Among those nations which today boast of nuclear warheads, South Africa is the only nation to have renounced it. As of this date 2017 there are ten nations which have nuclear weapons.
South Africa ended its nuclear weapons programme in 1989. All the bombs (six constructed and one under construction) were dismantled and South Africa acceded to the Treaty on the Non-Proliferation of Nuclear Weapons when South African Ambassador to the United States Harry Schwarz signed the treaty in 1991. On 19 August 1994, after completing its inspection, the International Atomic Energy Agency (IAEA) confirmed that one partially completed and six fully completed nuclear weapons had been dismantled. As a result, the IAEA was satisfied that South Africa's nuclear programme had been converted to peaceful applications. Following this, South Africa joined the Nuclear Suppliers Group (NSG) as a full member on 5 April 1995. South Africa played a leading role in the establishment of the African Nuclear-Weapon-Free Zone Treaty (also referred to as the Treaty of Pelindaba) in 1996, becoming one of the first members in 1997. South Africa also signed the Comprehensive Nuclear-Test-Ban Treaty in 1996 and ratified it in 1999. [From wikipedia]Whatever the political reasons, acknowledged or hidden, behind this voluntary disarmament, it is surprisingly to know that this is a reality, a possibility for others to emulate. May have slowed down the race to make nuclear warheads, but didn't inspire those already equipped to give them up. Makes me wonder if the notion of 'good example being inspirational' is true at all!