The discovery provides fresh evidence of the reach and sophistication of Pakistani scientist Abdul Qadeer Khan's global black market in nuclear know-how and equipment. It also exposes a previously undetected South African branch of the Khan network.
The startling dimensions of the plot began to emerge in September, when police raided a factory outside Johannesburg. They found the elements of a two-story steel processing system for the enrichment plant, packed in 11 freight containers for shipment to Libya.
South African officials have disclosed only that they discovered nuclear components. The Times has learned that the massive system was designed to operate an array of 1,000 centrifuges for enriching uranium.
Once assembled in Libya, the plant could have produced enough weapons-grade uranium to manufacture several nuclear bombs a year. Delivery of the plant would have greatly accelerated Libya's efforts to develop nuclear weapons.
Khan already had secretly shipped to Libya a supply of processed uranium fuel for the enrichment plant, according to later reports by international inspectors.
And some of the centrifuges for the plant were shipped separately from Malaysia. The interception of that cargo by U.S. and Italian authorities in October 2003 led to the Johannesburg raid and spurred Libyan leader Moammar Kadafi to renounce efforts to develop banned weapons.
In the Sept. 1 raid, police found a videotape that detailed the inner workings of Khan's top-secret government enrichment laboratory in Pakistan, along with trunks filled with designs from the lab.
The discovery of a South African connection to Khan's web has led to the arrests of four business and engineering figures, including some who had been involved in the former apartheid regime's nuclear program.
Leads developed in the inquiry have opened up new avenues for investigators from South Africa, other countries and the U.N.'s International Atomic Energy Agency, who are tracing the network's operations on three continents.
The questions confronting investigators include whether other countries sought Khan's help and whether tougher restrictions are necessary to prevent a repeat of what officials have called the most dangerous proliferation operation in history.
The processing system found at Tradefin, an engineering and manufacturing company in Vanderbijlpark, outside Johannesburg, had been designed and built over three years. It was then tested, painstakingly dismantled and packed into 40-foot containers, factory records show.
Daniel Jacobus Van Beek, director of South Africa's counter-proliferation office, participated in the raid and called the scheme "one of the most serious and extensive attempts" to breach international nuclear controls. He estimated that the 200 tons of equipment was worth about $33 million.
Khan, a German-trained metallurgist, used stolen designs and a shadowy network of European suppliers in the 1980s to build the Pakistani plant where uranium was enriched for that country's first atomic bomb.
A decade later, he resurrected the network to sell nuclear technology on the world market. Secrecy surrounding the Khan ring began to unravel last December, when Libya announced that it was giving up its effort to build an atomic bomb.
As part of a deal negotiated with the U.S. and Britain, Libya disclosed evidence that Khan and his associates had sold Tripoli $100 million worth of technology over 10 years, including designs for a nuclear warhead.
That information led to the immediate shutdown of a Malaysian operation that manufactured centrifuges and sent investigators scrambling to follow up on evidence that the ring had sold enrichment technology to Iran and North Korea.
Under international pressure, Pakistan forced Khan to confess on national television that he had sold the country's nuclear secrets. Pakistani President Pervez Musharraf pardoned Khan immediately. Investigators from the IAEA and the U.S. have not been allowed to interview the scientist, who is still revered in Pakistan.
As a result, investigators say they are still struggling to uncover the extent of the network.