 1981, pp. 22–23.
  93. ^ Jones 1985, p. 88.
  94. ^ a b Jones 1985, pp. 443–446.
  95. ^ Manhattan District 1947d, p. 6.7.
  96. ^ a b Jones 1985, pp. 438–439.
  97. ^ a b Jackson & Johnson 1977, p. 12.
  98. ^ Johnson & Jackson 1981, pp. 168–169.
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  103. ^ Freeman 2015, p. 84.
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  107. ^ Manhattan District 1947c, p. S4.
  108. ^ Manhattan District 1947c, p. E10.
  109. ^ Manhattan District 1947c, p. 5.5.
  110. ^ Jackson & Johnson 1977, p. 63.
  111. ^ Jackson & Johnson 1977, p. 50.
  112. ^ a b Jackson & Johnson 1977, pp. 60–61.
  113. ^ Manhattan District 1947a, pp. 37–38.
  114. ^ Manhattan District 1947a, p. S10.
  115. ^ Johnson & Jackson 1981, p. 158.
  116. ^ Johnson & Jackson 1981, p. 159.
  117. ^ Jones 1985, pp. 536–538.
  118. ^ Johnson & Jackson 1981, pp. 164–166.
  119. ^ Kiernan 2013, p. 271.
  120. ^ a b Jackson & Johnson 1977, p. 13.
  121. ^ Jackson & Johnson 1977, p. 187.
  122. ^ Brookshire & Wallace 2009, p. 33.
  123. ^ Jones 1985, p. 210.
  124. ^ Johnson & Schaffer 1994, p. 28.
  125. ^ Johnson & Schaffer 1994, p. 52.
  126. ^ Johnson & Schaffer 1994, p. 55.
  127. ^ Manhattan District 1947a, p. 36.
  128. ^ a b Johnson & Schaffer 1994, pp. 169–173.
  129. ^ Johnson & Schaffer 1994, p. 211.
  130. ^ Hewlett & Duncan 1969, p. 451.
  131. ^ Hewlett & Duncan 1969, pp. 454–457.
  132. ^ a b c Brookshire & Wallace 2009, p. 32.
  133. ^ Hewlett & Duncan 1969, pp. 454–455.
  134. ^ Ziemer, Paul L. (20 May 1992). "Memos and other documents" (PDF). Department of Energy. Archived from the original (PDF) on 29 August 2010. Retrieved 2 February 2015.
  135. ^ Hewlett & Duncan 1969, p. 459.
  136. ^ Hewlett & Duncan 1969, pp. 476–477.


Coordinates: 36°0′48″N 84°15′45″W / 36.01333°N 84.26250°W


CEW may refer to:

Clinton Engineer Works, a Manhattan Project plant

The IATA code for Bob Sikes Airport

Conducted electrical weapon, commonly known as TaserChief Executive Women an Australian incorporated body committed to the purpose of increasing women’s leadership


A calutron is a mass spectrometer originally designed and used for separating the isotopes of uranium. It was developed by Ernest Lawrence during the Manhattan Project and was based on his earlier invention, the cyclotron. Its name was derived from California University Cyclotron, in tribute to Lawrence's institution, the University of California, where it was invented. Calutrons were used in the industrial-scale Y-12 uranium enrichment plant at the Clinton Engineer Works in Oak Ridge, Tennessee. The enriched uranium produced was used in the Little Boy atomic bomb that was detonated over Hiroshima on 6 August 1945.

The calutron is a type of sector mass spectrometer, an instrument in which a sample is ionized and then accelerated by electric fields and deflected by magnetic fields. The ions ultimately collide with a plate and produce a measurable electric current. Since the ions of the different isotopes have the same electric charge but different masses, the heavier isotopes are deflected less by the magnetic field, causing the beam of particles to separate out into several beams by mass, striking the plate at different locations. The mass of the ions can be calculated according to the strength of the field and the charge of the ions. During World War II, calutrons were developed to use this principle to obtain substantial quantities of high-purity uranium-235, by taking advantage of the small mass difference between uranium isotopes.

