Operation Sandstone

Last updated

Operation Sandstone
SandstoneYoke.gif
Sandstone-Yoke, 49 kilotons.
Information
CountryUnited States
Test site
  • Aomon (Sally), Enewetak Atoll
  • Enjebi (Janet), Enewetak Atoll
  • Runit (Yvonne), Enewetak Atoll
Period1948
Number of tests3
Test typetower
Max. yield49 kilotonnes of TNT (210 TJ)
Test series chronology

Operation Sandstone was a series of nuclear weapon tests in 1948. It was the third series of American tests, following Trinity in 1945 and Crossroads in 1946, and preceding Ranger. Like the Crossroads tests, the Sandstone tests were carried out at the Pacific Proving Grounds, although at Enewetak Atoll rather than Bikini Atoll. They differed from Crossroads in that they were conducted by the Atomic Energy Commission, with the armed forces having only a supporting role. The purpose of the Sandstone tests was also different: they were primarily tests of new bomb designs rather than of the effects of nuclear weapons. Three tests were carried out in April and May 1948 by Joint Task Force 7, with a work force of 10,366 personnel, of whom 9,890 were military.

Contents

The successful testing of the new cores in the Operation Sandstone tests rendered every component of the old weapons obsolete. Even before the third test had been carried out, production of the old cores was halted, and all effort concentrated on the new Mark 4 nuclear bomb, which would become the first mass-produced nuclear weapon. More efficient use of fissionable material as a result of Operation Sandstone would increase the U.S. nuclear stockpile from 56 bombs in June 1948 to 169 in June 1949.

Origins

Enewetak Atoll Eniwetak Atoll.gif
Enewetak Atoll

Nuclear weapons were developed during World War II by the Manhattan Project, which created a network of production facilities, and the weapons research and design laboratory at the Los Alamos National Laboratory. [1] Two types of bombs were developed: the Mark 1 Little Boy, a gun-type fission weapon using uranium-235, and the Mark 3 Fat Man, an implosion-type nuclear weapon using plutonium. [2]

These weapons were not far removed from their laboratory origins. A great deal of work remained to improve ease of assembly, safety, reliability and storage before they were ready for production. There were also many improvements to their performance that had been suggested or recommended during the war that had not been possible under the pressure of wartime development. Norris Bradbury, who replaced Robert Oppenheimer as director at Los Alamos, felt that "we had, to put it bluntly, lousy bombs." [3]

Plutonium was produced by irradiating uranium-238 in three 250 MW nuclear reactors at the Hanford site. In theory they could produce 0.91 grams (0.032 oz) of plutonium per megawatt-day, or about 20 kilograms (44 lb) per month. In practice, production never approached such a level in 1945, when only between 4 and 6 kilograms (8.8 and 13.2 lb) was produced per month. A Fat Man core required about 6.2 kilograms (14 lb) of plutonium, of which 21% fissioned. Plutonium production fell off during 1946 due to swelling of the reactors' graphite neutron moderators. This is known as the Wigner effect, after its discoverer, the Manhattan Project scientist Eugene Wigner. [4]

These reactors were also required for the production (by irradiation of bismuth-209) of polonium-210, which was used in the initiators, a critical component of the nuclear weapons. Some 62 kilograms (137 lb) of bismuth-209 had to be irradiated for 100 days to produce 600 curies of polonium-210, a little over 132 milligrams (2.04 gr). Because polonium-210 has a half-life of only 138 days, at least one reactor had to be kept running. The oldest unit, B pile, was therefore closed down so that it would be available in the future. Investigation of the problem would take most of 1946 before a fix was found. [5]

Uranium-235 was derived from enrichment of natural uranium at the Y-12 plant and K-25 site in Oak Ridge, Tennessee. Improvements in the processes and procedures of the electromagnetic and gaseous isotope separation between October 1945 and June 1946 led to an increase in production to around 69 kilograms (152 lb) of uranium-235 per month, which was only enough for one of the very wasteful Little Boys. A Fat Man was 17.5 times as efficient as a Little Boy, but a ton of uranium ore could yield eight times as much uranium-235 as plutonium, and on a per-gram basis, plutonium cost somewhere between four and eight times as much to produce as uranium-235, [6] which at this time cost around $26 per gram. [7]

Weapon development 1945–1948

The objectives of the Sandstone series of tests were to:

