Nuclear weapons testing

Nuclear weapons testing. The experimental detonation of nuclear devices to verify performance, study effects, and advance military capabilities began with the Trinity test in 1945. Conducted by several nations throughout the Cold War and beyond, these tests have occurred in diverse environments including the atmosphere, underground, underwater, and in outer space. The practice has driven significant geopolitical developments, led to major international treaties, and left a lasting legacy of environmental contamination and public health concerns.

History

The era of testing commenced with the Manhattan Project's first successful detonation, codenamed Trinity, in the Jornada del Muerto desert of New Mexico. Following the atomic bombings of Hiroshima and Nagasaki, the United States conducted Operation Crossroads at Bikini Atoll in 1946, studying effects on naval vessels. The Soviet Union began its program with RDS-1 (Joe-1) in 1949 at the Semipalatinsk Test Site, escalating the arms race. The United Kingdom initiated tests with Operation Hurricane in 1952 aboard HMS *Plym* near the Montebello Islands, while France began with Gerboise Bleue in 1960 in Reggane, Algeria. The People's Republic of China entered the testing arena with Project 596 at Lop Nur in 1964. Major series like the Soviet Project K and the American Operation Castle tested increasingly powerful thermonuclear weapons. The period saw controversial tests like the Castle Bravo accident, which contaminated the Marshall Islands and the Japanese fishing vessel Daigo Fukuryū Maru.

Types of tests

Tests are categorized by the environment of detonation. Atmospheric tests, conducted in the air or on the surface, were common until the Partial Nuclear Test Ban Treaty and include airbursts like those over Nagasaki and surface bursts like the Baker test. Underwater tests, such as the Baker test at Bikini Atoll and the Wigwam test, studied effects on submarines and ships. Underground tests, which became the primary method after 1963, involve detonating devices in deep shafts or tunnels, like those at the Nevada Test Site and the Semipalatinsk Test Site; these can sometimes lead to venting, as occurred during the Baneberry test. Exoatmospheric and high-altitude tests, conducted in outer space or the upper atmosphere, include operations like Starfish Prime and Project K, which created artificial radiation belts and electromagnetic pulses. Subcritical tests, such as those conducted at the Nevada National Security Site, involve no sustained nuclear chain reaction and are not prohibited by treaties.

Effects and consequences

Testing has had profound environmental and health impacts. Atmospheric tests dispersed significant radioactive fallout globally, with isotopes like iodine-131 and strontium-90 entering the food chain, leading to increased cases of thyroid cancer and leukemia among exposed populations, notably downwinders near the Nevada Test Site and inhabitants of the Marshall Islands. Local ecosystems at test sites, such as Semipalatinsk, Maralinga, and Fangataufa, suffer from long-term contamination. The Comprehensive Nuclear-Test-Ban Treaty Organization monitors for clandestine tests using a global network of seismographic, radionuclide, hydroacoustic, and infrasound stations. Political consequences include fueling the Cold War arms race, influencing doctrines like mutually assured destruction, and catalyzing anti-nuclear movements such as the Campaign for Nuclear Disarmament.

Treaties and limitations

International efforts to curb testing began with the Partial Nuclear Test Ban Treaty of 1963, negotiated by parties including the United States, Soviet Union, and United Kingdom, which banned tests in the atmosphere, outer space, and underwater. The Threshold Test Ban Treaty of 1974 limited underground tests to a yield of 150 kilotons. The bilateral Peaceful Nuclear Explosions Treaty followed in 1976. A major milestone was the multilateral Comprehensive Nuclear-Test-Ban Treaty, adopted by the United Nations General Assembly in 1996, which bans all nuclear explosions; it has not entered into force due to the non-ratification of specific states including the United States, China, and North Korea. Other relevant agreements include the Nuclear Non-Proliferation Treaty and regional treaties like the Treaty of Rarotonga, which established a South Pacific Nuclear Free Zone.

List of test series by country

* United States: Major series include Operation Ivy, Operation Castle, Operation Redwing, and Operation Dominic, primarily conducted at the Nevada Test Site and the Pacific Proving Grounds. * Soviet Union/Russia: Tests were conducted at the Semipalatinsk Test Site in Kazakhstan and the Novaya Zemlya archipelago, including the detonation of the Tsar Bomba in 1961. * United Kingdom: Early tests occurred in Australia at the Montebello Islands and Maralinga, and later in the United States under the 1958 US–UK Mutual Defence Agreement. * France: Initial tests were in Reggane, Algeria, followed by extensive atmospheric and underground testing at Moruroa and Fangataufa in French Polynesia. * China: All tests were conducted at the Lop Nur site in Xinjiang. * India: Conducted its first test, Smiling Buddha, in 1974 at the Pokhran test range, followed by the Pokhran-II series in 1998. * Pakistan: Responded to Pokhran-II with its own tests, Chagai-I and Chagai-II, in the Ras Koh Hills and Kharan Desert. * North Korea: Has conducted six announced tests between 2006 and 2017 at the Punggye-ri test site.

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