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Operation Plumbbob
Plumbbob Priscilla
Information
Country United States
Test site Nevada Test Site
Period May–October 1957
Number of tests 29
Test type Atmospheric
Device type Fission/Thermonuclear
Max. yield 74 kt
Navigation
Previous test Project 57
Next test Project 58

Operation Plumbbob was a series of nuclear tests conducted between May 28 and October 7, 1957, at the Nevada Test Site, following Project 57, and preceding Project 58.[1] It was the biggest, longest, and most controversial test series in the continental United States.[citation needed]

Background[edit | edit source]

The operation consisted of 29 explosions, of which only two did not produce any nuclear yield. Twenty-one laboratories and government agencies were involved. While most Operation Plumbbob tests contributed to the development of warheads for intercontinental and intermediate range missiles, they also tested air defense and anti-submarine warheads with smaller yields. They included forty-three military effects tests on civil and military structures, radiation and bio-medical studies, and aircraft structural tests. Operation Plumbbob had the tallest tower tests to date in the U.S. nuclear testing program as well as high-altitude balloon tests. One nuclear test involved the largest troop maneuver ever associated with U.S. nuclear testing.

Almost 1,200 pigs were subjected to bio-medical experiments and blast-effects studies during Operation Plumbbob. On shot Priscilla (37 kt), 719 pigs were used in various experiments on Frenchman Flat. Some pigs were placed in elevated cages and provided with suits made of different materials, to test which materials provided best protection from the thermal pulse. As shown and reported in the PBS documentary Dark Circle, the pigs survived, but with third-degree burns to 80% of their bodies.[2] Other pigs were placed in pens behind large sheets of glass at measured distances from the hypocenter to test the effects of flying debris on living targets.

Approximately 18,000 members of the U.S. Air Force, Army, Navy and Marines participated in exercises Desert Rock VII and VIII during Operation Plumbbob. The military was interested in knowing how the average foot-soldier would stand up, physically and psychologically, to the rigors of the tactical nuclear battlefield.

Studies were conducted of radiation contamination and fallout from a simulated accidental detonation of a weapon; and projects concerning earth motion, blast loading and neutron output were carried out.

Nuclear weapons safety experiments were conducted to study the possibility of a nuclear weapon detonation during an accident. On July 26, 1957, a safety experiment, Pascal-A, was detonated in an unstemmed hole at NTS, becoming the first underground shaft nuclear test. The knowledge gained here would provide data to prevent nuclear yields in case of accidental detonations - for example, a plane crash.

The John shot on July 19, 1957 was the only test of the Air Force's AIR-2 Genie missile with a nuclear warhead.[3] It was fired from an F-89 Scorpion fighter over Yucca Flats at the NNSS. On the ground, the Air Force carried out a public relations event by having five Air Force officers and a photographer stand under ground zero of the blast, which took place at between 18,500 and 20,000 feet altitude, with the idea of demonstrating the possibility of the use of the weapon over civilian populations without ill effects. In 2012 the photographer and the last survivor of the five met in a restaurant in Dallas to reminisce.[4]

The Rainier shot, conducted September 19, 1957, was the first fully contained underground nuclear test, meaning that no fission products were vented into the atmosphere. This test of 1.7 kt could be detected around the world by seismologists using ordinary seismic instruments. The Rainier test became the prototype for larger and more powerful underground tests.

Some images from Upshot-Knothole Grable were accidentally relabeled as belonging to the Priscilla shot from Operation Plumbbob in 1957. As a consequence many publications including official government documents have the photo mislabeled.[5]

Radiological effects[edit | edit source]

Plumbbob released 58,300 kilocuries (2.16 EBq) of radioiodine (I-131) into the atmosphere. This produced total civilian radiation exposures amounting to 120 million person-rads of thyroid tissue exposure (about 32% of all exposure due to continental nuclear tests).

Statistically speaking, this level of exposure would be expected to eventually cause between 11,000 and 212,000 excess cases of thyroid cancer, leading to between 1,000 and 20,000 deaths.[6]

In addition to civilian exposure, troop exercises conducted near the ground near shot Smoky exposed over three thousand servicemen to relatively high levels of radiation. A survey of these servicemen in 1980 found significantly elevated rates of leukemia: ten cases, instead of the baseline expected four.[citation needed]

Propulsion of steel plate cap[edit | edit source]

