|Test site||NTS Area 12, Rainier Mesa; NTS Areas 5, 11, Frenchman Flat; NTS, Areas 1-4, 6-10, Yucca Flat|
|Number of tests||29|
|Test type||balloon, dry surface, high alt rocket (30–80 km), tower, underground shaft, underground tunnel|
|Max. yield||74 kilotonnes of TNT (310 TJ)|
|Previous test series||Project 57|
|Next test series||Project 58/58A|
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 58/58A. 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.
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.
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 radiation. 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. 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 photographer, Akira "George" Yoshitake, died in October, 2013, leaving only one person of the six, Donald A. Luttrell, still alive.
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 estimated that the nuclear explosion, combined with the specific design of the shaft, would accelerate the plate to approximately 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 tests
|Name [note 1]||Date time (UT)||Local time zone [note 2]||Location [note 3]||Elevation + height [note 4]||Delivery [note 5]
Purpose [note 6]
|Device [note 7]||Yield [note 8]||Fallout [note 9]||References||Notes|
|Boltzmann||28 May 1957 11:55:00.2||PST (-8 hrs)
||NTS Area 7c||1,294 m (4,245 ft) + 150 m (490 ft)||tower,
|XW-40||12 kt||I-131 venting detected, 1.9 MCi (70 PBq)||||XW-40 lightweight boosted fission warhead test.|
|Franklin||2 June 1957 11:54:59.9||PST (-8 hrs)
||NTS Area T3||1,229 m (4,032 ft) + 90 m (300 ft)||tower,
|XW-30 ?||140 t||I-131 venting detected, 19 kCi (700 TBq)||||XW-30 warhead test, fizzled. Retested successfully with Franklin Prime, with more fissile in the core and different explosives.|
|Lassen||5 June 1957 11:45:00.3||PST (-8 hrs)
||NTS Area B9a ~||1,595 m (5,233 ft) + 150 m (490 ft)||balloon,
|600 t||I-131 venting detected, 100 Ci (3,700 GBq)||||Fizzle, unboosted all-oralloy small weapon design.|
|Wilson||18 June 1957 11:45:00.3||PST (-8 hrs)
||NTS Area B9a ~||1,589 m (5,213 ft) + 150 m (490 ft)||balloon,
|XW-45X1||10 kt||I-131 venting detected, 1.5 MCi (56 PBq)||||XW-45X1 Swan test, gas-boosted composite pit.|
|Priscilla||24 June 1957 13:30:00.1||PST (-8 hrs)
||NTS Area 5||940 m (3,080 ft) + 210 m (690 ft)||balloon,
|Mk-15/39 primary||37 kt||I-131 venting detected, 5.8 MCi (210 PBq)||||Effects shot with OTS weapon. Similar to that tested in Redwing Lacrosse.|
|Coulomb-A||1 July 1957 17:30:??||PST (-8 hrs)
||NTS Area S3h||1,231 m (4,039 ft) + 0||dry surface,
|XW-31||no yield||||Safety experiment, successful.|
|Hood||5 July 1957 11:40:00.1||PST (-8 hrs)
||NTS Area B9a ~||1,285 m (4,216 ft) + 460 m (1,510 ft)||balloon,
|Swan||74 kt||I-131 venting detected, 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||15 July 1957 11:30:00.1||PST (-8 hrs)
||NTS Area T2b||1,367 m (4,485 ft) + 150 m (490 ft)||tower,
|Swan||17 kt||I-131 venting detected, 2.5 MCi (93 PBq)||||Very similar to the Shasta test device. 2 stage. Misfired at first firing attempt three days earlier.|
|John||19 July 1957 14:00:04.6||PST (-8 hrs)
||Launch from NTS, Areas 1-4, 6-10, Yucca Flat: 10
, elv: 1,220 + 5,600 m (4,000 + 18,370 ft);|
Detonation over NTS
|1,280 m (4,200 ft) + 5,639 m (18,501 ft)||high alt rocket (30–80 km),
|W-25||2 kt||I-131 venting detected, 6.1MCi?||||Proof test of AIR-2A Genie air-to-air rocket. Test made famous by five officers and a photographer standing at ground zero during the blast.|
