The second nation to test an atomic bomb was the United
States's Cold War rival, the Soviet
Union. This development
was not unexpected, but the timing was. The American
intelligence community generally believed the Soviet Union would not have
"the bomb" until 1952 or even later, not August 1949. Soviet wartime
espionage sped its weapons development, but probably only by a year or
two. (The bomb tested on August 29, 1949, closely resembled the implosion
device developed at Los Alamos.)
In August 1953, the Soviet Union tested its first "boosted fission"
bomb, which used fusion to increase its yield,
and in November 1955 the Soviet Union produced its first "true" thermonuclear
explosion (right).
In 1952, Britain became the next nation to join the
"nuclear club." This was not surprising, as the Manhattan Project had
essentially
been a joint Anglo-American
program, especially once the British Mission
of scientists arrived at Los Alamos in 1943 and 1944. The Atomic
Energy Act of 1946 prohibited the United States from assisting the
post-war British nuclear weapons program, but within six years Britain was able
to successfully perform a nuclear test. At midnight on October 3, 1952, off the Australian island of
Trimouille, a 25 kiloton nuclear weapon was detonated inside the hull of a
British frigate, H.M.S. Plym. The test was codenamed
"Hurricane" (right). On November 8, 1957, Britain conducted its first
fully successful thermonuclear test, "Grapple X/Round C."
France and China joined the nuclear club in the
1960s. The first French nuclear
explosion, "Gerboise Bleue," was an unusually large first test: 60-70
kilotons. It was detonated at Reggane, Algeria, on February 13,
1960. France tested a thermonuclear weapon on the Pacific atoll of
Fangatuafa on August 24, 1968. The first Chinese
atomic test (right), codenamed "596," took place at the Lop Nor Testing Ground
on October 16, 1964. (The leader of China, Mao Zedong, had famously
declared that nuclear weapons, and by extension the United States, were a
"paper tiger," but that did not prevent him from pushing the Chinese
nuclear program through to fruition.) Only three years later, on June 17,
1967, China conducted its first thermonuclear test.
On July 1, 1968, the Nuclear Non-Proliferation Treaty was
signed by the United States, Great Britain, the Soviet Union, and 59 other
nations. The purpose of the treaty was to prevent the acquisition of
nuclear weapons by any nation that did not already possess them. The treaty took
effect in March 1970, and in 1992 China and France joined as well. As of
2000, only Cuba, Israel, India, and Pakistan had not signed the
Non-Proliferation Treaty.
The nuclear weapons programs of the original five nuclear
powers were driven
primarily by Cold War concerns. In the 1970s, however,
a largely-unrelated arms
race in South Asia produced two more members of the nuclear club: India and
Pakistan. India conducted its first atomic test, "Smiling
Buddha," on May 18, 1974 (right). (The test was conducted underground.)
In the 1980s reports began to emerge that, although it
had not yet conducted a nuclear test, Pakistan possessed nuclear weapons as
well. In May 1998, as retaliation for a new series of Indian nuclear tests
the previous month, Pakistan conducted several tests of its own.
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