Electromagnetic separation for uranium enrichment was abandoned in the post-war period in favor of the more complicated, but more efficient, gaseous diffusion method. Although most of the calutrons of the Manhattan Project were dismantled at the end of the war, some remained in use to produce isotopically enriched samples of naturally occurring elements for military, scientific and medical purposes.

David Greenglass

David Greenglass (March 2, 1922 – July 1, 2014) was an atomic spy for the Soviet Union who worked on the Manhattan Project. He was briefly stationed at the Clinton Engineer Works uranium enrichment facility at Oak Ridge, Tennessee, and then worked at the Los Alamos laboratory in New Mexico from August 1944 until February 1946.

He provided testimony that helped convict his sister and brother-in-law Ethel and Julius Rosenberg, who were executed for their spying activity. Greenglass served nine and a half years in prison.

Ebb Cade

Ebb Cade (17 March 1890 – 13 April 1953) was a construction worker at Clinton Engineer Works at Oak Ridge, and an unwilling participant in the first human injection experiments with plutonium.

Ebb Cade was born on 17 March 1890 in Macon County, Georgia, the son of Evens and Carrie Cade. Ebb Cade was married to Ida Cade. At the age of 63, Cade died as a result of ventricular fibrillation followed by heart failure on 13 April 1953 in Greensboro, Guilford County, North Carolina.

Ed Westcott

James Edward Westcott (born January 20, 1922) is a photographer who worked for the United States government in Oak Ridge, Tennessee, during the Manhattan Project and the Cold War. As one of the few people permitted to have a camera in the Oak Ridge area during the Manhattan Project, he created the main visual record of the construction and operation of the Oak Ridge production facilities and of civilian life in the enclosed community of Oak Ridge.

Happy Valley, Oak Ridge, Tennessee

Happy Valley was a construction camp of trailer homes and hutments at the Clinton Engineer Works of the Manhattan Project in the 1940s. It was located near the K-25 gaseous diffusion plant in Oak Ridge, Tennessee, to lessen travelling time for the seventeen thousand construction men working there.The Happy Valley settlement was dismantled in the early 1950s.

Harrison Brown

Harrison Scott Brown (September 26, 1917 – December 8, 1986) was an American nuclear chemist and geochemist. He was a political activist, who lectured and wrote on the issues of arms limitation, natural resources and world hunger.

During World War II, Brown worked at the Manhattan Project's Metallurgical Laboratory and Clinton Engineer Works, where he worked on ways to separate plutonium from uranium. The techniques he helped develop were used at the Hanford Site to produce the plutonium used in the Fat Man bomb dropped on Nagasaki. After the war he lectured on the dangers of nuclear weapons.

After the war, he worked at the University of Chicago, where he pioneered nuclear geochemistry. The study of meteorites by Brown and his students led to the first close approximation of the age of the Earth and the solar system. Between 1951 and 1977, he worked at the California Institute of Technology (Caltech) where he contributed to advancements in telescopic instrumentation, jet propulsion, and infrared astronomy. In the early 1970s, he began working more directly on the resource/environment issues that he had been developing in his books. In 1977, he became director of the newly created Resource Systems Institute of the East-West Center in Hawaii where he turned full time to work on understanding and influencing the interactions of energy, mineral, and food systems in the Asia-Pacific Region, themes he had developed in his books since the 1950s.

J.A. Jones Construction

J.A. Jones Construction was a heavy construction company headquartered in Charlotte, North Carolina. Operating internationally since the 1950s, it merged with Germany's Philipp Holzmann AG in 1979. In 2003 the company ceased operations due to the failure of its parent company.

Joseph H. Rush

Joseph Harold Rush (April 17, 1911 – September 12, 2006) was a physicist, parapsychologist and author. He was the first secretary-treasurer of the Federation of American Scientists, and published numerous articles and two textbooks.

Rush was born in Mt. Calm, Texas. In the 1930s his employment as a radio operator in the Dallas Police Department became a way to support his family during the Great Depression. After earning a master's degree in physics, he taught at Texas Technical College in Lubbock and at Denison University. In 1944 he joined the Manhattan Project at the Clinton Engineer Works in Oak Ridge, Tennessee. After the end of the war, he became secretary-treasurer of the Federation of American Scientists, working in Washington to secure civilian control of nuclear power.