|Kepler||24 July 1957 11:49:59.9||PST (-8 hrs)
||NTS Area 4||1,318 m (4,324 ft) + 150 m (490 ft)||tower,
|XW-35 primary !||10 kt||I-131 venting detected, 1.7 MCi (63 PBq)||||ICBM warhead, similar to Hardtack I/Koa.|
|Owens||25 July 1957 13:29:59.7||PST (-8 hrs)
||NTS Area B9b ~||1,260 m (4,130 ft) + 150 m (490 ft)||balloon,
|XW-51 ?||9.7 kt||I-131 venting detected, 1.7 MCi (63 PBq)||||Very small boosted plutonium device, XW-51 progenitor.|
|Pascal-A||26 July 1957 08:00:00.0||PST (-8 hrs)
||NTS Area U3j||1,202 m (3,944 ft) - 150 m (490 ft)||underground shaft,
|55 t||I-131 venting detected, 10 kCi (370 TBq)||||Originally Galileo A. One-point safety experiment, failure. Expected yield was less than 1 kg. A concrete cylinder perhaps 2 m (6 ft 7 in) thick 100 m (330 ft) up the tube disappeared.|
|Stokes||7 August 1957 12:25:00.2||PST (-8 hrs)
||NTS Area B7b ~||1,250 m (4,100 ft) + 460 m (1,510 ft)||balloon,
|XW-30||19 kt||I-131 venting detected, 2.8 MCi (100 PBq)||||Tactical Atomic Demolition Munition (TADM) and Talos SAM warhead.|
|Saturn||10 August 1957 00:59:55.1||PST (-8 hrs)
||NTS Area U12c.02||1,231 m (4,039 ft) - 39.01 m (128.0 ft)||underground tunnel,
|XW-45X1||50 kg||||One-point safety experiment; first shot in a Rainier tunnel.|
|Shasta||18 August 1957 12:00:00.0||PST (-8 hrs)
||NTS Area 2a||1,339 m (4,393 ft) + 150 m (490 ft)||tower,
|Swan||17 kt||I-131 venting detected, 2.5 MCi (93 PBq)||||2 stage thermonuclear design.|
|Doppler||23 August 1957 12:30:00.1||PST (-8 hrs)
||NTS Area B7b ~||1,282 m (4,206 ft) + 460 m (1,510 ft)||balloon,
|XW-34 ?||11 kt||I-131 venting detected, 1.7 MCi (63 PBq)||||LASL gas boosted implosion device, possible XW-34 test.|
|Pascal-B||27 August 1957 22:35:00.0||PST (-8 hrs)
||NTS Area U3d||1,229 m (4,032 ft) - 150 m (490 ft)||underground shaft,
|300 t||||Shaft safety experiment, failed. Sent a 4 in (100 mm) thick steel cap weighing several hundred pounds possibly into solar orbit or burn up in atmosphere, estimated velocity 36 km/s (22 mi/s).|
|Franklin Prime||30 August 1957 12:39:59.9||PST (-8 hrs)
||NTS Area B7b ~||1,282 m (4,206 ft) + 230 m (750 ft)||balloon,
|4.7 kt||I-131 venting detected, 690 kCi (26,000 TBq)||||Retest of Franklin with more U-235.|
|Smokey||31 August 1957 12:30:00.0||PST (-8 hrs)
||NTS Area T2c||1,367 m (4,485 ft) + 210 m (690 ft)||tower,
|TX-41 primary||44 kt||I-131 venting detected, 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||2 September 1957 12:40:00.0||PST (-8 hrs)
||NTS Area T1||1,294 m (4,245 ft) + 150 m (490 ft)||tower,
|11 kt||I-131 venting detected, 1.9 MCi (70 PBq)||||LASL diagnostic/exploratory test of boosted fission device. Desert Rock VIII.|
|Wheeler||6 September 1957 12:45:00.0||PST (-8 hrs)
||NTS Area B9a ~||1,286 m (4,219 ft) + 150 m (490 ft)||balloon,
|XW-51 ?||197 t||I-131 venting detected, 27 kCi (1,000 TBq)||||Retest of redesigned Lassen device, possible XW-51 air-to-air warhead progenitor.|
|Coulomb-B||6 September 1957 20:05:00.6||PST (-8 hrs)
||NTS Area S3g||1,225 m (4,019 ft) + 0||dry surface,
|XW-31||300 t||I-131 venting detected, 42 kCi (1,600 TBq)||||One-point safety experiment, high limits test, expected 1 kg TNT equivalent, max .2 kt - failure.|
|Laplace||8 September 1957 12:59:59.8||PST (-8 hrs)
||NTS Area B7b ~||1,282 m (4,206 ft) + 230 m (750 ft)||balloon,
|XW-33 "Fleegle"||1 kt||I-131 venting detected, 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||14 September 1957 16:44:59.8||PST (-8 hrs)
