PELINDABA, South Africa — Enough nuclear explosive to fuel half a dozen bombs, each powerful enough to obliterate central Washington or most of Lower Manhattan, is locked in a former silver vault at a nuclear research center near the South African capital.
Technicians extracted the highly enriched uranium from the apartheid regime’s nuclear weapons in 1990, then melted the fuel down and cast it into ingots. Over the years, some of the cache has been used to make medical isotopes, but roughly 485 pounds remains, and South Africa is keeping a tight grip on it.
That gives this country — which has insisted that the United States and other world powers destroy their nuclear arsenals — a theoretical ability to regain its former status as a nuclear-weapons state. But what really worries the United States is that the nuclear explosives here could be stolen and used by militants to commit the worst terror attack in history.
Senior current and former U.S. officials say they have reason to be concerned. On a cold night in November 2007, two teams of raiders breached the fences here at the Pelindaba research center, set in the rolling scrubland a half-hour’s drive west of Pretoria, the country’s administrative capital. One group penetrated deep into the site unchallenged and broke into the site’s central alarm station. They were stopped only because a substitute watch officer summoned others.