Complex sentence: Shortly after South Africa's nuclear program was dismantled, the African Nuclear Weapons Free Zone Treaty or the Pelindaba Treaty was signed in 1996 and came into effect on 15 July 2009 once it had been sufficiently ratified.
Split into simpler sentences: Shortly after South Africa's nuclear program was dismantled, the African Nuclear Weapons Free Zone Treaty (the Pelindaba Treaty) was signed in 1996. It came into effect on 15 July 2009 once it had been sufficiently ratified.