S-50 (Manhattan Project)
35°54′58″N 84°24′43″W / 35.91611°N 84.41194°W
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
Pilot plants were built at the
The S-50 plant ceased production in September 1945, but it was reopened in May 1946, and used by the
Background
The discovery of the
At the
Liquid thermal diffusion
The liquid thermal diffusion process was based on the discovery by
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 Klaus Clusius and Gerhard Dickel in Germany in 1938, who used it to separate isotopes of neon. They used an apparatus called a "column", consisting of a vertical tube with a hot wire down the center.[16][17] In the United States, Arthur Bramley at the United States Department of Agriculture improved on this design by using concentric tubes with different temperatures.[18]
Research and development
The next step was to repeat the experiments with uranium. He studied the process with aqueous solutions of uranium salts, but found that they tended to
Uranium hexafluoride was not readily available, so Abelson devised his own method of producing it in quantity at the NRL, through fluoridation of the more easily produced
Abelson erected eleven columns at the Bureau of Standards, all approximately 1.5 inches (38 mm) in diameter, but ranging from 2 to 12 feet (0.61 to 3.66 m) high. Test runs were carried out with potassium salts, and then, in April 1941, with uranium hexafluoride. On 1 June 1941, Abelson became an employee of the NRL, and he moved to the Anacostia Naval Air Station. In September 1941, he was joined by John I. Hoover, who became his deputy. They constructed an experimental plant there with 36-foot (11 m) columns.[24][23] Steam was provided by a 20-horsepower (15 kW) gas-fired boiler.[26] They were able to separate isotopes of chlorine, but the apparatus was ruined in November by the decomposition products of the carbon tetrachloride.[24][23] The next run indicated 2.5% separation, and it was found that the optimal spacing of the columns was between 0.21 and 0.38 millimetres (0.0083 and 0.0150 in).[24] Abelson regarded a run on 22 June with a 9.6% result as the first successful test of liquid thermal diffusion with uranium hexafluoride. In July, he was able to achieve 21%.[27]
Relations with the Manhattan Project
The NRL authorized a pilot plant in July 1942, which commenced operation on 15 November.
The S-1 Executive Committee superseded the Uranium Committee on 19 June 1942, dropping Gunn from its membership in the process.
James B. Conant, the chairman of the NDRC and the S-1 Executive Committee, was concerned that the navy was running its own nuclear project, but Bush felt that it did no harm. He met with Gunn at Anacostia on 14 January 1943, and explained the situation to him. Gunn responded that the navy was interested in nuclear marine propulsion for nuclear submarines. Liquid thermal diffusion was a viable means of producing enriched uranium, and all he needed was details about nuclear reactor design, which he knew was being pursued by the Metallurgical Laboratory in Chicago. He was unaware that it had already built Chicago Pile-1, a working nuclear reactor. Bush was unwilling to provide the requested data, but arranged with Rear Admiral William R. Purnell, a fellow member of the Military Policy Committee that ran the Manhattan Project, for Abelson's efforts to receive additional support.[32]
The following week, Briggs, Urey, and Eger V. Murphree from the S-1 Executive Committee, along with Karl Cohen and W. I. Thompson from Standard Oil, visited the pilot plant at Anacostia. They were impressed with the simplicity of the process, but disappointed that no enriched uranium product had been withdrawn from the plant; production had been calculated by measuring the difference in concentration. They calculated that a liquid thermal diffusion plant capable of producing 1 kg per day of uranium enriched to 90% uranium-235 would require 21,800 36-foot (11 m) columns, each with a separation factor of 30.7%. It would take 18 months to build, assuming the use of the Manhattan Project's overriding priority for materials. This included 1,700 short tons (1,500 t) of scarce copper for the outer tubes and nickel for the inner, which would be required to resist corrosion by the steam and uranium hexafluoride respectively.[34][35]
The estimated cost of such a plant was around $32.6 million to build and $62,600 per day to run. What killed the proposal was that the plant would require 600 days to reach equilibrium, by which time $72 million would have been spent, which the S-1 Executive Committee rounded up to $75 million. Assuming that work started immediately, and the plant worked as designed, no enriched uranium could be produced before 1946. Murphree suggested that a liquid thermal diffusion plant producing uranium enriched to 10% uranium-235 might be a substitute for the lower stages of a gaseous diffusion plant, but the S-1 Executive Committee decided against this.[34][35] Between February and July 1943 the Anacostia pilot plant produced 236 pounds (107 kg) of slightly enriched uranium hexafluoride, which was shipped to the Metallurgical Laboratory.[36] In September 1943, the S-1 Executive Committee decided that no more uranium hexafluoride would be allocated to the NRL, although it would exchange enriched uranium hexafluoride for regular uranium hexafluoride. Groves turned down an order from the NRL for additional uranium hexafluoride in October 1943. When it was pointed out that the navy had developed the production process for uranium hexafluoride in the first place, the army reluctantly agreed to fulfil the order.[35]
Philadelphia pilot plant
Abelson's studies indicated that in order to reduce the equilibrium time, he needed to have a much greater temperature gradient.