  1. test nuclear cores and initiators;
  2. improve the theory and knowledge of implosion type weapons;
  3. test levitated cores;
  4. test composite cores; and
  5. determine the most economic designs in terms of efficient use of fissionable material. [8]

Levitation meant that instead of being immediately inside the tamper, there would be an air gap between the tamper and the core, which would be suspended inside on wires. This would allow the tamper to gain more momentum before striking the core. The principle was similar to swinging a hammer at a nail versus putting the hammerhead directly on the nail and pushing as hard as possible. In order for this to work outside the laboratory, the wires had to be strong enough to withstand being dropped from an aircraft, but thin enough to not disturb the spherical symmetry of the implosion. [9] The Theoretical Division at Los Alamos, known as T Division, had run computer calculations on the levitated core as early as March 1945. [10] The use of the levitated core had been proposed during the planning for Operation Crossroads, but it had been decided instead to use the existing solid core "Christy" design. [11] This was named after its designer, Robert Christy. [12] For Sandstone, however, it was decided that at least two of the three tests would use levitated cores. [8]

The motivation behind the composite core was to make better use of the available fissionable material. The use of uranium-235 in an implosion weapon instead of the inefficient gun type Little Boy was an obvious development. However, while plutonium was more expensive and harder to produce than uranium-235, it fissions faster, because it makes better use of the neutrons its fission produces. On the other hand, the slower reaction of uranium-235 permits the assembly of super-critical masses, making it theoretically possible to produce weapons with high yields. [13] By July 1945, Oppenheimer and Groves were considering using both materials in a composite core containing 3.25 kilograms (7.2 lb) of plutonium and 6.5 kilograms (14 lb) of uranium-235. The composite cores became available in 1946. Los Alamos' priority then became the development of an all-uranium-235 core. [14] By January 1948 the national stockpile contained 50 cores, of which 36 were composite Christy cores, nine were plutonium Christy cores, and five were composite levitated cores. [15] Testing the new levitated, composite and uranium-235 cores would require at least three test firings. [14]

More efficient weapons would require less efficient initiators. This meant that less polonium would be required. At the time of Sandstone, the national stockpile of polonium-beryllium initiators consisted of 50 A-Class initiators, with more than 25 curies of polonium, and 13 B-Class initiators with 12 to 25 curies. During Sandstone, at least one test would be conducted with a B-Class initiator. [16]

Preparations

Organization

Briefing on the USS Mount McKinley. Pictured are Colonel T. J. Sands, Captain James S. Russell, Dr. D. K. Froman, Brigadier General David A. Ogden, Major General J. D. Barker, Major General W. E. Kepner, Lieutenant General John E. Hull, Rear Admiral William S. Parsons, Rear Admiral Francis C. Denebrink, and Brigadier General Claude B. Ferenbaugh. Sandstone meeting.jpg
Briefing on the USS Mount McKinley. Pictured are Colonel T. J. Sands, Captain James S. Russell, Dr. D. K. Froman, Brigadier General David A. Ogden, Major General J. D. Barker, Major General W. E. Kepner, Lieutenant General John E. Hull, Rear Admiral William S. Parsons, Rear Admiral Francis C. Denebrink, and Brigadier General Claude B. Ferenbaugh.

The tests were authorized by President Harry S. Truman on June 27, 1947. The Atomic Energy Commission's Director of Military Applications, Brigadier General James McCormack and his deputy, Captain James S. Russell, met with Bradbury and John Henry Manley at Los Alamos on July 9 to make arrangements for the tests. They readily agreed that they would be scientific in nature, with Los Alamos supplying the technical direction and the armed forces providing supplies and logistical support. The cost of the tests, around $20 million, was divided between the Department of Defense and the Atomic Energy Commission. Lieutenant General John E. Hull was designated as test commander. [17] Rear Admiral William S. Parsons and Major General William E. Kepner reprised their Operation Crossroads roles as deputy commanders. [18] Joint Task Force 7 was formally activated on October 18, 1947. As its commander, Hull was answerable to both the Joint Chiefs of Staff and the Atomic Energy Commission. [19]

