World overview

The figures throughout this chapter are approximate and based on official government sources, as well as on information provided by research institutions such as the Natural Resources Defence Council in Washington D.C., and the Stockholm International Peace Research Institute (SIPRI).

For the purposes of this chapter, a nuclear test is defined as a nuclear explosion detonated for either military or peaceful purposes. Of the nearly 2,050 nuclear explosions detonated between 1945-1996, over 150 were for peaceful purposes. 

The history of nuclear testing began early on the morning of 16 July 1945 at a desert test site in Alamogordo, New Mexico when the United States exploded its first atomic bomb. Designated as the Trinity Site, this initial test was the culmination of years of scientific research under the banner of the so-called “Manhattan Project”.

One of the few colour photographs of the "Trinity" explosion.

In the five decades between that fateful day in 1945 and the opening for signature of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) in 1996, over 2,000 nuclear tests were carried out all over the world.

  • The United States conducted 1,032 tests between 1945 and 1992.
  • The Soviet Union carried out 715 tests between 1949 and 1990.
  • The United Kingdom carried out 45 tests between 1952 and 1991.
  • France carried out 210 tests between 1960 and 1996.
  • China carried out 45 tests between 1964 and 1996.
In the five decades between 1945 and 1996, over 2,000 nuclear tests were carried out all over the world.
SIPRI Nuclear Testing Tally table (PDF)

After the CTBT was opened for signature in September 1996, ten nuclear tests have been conducted: 

  • India conducted two tests in 1998 (India had also conducted one so-called peaceful nuclear explosion in 1974.)
  • Pakistan conducted two tests in 1998.
  • The Democratic People’s Republic of Korea announced that it conducted one nuclear test in 2006, 2009 and 2013, two in 2016 (January and September), and one in 2017.

For more details:
Nuclear Testing Tally: A numeric breakdown of the number of atmospheric and underground nuclear tests conducted by each testing country for each year from 1945-2006.

Nuclear test sites

Former French nuclear test site at Moruroa, South Pacific.

Between 1945 and 2006, over 60 locations throughout the world were used to detonate more than 2,000 nuclear explosions for military or for peaceful purposes. The United States, the Soviet Union and China conducted the majority of their nuclear tests within their respective continental territories. France tested in the Algerian Sahara and in French Polynesia in the South Pacific. The United Kingdom conducted most of its tests either in a joint series with the United States or in Australia, part of the British Commonwealth.

Between 1945 and 2006, over 60 test sites throughout the world were used.

To learn more about the nuclear test sites worldwide, see the interactive world map from which information is provided on the over 60 nuclear testing locations.

In terms of geography, the test sites offer stunning contrasts. Seemingly idyllic South Pacific atolls served as test sites for the United States, the United Kingdom and France. Far from idyllic, Novaya Zemlya, the former Soviet Union’s test site, is a remote ice-bound archipelago in the Arctic Ocean in extreme northeastern Europe, while China’s Lop Nur test site is a landlocked salt lake marsh—the last remnant of the post-glacial Tarim Lake, which once covered more than 10,000 square kilometers. Today the arid desert test site of southeastern Xinjiang Uygur Autonomous Region is home only to roaming wild camels.

The demographics also differ. While some test sites were virtually uninhabited, others were densely inhabited and the local population suffered the effects of radioactive fallout on several occasions. 

While some test sites were virtually uninhabited, others were densely inhabited and the local population suffered the effects of radioactive fallout on several occasions.
Test Site in Neveda, USA

In terms of testing numbers, the Nevada Test Site in the United States was the site of the greatest number of tests (over 900), followed by Semipalatinsk, Kazakhstan (which was the former Soviet Socialist Republic of Kazakhstan) with over 450 tests. France's testing in the Pacific exceeded 190 tests, including Mururoa atoll (179) and Fangataufa atoll (14). 

130 tests were conducted by the USSR on the Novaya Zemlya Island in the Arctic Ocean. The United States’ testing in the Pacific totaled over 100, including the Marshall Islands’ Eniwetok Atoll (43), Bikini Atoll (23), Christmas Island (33 including nine tests conducted by the United Kingdom) and Johnston Atoll (12). Lop Nur Test Site in Western China has been the site of some 45 tests.

France conducted 17 tests in Regaane and near In Ekker in Algeria while the United Kingdom conducted 12 nuclear tests in mainland South Australia at Maralinga and Emu field, and in the Monte Bello Islands off the western coast of Australia.

World view of former and inactive nuclear test sites. Click the image to visit our fullscreen interactive map.

Why test?

The purpose of nuclear testing for military purposes is multifaceted. From a technical point of view, nuclear testing provides information on how well nuclear weapons work, how they behave under various conditions and how adjacent structures react to nuclear explosions. However, there is also the political aspect: that is, the importance of making a political statement of national, scientific and military preeminence.

Different testing purposes

Nuclear tests have been categorized by the purpose of the test itself. Tests designed to glean information about how well the weapons work were called weapons-related tests, while those conducted to gain information about the weapons’ effects on structures or organisms were known as weapons effects tests. Additional types of nuclear tests have been considered possible as well (e.g. nuclear tests as part of anti-ballistic missile testing).

Nuclear-weapons-related testing which purposely results in no yield is known as sub-critical testing, referring to the absence of a critical mass of fissile material. Such a test is not considered a nuclear test.

To read more about the discussion about sub-critical testing in the CTBT negotiations, see Treaty: 1994-96: Debating the Basic Issues, Banning nuclear test explosions.


Next chapter: Types of Nuclear Weapons Tests