South Africa tests its first full-scale nuclear explosive device, based on a gun-type design. Accounts differ as to whether the government had yet switched the goal of their nuclear program from peaceful to military; a decision that was taken between 1973 and 1978. Soviet discovery of the test site leads to international pressure on South Africa, and the country abandons the test site in August.
South Africa finishes its first tungsten gun device to be used in a nuclear weapon.
The United States announces it has tested a neutron bomb. Described as an "enhanced radiation weapon," it is a small hydrogen bomb with only one-tenth of the blast, heat, and fallout produced by a normal hydrogen bomb. It is intended to disable or kill troops by producing a huge shower of neutrons that can pass through steel or concrete. Egon Bahr, a West German parliamentarian, calls the bomb the result of "perverted thinking" (Perversion des Denkens).
The Soviet Union discovers that South Africa is preparing a nuclear test in the Kalahari Desert.
A Soviet Delta class nuclear-powered ballistic missile submarine accidentally jettisons a nuclear warhead near Kamchatka in the Pacific. The bomb is recovered.