Institute for Science and International Security March 14, 2001
South Africa is the only country to voluntarily give up its nuclear weapons. Many other states, such as South Korea, Taiwan, Argentina, and Brazil, abandoned their nuclear programs before they developed a weapon capability. However, South Africa’s abandonment of its twenty- to thirty-year-old nuclear weapons program remains unique.
South Africa’s first device was completed in 1979. A decade of weapons development followed, leading to plans to mate nuclear warheads with ballistic missiles. In 1990, President F. W. de Klerk terminated the program and in 1991 South Africa signed the Nuclear Non-Proliferation Treaty (NPT). The IAEA then conducted an unprecedented verification of nuclear rollback. Although the IAEA was traditionally concerned only with the accuracy of a nation’s declaration, after the agency’s failure to detect Iraq’s nuclear program the IAEA shifted its focus also to verifying the completeness of a nation’s declaration of nuclear activities and facilities.
The official history of South Africa’s nuclear weapons program as stated by South African government officials sidesteps some issues and is misleading on others. ISIS has interviewed South African nuclear scientists and government officials and collected material from South Africa and the IAEA to develop a more complete history of this program. The case of South Africa provides the only example of verification of nuclear rollback and highlights the extreme difficulty of verifying nuclear disarmament.
South Africa’s nuclear program began during World War II with the discovery of major uranium deposits in the country. South Africa’s first large-scale nuclear research and development project was initiated in 1959 under the auspices of the Atomic Energy Board (AEB). Although members of the former apartheid government claim that this project was not weapons-related, the African National Congress (ANC) believes that the ultimate goal of this early project was a nuclear weapon. The heart of the program was an indigenous nuclear power reactor fueled with natural uranium. Research on uranium enrichment was also commenced. A nuclear research center, including a US-provided research reactor, was established at Pelindaba. In 1967, South Africa abandoned the indigenous power reactor program while moving uranium enrichment to the pilot plant stage.
In 1967, South Africa combined its experience gained with the power reactor and uranium enrichment programs to launch a program to build peaceful nuclear explosives (PNEs). In 1970, South Africa announced the construction of a uranium enrichment plant, called the Y-Plant, at Valindaba, next to Pelindaba. Realizing that the large facility could not be hidden from outsiders, South Africa publicly announced the existence of the plant but kept secret the uranium enrichment technology and its plans to produce weapons-grade uranium. South Africa had tremendous problems getting the plant to work properly and the net effect was that output was only half as much as expected. Despite these problems, by the end of the 1980s, the plant had produced roughly 500 kilograms of uranium enriched to at least 80%.
In 1970, a committee within the AEB recommended that the government develop several types of PNEs including those based on gun-type and implosion-type designs (Type A) as well as boosted fission (Type A*) and thermonuclear designs (Type B). In 1971, the Minister of Mines approved development of the Type A devices. In 1973, theoretical work on Type B devices was approved and two years later approval was granted for the construction of facilities to produce the material needed for thermonuclear devices.
The AEB scientists chose to focus on the gun-type design and had completed theoretical work on such a design by 1973. In 1976, the first full scale test of the device, using natural uranium instead of enriched uranium, was conducted successfully. The next year, South Africa completed its first full-scale device (minus the highly enriched uranium). The huge device, 4.5 meters long and 3400 kilograms in weight, was suitable only for a static test. South Africa began its search for a test site in 1973 and by 1977 had completed two shafts in the Kalahari Desert. Preparations for a cold test were detected in August 1977 by the United States and Soviet Union forcing South Africa to halt its test preparation activities. Following this episode, AEB scientists miniaturized the design of the device so that it was only 2 meters long, weighed 750 kilograms and would be ready for testing at short notice.
By 1977, AEB also established nuclear weapon research and development and production facilities at Pelindaba. Around this time, South Africa’s security environment had deteriorated with the introduction of Cuban forces into Angola and the imposition of a military embargo by the United Nations. In 1978, P.W. Botha became prime minister of South Africa and a nuclear strategy was developed. While the AEB felt that an underground test would be a sufficient deterrent, the military believed that a fully weaponized nuclear capability was needed to provide a credible deterrent. As a result, responsibility for the weaponization program was transferred to Armscor, South Africa’s primary weapon development agency. By 1982, Armscor had built its first device, a relatively simple bomb. Subsequently it made extensive modifications to the AEB weapon design to meet the military’s requirements for safety, security and reliability.
In 1985, the government capped the weapons program at seven gun-type devices and limited HEU production at the Y-Plant to that needed to meet this goal. Research on implosion, boosted fission and thermonuclear designs continued but work on plutonium-based weapons was halted. In addition, development of a ballistic missile to replace the aging Buccaneer bombers as a nuclear delivery system was continued. Armscor also received additional funds to build a new weapon production facility called Advena Central Laboratory.
South Africa’s nuclear strategy, originally developed in the late 1970s, had three phases. Phase one consisted of perpetuating strategic uncertainty regarding South Africa’s nuclear capabilities. If South Africa faced an overwhelming conventional military threat and the West was unwilling to intervene on its behalf, South Africa would implement phase two of the strategy. Under this phase, South Africa would covertly acknowledge the existence of its nuclear weapons to key Western powers in the hope of inducing their intervention. If this approach did not succeed, South Africa would move to phase three, the adoption of an overt deterrent posture, which included several options. South Africa would publicly acknowledge the existence of its nuclear stockpile, conduct an underground nuclear test, or detonate a nuclear explosion on the surface. South Africa calculated that the West’s determination to prevent the spread of nuclear weapons would force them to place South Africa under their nuclear umbrella in the event of a crisis. The implementation of South Africa’s nuclear strategy never progressed beyond phase one.
By 1989, South Africa had six devices in its arsenal, each containing 55 kilograms of HEU, and enough HEU for a seventh device. South Africa took several precautions to safeguard its weapon stockpile. All the devices were stored unassembled with the front and rear portions of the weapons stored in separate vaults. Four codes, including one held by the president, were required to assemble the two parts into a weapon. In addition, to prevent premature detonation of a device, the weapons would only arm once they reached a certain altitude on board their delivery aircraft. Armscor based its safeguards largely on American practices.
By late 1989, the departure of Cuban forces from Angola, the decline of the Soviet Union and the independence of Namibia, had significantly improved South Africa’s security situation. President F.W. de Klerk, elected in September 1989, sought an end to the apartheid regime and South Africa’s acceptance back into the international community. The nuclear weapons program was viewed an obstacle to these goals and orders were issued for the termination of the program. By the time South Africa joined the NPT in the summer of 1991 and IAEA inspections began later that year the program had been dismantled and its nuclear weapon manufacturing facilities had been decontaminated. Largely because of domestic and international pressure, de Klerk announced the existence of the former weapons program and began cooperating with IAEA efforts to verify the rollback of the program.
With access to South African records, the IAEA recalculated the Y-Plant’s production on a day-to-day basis and arrived at a final estimate within about 5-10 kilograms of South Africa’s declaration. The IAEA was able to verify the scope and timing of the South African nuclear weapons program and its subsequent dismantlement.
South Africa’s success in developing nuclear weapons can be attributed to five elements. First, South Africa mastered the highly enriched uranium production process. Second, the nation had a defense industry which could produce nuclear delivery systems. Third, the program had good scientists and technicians. Fourth, the program had a good foreign procurement network. Fifth, the weapons’ design was kept simple and low in cost. The international sanctions placed on South Africa in the 1970s slowed but did not stop its nuclear weapon program. In fact, the imposition of the sanctions in the 1970s may have hardened South Africa’s determination to build nuclear weapons.
Rapporteur: Gregory Koblentz
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