Rush received his PhD in Physics from Duke University in 1950, and moved to Boulder, Colorado to work at the High Altitude Observatory of the University of Colorado. He joined the National Center for Atmospheric Research upon its inception, and retired in 1974.

Over his lifetime, Rush authored many articles and books, including The Dawn of Life, a book examining the origins of life on Earth, and Foundations of Parapsychology: Exploring the Boundaries of Human Capability, a textbook on parapsychology.


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 1,640,000 square feet (152,000 m2) of floor space and a volume of 97,500,000 cubic feet (2,760,000 m3).

Gaseous diffusion is based on Graham's law, which states that the rate of effusion of a gas is inversely proportional to the square root of its molecular mass. The highly corrosive uranium hexafluoride (UF6) was the only known compound of uranium sufficiently volatile to be used in this process. Before this could be done, the Special Alloyed Materials (SAM) Laboratories at Columbia University and the Kellex Corporation had to overcome formidable difficulties to develop a suitable barrier.

Construction of the K-25 facility was undertaken by J. A. Jones Construction. At the height of construction, over 25,000 workers were employed on the site. Gaseous diffusion was but one of three enrichment technologies used by the Manhattan Project. Slightly enriched product from the S-50 thermal diffusion plant was fed into the K-25 gaseous diffusion plant. Its product in turn was fed into the Y-12 electromagnetic plant. The enriched uranium was used in the Little Boy atomic bomb used in the atomic bombing of Hiroshima. In 1946, the K-25 gaseous diffusion plant became capable of producing highly enriched product.

After the war, four more gaseous diffusion plants named K-27, K-29, K-31 and K-33 were added to the site. The K-25 site was renamed the Oak Ridge Gaseous Diffusion Plant in 1955. Production of enriched uranium ended in 1964, and gaseous diffusion finally ceased on the site on 27 August 1985. The Oak Ridge Gaseous Diffusion Plant was renamed the Oak Ridge K-25 Site in 1989, and the East Tennessee Technology Park in 1996. Demolition of all five gaseous diffusion plants was completed in February 2017.

Kellex Corporation

The Kellex Corporation was a wholly owned subsidiary of M. W. Kellogg Company. Kellex was formed in 1942 so that Kellogg's operations relating to the Manhattan Project could be kept separate and secret. "Kell" stood for "Kellogg" and "X" for secret. The new company's goal was to design a facility for the production of enriched uranium through gaseous diffusion. In gaseous diffusion, isotopes of Uranium-235 could be separated from Uranium-238 by turning uranium metal into uranium hexafluoride gas and straining it through a barrier material.

Kenneth Nichols

Major General Kenneth David Nichols (13 November 1907 – 21 February 2000), also known by Nick, was an officer in the United States Army, and a civil engineer who is notable for his classified works in the Manhattan Project, which developed the atomic bomb during World War II, as Deputy District Engineer to James C. Marshall, and from 13 August 1943 as the District Engineer of the Manhattan Engineer District. He was responsible for both the uranium production facility at the Clinton Engineer Works at Oak Ridge, Tennessee, and the plutonium production facility at Hanford Engineer Works in Washington State.

Nichols remained with the Manhattan Project after the war until it was taken over by the Atomic Energy Commission in 1947. He was the military liaison officer with the Atomic Energy Commission from 1946 to 1947. After briefly teaching at the United States Military Academy at West Point, he was promoted to major general and became chief of the Armed Forces Special Weapons Project, responsible for the military aspects of atomic weapons, including logistics, handling and training. He was Deputy Director for the Atomic Energy Matters, Plans and Operations Division of the Army's general staff, and was the senior Army member of the military liaison committee that worked with the Atomic Energy Commission.

In 1950, General Nichols became Deputy Director of the Guided Missiles Division of the Department of Defense. He was appointed chief of research and development when it was reorganized in 1952. In 1953, he became the general manager of the Atomic Energy Commission, where he promoted the construction of nuclear power plants. He played a key role in the proceedings brought against J. Robert Oppenheimer that resulted in Oppenheimer's security clearance being revoked. In later life, Nichols became an engineering consultant on private nuclear power plants.

