Nuclear weapons testing

Nuclear weapons
Background
Nuclear explosion History Warfare Design Testing Delivery Yield Effects Workers Ethics Arsenals Target selection Arms race Blackmail Espionage Proliferation Disarmament Terrorism Umbrella Opposition Winter
Nuclear-armed states
NPT recognized United States Russia United Kingdom France China Others India Israel (undeclared) Pakistan North Korea Former South Africa Belarus Kazakhstan Ukraine
v t e

Weapons of mass destruction
By type
Biological Chemical Nuclear Radiological
By country
Albania Algeria Argentina Australia Brazil Bulgaria Canada China Egypt France Germany India Iran Iraq Israel Italy Japan Kazakhstan Libya Mexico Myanmar Netherlands North Korea Pakistan Philippines Poland Rhodesia Romania Russia (Soviet Union) Saudi Arabia South Africa South Korea Spain Sweden Switzerland Syria Taiwan Ukraine United Kingdom United States Yugoslavia
Proliferation
Chemical Nuclear Missiles
Treaties
List of treaties (treaty parties)
Category
v t e

Nuclear weapons tests are experiments carried out to determine the performance, yield, and effects of nuclear weapons. Testing nuclear weapons offers practical information about how the weapons function, how detonations are affected by different conditions, and how personnel, structures, and equipment are affected when subjected to nuclear explosions. However, nuclear testing has often been used as an indicator of scientific and military strength. Many tests have been overtly political in their intention; most nuclear weapons states publicly declared their nuclear status through a nuclear test.

The first nuclear device was detonated as a test by the United States at the Trinity site in New Mexico on July 16, 1945, with a yield approximately equivalent to 20 kilotons of TNT. The first thermonuclear weapon technology test of an engineered device, codenamed Ivy Mike, was tested at the Enewetak Atoll in the Marshall Islands on November 1, 1952 (local date), also by the United States. The largest nuclear weapon ever tested was the Tsar Bomba of the Soviet Union at Novaya Zemlya on October 30, 1961, with the largest yield ever seen, an estimated 50–58 megatons.

With the advent of nuclear technology and its increasing impact an anti-nuclear movement formed and in 1963, three (UK, US, Soviet Union) of the then four nuclear states 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 nuclear testing. France continued atmospheric testing until 1974, and China continued until 1980. Neither has signed the treaty.^[1]

Underground tests conducted by the Soviet Union continued until 1990, the United Kingdom until 1991, the United States until 1992, and both China and France until 1996. In signing the Comprehensive Nuclear-Test-Ban Treaty in 1996, these countries pledged to discontinue all nuclear testing; the treaty has not yet entered into force because of its failure to be ratified by eight countries. Non-signatories India and Pakistan last tested nuclear weapons in 1998. North Korea conducted nuclear tests in 2006, 2009, 2013, January 2016, September 2016 and 2017. The most recent confirmed nuclear test occurred^[update] in September 2017 in North Korea.