Underground nuclear weapons testing
Nuclear weapons |
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Background |
Nuclear-armed states |
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Underground nuclear testing is the
The extreme heat and pressure of an underground nuclear explosion causes changes in the surrounding rock. The rock closest to the location of the test is
The first underground test took place in 1951. Further tests soon led scientists to conclude that even notwithstanding environmental and diplomatic considerations, underground testing was of far greater scientific value than all other forms of testing. This understanding strongly influenced the governments of the first three nuclear powers to sign of the
Background
Public concern about fallout from nuclear testing grew in the early 1950s.
The fallout from the March 1954 Bravo test in the Pacific Ocean had "scientific, political and social implications that have continued for more than 40 years".[3] The multi-megaton test caused fallout to occur on the islands of the Rongerik and Rongelap atolls, and a Japanese fishing boat known as the Daigo Fukuryū Maru (Lucky Dragon).[3] Prior to this test, there was "insufficient" appreciation of the dangers of fallout.[3]
The test became an international incident. In a
Knowledge about
Early history of underground testing
The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject. (December 2010) |
Following analysis of underwater detonations that were part of Operation Crossroads in 1946, inquiries were made regarding the possible military value of an underground explosion.[7] The US Joint Chiefs of Staff thus obtained the agreement of the United States Atomic Energy Commission (AEC) to perform experiments on both surface and sub-surface detonations.[7] The Alaskan island of Amchitka was initially selected for these tests in 1950, but the site was later deemed unsuitable and the tests were moved to the Nevada Test Site.[8]
The first underground nuclear test was conducted on 29 November 1951.
The next underground test was Teapot Ess, on 23 March 1955.
On 26 July 1957, Plumbbob Pascal-A was detonated at the bottom of a 148 m (486 ft) shaft.[17][18] According to one description, it "ushered in the era of underground testing with a magnificent pyrotechnic roman candle!"[19] As compared with an above-ground test, the radioactive debris released to the atmosphere was reduced by a factor of ten.[19] Theoretical work began on possible containment schemes.[19]
Plumbbob Rainier was detonated at 899 ft (274 m) underground on 19 September 1957.[17] The 1.7 kt explosion was the first to be entirely contained underground, producing no fallout.[20] The test took place in a 1,600[21] – 2,000 ft[22] (488 – 610 m) horizontal tunnel in the shape of a hook.[22] The hook "was designed so explosive force will seal off the non-curved portion of tunnel nearest the detonation before gases and fission fragments can be vented around the curve of the tunnel's hook".[22] This test would become the prototype for larger, more powerful tests.[20] Rainier was announced in advance, so that seismic stations could attempt to record a signal.[23] Analysis of samples collected after the test enabled scientists to develop an understanding of underground explosions that "persists essentially unaltered today".[23] The information would later provide a basis for subsequent decisions to agree to the Limited Test Ban Treaty.[23]
Cannikin, the last test at the facility on Amchitka, was detonated on 6 November 1971. At approximately 5 megatons, it was the largest underground test in US history.[24]
Effects
The effects of an underground nuclear test may vary according to factors including the depth and
Name | Radius[26] |
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Melt cavity | 4–12 m/kt1/3 |
Crushed zone | 30–40 m/kt1/3 |
Cracked zone | 80–120 m/kt1/3 |
Zone of irreversible strain | 800–1100 m/kt1/3 |
The energy of the nuclear explosion is released in one
Several minutes to days later, once the heat dissipates enough, the steam condenses, and the pressure in the cavity falls below the level needed to support the overburden, the rock above the void falls into the cavity. Depending on various factors, including the yield and characteristics of the burial, this collapse may extend to the surface. If it does, a subsidence crater is created.[26] Such a crater is usually bowl-shaped, and ranges in size from a few tens of metres to over a kilometre in diameter.[26] At the Nevada Test Site, 95 percent of tests conducted at a scaled depth of burial (SDOB) of less than 150 caused surface collapse, compared with about half of tests conducted at a SDOB of less than 180.[26] The radius r (in feet) of the cavity is proportional to the cube root of the yield y (in kilotons), r = 55 * ; an 8 kiloton explosion will create a cavity with radius of 110 feet (34 m).[28]
Other surface features may include disturbed ground, pressure ridges, faults, water movement (including changes to the water table level), rockfalls, and ground slump.[26] Most of the gas in the cavity is composed of steam; its volume decreases dramatically as the temperature falls and the steam condenses. There are however other gases, mostly carbon dioxide and hydrogen, which do not condense and remain gaseous. The carbon dioxide is produced by thermal decomposition of carbonates, hydrogen is created by reaction of iron and other metals from the nuclear device and surrounding equipment. The amount of carbonates and water in the soil and the available iron have to be considered in evaluating the test site containment; water-saturated clay soils may cause structural collapse and venting. Hard basement rock may reflect shock waves of the explosion, also possibly causing structural weakening and venting. The noncondensible gases may stay absorbed in the pores in the soil. Large amount of such gases can however maintain enough pressure to drive the fission products to the ground.[28]