During the Pascal-B nuclear test, a 900-kilogram (2,000 lb) steel plate cap (a piece of armor plate) was blasted off the top of a test shaft at a speed of more than 66 kilometres per second (41 mi/s). Before the test, experimental designer Dr. Brownlee had performed a highly approximate calculation that suggested that the nuclear explosion, combined with the specific design of the shaft, would accelerate the plate to six times escape velocity.[7] The plate was never found, but Dr. Brownlee believes that the plate never left the atmosphere, as it may even have been vaporized by compression heating of the atmosphere due to its high speed. The calculated velocity was sufficiently interesting that the crew trained a high-speed camera on the plate, which unfortunately only appeared in one frame, but this nevertheless gave a very high lower bound for the speed. After the event, Dr. Robert R. Brownlee described the best estimate of the cover's speed from the photographic evidence as "going like a bat out of hell!"[8][9] The use of a subterranean shaft and nuclear device to propel an object to escape velocity has since been termed a "thunder well".

This incident was reputedly used as part of the technical justification for the Orion project for possible use of nuclear blasts for outer-space propulsion.[citation needed]

List of test blasts[edit | edit source]

Test Name Date Time (UT[10]) Location Yield Notes
Boltzmann[11] May 28, 1957 11:55:00.2 NTS Area 7 37°05′41″N 116°01′28″W / 37.0947°N 116.0245°W / 37.0947; -116.0245 12 kt 150 metres (490 ft) tower; weapon development test; XW40.
Franklin[11] June 2, 1957 11:54:59.9 NTS Area 3 37°02′52″N 116°01′19″W / 37.0477°N 116.022°W / 37.0477; -116.022 140 tons 90 metres (300 ft) tower; weapon development test; XW30; Fizzled; retested later as Franklin Prime.
Lassen[11] June 5, 1957 11:45:00.3 NTS Area 9 37°08′05″N 116°02′30″W / 37.1347°N 116.0417°W / 37.1347; -116.0417 0.5 tons Ballon at 150 metres (490 ft) height; weapon development test; unboosted all-oralloy small design; Fizzled.
Wilson[11] June 18, 1957 11:45:00.3 NTS Area 9 37°08′05″N 116°02′30″W / 37.1347°N 116.0417°W / 37.1347; -116.0417 10 kt Balloon shot at 150 metres (490 ft) height; weapon development test; XW-45X1.
Priscilla[12] June 24, 1957 13:30:00.1 NTS Area 5 36°47′53″N 115°55′47″W / 36.798°N 115.9298°W / 36.798; -115.9298 37 kt Balloon shot at 210 metres (690 ft) height; weapon development test; Mark 15/39 pr.
Coulomb-A July 1, 1957 17:30 NTS Area 37°03′11″N 116°02′02″W / 37.053°N 116.034°W / 37.053; -116.0340 zero yield Surface; safety test; XW-31; successful.
Hood July 5, 1957 11:40:00.1 NTS Area 9 37°08′05″N 116°02′30″W / 37.1347°N 116.0417°W / 37.1347; -116.0417 74 kt Balloon shot at 460 metres (1,510 ft) height; weapon development test; Desert Rock VII; largest atmospheric test in the continental United States.
Diablo July 15, 1957 11:30:00.1 NTS Area 2 37°09′01″N 116°06′34″W / 37.1502°N 116.1095°W / 37.1502; -116.1095 17 kt 150 metres (490 ft) tower shot; weapon development test.
John July 19, 1957 14:00:04.6 NTS Area 10 37°09′38″N 116°03′14″W / 37.1605°N 116.0539°W / 37.1605; -116.0539 1.5 kt[13] Free fired air-to-air rocket AIR-2 Genie at 5,970 metres (19,590 ft) height; weapon effects test; W25; publicity stunt with five officers standing at ground zero.
Kepler July 24, 1957 11:49:59.9 NTS Area 4 37°05′44″N 116°06′13″W / 37.09549°N 116.10354°W / 37.09549; -116.10354 10 kt 150 metres (490 ft) tower shot; weapon development test; XW-35 ICBM warhead.
Owens July 25, 1957 13:29:59.7 NTS Area 9 37°08′05″N 116°02′30″W / 37.1347°N 116.0417°W / 37.1347; -116.0417 9.7 kt Balloon shot at 150 metres (490 ft) high; weapon development test; XW-51 progenitor.
Pascal-A July 26, 1957 8:00:00.0 NTS Area 3 37°03′06″N 116°02′03″W / 37.05175°N 116.03415°W / 37.05175; -116.03415 55 tons; expected 1-2 pounds[14] In shaft 150 metres (490 ft) deep; one-point safety test unsuccessful; yield described as "slight".