The Philadelphia pilot plant occupied 13,000 square feet (1,200 m2) of space on a site one block west of Broad Street, near the Delaware River. The plant consisted of 102 48-foot (15 m) columns, known as a "rack", arranged into a cascade of seven stages. The plant was intended to be able to produce one gram per day of uranium enriched to 6% uranium-235. The outer copper tubes were cooled by 155 °F (68 °C) water flowing between them and the external 4-inch steel pipes. The inner nickel tubes were heated by high pressure steam at 545 °F (285 °C) and 1,000 pounds per square inch (6,900 kPa). Each column therefore held about 1.6 kilograms (3.5 lb) of uranium hexafluoride. This was driven by vapor pressure; the only working parts were the water pumps. In operation, the rack consumed 11.6 MW of power. Each column was connected to a reservoir of 3 to 170 kilograms (6.6 to 374.8 lb) of uranium hexafluoride. Because of the dangers involved in handling uranium hexafluoride, all work with it, such as replenishing the reservoirs from the shipping cylinders, was accomplished in a transfer room.[40] The columns at the Philadelphia plant were operated in parallel instead of in series, so the Philadelphia pilot plant eventually produced over 5,000 pounds (2,300 kg) of uranium hexafluoride enriched to 0.86 percent uranium-235, which was handed over to the Manhattan Project.[41] The Philadelphia pilot plant was disposed of in September 1946, with salvageable equipment being returned to the NRL, while the rest was dumped at sea.[42]
Construction
In early 1944, news of the Philadelphia pilot plant reached
Groves obtained permission from the Military Policy Committee to renew contact with the navy,
Sites at Watts Bar Dam, Muscle Shoals and Detroit were considered, but it was decided to build it at the Clinton Engineer Works, where water could be obtained from the Clinch River and steam from the K-25 powerhouse.[49] The thermal diffusion project was codenamed S-50.[15] An S-50 Division was created at the Manhattan District headquarters in June under Lieutenant Colonel Mark C. Fox, with Major Thomas J. Evans, Jr., as his assistant with special authority for plant construction. Groves selected the H. K. Ferguson Company of Cleveland, Ohio, as the prime construction contractor on its record of finishing jobs on time,[50] notably the Gulf Ordnance Plant in Mississippi,[51] on a cost plus fixed fee contract. The H. A. Jones Construction Company would build the steam plant, with H. K. Ferguson as engineer-architect.[49] Although his advisors had estimated that it would take six months to build the plant, Groves gave H. K. Ferguson just four,[50] and he wanted operations to commence in just 75 days.[52]
Groves, Tolman, Fox, and Wells N. Thompson from H. K. Ferguson, collected blueprints of the Philadelphia pilot from there on 26 June.[51] The production plant would consist of twenty-one 102-column racks, arranged in three groups of seven, a total of 2,142 48-foot (15 m) columns. Each rack was a copy of the Philadelphia pilot plant.[53] The columns had to be manufactured to fine tolerances; ±0.0003 inches (0.0076 mm) for the diameter of the inner nickel tubes, and ±0.002 inches (0.051 mm) between the inner nickel tubes and the outer copper tubes.[51] The first orders for columns were placed on 5 July.[52] Twenty-three companies were approached, and the Grinnell Company of Providence, Rhode Island, and the Mehring and Hanson Company of Washington, D.C., accepted the challenge.[53]
Ground was broken at the site on 9 July 1944. By 16 September, with about a third of the plant complete, the first rack had commenced operation.[52] Testing in September and October revealed problems with leaking pipes that required further welding. Nonetheless, all racks were installed and ready for operations in January 1945. The construction contract was terminated on 15 February, and the remaining insulation and electrical work was assigned to other firms in the Oak Ridge area. They also completed the auxiliary buildings, including the new steam plant. The plant became fully operational in March 1945.[54] Construction of the new boiler plant was approved on 16 February 1945. The first boiler was started on 5 July 1945, and operations commenced on 13 July. Work was completed on 15 August 1945.[52]