Joint Task Force 7 consisted of 10,366 personnel, 9,890 of them military. [20] Its headquarters consisted of about 175 men, of whom 96 were on board the USS Mount McKinley. The rest were accommodated on the USS Albemarle, Curtiss and Bairoko. [21] A special division of the Los Alamos National Laboratory, known as J Division, was created specifically to manage nuclear testing. An Atomic Energy Commission group (Task Group 7.1) was responsible for preparing and detonating the nuclear weapons, and conducting the experiments. It consisted of some 283 scientists and technicians responsible for nuclear tests from J Division, the Armed Forces Special Weapons Project, the Naval Research Laboratory, the Naval Ordnance Laboratory, Argonne National Laboratory, the Aberdeen Proving Ground, the Atomic Energy Commission, Edgerton, Germeshausen & Grier, and other agencies. [21]

Each dealt with a different aspect of the tests. The Naval Ordnance Laboratory handled the blast measurement tests, while the Naval Research Laboratory conducted the radiation measurement experiments, and Argonne National Laboratory did gamma ray measurements. Edgerton, Germeshausen, and Grier were contractors hired to design and install the timing and firing systems. [21] Seven experimental weapon assemblies and six cores were delivered to San Pedro, California, and loaded on the weapon assembly ship USS Curtiss, in February 1948, but the Atomic Energy Commission only gave permission for the expenditure of three cores in the tests. [22]

Ships

The naval forces were organized as Task Group 7.3. It consisted of:

Source: Berkhouse et al, Operation Sandstone, p. 40

Civil affairs

A Sikorsky HO3S helicopter picks up water sample from balsa raft attached to a water sample cable Sandstone HO3S.jpg
A Sikorsky HO3S helicopter picks up water sample from balsa raft attached to a water sample cable

In September 1947, Hull, Russell, who was designated test director on October 14, and Joint Task Force 7's scientific director, Darol K. Froman from the Los Alamos Laboratories, set out with a group of scientists and military officers to examine various proposed test sites in the Pacific. [17] Enewetak Atoll was chosen as the test site on October 11. [23] The island was remote, but with a good harbor and an airstrip. It also had ocean currents and trade winds that would carry fallout out to sea, an important consideration in view of what had happened at Bikini Atoll during Operation Crossroads. [17]

As the Trust Territory of the Pacific Islands was a United Nations trust territory administered by the United States, the United Nations Security Council was notified of the upcoming tests on December 2. The atoll was inhabited by the dri-Enewetak, who lived on Aomon, and the dri-Enjebi, who lived on Bijire. Their original homes had been on Enewetak and Enjebi, but they had been moved during the war to make way for military bases. The population, about 140 in number, had been temporarily relocated to Meck Island during Operation Crossroads. This time, Ujelang Atoll, an uninhabited atoll 124 nautical miles (230 km; 143 mi) southwest of Enewetak, was selected as a relocation site. A Naval Construction Battalion group arrived there on November 22 to build accommodation and amenities. The military authorities met with the local chiefs on December 3, and they agreed to the relocation, which was carried out by USS King County by December 20. [24] An LST and four Douglas C-54 Skymaster aircraft were placed on standby to evacuate Ujelan in case it was affected by fallout, but were not required. [25]

Unlike the Crossroads tests, which were conducted in the media spotlight, the Sandstone tests were carried out with minimal publicity. On April 15, there was still discussion in Washington about whether or not there should be any public announcement of the tests at all. Hull opposed making any announcement until after the series was completed, but the AEC commissioners felt that the news would leak out, and the United States would look secretive. It was therefore decided to make a last minute announcement. There was no announcement of the purpose of the tests, and only cursory press releases. On 18 May, after the series was over, Hull held a press conference in Hawaii, but only permitted the media to quote from written statements. [26]

Construction

One of the three shot-towers used for the Sandstone-series of tests; unknown device. SandstoneTower 1.jpg
One of the three shot-towers used for the Sandstone-series of tests; unknown device.

Enjebi, Aomon, and Runit Islands were cleared of vegetation and graded level to make it easier to install the required instrumentation, and a causeway was built between Aomon and Bijire so the instrument cables could be run from the test tower on Aomon to the control station on Bijire. The detonations were ordered so that later test areas would suffer minimal fallout from the earlier shots. [27] The Army component, Task Group 7.2, was responsible for construction work. It consisted of the 1220th Provisional Engineer Battalion, with the 1217th and 1218th Composite Service Platoons, the 18th Engineer Construction Company and 1219th Signal Service Platoon; Companies D and E of the 2nd Engineer Special Brigade's 532nd Engineer Boat and Shore Regiment; the 461st Transportation Amphibious Truck Company; 854th Transportation Port Company; 401st CIC Detachment; and the Naval Shore Base Detachment. [28]

