|Test site||Nevada Test Site|
|Number of tests||29|
|Max. yield||74 kt|
|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. It was the biggest, longest, and most controversial test series in the continental United States.
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. 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. 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.
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.
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).
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.
Propulsion of steel plate cap
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. 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!" The use of a subterranean shaft and nuclear device to propel an object to escape velocity has since been termed a "thunder well".
List of test blasts
The detonations[table 1] in the Operation Plumbbob are listed below:
|Name[table 2]||Date Time (UT[table 3])||Location[table 4]||Elevation + Height[table 5]||Delivery[table 6]||Purpose[table 7]||Device[table 8]||Yield[table 9]||Venting[table 10]||Notes|
|Boltzmann||May 28, 1957 11:00:55.2||NTS Area 7c||1,294 m (4,245 ft) + 150 m (490 ft)||Tower||Weapons development||XW-40||12 kt||Vent (I131), 1.9 MCi (70 PBq)||XW-40 light weight boosted fission warhead test.|
|Franklin||June 2, 1957 11:54:59.9||NTS Area T3||1,229 m (4,032 ft) + 90 m (300 ft)||Tower||Weapons development||XW-30 ?||140 t||Vent (I131), 19 kCi (700 TBq)||XW-30 warhead test, fizzled. Retested successfully with Franklin Prime, with more fissile in the core and different explosives.|
|Lassen||June 5, 1957 11:00:45.3||NTS Area B9a ~||1,595 m (5,233 ft) + 150 m (490 ft)||Balloon||Weapons development||600 t||Vent (I131), 100 Ci (3,700 GBq)||Fizzle, unboosted all-oralloy small weapon design.|
|Wilson||June 18, 1957 11:00:45.3||NTS Area B9a ~||1,589 m (5,213 ft) + 150 m (490 ft)||Balloon||Weapons development||XW-45X1||10 kt||Vent (I131), 1.5 MCi (56 PBq)||XW-45X1 Swan test, gas-boosted composite pit.|
|Priscilla||June 24, 1957 13:00:30.1||NTS Area 5||940 m (3,080 ft) + 210 m (690 ft)||Balloon||Weapons development||Mk-15/39 primary||37 kt||Vent (I131), 5.8 MCi (210 PBq)||Effects shot with OTS weapon. Similar to that tested in Redwing Lacrosse.|
|Coulomb-A||July 1, 1957 17:30:--||NTS Area S3h||1,231 m (4,039 ft) + 0||Dry surface||Safety experiment||XW-31||no yield||Safety experiment, successful.|
|Hood||July 5, 1957 11:00:40.1||NTS Area B9a ~||1,285 m (4,216 ft) + 460 m (1,510 ft)||Balloon||Weapons development||Swan||74 kt||Vent (I131), 11 MCi (410 PBq)||Largest atmospheric test in CONUS. Was a 2 stage thermonuke, even though AEC stated that no thermonukes were being tested at the NTS. Desert Rock VII.|
|Diablo||July 15, 1957 11:00:30.1||NTS Area T2b||1,367 m (4,485 ft) + 150 m (490 ft)||Tower||Weapons development||Swan||17 kt||Vent (I131), 2.5 MCi (93 PBq)||Very similar to the Shasta test device. 2 stage. Misfired at first firing attempt three days earlier.|
|John||July 19, 1957 14:00:04.6||NTS Area 10||N/A + 5,970 m (19,590 ft)||High altitude rocket (30-80 km)||Weapon effect||W-25||2 kt||Vent (I131), 6.1MCi?||Proof test of AIR-2 Genie air-to-air rocket. Test made famous by 5 officers and a photographer being at ground zero during the blast.|