The Thermal Diffusion Process Building (F01) was a black structure 522 feet (159 m) long, 82 feet (25 m) wide, and 75 feet (23 m) high. There was one control room and one transfer room for each pair of racks, except for the final one, which had its own control and transfer rooms for training purposes.[54] Four pumps drew 15,000 US gallons (57,000 L) per minute of cooling water from the Clinch River. Steam pumps were specially designed by Pacific Pumps Inc. The plant was designed to use the entire output of the K-25 powerhouse, but as K-25 stages came online there was competition for this. It was decided to build a new boiler plant. Twelve surplus 450 pounds per square inch (3,100 kPa) boilers originally intended for destroyer escorts were acquired from the navy. The lower hot wall temperature due to the reduced steam pressure (450 pounds per square inch (3,100 kPa) instead of the 1,000 pounds per square inch (6,900 kPa) of the pilot plant) was compensated for by the ease of operation. Because they were oil-fired, a 6,000,000-US-gallon (23,000,000 L) oil tank farm was added, with sufficient storage to operate the plant for 60 days.[53] In addition to the Thermal Diffusion Process Building (F01) and the new steam plant (F06) buildings, structures in the S-50 area included the pumping station (F02), laboratories, a cafeteria, machine shop (F10), warehouses, a gas station, and a water treatment plant (F03).[53][55]
Production
For security reasons, Groves wanted H. K. Ferguson to operate the new plant, but it was a
On 2 September 1944, SED Private Arnold Kramish, and two civilians, Peter N. Bragg, Jr., an NRL chemical engineer, and Douglas P. Meigs, a Fercleve employee, were working in a transfer room when a 600-pound (270 kg) cylinder of uranium hexafluoride exploded, rupturing nearby steam pipes.[57][58] The steam reacted with the uranium hexafluoride to create hydrofluoric acid, and the three men were badly burned. Private John D. Hoffman ran through the toxic cloud to rescue them, but Bragg and Meigs died from their injuries. Another eleven men, including Kramish and four other soldiers, were injured but recovered. Hoffman, who suffered burns, was awarded the Soldier's Medal, the United States Army's highest award for an act of valor in a non-combat situation, and the only one awarded to a member of the Manhattan District.[57][58][59] Bragg was posthumously awarded the Navy Meritorious Civilian Service Award on 21 June 1993.[60]
Colonel Stafford L. Warren, the chief of the Manhattan District's Medical Section, removed the internal organs of the dead and sent them back to Oak Ridge for analysis. They were buried without them.[57] An investigation found that the accident was caused by the use of steel cylinders with nickel linings instead of seamless nickel cylinders because the army had pre-empted nickel production.[59] The Navy Hospital did not have procedures for the treatment of people exposed to uranium hexafluoride, so Warren's Medical Section developed them. Groves ordered a halt to training at the Philadelphia pilot plant, so Abelson and 15 of his staff moved to Oak Ridge to train personnel there.[61]
There were no fatal accidents at the production plant,
Post-war years
Soon after the war ended in August 1945, Lieutenant Colonel
Starting May 1946, the S-50 plant buildings were utilised, not as a production facility, but by the
Notes
- ^ a b Hewlett & Anderson 1962, pp. 10–14.
- ^ Rhodes 1986, pp. 251–254.
- ^ Rhodes 1986, pp. 256–263.
- ^ Jones 1985, p. 12.
- ^ Bohr & Wheeler 1939, pp. 426–450.
- ^ Wheeler & Ford 1998, pp. 27–28.
- ^ Smyth 1945, p. 32.
- ^ Rhodes 1986, pp. 322–325.
- ^ Hewlett & Anderson 1962, p. 42.
- ^ Hewlett & Anderson 1962, pp. 29–30.
- ^ Frisch 1979, p. 126.
- ^ Abelson, Rosen & Hoover 1951, pp. 19–22.
- ^ Chapman & Dootson 1917, pp. 248–253.
- ^ Chapman & Cowling 1970, p. 268.
- ^ a b Brown & MacDonald 1977, p. 301.
- ^ Smyth 1945, pp. 161–162.
- ^ Clusius & Dickel 1938, p. 546.
- ^ a b c Reed 2011, pp. 164–165.
- ^ Rhodes 1986, pp. 273–275.
- ^ Abelson 1939, p. 418.
- ^ McMillan & Abelson 1940, pp. 1185–1186.
- ^ Rhodes 1986, pp. 348–351.
- ^ a b c d e f g Abelson, Rosen & Hoover 1951, pp. 29–31.
- ^ a b c d e Brown & MacDonald 1977, pp. 301–302.
- ^ Hewlett & Anderson 1962, p. 66.
- ^ Jones 1985, p. 173.
- ^ Reed 2011, p. 168.
- ^ a b Reed 2011, pp. 169–170.
- ^ Hewlett & Anderson 1962, p. 169.