Manhattan Project

The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. 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 U.S. Army Corps of Engineers. Nuclear physicist Robert Oppenheimer was the director of the Los Alamos Laboratory that designed the actual bombs. The Army component of the project was designated the Manhattan District; Manhattan gradually superseded the official codename, Development of Substitute Materials, 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 (about $22 billion in 2016 dollars). Over 90% of the cost was for building factories and to produce fissile material, with less than 10% for development and production of the weapons. Research and production took place at more than 30 sites across the United States, the United Kingdom, and Canada.

Two types of atomic bombs were 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, and therefore a simpler gun-type called Little Boy was developed that used uranium-235, an isotope that makes up only 0.7 percent of natural uranium. Chemically identical to the most common isotope, uranium-238, and with almost the same mass, it proved difficult to separate the two. Three methods were employed for uranium enrichment: electromagnetic, gaseous and thermal. Most of this work was performed at the Clinton Engineer Works at Oak Ridge, Tennessee.

In parallel with the work on uranium was an effort to produce plutonium. After the feasibility of the world's first artificial nuclear reactor was demonstrated in Chicago at the Metallurgical Laboratory, it designed the X-10 Graphite Reactor at Oak Ridge and the production reactors in Hanford, Washington, in which uranium was irradiated and transmuted into plutonium. The plutonium was then chemically separated from the uranium, using the bismuth phosphate process. 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 the Manhattan Project's tight security, Soviet atomic spies successfully penetrated the program.

The first nuclear device ever detonated was an implosion-type bomb at the Trinity test, conducted at New Mexico's Alamogordo Bombing and Gunnery Range 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, 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 in January 1947.

Metallurgical Laboratory

The Metallurgical Laboratory (or Met Lab) 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 Metallurgical Laboratory was established as part of the Metallurgical Project, also known as the "Pile" or "X-10" Project, headed by Arthur H. Compton, a Nobel Prize laureate. In turn, this was part of the Manhattan Project – the Allied effort to develop the atomic bomb during World War II. The Metallurgical Laboratory was successively led by Richard L. Doan, Samuel K. Allison, Joyce C. Stearns and Farrington Daniels. Scientists who worked there included Enrico Fermi, James Franck, Eugene Wigner and Glenn Seaborg. At its peak on 1 July 1944, it had 2,008 staff.

Chicago Pile-1 was soon moved by the lab to a more remote site in the Argonne Forest, where its original materials were used to build an improved Chicago Pile-2. Another reactor, Chicago Pile-3, was built at the Argonne site in early 1944. This was the world's first reactor to use heavy water as a neutron moderator. It went critical in May 1944, and was first operated at full power in July 1944. The Metallurgical Laboratory also designed the X-10 Graphite Reactor at the Clinton Engineer Works in Oak Ridge, Tennessee, and the B Reactor at the Hanford Engineer Works in the state of Washington.

As well as the work on reactor development, the Metallurgical Laboratory studied the chemistry and metallurgy of plutonium, and worked with DuPont to develop the bismuth phosphate process used to separate plutonium from uranium. When it became certain that nuclear reactors would involve radioactive materials on a gigantic scale, there was considerable concern about the health and safety aspects, and the study of the biological effects of radiation assumed greater importance. It was discovered that plutonium, like radium, was a bone seeker, making it especially hazardous. The Metallurgical Laboratory became the first of the national laboratories, the Argonne National Laboratory, on 1 July 1946. The work of the Met Lab also led to the creation of the Enrico Fermi Institute and the James Franck Institute at the university.

Oak Ridge Historic District

Oak Ridge Historic District (also known as Clinton Engineer Works Townsite) is a historic district in Oak Ridge, Tennessee, that is listed on the National Register of Historic Places.

Roughly bounded by East Drive, Outer and West Outer Drives, Louisiana Avenue, and Tennessee Avenue, the district comprises much of Oak Ridge's original Manhattan Project townsite, laid out by Skidmore, Owings and Merrill.

