Search in Iraq Fails to Find Nuclear Threat

"If you told me they had access to these tubes and have chosen not to seize and destroy them, it undermines the judgment that these tubes are usable for, if not intended for, centrifuge development," said Robert Gallucci, dean of Georgetown University's School of Foreign Service, who retains his classified clearances and still consults with government analysts on Iraq.

Meekin said he no longer knows the whereabouts of the tubes once stacked at Nasr. "They weren't our highest priority," he said. "The thing's innocuous." Unguarded, the tubes "could be in arms plants, scattered around, being grabbed by looters, perhaps in scrap metal yards."

Scavengers, he said, most likely have "sold them as drain pipe."

The day Marines and Army mechanized troops marched past the remnants of Iraq's nuclear past, Baghdad's three most important nuclear weapons scientists met three distinct fates.

Mahdi Obeidi, chief of the pre-1991 centrifuge program to enrich uranium, sat anxiously at home awaiting U.S. investigators. Jaffar Dhai Jaffar, who directed alternative enrichment efforts and other component designs under the code name Petrochemical Three, watched the U.S.-led coalition's invasion from the United Arab Emirates, to which he had decamped before fighting began. Khalid Ibrahim Said, the principal overseer of Iraq's nuclear warhead designs, drove incautiously through a newly established U.S. checkpoint. He died in a burst of gunfire from Marines.

A short and pugnacious man, unpopular among his Iraqi contemporaries, Said had been less forthcoming than the other two men in contacts with U.N. inspectors from 1991 to 1998. His loss struck a blow to U.S. occupation authorities, because there were unanswered questions about his portion of the 1991 "crash program" to build a bomb.

Said was believed to have kept comprehensive records of his work, including design details and assembly diagrams, on optical disks. Iraq delivered much of its information to inspectors in electronic form, and it did so again in its seven-volume report of Dec. 3, 2002, titled "Currently Accurate, Full and Complete Declaration of the Past Nuclear Program." That report, a copy of which has been made available to The Washington Post, was not thought to include all the technical details in Iraq's possession.

Kay said this month that Iraq took "steps to preserve some technological capability from the pre-1991 nuclear weapons program." If true, that would represent a violation of U.N. Security Council resolutions, but would fall far short of a resumption of illegal development.

"Everybody, including Donald Rumsfeld, agrees the program was destroyed 12 years ago," said one U.S. expert with long experience on Iraq. "The question for David [Kay] is whether it restarted."

Jaffar, who remains under the protection of the UAE government, agreed to voluntary interviews with U.S. and British investigators. Those familiar with his statements said he was combative, telling the Americans -- as he did during years of U.N. inspections -- that there was no hidden nuclear weapons program. Iraq, he said, never resumed the effort after U.S. bombs destroyed the Tuwaitha reactors during the Gulf War, and the International Atomic Energy Agency dismantled enrichment and design facilities over the next five years.

It was Obeidi's former program -- the use of centrifuges to enrich uranium -- that the Bush administration maintained had been resurrected. Obeidi had heard the public statements, according to two close associates, and he waited with growing anxiety for arriving troops to knock at his door.

Anxiety turned to puzzlement when they did not. After two weeks, the Iraqi scientist turned to an unlikely source of help: David Albright, a U.S. nuclear expert and cordial antagonist during Albright's years as a consultant to the IAEA. One of the first things Obeidi told Albright, by the American's account, was that he had read Albright's published writings closely in the mid-1990s to learn which of Iraq's cover stories was working.