Operations

As in Operation Crossroads, each detonation was given its own code name, taken from the Joint Army/Navy Phonetic Alphabet. All used modified Mark III assemblies, and were detonated from 200-foot (61 m) towers. [29] The timing of the detonations was a matter of compromise. The gamma ray measurement experiments required darkness, but the Boeing B-17 Flying Fortress drones that would sample the clouds needed daylight to control them. As a compromise, the Sandstone detonations all took place shortly before dawn. [30]

The detonations in the United States' Sandstone series are listed below:

United States' Sandstone series tests and detonations
Name Date time (UT) Local time zone Location Elevation + height Delivery, purpose Device Yield Fallout Notes References
X-rayApril 14, 1948 18:16:59.0 MHT (11 hrs)
Enjebi (Janet), Enewetak Atoll 11°39′46″N162°14′16″E / 11.66276°N 162.23785°E / 11.66276; 162.23785 (X-ray) 1 m (3 ft 3 in) + 61 m (200 ft)tower,
weapons development 		Mk-3, Type B levitated 37 ktI-131 venting detected, 140 kCi (5,200 TBq)2:1 oralloy-plutonium, levitated core. 2.38 kg (5.2 lb) Pu + 4.77 kg (10.5 lb) oralloy yielded 37 kt at 21% efficiency. Levitation was considered a top secret technique until 1980. [31] [32] [33] [34]
YokeApril 30, 1948 18:08:59.0 MHT (11 hrs)
Aomon (Sally), Enewetak Atoll 11°36′56″N162°19′10″E / 11.61569°N 162.3194°E / 11.61569; 162.3194 (Yoke) 1 m (3 ft 3 in) + 61 m (200 ft)tower,
weapons development 		Mk-3, Type B levitated 49 ktI-131 venting detected, 1.3 MCi (48 PBq)Oralloy core 2.5 kg (5.5 lb) Pu, 5 kg (11 lb) U235. (Hanson and Sublette state it probably was all U-235), levitated core. [31] [32] [33] [34]
ZebraMay 14, 1948 18:04:00.0 MHT (11 hrs)
Runit (Yvonne), Enewetak Atoll 11°32′07″N162°21′38″E / 11.5352°N 162.36063°E / 11.5352; 162.36063 (Zebra) 1 m (3 ft 3 in) + 61 m (200 ft)tower,
weapons development 		Mk-3, Type B levitated 18 ktI-131 venting detected, 100 kCi (3,700 TBq)Uranium core. Used less than 1/10 the U-235 of Little Boy. Considered so optimal that it was put into immediate production for Mark 4. [31] [32] [33] [34]

X-Ray

Sandstone X-Ray, 37-kilotons. Sandstone XRay.gif
Sandstone X-Ray, 37-kilotons.

The X-Ray nuclear device used a levitated composite core. [29] It was detonated on Enjebi just before sunrise at 06:17 on April 15, 1948, [35] with a yield of 37 kilotons. [36] The efficiency of utilization of the plutonium was about 35%; that of the uranium-235 was 25% or more. This was somewhat higher than Los Alamos' prediction. [29] Observers watching from ships in the lagoon saw a brilliant flash and felt the radiant heat. A condensation cloud 5 nautical miles (9.3 km; 5.8 mi) in diameter quickly enveloped the fireball, which glowed within the cloud. It took 45 to 50 seconds for the thunderous roar of the explosion to reach the observers. [35]

About 20 minutes later, Bairoko launched a helicopter to check on the cable winch which was to collect samples. It also lowered boats to test radioactivity levels in the lagoon. B-17 pilotless drone aircraft were flown through the clouds, and a drone light tank was used to recover soil samples from the crater. Unfortunately, it became bogged and had to be towed out ten days later. [37]

Yoke

Sandstone-Yoke, 49 kilotons. SandstoneYoke2.gif
Sandstone-Yoke, 49 kilotons.

