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Nuclear testing

A nuclear test explosion is an experiment involving the detonation of a nuclear weapon.

Motivations for testing generally are broken into the categories:

  • "weapons related" (verifying that a weapon works, or examining exactly how it works)
  • "weapons effects" (how weapons behave under various conditions, and how structures behave when subjected to weapons).

Often, though, testing has also been a demonstration of the possessing nation's military and scientific strength.

Nuclear weapons tests are generally classified as being either "atmospheric" (in or above the atmosphere), "underground," or "underwater." Of these, underground testing contained in deep shafts poses the least health risk in terms of fallout. Atmospheric testing which comes in contact with the ground or other materials poses the highest risk. Nuclear weapons have been tested by dropping them from planes (an "airdrop"), from the tops of towers, hoisted from balloons, on barges at sea, attached to the bottom of ships, and even shot into outer space by rockets (for the latter see below).

The first atomic test was detonated by the United States at the Trinity site on July 16, 1945, with a yield approximately equivalent to 20 kilotons. The first hydrogen bomb, codenamed "Mike", was tested at Eniwetok island in the Bikini atoll on November 1, 1952, also by the United States. The largest nuclear weapon ever tested was the Tsar Bomba of the Soviet Union at Novaya Zemlya, with an estimated yield of around 50 megatons.

In 1963, all nuclear and many non-nuclear states signed the Limited Test Ban Treaty, pledging to refrain from testing nuclear weapons in the atmosphere, underwater, or in outer space. The treaty permitted underground tests. France continued atmospheric testing until 1974, while China continued up until 1980. The last underground test by the United States was in 1992, the Soviet Union in 1990, the United Kingdom in 1991, and both France and China have continued testing up until 1996. After adopting the Comprehensive Test Ban Treaty in 1996, all of these states have pledged to discontinue all nuclear testing. Non-signatories India and Pakistan both last tested nuclear weapons in 1998.

There have been around 2,000 nuclear test explosions:

Additionally, there may have been at least three alleged/disputed/unacknowledged nuclear explosions (see below).

From the first nuclear test in 1945 until the latest tests by Pakistan in 1998, there was never a period of more than 22 months with no nuclear testing. Therefore, the period from June of 1998 to the present has been, by far, the longest period since 1945 with no acknowledged nuclear tests.

Peter Kuran's documentary film Trinity and Beyond (1996) incorporates a good deal of footage from US, Soviet, and Chinese tests.


Known test series designations


An American atmospheric nuclear test from .
An American atmospheric nuclear test from 1951.

The United States has conducted numerous nuclear tests throughout the nation including the Nevada Test Site, the Marshall Islands, Alaska, and even Farmington, New Mexico.


Last test: October 24, 1990.


Last test: November 26, 1991, vertical shaft.


  • Operation Gerboise Bleue , 1960 and three more - Reggane, Algeria; in the atmosphere
  • Operation Beryl , 1 May, 1962 and 12 more - In Ekker, Algeria; underground
  • Operation Marquis , 1974

Last test: January 27, 1996, underground.


Last test: July 29, 1996, underground.



Tests in response to the Indian tests:

  • May 28, 1998 - five simultaneously (number is disputed by observers, but assumed to be at least two)
  • May 30, 1998 - one

See also

Alleged tests

There have been a number of significant alleged/disputed/unacknowledged accounts of countries testing nuclear explosives. None are generally accepted as having occurred by mainstream governments, news sources, or historians.


There is a disputed report about the Japanese atomic program being able to test a nuclear weapon in Korea on August 12 1945, a few days after the atomic bombings of Hiroshima and Nagasaki on August 6 and 9, and three days before the Japanese surrender on August 15, but this is seen as being highly unlikely by mainstream historians. See Japanese atomic program for more information.

Israel/South Africa

In what is known as the Vela Incident, Israel and/or South Africa may have detonated a nuclear device on September 22, 1979 in the Indian Ocean, according to satellite data. Knowledge of whether there was actually a test, much less who would have been responsible for it, is not fully known. See Vela Incident for more information.

North Korea

On September 9, 2004 it was reported by South Korean media that there had been a large explosion at the Chinese/North Korean border. This explosion left a crater visible by satellite and precipitated a large (2 mile diameter) mushroom cloud. The United States and South Korea quickly downplayed this, explaining it away as a forest fire which had nothing to do with the DPRK's nuclear weapons program. See Ryanggang explosion for more information.

Nuclear tests with the nuclear warhead launched by a rocket

Missiles and nuclear warheads have usually been tested separately. The only US live test of an operational missile was the following:

  • Frigate Bird - on May 6, 1962, a UGM-27 Polaris A-1 missile with a live 600 kt W47 warhead was launched from the USS Ethan Allen (SSBN-608), it flew 1900 km, re-entered the atmosphere, and detonated at an altitude of 3.4 km over the South Pacific; part of Operation Dominic I. Planned as a method to dispel doubts about whether the USA's nuclear missiles would actually function in practice, it had less effect than was hoped, as the stockpile warhead was substantially modified prior to testing, and the missile tested was a relatively low-flying SLBM and not a high-flying ICBM.

Other live tests with the nuclear explosive delivered by rocket by the USA include:

  • Operation Argus - three tests
  • On August 1, 1958, Redstone rocket #CC50 launched nuclear test Teak that detonated at an altitude of 77.8-km. On August 12, 1958, Redstone #CC51 launched nuclear test Orange to a detonation altitude of 43 km. Both were part of Operation Hardtack and had a yield of 3.75 Mt
  • On July 9, 1962, Thor missile 195 launched a Mk4 reentry vehicle containing a W49 thermonuclear warhead to an altitude of 248 miles (400 km). The warhead detonated with a yield of 1.45 Mt. This was the Starfish-Prime event of nuclear test operation Dominic-Fishbowl
  • In the same series in 1962: Checkmate, Bluegill, Kingfish, and Tightrope

The Soviet Union tested a number of nuclear explosives on rockets as part of their development of a localised anti-ballistic missile system in the 1960s.

See also

External links

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