From the 1960s to the 1990s, South Africa pursued research into weapons of mass destruction, including nuclear, biological, and chemical weapons under the apartheid government. Six nuclear weapons were assembled. South African strategy was, if political and military instability in Southern Africa became unmanageable, to conduct a nuclear weapon test in a location such as the Kalahari desert, where an underground testing site had been prepared, to demonstrate its capability and resolve—and thereby highlight the peril of intensified conflict in the region—and then invite a larger power such as the United States to intervene.
Before the anticipated changeover to a majority-elected African National Congress–led government in the 1990s, the South African government dismantled all of its nuclear weapons, the first state in the world which voluntarily gave up all nuclear arms it had developed itself. The country has been a signatory of the Biological Weapons Convention since 1975, the Treaty on the Non-Proliferation of Nuclear Weapons since 1991, and the Chemical Weapons Convention since 1995. In February 2019, South Africa ratified the Treaty on the Prohibition of Nuclear Weapons, becoming the first country to have had nuclear weapons, disarmed them and gone on to sign the treaty.
Nuclear weapons
The Republic of South Africa's ambitions to develop nuclear weapons began in 1948 after giving commission to South African Atomic Energy Corporation (SAAEC), the forerunner corporation to oversee the nation's uranium mining and industrial trade. In 1957, South Africa reached an understanding with the United States after signing a 50-year collaboration under the U.S.-sanctioned programme, Atoms for Peace. The treaty concluded the South African acquisition of a single nuclear research reactor and an accompanying supply of highly enriched uranium (HEU) fuel, located in Pelindaba.
In 1965, the U.S. subsidiary, the Allis-Chalmers Corporation, delivered the 20 MW research nuclear reactor, SAFARI-1, along with ~90% HEU fuel to South African nuclear authority. In 1967, South Africa decided to pursue plutonium capability and constructed its own reactor, SAFARI-2 reactor also at Pelindaba, that went critical using 606 kg of 2% enriched uranium fuel, and 5.4 tonnes of heavy water, both supplied by the United States.
The SAFARI-2 reactor was intended to be moderated by heavy water, fuelled by natural uranium while the reactor's cooling system used molten sodium. In 1969, the project was abandoned by the South African government because the reactor was draining resources from the uranium enrichment program that had begun in 1967. South Africa began to focus on the success of its uranium enrichment programme which was seen by its scientists as easier compared to plutonium.
South Africa was able to mine uranium ore domestically, and used aerodynamic nozzle enrichment techniques to produce weapons-grade material. In 1969, a pair of senior South African scientists met with Sultan Bashiruddin Mahmood, a nuclear engineer from Pakistan based at the University of Birmingham, to conduct studies, research and independent experiments on uranium enrichment. The South African and Pakistani scientists studied the use of aerodynamic-jet nozzle process to enrich the fuel at the University of Birmingham, later building their national programs in the 1970s.
South Africa gained sufficient experience with nuclear technology to capitalise on the promotion of the U.S. government's Peaceful Nuclear Explosions (PNE) program. Finally in 1971, South African minister of mines Carl de Wet gave approval of the country's own PNE programme with the publicly stated objective of using PNEs in the mining industry. The date when the South African PNE programme transformed into a weapons program is a matter of some dispute. The possibility of South Africa collaborating with France and Israel in the development of nuclear weapons was the subject of speculation during the 1970s.
South Africa developed a small finite deterrence arsenal of gun-type fission weapons in the 1980s. Six were constructed and another was under construction at the time the program ended.
South Africa only produced an operational weapon after Armscor took over production. In 1982, Armscor built the first operational weapon, code-named Hobo and later called Cabot. This device reportedly had a yield of 6 kilotons of TNT. It was eventually disassembled and the warhead reused in a production model bomb. Armscor then built a series of pre-production and production models under the code-name Hamerkop (a bird). While Hobo/Cabot were not functional, the Hamerkop series were smart television-guided glide bombs.