Stokes August 7, 1957 12:25:00.2 NTS Area 7 37°05′12″N 116°01′28″W / 37.0866°N 116.0245°W / 37.0866; -116.0245 19 kt Balloon at 460 metres (1,510 ft); weapon development test; XW-30; TADM or Talos SAM warhead.
Saturn August 10, 1957 12:59:55.1 NTS Area 12 37°11′37″N 116°12′02″W / 37.19355°N 116.20059°W / 37.19355; -116.20059 Zero yield Tunnel safety experiment 40 metres (130 ft) deep; successful one-point safety test; XW-45X1; the first shot in a Ranier Mesa tunnel.
Shasta August 18, 1957 12:00:00.0 NTS Area 2 37°07′41″N 116°06′26″W / 37.128°N 116.1073°W / 37.128; -116.1073 17 kt 150 metres (490 ft) tower; weapon development test; 2 stage experimental design.
Doppler August 23, 1957 12:30:00.1 NTS Area 7 37°05′12″N 116°01′28″W / 37.0866°N 116.0245°W / 37.0866; -116.0245 11 kt Balloon at 400 metres (1,300 ft) high; weapon development test; XW-34.
Pascal-B August 27, 1957 22:35:00.0 NTS Area 3 37°02′57″N 116°02′05″W / 37.04903°N 116.0347°W / 37.04903; -116.0347 300 tons; expected 1-2 pounds[9] Shaft safety experiment 150 metres (490 ft) deep; one-point safety test unsuccessful; may have sent a 4 inches (100 mm) steel cap into solar orbit at 36 km/s.
Franklin Prime August 30, 1957 12:39:59.9 NTS Area 7 37°05′12″N 116°01′28″W / 37.0866°N 116.0245°W / 37.0866; -116.0245 4.7 kt Balloon at 230 metres (750 ft) high; weapon development test; retest of Franklin with heavier core.
Smoky[15] August 31, 1957 12:30:00.0 NTS Area 2 37°11′14″N 116°04′08″W / 37.18712°N 116.06887°W / 37.18712; -116.06887 44 kt 210 metres (690 ft) tower; weapon development test; TX-41 pr; Desert Rock VII, 3000 servicemen irradiated by fallout; last pristine air-drop location at the NTS.
Galileo[16] September 2, 1957 12:40:00.0 NTS Area 1 37°03′11″N 116°06′12″W / 37.053°N 116.1034°W / 37.053; -116.1034 11 kt 150 metres (490 ft) tower shot; weapon development test; Desert Rock VII.
Wheeler September 6, 1957 12:45:00.0 NTS Area 9 37°08′05″N 116°02′30″W / 37.1347°N 116.0417°W / 37.1347; -116.0417 197 tons Balloon at 150 metres (490 ft) high; weapon development test; XW-51; retest of Lassen.
Coulomb-B September 6, 1957 20:05:00.6 NTS Area 3 37°02′34″N 116°01′40″W / 37.0427°N 116.0277°W / 37.0427; -116.0277 300 tons; expected 1-2 pounds Surface; unsuccessful one-point safety test; XW-31.
Laplace September 8, 1957 12:59:59.8 NTS Area 7 37°05′12″N 116°01′28″W / 37.0866°N 116.0245°W / 37.0866; -116.0245 1 kt Balloon at 230 metres (750 ft) high; weapon development test; XW-33 gun-type weapon (one of four ever fired).
Fizeau September 14, 1957 16:44:59.8 NTS Area 3 37°02′01″N 116°01′56″W / 37.0336°N 116.0323°W / 37.0336; -116.0323 11 kt 150 metres (490 ft) tower; weapon development test; XW-34 SADM (depth bomb).
Newton September 16, 1957 12:49:59.9 NTS Area 7 37°05′12″N 116°01′28″W / 37.0866°N 116.0245°W / 37.0866; -116.0245 12 kt Balloon at 460 metres (1,510 ft) high; weapon development test; XW-31; while it looks like a fizzle, that is not official report.
Rainier September 19, 1957 16:59:59.45 NTS Area 12 37°11′45″N 116°12′15″W / 37.19573°N 116.20404°W / 37.19573; -116.20404 1.7 kt Tunnel at 273 metres (896 ft) deep; weapon development test; W25; first US underground nuclear test.
Whitney September 23, 1957 0:29:59.8 NTS Area 2 37°08′18″N 116°07′06″W / 37.1383°N 116.1184°W / 37.1383; -116.1184 19 kt 150 metres (490 ft) tower; weapon development test; W27 pr.
Charleston September 28, 1957 0:59:59.9 NTS Area 9 37°08′05″N 116°02′30″W / 37.1347°N 116.0417°W / 37.1347; -116.0417 12 kt Balloon at 460 metres (1,510 ft) high; weapons development test; small "clean" tactical thermonuclear design; second stage Fizzled.
Morgan October 7, 1957 13:00:00.1 NTS Area 9 37°08′05″N 116°02′30″W / 37.1347°N 116.0417°W / 37.1347; -116.0417 8 kt Balloon at 150 metres (490 ft) high; weapons development test; XW-45X1.