|Kepler||July 24, 1957 11:49:59.9||NTS Area 4||1,318 m (4,324 ft) + 150 m (490 ft)||Tower||Weapons development||XW-35 primary !||10 kt||Vent (I131), 1.7 MCi (63 PBq)||ICBM warhead, similar to Hardtack I/Koa.|
|Owens||July 25, 1957 13:29:59.7||NTS Area B9b ~||1,260 m (4,130 ft) + 150 m (490 ft)||Balloon||Weapons development||XW-51 ?||9.7 kt||Vent (I131), 1.7 MCi (63 PBq)||Very small boosted plutonium device, XW-51 progenitor.|
|Pascal-A||July 26, 1957 08:00:00.0||NTS Area U3j||1,202 m (3,944 ft) - 150 m (490 ft)||Underground shaft||Safety experiment||55 t||Vent (I131), 10 kCi (370 TBq)||Originally Galileo A. One-point safety experiment, failure. Expected yield was 1–2 pounds. A concrete cylinder perhaps 2 meters thick 100 m up the tube disappeared.|
|Stokes||August 7, 1957 12:00:25.2||NTS Area B7b ~||1,250 m (4,100 ft) + 460 m (1,510 ft)||Balloon||Weapons development||XW-30||19 kt||Vent (I131), 2.8 MCi (100 PBq)||TADM and Talos SAM warhead.|
|Saturn||August 10, 1957 00:59:55.1||NTS Area U12c.02||1,231 m (4,039 ft) - 39.01 m (128.0 ft)||Underground tunnel||Safety experiment||XW-45X1||50 kg||One-point safety experiment; 1st shot in a Rainier tunnel.|
|Shasta||August 18, 1957 12:00:00.0||NTS Area 2a||1,339 m (4,393 ft) + 150 m (490 ft)||Tower||Weapons development||Swan||17 kt||Vent (I131), 2.5 MCi (93 PBq)||2 stage thermonuclear design.|
|Doppler||August 23, 1957 12:00:30.1||NTS Area B7b ~||1,282 m (4,206 ft) + 460 m (1,510 ft)||Balloon||Weapons development||XW-34 ?||11 kt||Vent (I131), 1.7 MCi (63 PBq)||LASL gas boosted implosion device, possible XW-34 test.|
|Pascal-B||August 27, 1957 22:00:35.0||NTS Area U3d||1,229 m (4,032 ft) - 150 m (490 ft)||Underground shaft||Safety experiment||10 t||Shaft safety experiment, failed. Sent a 4-inch (10 cm) thick steel cap weighing several hundred pounds possibly into solar orbit or burn up in atmosphere, estimated to be going 36 km/s.|
|Franklin Prime||August 30, 1957 12:39:59.9||NTS Area B7b ~||1,282 m (4,206 ft) + 230 m (750 ft)||Balloon||Weapons development||4.7 kt||Vent (I131), 690 kCi (26,000 TBq)||Retest of Franklin with more U-235.|
|Smokey||August 31, 1957 12:00:30.0||NTS Area T2c||1,367 m (4,485 ft) + 210 m (690 ft)||Tower||Weapons development||TX-41 primary||44 kt||Vent (I131), 6.4 MCi (240 PBq)||2 stages of 3 stage thermonuke, similar to Redwing/Zuni and Tewa. Desert Rock VII; 3000 servicemen irradiated; 10 of 4 expected leukemia cases in the 80s. Last pristine air-drop location at the NTS.|
|Galileo||September 2, 1957 12:00:40.0||NTS Area T1||1,294 m (4,245 ft) + 150 m (490 ft)||Tower||Weapons development||11 kt||Vent (I131), 1.9 MCi (70 PBq)||LASL diagnostic/exploratory test of boosted fission device. Desert Rock VIII.|
|Wheeler||September 6, 1957 12:00:45.0||NTS Area B9a ~||1,286 m (4,219 ft) + 150 m (490 ft)||Balloon||Weapons development||XW-51 ?||197 t||Vent (I131), 27 kCi (1,000 TBq)||Retest of redesigned Lassen device, possible XW-51 air-to-air warhead progenitor.|
|Coulomb-B||September 6, 1957 20:00:05.6||NTS Area S3g||1,225 m (4,019 ft) + 0||Dry surface||Safety experiment||XW-31||300 t||Vent (I131), 42 kCi (1,600 TBq)||One-point safety experiment, high limits test, expected 1-2 lbs, max .2 kt - failure.|