||NTS Area T3b||1,220 m (4,000 ft) + 150 m (490 ft)||tower,
|XW-34 ?||11 kt||I-131 venting detected, 1.7 MCi (63 PBq)||||LASL boosted fission device. Possibly a test of the XW-34 depth bomb.|
|Newton||16 September 1957 12:49:59.9||PST (-8 hrs)
||NTS Area B7a ~||1,282 m (4,206 ft) + 460 m (1,510 ft)||balloon,
|XW-31||12 kt||I-131 venting detected, 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||19 September 1957 16:59:59.45||PST (-8 hrs)
||NTS Area U12b||2,295 m (7,530 ft) - 272.8 m (895 ft)||underground tunnel,
|W-25||1.7 kt||||First US underground nuclear test. Evaluate containment and detection of underground testing, formed a chimney of broken rock which provided data on possible underground engineering applications of nuclear explosives.|
|Whitney||23 September 1957 12:29:59.8||PST (-8 hrs)
||NTS Area T2||1,370 m (4,490 ft) + 150 m (490 ft)||tower,
|W27 primary||19 kt||I-131 venting detected, 2.9 MCi (110 PBq)||||Test of boosted Swan primary in W-27 thermonuclear system mockup.|
|Charleston||28 September 1957 12:59:59.9||PST (-8 hrs)
||NTS Area B9a ~||1,285 m (4,216 ft) + 460 m (1,510 ft)||balloon,
|12 kt||I-131 venting detected, 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||7 October 1957 13:00:00.1||PST (-8 hrs)
||NTS Area B9a ~||1,285 m (4,216 ft) + 150 m (490 ft)||balloon,
|XW-45X1 Swan/Flamingo||8 kt||I-131 venting detected, 1.2 MCi (44 PBq)|||
|Wikimedia Commons has media related to Operation Plumbbob.|
- Yang, Xiaoping; North, Robert; Romney, Carl (August 2000), CMR Nuclear Explosion Database (Revision 3), SMDC Monitoring Research
- 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 (2012-07-20). "George Yoshitake, Nuclear Test Photographer, Recalls Filming Nuclear Blast 55 Years Ago". Huffington Post.
- "Akira "George" Yoshitake (obituary)". Lompoc Record (Lompoc, California, USA). 22 October 2013. Retrieved 17 May 2014.
- 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.
- Pascal B test at the Nuclear Weapon Archive
- "Timezone Historical Database". iana.com. Retrieved March 8, 2014.
- Harris, =P.S.; Lowery, C.; Nelson, A. (1981), Plumbbob Series, 1957 Final (DNA6005F), Defense Nuclear Agency, retrieved 2014-01-06
- Estimated exposures and thyroid doses received by the American people from Iodine-131 in fallout following Nevada atmospheric nuclear bomb tests, Chapter 2, National Cancer Institute, 1997, retrieved 2014-01-05
- Sublette, Carey, Nuclear Weapons Archive, retrieved 2014-01-06
- Hansen, Chuck (1995), The Swords of Armageddon, Vol. 8, Sunnyvale, CA: Chukelea Publications, ISBN 978-0-9791915-1-0
- United States Nuclear Tests: July 1945 through September 1992 (DOE/NV-209 REV15), Las Vegas, NV: Department of Energy, Nevada Operations Office, 2000-12-01, retrieved 2013-12-18
- Norris, Robert Standish; Cochran, Thomas B. (1 February 1994), "United States nuclear tests, July 1945 to 31 December 1992 (NWD 94-1)", Nuclear Weapons Databook Working Paper (Washington, DC: Natural Resources Defense Council), retrieved 2013-10-26
- Official list of underground nuclear explosions, Sandia National Laboratories, 1994-07-01, retrieved 2013-12-18
- Shot Smoky: A Test of the Plumbbob Series, 31 August 1957 (DNA-6004F), Washington, DC: Defense Nuclear Agency, Department of Defense, 1981, retrieved 2013-10-28
- Video clip: Historic color footage of shot "Owens" during Operation Plumbbob
- Plumbbob page on the Nuclear Weapons Archive (also refers to manhole cover issue mentioned above).