24 May 1973
South African Prime Minister, Balthazar Johannes Vorster disclosed in July 1970 in the House of Assembly that the government has decided to make funds available for a uranium enrichment programme. The funds were made available for preparatory work for establishing a full-scale prototype plant for the economic enrichment of uranium.  Uranium was used to manufacture nuclear weapons by the South Africa government. The history of nuclear energy in the country can  be traced to 1959 when the country's first large-scale nuclear research and development project was initiated under the auspices of the Atomic Energy Board (AEB). In 1990 South African President, F. W. de Klerk terminated the program and in 1991 South Africa signed the Nuclear Non-Proliferation Treaty (NPT).
References

Albright, D. (2001) ‘South Africa's Nuclear Weapons Program’, from MIT, 14 March, [online], available at web.mit.edu (Accessed: 23 April 2013)|

O’Malley, P. ‘1973’, from Nelson Mandela Centre of Memory, [online], available at www.nelsonmandela.org.za (Accessed: 23 April 2013)