|Laplace||September 8, 1957 12:59:59.8||NTS Area B7b ~||1,282 m (4,206 ft) + 230 m (750 ft)||Balloon||Weapons development||XW-33 "Fleegle"||1 kt||Vent (I131), 140 kCi (5,200 TBq)||The third of only four gun-type weapons, with Little Boy, Grable and Aardvark. The XW-33 was a gun shell.|
|Fizeau||September 14, 1957 16:44:59.8||NTS Area T3b||1,220 m (4,000 ft) + 150 m (490 ft)||Tower||Weapons development||XW-34 ?||11 kt||Vent (I131), 1.7 MCi (63 PBq)||LASL boosted fission device. Possibly a test of the XW-34 depth bomb.|
|Newton||September 16, 1957 12:49:59.9||NTS Area B7a ~||1,282 m (4,206 ft) + 460 m (1,510 ft)||Balloon||Weapons development||XW-31||12 kt||Vent (I131), 2.1 MCi (78 PBq)||LASL test of XW-31 variant, boosted primary in thermonuclear system mockup. Sounds like a fizzle, but no one says so.|
|Rainier||September 19, 1957 16:59:59.45||NTS Area U12b||2,295 m (7,530 ft) - 272.8 m (895 ft)||Underground tunnel||Weapons development||W-25||1.7 kt||First US underground nuclear test. Evaluate containment and detection of of testing.|
|Whitney||September 23, 1957 12:29:59.8||NTS Area T2||1,370 m (4,490 ft) + 150 m (490 ft)||Tower||Weapons development||W27 primary||19 kt||Vent (I131), 2.9 MCi (110 PBq)||Test of boosted Swan primary in W-27 thermonuclear system mockup.|
|Charleston||September 28, 1957 12:59:59.9||NTS Area B9a ~||1,285 m (4,216 ft) + 460 m (1,510 ft)||Balloon||Weapons development||12 kt||Vent (I131), 1.8 MCi (67 PBq)||UCRL test of a small "clean" tactical 2-stage thermonuclear device. Device fizzled when second stage failed to fire.|
|Morgan||October 7, 1957 13:00:00.1||NTS Area B9a ~||1,285 m (4,216 ft) + 150 m (490 ft)||Balloon||Weapons development||XW-45X1 Swan/Flamingo||8 kt||Vent (I131), 1.2 MCi (44 PBq)|
- A bomb test may be a salvo test, defined as two or more explosions "where a period of time between successive individual explosions does not exceed 5 seconds and where the burial points of all explosive devices can be connected by segments of straight lines, each of them connecting two burial points and does not exceed 40 kilometers in length". Mikhailov, V. N., Editor in Chief. Catalog of World Wide Nuclear Testing. Begell-Atom, LLC.
- The event number from the official list, occasionally a name as well. An appended number represents a member of a salvo test. They usually all have the same name, like Tub-A, Tub-B, ..., but early on had separate names, so other members are denoted by "(with xyz)".
- Universal Time in National Test Site is 8 hours after local time; UT dates are one day after local date for UT times after 16:00.
- Rough place name and a Latitude/Longitude reference. Some are extremely accurate; others (like airdrops and space blasts) may be quite inaccurate. '~' indicates a likely pro-forma rough location, shared with other tests in that same area.
- Elevation is the ground level at the point directly below the explosion relative to sea level; height is the additional distance added or subtracted by tower, balloon, shaft, tunnel or other contrivance. For air bursts it is the absolute altitude of the explosion disregarding ground level (though the ground level is given for comparison), and for rockets the ground level is "N/A".
- Atmospheric, airdrop, balloon, gun, cruise missile, rocket, surface, tower, barge and cratering are all disallowed by the Partial Nuclear Test Ban Treaty. Sealed shaft and tunnel are underground, and remained useful under the PTBT.