The Yoke nuclear device used a levitated all-uranium-235 core. [29] It was detonated on Aomon just before sunrise on May 1, 1948, at 06:09, a day late due to unfavorable winds. [38] The observers saw a similar flash and felt the same heat as the X-Ray blast, but the 6-nautical-mile (11 km; 6.9 mi) wide condensation cloud was larger, and the sound of the explosion more forceful. One observer likened it to the sound of "a paper bag which is forcefully burst in a small room". [38] They were correct: its yield of 49 kilotons made it the largest nuclear detonation up to that time, [36] but it was considered inefficient and wasteful of the fissile material. [29]

Zebra

Sandstone-Zebra, 18-kilotons. Sandstone-Zebra.gif
Sandstone-Zebra, 18-kilotons.

Zebra, the third test, and the last of the Sandstone series, was detonated on Runit just before sunrise at 06:04 on May 15, 1948. [39] This test was characterized by AEC Chairman David Lilienthal as the "hardest and most important" test of the three. By using one of the B-class initiators, it demonstrated that these could still be used with confidence. [40] The observers perceived the flash and blast as similar to the previous two tests, but this time the base of the condensation cloud was at 2,000 feet (610 m), which gave the observers an unobstructed view of the fireball, which therefore appeared to be brighter and last longer than the other two. [39] Looks were deceiving: its levitated uranium-235 core produced a yield of 18 kilotons. [36]

The procedures used in the previous tests were repeated, but this time the winch cable snagged, and the test samples had to be retrieved by a jeep, exposing its crew to more radiation. The Los Alamos personnel assigned to remove the filters from the B-17 drones had apparently carried out the procedure on X-Ray and Yoke without problems, but this time three of them suffered radiation burns on their hands serious enough to be hospitalized and need skin grafting. One of the men who had carried out the procedure for Yoke was then also found to have burns on his hands and was hospitalized too, but was discharged on 28 May. Once again the drone tank gave trouble, and bogged in the crater, but the soil samples were retrieved by the backup drone tank. Both tanks were subsequently dumped in the ocean. [41]

Outcome

Filters are being removed from a US Air Force Boeing B-17 drone after a flight through the radioactive cloud Boeing B-17 drone at Eniwetok 1948.jpg
Filters are being removed from a US Air Force Boeing B-17 drone after a flight through the radioactive cloud

The successful testing of the new cores in the Sandstone tests had a profound effect. Practically every component of the old weapons was rendered obsolete. [8] Even before the third test had been carried out, Bradbury had halted production of the old cores, and ordered that all effort was to be concentrated on the Mark 4 nuclear bomb, which would become the first mass-produced nuclear weapon. [42] The more efficient use of fissionable material would increase the nuclear stockpile from 56 bombs in June 1948 to 169 in June 1949. [43] The Mark III bombs were withdrawn from service in 1950. [44] At the same time, new production plants were coming online and the Wigner effect problem had been solved. By May 1951, plutonium production was twelve times that of 1947, while uranium-235 production had increased eight-fold. [45] The Chief of the Armed Forces Special Weapons Project, Major General Kenneth D. Nichols, saw clearly that the era of scarcity was over. He now "recommended that we should be thinking in terms of thousands of weapons rather than hundreds." [46]