- ^ Groves 1962, p. 23.
- ^ Hewlett & Anderson 1962, p. 75.
- ^ a b c d Hewlett & Anderson 1962, pp. 169–170.
- ^ a b c Ahern 2003, pp. 224–225.
- ^ a b Reed 2011, pp. 170–171.
- ^ a b c d e f Hewlett & Anderson 1962, pp. 170–172.
- ^ Reed 2011, p. 172.
- ^ a b Ahern 2003, p. 226.
- ^ a b c Abelson, Rosen & Hoover 1951, p. 33.
- ^ Rhodes 1986, p. 551.
- ^ Reed 2011, p. 173.
- ^ Ahern 2003, p. 231.
- ^ a b c Reed 2011, p. 179.
- ^ a b Rhodes 1986, p. 552.
- ^ Reed 2011, p. 174.
- ^ a b c Groves 1962, p. 120.
- ^ Smyth 1945, p. 202.
- ^ a b Jones 1985, p. 176.
- ^ Jones 1985, p. 177.
- ^ a b Brown & MacDonald 1977, p. 303.
- ^ a b Jones 1985, p. 178.
- ^ a b c Reed 2011, p. 175.
- ^ a b c d Brown & MacDonald 1977, p. 305.
- ^ a b c d Brown & MacDonald 1977, p. 304.
- ^ a b c Jones 1985, p. 179.
- ^ "K-25 Virtual Museum – Site Tour". United States Department of Energy. Retrieved 10 December 2016.
- ^ Jones 1985, p. 180.
- ^ a b c d e Kramish, Arnold (15 December 1991). "They Were Heroes Too". The Washington Post. Retrieved 9 December 2016.
- ^ a b "Atomic Accidents". Atomic Heritage Foundation. Retrieved 9 December 2016.
- ^ a b Ahern 2003, pp. 176–177.
- ^ "Peter N. Bragg, Jr". Arkansas Academy of Chemical Engineers. Retrieved 9 December 2016.
- ^ a b c Jones 1985, pp. 180–183.
- ^ a b "Manhattan District History – Book VI Liquid Thermal Diffusion (S-50) Project – Secret Supplement" (PDF). Department of Energy. Retrieved 10 December 2016.
- ^ Hewlett & Anderson 1962, pp. 300–302.
- ^ a b c d Hewlett & Anderson 1962, p. 624.
- ^ "Arthur V. "Pete" Peterson, Nuclear Pioneer, Dies at 95". Westport Now. Westport, Connecticut. 2 April 2008. Retrieved 23 December 2015.
- ^ a b c "Summary Site Profile for the S-50 Liquid Thermal Diffusion Project" (PDF). National Institute for Occupational Safety and Health (NIOSH). Retrieved 7 December 2016.
- ^ "Oak Ridge Thermal Diffusion Plant". Energy Employees Claimant Assistance Project. Retrieved 7 December 2016.
- ^ "The Decay of the Atomic Powered Aircraft Program". Megazone. Worcester Polytechnic Institute. 1993. Retrieved 7 December 2016.
References
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- OCLC 631512. Retrieved 7 December 2016.
- Ahern, Joseph-James (2003). "'We Had the Hose Turned on Us!': Ross Gunn and the Naval Research Laboratory's Early Research into Nuclear Propulsion, 1939–1946". .
- .
- OCLC 4433564013.
- Chapman, S.; Dootson, F. W. (March 1917). "A Note on Thermal Diffusion". Philosophical Magazine. 33 (6): 248–253.
- Chapman, Sydney; Cowling, T. G. (1970). The Mathematical Theory of Non-uniform Gases: an Account of the Kinetic Theory of Viscosity, Thermal Conduction and Diffusion in Gases. Cambridge: Cambridge University Press. OCLC 615469776.
- S2CID 10633448.
- OCLC 911308407.
- OCLC 537684.
- OCLC 637004643. Retrieved 26 March 2013.
- Jones, Vincent (1985). Manhattan: The Army and the Atomic Bomb (PDF). Washington, D.C.: United States Army Center of Military History. OCLC 10913875. Archived from the original(PDF) on 7 October 2014. Retrieved 25 August 2013.
- .
- Reed, B. Cameron (June 2011). "Liquid Thermal Diffusion during the Manhattan Project". S2CID 195339137.
- ISBN 0-671-44133-7.
- OCLC 770285.
- ISBN 0-393-04642-7.
External links
- "The Navy and Thermal Diffusion". United States Department of Energy. Retrieved 7 December 2016.
- "K-25 Virtual Museum – Site Tour". United States Department of Energy. Retrieved 10 December 2016.