- Include weapons development, weapon effects, safety test, transport safety test, war, science, joint verification and industrial/peaceful, which may be further broken down.
- Designations for test items where known, nicknames for individual bombs in quotes.Names are "Mark #" or "B#" for bombs, "W#" for rocket warheads, "X#" for experimental, plus code names like "Piccolo". "Primary" refers to a test of only the primary (fission) stage of a multi-stage bomb.
- Estimated energy yield in tonnes, kilotonnes, and megatonnes (all metric units).
- Emissions to atmosphere, where known. No entry means unknown, probably none if underground and "all" if not; otherwise notation for whether measured on the site only or off the site, and the maximum amount released`.
- "United States Nuclear Tests, July 1945 through September 1992 (DOE/NV-209)" (pdf). U.S. Department of Energy Nevada Operations Office. 2000. Original source for test information.
- Plumbbob page on the Nuclear Weapons Archive (also refers to manhole cover issue mentioned above).
- "Estimated Exposures and Thyroid Doses Received by the American People from Iodine-131 in Fallout Following Nevada Atmospheric Nuclear Bomb Tests". National Cancer Institute. 1997.
- Griggs, D. T., and Frank Press (1961). "Probing the earth with nuclear explosions". Journal of Geophysical Research. 66(1): 237–258.
- United States Nuclear Tests: July 1945 through September 1992 (Revision 15). Department of Energy, Nevada Operations Office. December 2000. Retrieved 2013-10-26.
- Yang, Xiaoping, Robert North, and Carl Romney (August 2000). CMR Nuclear Explosion Database (Revision 3). SMDC Monitoring Research. Retrieved 2013-10-26.
- Hansen, Chuck (1995). The Swords of Armageddon, Vol. 8. Chukelea Publications (Sunnyvale, CA). ISBN 978-0-9791915-1-0.
- P.S. Harris, C. Lowery, A. Nelson, et al (1981). Plumbbob Series, 1957 Final. DNA6005F. Defense Nuclear Agency, Department of Defense (Washington, DC).
|Wikimedia Commons has media related to Operation Plumbbob.|
- U.S. Department of Energy, Nevada Operations Office (December 2000), United States Nuclear Tests - July 1945 through September 1992
- 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/
- Robert Krulwich. "Five Men Agree To Stand Directly Under An Exploding Nuclear Bomb". NPR.
- Timothy Stenovec. "George Yoshitake, Nuclear Test Photographer, Recalls Filming Nuclear Blast 55 Years Ago". Huffington Post.
- Carey Sublette, "Operation Plumbbob," Nuclear Weapon Archive, http://nuclearweaponarchive.org/Usa/Tests/Plumbob.html. (accessed December 27, 2006).
- 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.
- Brownlee, Robert R. (June 2002). "Learning to Contain Underground Nuclear Explosions". Retrieved 2006-07-31.
- Learning to Contain Underground Nuclear Explosions By Dr. Robert R. Brownlee - June 2002
- Pascal B test at the Nuclear Weapon Archive
- Shots BOLTZMANN to WILSON : the first four tests of the PLUMBBOB series, 28 May - 18 June 1957. DNA6008F. Defense Nuclear Agency, Department of Defense (Washington, DC). 1981. Retrieved 2013-10-28.
- Shot PRISCILLA : a test of the PLUMBBOB series, 24 June 1957. DNA6003F. Defense Nuclear Agency, Department of Defense (Washington, DC). 1981. Retrieved 2013-10-28.
- Shot Smoky: A Test of the Plumbbob Series, 31 August 1957. DNA6004F. Defense Nuclear Agency, Department of Defense (Washington, DC). 1981. Retrieved 2013-10-28.
- Shot GALILEO : a test of the PLUMBBOB series, 2 September 1957. DNA6001F. Defense Nuclear Agency, Department of Defense (Washington, DC). 1981. Retrieved 2013-10-28.