Contributing properties in the historic district include United Church, The Chapel on the Hill, the Alexander Inn, and Highland View Elementary School, which houses the Children's Museum of Oak Ridge. The district was added to the National Register in 1991.

Oak Ridge nuclear facility

Oak Ridge nuclear facility may refer to one of several active or historical U.S. federal government facilities in Oak Ridge, Tennessee, including:

Clinton Engineer Works, the complex of production facilities at Oak Ridge during the World War II Manhattan Project, superseded by the following:

K-25/K-27, facility for uranium enrichment by gaseous diffusion during World War II and for many years thereafter

S-50, conducted uranium enrichment by thermal diffusion during the Manhattan Project

Oak Ridge National Laboratory, a U.S. Department of Energy multipurpose national laboratory and the site of several active and historical nuclear energy projects

X-10 Graphite Reactor, on the Oak Ridge National Laboratory campus, built during World War II and the first reactor designed and built for continuous operation

Y-12 National Security Complex, conducted uranium enrichment during World War II, more recently used for nuclear weapons production and management of highly enriched uranium

Robert Lyster Thornton

Robert Lyster Thornton (29 November 1908 – 28 September 1985) was a British-Canadian-American physicist who worked on the cyclotrons at Ernest Lawrence's Radiation Laboratory in the 1930s. During World War II he assisted with the development of the calutron as part of the Manhattan Project. He returned to Berkeley in 1945 to lead the construction of the 184-inch (470 cm) cyclotron, and spent the rest of his career there.

S-50 (Manhattan Project)

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 liquid thermal diffusion process was not one of the enrichment technologies initially selected for use in the Manhattan Project, and was developed independently by Philip H. Abelson and other scientists at the United States Naval Research Laboratory. This was primarily due to doubts about the process's technical feasibility, but inter-service rivalry between the United States Army and United States Navy also played a part.

Pilot plants were built at the Anacostia Naval Air Station and the Philadelphia Navy Yard, and a production facility at the Clinton Engineer Works in Oak Ridge, Tennessee. This was the only production-scale liquid thermal diffusion plant ever built. It could not enrich uranium sufficiently for use in an atomic bomb, but it could provide slightly enriched feed for the Y-12 calutrons and the K-25 gaseous diffusion plants. It was estimated that the S-50 plant had sped up production of enriched uranium used in the Little Boy bomb employed in the atomic bombing of Hiroshima by a week.

The S-50 plant ceased production in September 1945, but it was reopened in May 1946, and used by the United States Army Air Forces Nuclear Energy for the Propulsion of Aircraft (NEPA) project. The plant was demolished in the late 1940s.

X-10 Graphite Reactor

The X-10 Graphite Reactor at Oak Ridge National Laboratory 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-1), and the first designed and built for continuous operation. It was built during World War II as part of the Manhattan Project.

While Chicago Pile-1 demonstrated the feasibility of nuclear reactors, the Manhattan Project's goal of producing enough plutonium for atomic bombs required reactors a thousand times as powerful, along with facilities to chemically separate the plutonium bred in the reactors from uranium and fission products. An intermediate step was considered prudent. The next step for the plutonium project, codenamed X-10, was the construction of a semiworks where techniques and procedures could be developed and training conducted. The centerpiece of this was the X-10 Graphite Reactor. It was air-cooled, used nuclear graphite as a neutron moderator, and pure natural uranium in metal form for fuel.

DuPont commenced construction of the plutonium semiworks at the Clinton Engineer Works in Oak Ridge on February 2, 1943. The reactor "went critical" on November 4, 1943, and produced its first plutonium in early 1944. It supplied the Los Alamos Laboratory with its first significant amounts of plutonium, and its first reactor-bred product. Studies of these samples heavily influenced bomb design. The reactor and chemical separation plant provided invaluable experience for engineers, technicians, reactor operators, and safety officials who then moved on to the Hanford site. X-10 operated as a plutonium production plant until January 1945, when it was turned over to research activities, and the production of radioactive isotopes for scientific, medical, industrial and agricultural uses. It was shut down in 1963 and was designated a National Historic Landmark in 1965.

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