Notes

  1. ↑ Brahmstedt 2002, pp. 2–8.
  2. ↑ Hansen 1995, pp. 82–83.
  3. ↑ Rhodes 1995, pp. 212–213.
  4. ↑ Hansen 1995, pp. 83, 208–213.
  5. ↑ Hansen 1995, pp. 213–215.
  6. ↑ Hansen 1995, pp. 83, 212.
  7. ↑ Hansen 1995, p. 264.
  8. 1 2 3 Hansen 1995, p. 205.
  9. ↑ Rhodes 1995, pp. 188–189.
  10. ↑ Fitzpatrick 1999, p. 94.
  11. ↑ Hansen 1995, p. 203.
  12. ↑ Hansen 1995, p. 126.
  13. ↑ Hansen 1995, p. 207.
  14. 1 2 Hansen 1995, pp. 224–227.
  15. ↑ Hansen 1995, p. 240.
  16. ↑ Hansen 1995, pp. 216, 240, 245.
  17. 1 2 3 Hewlett & Duncan 1962, pp. 139–141.
  18. ↑ Christman 1998, pp. 234–239.
  19. ↑ Berkhouse et al. 1983, p. 30.
  20. ↑ Berkhouse et al. 1983, p. 1.
  21. 1 2 3 Berkhouse et al. 1983, pp. 30–35.
  22. ↑ Hansen 1995, pp. 240–241.
  23. ↑ Berkhouse et al. 1983, p. 18.
  24. ↑ Berkhouse et al. 1983, pp. 18–21.
  25. ↑ Berkhouse et al. 1983, p. 103.
  26. ↑ Hewlett & Duncan 1962, pp. 163–164.
  27. ↑ Berkhouse et al. 1983, p. 102.
  28. ↑ Berkhouse et al. 1983, p. 38.
  29. 1 2 3 4 5 Hansen 1995, pp. 242–245.
  30. ↑ Berkhouse et al. 1983, p. 104.
  31. 1 2 3 Operation Sandstone, 1948 (PDF) (DNA-6033F). Washington, DC: Defense Nuclear Agency, Department of Defense. 1983. Archived from the original (PDF) on October 21, 2013. Retrieved January 6, 2014.
  32. 1 2 3 Sublette, Carey. "Nuclear Weapons Archive" . Retrieved January 6, 2014.
  33. 1 2 3 Norris, Robert Standish; Cochran, Thomas B. (February 1, 1994). "United States nuclear tests, July 1945 to 31 December 1992 (NWD 94-1)" (PDF). Nuclear Weapons Databook Working Paper. Washington, DC: Natural Resources Defense Council. Archived from the original (PDF) on October 29, 2013. Retrieved October 26, 2013.
  34. 1 2 3 United States Nuclear Tests: July 1945 through September 1992 (PDF) (DOE/NV-209 REV15). Las Vegas, NV: Department of Energy, Nevada Operations Office. December 1, 2000. Archived from the original (PDF) on October 12, 2006. Retrieved December 18, 2013.
  35. 1 2 Berkhouse et al. 1983, p. 105.
  36. 1 2 3 Hewlett & Duncan 1962, p. 672.
  37. ↑ Berkhouse et al. 1983, pp. 105–109.
  38. 1 2 Berkhouse et al. 1983, p. 110.
  39. 1 2 Berkhouse et al. 1983, p. 114.
  40. ↑ Hansen 1995, p. 245.
  41. ↑ Berkhouse et al. 1983, pp. 114–116.
  42. ↑ Hewlett & Duncan 1962, pp. 175–176.
  43. ↑ Hansen 1995, p. 149.
  44. ↑ Hansen 1995, p. 229.
  45. ↑ Hansen 1995, p. 255.
  46. ↑ Nichols 1987, p. 269.

Related Research Articles

<span class="mw-page-title-main">Fat Man</span> U.S. atomic bomb type used at Nagasaki, 1945

"Fat Man" was the codename for the type of nuclear weapon the United States detonated over the Japanese city of Nagasaki on 9 August 1945. It was the second of the only two nuclear weapons ever used in warfare, the first being Little Boy, and its detonation marked the third nuclear explosion in history. The first one was built by scientists and engineers at Los Alamos Laboratory using plutonium manufactured at the Hanford Site and was dropped from the Boeing B-29 Superfortress Bockscar piloted by Major Charles Sweeney.

<span class="mw-page-title-main">Little Boy</span> Atomic bomb dropped on Hiroshima

Little Boy is the name of the type of atomic bomb used in the bombing of the Japanese city of Hiroshima on 6 August 1945 during World War II, making it the first nuclear weapon used in warfare. The bomb was dropped from the Boeing B-29 Superfortress Enola Gay piloted by Colonel Paul W. Tibbets Jr., commander of the 509th Composite Group, and Captain Robert A. Lewis. It exploded with an energy of approximately 15 kilotons of TNT (63 TJ) and had an explosion radius of approximately 1.3 kilometers which caused widespread death across the city. The Hiroshima bombing was the second nuclear explosion in history, after the Trinity nuclear test.

<span class="mw-page-title-main">Manhattan Project</span> World War II Allied nuclear weapons program

The Manhattan Project was a research and development program undertaken during World War II to produce the first nuclear weapons. It was led by the United States in collaboration with the United Kingdom and Canada. From 1942 to 1946, the project was directed by Major General Leslie Groves of the U.S. Army Corps of Engineers. Nuclear physicist J. Robert Oppenheimer was the director of the Los Alamos Laboratory that designed the bombs. The Army program was designated the Manhattan District, as its first headquarters were in Manhattan; the name gradually superseded the official codename, Development of Substitute Materials, for the entire project. The project absorbed its earlier British counterpart, Tube Alloys, and subsumed the program from the American civilian Office of Scientific Research and Development. The Manhattan Project employed nearly 130,000 people at its peak and cost nearly US$2 billion, over 80 percent of which was for building and operating the plants that produced the fissile material. Research and production took place at more than 30 sites across the US, the UK, and Canada.