See also[edit | edit source]

References[edit | edit source]

Notes[edit | edit source]

  1. U.S. Department of Energy, Nevada Operations Office (December 2000). "United States Nuclear Tests - July 1945 through September 1992". http://www.nv.doe.gov/library/publications/historical/DOENV_209_REV15.pdf. 
  2. Dark Circle, DVD release date March 27, 2007, Directors: Judy Irving, Chris Beaver, Ruth Landy. ISBN 0-7670-9304-6. http://www.pbs.org/pov/darkcircle/
  3. Robert Krulwich. "Five Men Agree To Stand Directly Under An Exploding Nuclear Bomb". NPR. http://www.npr.org/blogs/krulwich/2012/07/16/156851175/five-men-agree-to-stand-directly-under-an-exploding-nuclear-bomb. 
  4. Timothy Stenovec. "George Yoshitake, Nuclear Test Photographer, Recalls Filming Nuclear Blast 55 Years Ago". Huffington Post. http://www.huffingtonpost.com/2012/07/20/george-yoshitake-nuclear-test-five-5-men-nevada_n_1687233.html. 
  5. Carey Sublette, "Operation Plumbbob," Nuclear Weapon Archive, http://nuclearweaponarchive.org/Usa/Tests/Plumbob.html. (accessed December 27, 2006).
  6. Institute of Medicine (U.S.). Committee on Thyroid Screening Related to I-131 Exposure, National Research Council (U.S.). Committee on Exposure of the American People to I-131 from the Nevada Atomic Bomb Tests, ed (1999). Exposure of the American people to Iodine-131 from Nevada nuclear-bomb tests: review of the National Cancer Institute report and public health implications. National Academies Press. pp. 113–114. ISBN 978-0-309-06175-9. http://books.google.com/books?id=vGtce6RjjM0C&pg=PA114&dq=%22operation+plumbbob%22+OR+nevada+atmospheric+%22thyroid+cancer%22&cd=2#v=onepage&q=%22operation%20plumbbob%22%20OR%20nevada%20atmospheric%20%22thyroid%20cancer%22&f=false. 
  7. Brownlee, Robert R. (June 2002). "Learning to Contain Underground Nuclear Explosions". http://nuclearweaponarchive.org/Usa/Tests/Brownlee.html. Retrieved 2006-07-31. 
  8. Learning to Contain Underground Nuclear Explosions By Dr. Robert R. Brownlee - June 2002
  9. 9.0 9.1 Pascal B test at the Nuclear Weapon Archive
  10. Local time (PST) is 8 hours less than UT (7 for PDT); local date is the day before UT if UT time is before 08:00 (07:00 PDT).
  11. 11.0 11.1 11.2 11.3 "Shots BOLTZMANN to WILSON : the first four tests of the PLUMBBOB series, 28 May - 18 June 1957". Defense Nuclear Agency, Department of Defense (Washington, DC). 1981. http://hdl.handle.net/2027/uiug.30112075684305. Retrieved 2013-10-28. 
  12. "Shot PRISCILLA : a test of the PLUMBBOB series, 24 June 1957". Defense Nuclear Agency, Department of Defense (Washington, DC). 1981. http://hdl.handle.net/2027/uiug.30112075684354. Retrieved 2013-10-28. 
  13. http://www.boeing.com/history/mdc/genie.html
  14. Pascal A test at the Nuclear Weapon Archive
  15. "Shot Smoky: A Test of the Plumbbob Series, 31 August 1957". Defense Nuclear Agency, Department of Defense (Washington, DC). 1981. http://hdl.handle.net/2027/uiug.30112075684347. Retrieved 2013-10-28. 
  16. "Shot GALILEO : a test of the PLUMBBOB series, 2 September 1957". Defense Nuclear Agency, Department of Defense (Washington, DC). 1981. http://hdl.handle.net/2027/uiug.30112075684388. Retrieved 2013-10-28. 

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