How, where and when has nuclear testing been carried out?

Nuclear testing (also called a nuclear test explosion) refers to an experiment that involves detonating a nuclear weapon. This type of testing officially takes place for two reasons: "weapons-related" testing is undertaken to verify that the weapon works, or to examine how it works, whereas "weapons effects" testing reveals how specific nuclear weapons behave under a variety of testing conditions, as well as how target structures behave in response to the weapon. Practically speaking, however, nuclear testing is often used to demonstrate a nation's military strength and technological sophistication.

Nuclear Testing Classifications and Risk

Three categories of nuclear test exist, based on topographical location: "atmospheric" tests occur in or above the earth's atmosphere), whereas "underground" and "underwater" tests occur where stated. Although all three types of nuclear test pose health risks in terms of nuclear fallout, atmospheric testing that comes in contact with the ground's surface or other substances is the most risky. In contrast, underground testing that takes place in deep shafts within the earth poses the lowest risk with regard to fallout. To date, approximately 2,000 nuclear tests have taken place around the globe.

In addition to the danger of radioactive fallout, in the 1970s scientists began investigating the potential impact of nuclear war on the environment. The collective effects of the environmental damage that could result from a large number of nuclear explosions has been termed nuclear winter.

Conducting Nuclear Tests

Military operations in various countries have taken some creative approaches to nuclear testing. Nuclear weapons have been dropped from towers and planes, hoisted out of hot-air balloons, floated out to sea on large ships, and shot into space on rockets. The first nuclear weapon detonation occurred in the United States on July 16, 1945 at the Trinity site, part of the Alamogordo Bombing Range and now the White Sands Missile Range. This was a plutonium bomb with a yield approximately equivalent to 20 kilotons.

Seven years later, the first hydrogen bomb (codename: Mike) was detonated on November 1, 1952 at Eniwetok island in the Bikini atoll - also by the United States. To date, the largest nuclear weapon tested was the Soviet Union's Tsar Bomba, detonated at Novaya Zemlya, with an estimated yield of approximately 50 megatons.

The Limited Test Ban Treaty

Known health risks of nuclear testing in part prompted the creation in 1963 of the Limited Test Ban Treaty, in which various nuclear and non-nuclear states pledged to refrain from atmospheric and underwater nuclear testing, as well as testing weapons in outer space; however, the treaty permitted continuation of underground nuclear tests.

Not all countries were compliant, however, and some continued non-atmospheric testing until quite recently:

  • France continued atmospheric testing until 1974.
  • China continued atmospheric testing until 1980.
  • The United States' last underground test was in 1992.
  • The Soviet Union's last test was in 1990.
  • The United Kingdom's last test was in 1991.
  • Both France and China have continued testing up until 1996.

Importantly, after they adopted a new treaty - the Comprehensive Test Ban Treaty - in 1996, all of these states pledged to discontinue all nuclear testing. India and Pakistan, both non-signatories of the treaty, both last tested nuclear weapons in 1998.

Official Nuclear Tests

There have been around 2,000 official nuclear test explosions:US - 1,030 tests (involving 1,125 devices)

  • Soviet Union - 715 tests
  • France - 210 tests
  • Britain - 45 tests (21 in Australian territory, including 9 in mainland South Australia at Maralinga and Emu Field, many others in the U.S.)
  • China - 45 tests (23 atmospheric, 22 underground, all conducted at Lop Nur Nuclear Weapons Test Base, Malan, Xinjiang)
  • India - 6 tests
  • Pakistan - 6 tests

Moreover, there may have been at least three alleged/unacknowledged nuclear explosions, by Japan, Israel/SouthAfrica and Korea.

Interestingly, from 1945, when the first nuclear test was conducted, until 1998, when Pakistan conducted the most recent tests, no more than 22 months has elapsed without nuclear testing. Therefore, the period from June of 1998 to the present has by far been the longest period since 1945 with no acknowledged nuclear tests.

Known Test Series Designations

United States

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.

Operation Trinity - 17 July 1945
Operation Crossroads - 1946
Operation Sandstone - 1948
Operation Ranger - 1951
Operation Greenhouse - 1951
Operation Buster-Jangle - 1951
Operation Tumbler-Snapper - 1952
Operation Ivy - 1952
Ivy Mike - first hydrogen bomb
Operation Upshot-Knothole - 1953
Operation Castle - 1954
Castle Bravo - March 1 - 1954 - most powerful ever by the US (15 megatons)
Operation Teapot - 1955
Operation Wigwam - 14 May 1955
Operation Red Wing - 1956
Operation Plumbbob - 1957
Operation Chariot - 1958 (cancelled)

An RB-57 Canberra observes Operation Hardtacks's Juniper test. Operation Hardtack - 1958
Operation Argus - 1958
Operation Dominic - 1962 - 1963
Operation Nougat - 1963 - 1964
Operation Little Feller - July - 1962
Operation Niblick - 1963 - 1964
Operation Whetstone - 1964 - 1965
Operation Flintlock - 1965 - 1966
Operation Latchkey - 1966 - 1967
Operation Crosstie - 1967 - 1968
Operation Bowline - 1968 - 1969
Operation Mandrel - 1969
Operation Emery 1970

Preparing for an underground test at Nevada Test Site. Operation Grommet - 1971 - 1972
Operation Toggle - 1972 - 1973
Operation Arbor - 1973 -1974
Operation Bedrock - 1974- 1975
Operation Anvil - 1975 - 1976
Operation Fulcrum - 1976 -1977
Operation Crescent - 1977 - 1978
Operation Quicksilver - 1978 - 1979
Operation Tinderbox - 1979 - 1980
Operation Guardian - 1980 - 1981
Operation Praetorian - 1981
Operation Phalanx - 1982 - 1983
Operation Fusileer - 1983 - 1984
Operation Grenadier - 1984 - 1985
Operation Charioteer - 1985
Operation Divider - 23 September 1992

USSR

Operation First Lightning - 29 August 1949
Last test: October 24 - 1990.

UK

Operation Hurricane - 3 October 1952
Operation Rats - 1953
Operation Mosaic - 1956
Operation Buffalo - 1956
Operation Antler - 1957
Operation Grapple - 1957 - 1958
Operation Totem - 1953
Operation Vixens - 1963
Last test: November 26 - 1991 - vertical shaft.

France

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.

China

Last test: July 29 - 1996 - underground.

India

Operation Smiling Buddha - 18 May 1974 - implosion type - plutonium - underground - 6 to 20 kt
Operation Shakti - all underground:
11 May 1998 - three simultaneously - of which one was claimed to be a fusion device (this is disputed by outsider observers)
13 May 1998 - two simultaneously

Pakistan

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