<span class="mw-page-title-main">Nuclear weapon design</span> Process by which nuclear WMDs are designed and produced

Nuclear weapon designs are physical, chemical, and engineering arrangements that cause the physics package of a nuclear weapon to detonate. There are three existing basic design types:

<span class="mw-page-title-main">William Sterling Parsons</span> American naval officer (1901–1953)

William Sterling Parsons was an American naval officer who worked as an ordnance expert on the Manhattan Project during World War II. He is best known for being the weaponeer on the Enola Gay, the aircraft which dropped an atomic bomb on Hiroshima, Japan, in 1945. To avoid the possibility of a nuclear explosion if the aircraft crashed and burned on takeoff, he decided to arm the bomb in flight. While the aircraft was en route to Hiroshima, Parsons climbed into the cramped and dark bomb bay, and inserted the powder charge and detonator. He was awarded the Silver Star for his part in the mission.

<span class="mw-page-title-main">Operation Hurricane</span> 1952 British atomic bomb test in Western Australia

Operation Hurricane was the first test of a British atomic device. A plutonium implosion device was detonated on 3 October 1952 in Main Bay, Trimouille Island, in the Montebello Islands in Western Australia. With the success of Operation Hurricane, Britain became the third nuclear power, after the United States and the Soviet Union.

<span class="mw-page-title-main">Timeline of the Manhattan Project</span>

The Manhattan Project was a research and development project that produced the first atomic bombs during World War II. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the US Army Corps of Engineers. The Army component of the project was designated the Manhattan District; "Manhattan" gradually became the codename for the entire project. Along the way, the project absorbed its earlier British counterpart, Tube Alloys. The Manhattan Project began modestly in 1939, but grew to employ more than 130,000 people and cost nearly US$2 billion. Over 90% of the cost was for building factories and producing the fissionable materials, with less than 10% for development and production of the weapons.

<span class="mw-page-title-main">Plutonium-238</span> Isotope of plutonium used in radioisotope thermoelectric generators

Plutonium-238 is a radioactive isotope of plutonium that has a half-life of 87.7 years.

<span class="mw-page-title-main">Thin Man (nuclear bomb)</span> Nuclear weapon (development abandoned)

"Thin Man" was the code name for a proposed plutonium-fueled gun-type nuclear bomb that the United States was developing during the Manhattan Project. Its development was abandoned in 1944 after it was discovered that the spontaneous fission rate of nuclear reactor-bred plutonium was too high for use in a gun-type design due to the high concentration of the isotope plutonium-240.

<span class="mw-page-title-main">Mark 4 nuclear bomb</span> Air-dropped Nuclear fission weapon

The Mark 4 nuclear bomb was an American implosion-type nuclear bomb based on the earlier Mark 3 Fat Man design, used in the Trinity test and the bombing of Nagasaki. With the Mark 3 needing each individual component to be hand-assembled by only highly trained technicians under closely controlled conditions, the purpose of the Mark 4 was to produce an atomic weapon as a practical piece of ordnance. The Mark 4 Mod 0 entered the stockpile starting March 19, 1949 and was in use until 1953. With over 500 units procured, the Mark 4 was the first mass-produced nuclear weapon.

<span class="mw-page-title-main">Plutonium</span> Chemical element with atomic number 94 (Pu)

Plutonium is a chemical element; it has symbol Pu and atomic number 94. It is a silvery-gray actinide metal that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation states. It reacts with carbon, halogens, nitrogen, silicon, and hydrogen. When exposed to moist air, it forms oxides and hydrides that can expand the sample up to 70% in volume, which in turn flake off as a powder that is pyrophoric. It is radioactive and can accumulate in bones, which makes the handling of plutonium dangerous.

A modulated neutron initiator is a neutron source capable of producing a burst of neutrons on activation. It is a crucial part of some nuclear weapons, as its role is to "kick-start" the chain reaction at the optimal moment when the configuration is prompt critical. It is also known as an internal neutron initiator. The initiator is typically placed in the center of the plutonium pit, and is activated by impact of the converging shock wave.