Escape of radioactivity from the cavity is known as containment failure. Massive, prompt, uncontrolled releases of fission products, driven by the pressure of steam or gas, are known as venting; an example of such failure is the
The released nuclides can undergo
Although there were early concerns about earthquakes arising as a result of underground tests, there is no evidence that this has occurred.[25] However, fault movements and ground fractures have been reported, and explosions often precede a series of aftershocks, thought to be a result of cavity collapse and chimney formation. In a few cases, seismic energy released by fault movements has exceeded that of the explosion itself.[25]
International treaties
Signed in Moscow on August 5, 1963, by representatives of the United States, the Soviet Union, and the United Kingdom, the Limited Test Ban Treaty agreed to ban nuclear testing in the atmosphere, in space, and underwater.[6] Due to the Soviet government's concern about the need for on-site inspections, underground tests were excluded from the ban.[6] 108 countries would eventually sign the treaty, with the significant exception of China.[29]
In 1974, the United States and the Soviet Union signed the Threshold Test Ban Treaty (TTBT) which banned underground tests with yields greater than 150 kilotons.[30] By the 1990s, technologies to monitor and detect underground tests had matured to the point that tests of one kiloton or over could be detected with high probability, and in 1996 negotiations began under the auspices of the United Nations to develop a comprehensive test ban.[29] The resulting Comprehensive Nuclear-Test-Ban Treaty was signed in 1996 by the United States, Russia, United Kingdom, France, and China.[29] However, following the United States Senate decision not to ratify the treaty in 1999, it is still yet to be ratified by 8 of the required 44 'Annex 2' states and so has not entered into force as United Nations law.
Monitoring
In the late 1940s, the United States began to develop the capability to detect atmospheric testing using air sampling; this system was able to detect the first Soviet test in 1949.[30] Over the next decade, this system was improved, and a network of seismic monitoring stations was established to detect underground tests.[30] Development of the Threshold Test Ban Treaty in the mid-1970s led to an improved understanding of the relationship between test yield and resulting seismic magnitude.[30]
When negotiations began in the mid-1990s to develop a comprehensive test ban, the international community was reluctant to rely upon the detection capabilities of individual
Gallery
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Buster-Jangle Uncle
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Teapot Ess
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Sedan Crater
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Bowline Schooner
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Nevada Test Site subsidence craters
See also
- Nuclear weapons testing
- Subsidence crater
- Tired mountain syndrome
- Nuclear bunker buster
- List of induced seismic events
Notes and references
- ^ a b "History of the Comprehensive Nuclear-Test-Ban Treaty (CTBT)". The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization. Archived from the original on 2007-03-03.
- ^ .
- ^ PMID 9199215. Archived from the original(PDF) on October 14, 2006.
- ^ "Martha Smith on: The Impact of the Bravo Test". Public Broadcasting Service. Archived from the original on 2016-08-01. Retrieved 2017-09-03.
- ^ a b c "Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water". US Department of State.
- ^ a b c d "JFK in History: Nuclear Test Ban Treaty". John F. Kennedy Presidential Library and Museum.
- ^ a b Gladeck, F.; Johnson, A. (1986). For the Record – A History of the Nuclear Test Personnel Review Program, 1978–1986 (DNA 601F). Defense Nuclear Agency. Archived from the original on May 22, 2011.
- doi:10.2172/758922. Retrieved 2006-10-09.
- ^ "Today in Technology History: November 29". The Center for the Study of Technology and Society. Archived from the original on 2002-04-21.
- ^ a b c Adushkin, Vitaly V.; Leith, William (September 2001). "USGS Open File Report 01-312: Containment of Soviet underground nuclear explosions" (PDF). US Department of the Interior Geological Survey. Archived from the original (PDF) on 2013-05-09.
- ^ Some sources identify later tests as the "first". Adushkin (2001) defines such a test as "the near-simultaneous detonation of one or more nuclear charges inside one underground excavation (a tunnel, shaft or borehole)", and identifies Uncle as the first.
- ^ Some sources refer to the test as Jangle Uncle (e.g., Adushkin, 2001) or Project Windstorm (e.g., DOE/NV-526, 1998). Operation Buster and Operation Jangle were initially conceived as separate operations, and Jangle was at first known as Windstorm, but the AEC merged the plans into a single operation on 19 June 1951. See Gladeck, 1986.