<span class="mw-page-title-main">Uranium hydride bomb</span> Type of atomic bomb

The uranium hydride bomb was a variant design of the atomic bomb first suggested by Robert Oppenheimer in 1939 and advocated and tested by Edward Teller. It used deuterium, an isotope of hydrogen, as a neutron moderator in a uranium-deuterium ceramic compact. Unlike all other fission-bomb types, the concept relies on a chain reaction of slow nuclear fission. Bomb efficiency was harmed by the slowing of neutrons since the latter delays the reaction, as delineated by Rob Serber in his 1992 extension of the original Los Alamos Primer.

<span class="mw-page-title-main">Pit (nuclear weapon)</span> Core of a nuclear implosion weapon

In nuclear weapon design, the pit is the core of an implosion nuclear weapon, consisting of fissile material and any neutron reflector or tamper bonded to it. Some weapons tested during the 1950s used pits made with uranium-235 alone, or as a composite with plutonium. All-plutonium pits are the smallest in diameter and have been the standard since the early 1960s. The pit is named after the hard core found in stonefruit such as peaches and apricots.

<span class="mw-page-title-main">Armed Forces Special Weapons Project</span> U.S. nuclear weapons agency until 1947

The Armed Forces Special Weapons Project (AFSWP) was a United States military agency responsible for those aspects of nuclear weapons remaining under military control after the Manhattan Project was succeeded by the Atomic Energy Commission on 1 January 1947. These responsibilities included the maintenance, storage, surveillance, security and handling of nuclear weapons, as well as supporting nuclear testing. The AFSWP was a joint organization, staffed by the United States Army, United States Navy and United States Air Force; its chief was supported by deputies from the other two services. Major General Leslie R. Groves, the former head of the Manhattan Project, was its first chief.

<span class="mw-page-title-main">Marshall Holloway</span> American physicist (1912–1991)

Marshall Glecker Holloway was an American physicist who worked at the Los Alamos Laboratory during and after World War II. He was its representative, and the deputy scientific director, at the Operation Crossroads nuclear tests at Bikini Atoll in the Pacific in July 1946. Holloway became the head of the Laboratory's W Division, responsible for new weapons development. In September 1952 he was charged with designing, building and testing a thermonuclear weapon, popularly known as a hydrogen bomb. This culminated in the Ivy Mike test in November of that year.

<span class="mw-page-title-main">Project Y</span> Secret laboratory established by the Manhattan Project

The Los Alamos Laboratory, also known as Project Y, was a secret laboratory established by the Manhattan Project and operated by the University of California during World War II. Its mission was to design and build the first atomic bombs. Robert Oppenheimer was its first director, serving from 1943 to December 1945, when he was succeeded by Norris Bradbury. In order to enable scientists to freely discuss their work while preserving security, the laboratory was located on the isolated Pajarito Plateau in Northern New Mexico. The wartime laboratory occupied buildings that had once been part of the Los Alamos Ranch School.

<span class="mw-page-title-main">British hydrogen bomb programme</span> British effort to develop hydrogen bombs between 1952 and 1958

The British hydrogen bomb programme was the ultimately successful British effort to develop hydrogen bombs between 1952 and 1958. During the early part of the Second World War, Britain had a nuclear weapons project, codenamed Tube Alloys. At the Quebec Conference in August 1943, British prime minister Winston Churchill and United States president Franklin Roosevelt signed the Quebec Agreement, merging Tube Alloys into the American Manhattan Project, in which many of Britain's top scientists participated. The British government trusted that America would share nuclear technology, which it considered to be a joint discovery, but the United States Atomic Energy Act of 1946 ended technical cooperation. Fearing a resurgence of American isolationism, and the loss of Britain's great power status, the British government resumed its own development effort, which was codenamed "High Explosive Research".

<span class="mw-page-title-main">High Explosive Research</span> UK atomic bomb development project

High Explosive Research (HER) was the British project to develop atomic bombs independently after the Second World War. This decision was taken by a cabinet sub-committee on 8 January 1947, in response to apprehension of an American return to isolationism, fears that Britain might lose its great power status, and the actions by the United States to withdraw unilaterally from sharing of nuclear technology under the 1943 Quebec Agreement. The decision was publicly announced in the House of Commons on 12 May 1948.

Zinaida Vasilyevna Yershova was a Soviet and Russian chemist, physicist and engineer. She spent her entire career working with radioactive elements and headed laboratories producing radioactive materials used mostly in the Soviet atomic bomb project and the Soviet space program.

References

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.