- ^ a b "Operation Buster-Jangle". The Nuclear Weapons Archive.
- ^ Ponton, Jean; et al. (June 1982). Shots Sugar and Uncle: The final tests of the Buster-Jangle series (DNA 6025F) (PDF). Defense Nuclear Agency. Archived from the original (PDF) on 2007-07-10.
- ^ a b c Ponton, Jean; et al. (November 1981). Shots Ess through Met and Shot Zucchini: The final Teapot tests (DNA 6013F) (PDF). Defense Nuclear Agency. Archived from the original (PDF) on 2007-07-10.
- ^ a b "Operation Teapot". The Nuclear Weapons Archive.
- ^ a b "Operation Plumbbob". The Nuclear Weapons Archive.
- yieldis described as "slight", but was approximately 55 tons.
- ^ a b c Campbell, Bob; et al. (1983). "Field Testing: The Physical Proof of Design Principles" (PDF). Los Alamos Science.
- ^ a b "Operation Plumbbob". Department of Energy. Archived from the original on 2006-09-25.
- ^ Rollins, Gene (2004). ORAU Team: NIOSH Dose Reconstruction Project (PDF). Centers for Disease Control. Archived from the original (PDF) on 2006-06-25. Retrieved 2017-09-17.
- ^ a b c "Plumbbob Photographs" (PDF). Los Alamos National Laboratory.
- ^ a b c "Accomplishments in the 1950s". Lawrence Livermore National Laboratory. Archived from the original on 2004-12-05.
- ^ Miller, Pam. "Nuclear Flashback: Report of a Greenpeace Scientific Expedition to Amchitka Island, Alaska – Site of the Largest Underground Nuclear Test in U.S. History" (PDF). Archived from the original (PDF) on September 28, 2006. Retrieved 2006-10-09.
- ^ ISBN 0-19-829120-5.
- ^ a b c d e f g h i Hawkins, Wohletz (1996). "Visual Inspection for CTBT Verification" (PDF). Los Alamos National Laboratory. Archived from the original (PDF) on 2008-10-30. Retrieved 2008-05-05.
- ^ Hawkins and Wohletz specify a figure of 90–125.
- ^ a b c d e The Containment of Underground Nuclear Explosions. (PDF) . Retrieved on 2010-02-08.
- ^ a b c "The Making of the Limited Test Ban Treaty, 1958–1963". The George Washington University.
- ^ ISBN 0-309-08506-3.
- ^ "An Overview of the Verification Regime". Comprehensive Nuclear-Test-Ban Treaty Organization. Archived from the original on 2008-05-09.
- ^ "Verification Technologies: Seismology". Comprehensive Nuclear-Test-Ban Treaty Organization. Archived from the original on 2003-06-21.
- ^ "Verification Technologies: Radionuclide". Comprehensive Nuclear-Test-Ban Treaty Organization. Archived from the original on 2004-06-10.
- ^ "Verification Technologies: Hydroacoustics". Comprehensive Nuclear-Test-Ban Treaty Organization. Archived from the original on 2003-02-19.
- ^ "Verification Technologies: Infrasound". Comprehensive Nuclear-Test-Ban Treaty Organization.[permanent dead link]
Further reading
- "The Containment of Underground Nuclear Explosions", Project Director Gregory E van der Vink, U.S. Congress, Office of Technology Assessment, OTA-ISC-414, (Oct 1989).
- IAEA review of the 1968 book: The constructive uses of nuclear explosions by Edward Teller.
External links
- https://web.archive.org/web/20060908032343/http://www.princeton.edu/~globsec/publications/pdf/3_3-4Adushkin.pdf
- Nuclear Pursuits[permanent dead link], The Bulletin of the Atomic Scientists, September/October 2003
- http://www.unscear.org/unscear/en/publications.html
- https://web.archive.org/web/20041218041325/http://www.ingv.it/~roma/SITOINGLESE/research_projects/CTBTO/explosions.html
- http://www.globalsecurity.org/wmd/intro/ugt.htm
- https://fas.org/nuke/intro/nuke/ugt-nts.htm Archived 2015-04-09 at the Wayback Machine
- http://www.atomictraveler.com/UndergroundTestOTA.pdf
- http://www-pub.iaea.org/MTCD/publications/PDF/Pub1215_web.pdf
- The Soviet Program for Peaceful Uses of Nuclear Explosions, M. D. Nordyke, UCRL-ID-12441O Rev 2
- https://web.archive.org/web/20090227073933/http://www.princeton.edu/~globsec/publications/effects/effects.shtml