WASHINGTON -- Independent experts, including a Nobel physicist, question the Pentagon's assurances that allied bombs have destroyed Iraq's nuclear weapons-making capacity.
Military spokesmen reaffirmed last Thursday a statement made earlier by Gen. Colin L. Powell, chairman of the Joint Chiefs of Staff, that the destruction of Iraq's only two operating reactors had broken the country's ability to make an atom bomb.
Three U.S. specialists in nuclear proliferation said, however, that the reactors at Tuwaitha near Baghdad, built in the 1970s for nuclear research, were too small to produce enough high-grade uranium for a bomb.
Iraq's nuclear weapons potential, these experts said, lay instead in other facilities President Saddam Hussein was believed to have been secretly developing in the northeast of the country with West German assistance over the last five years, and about which the U.S. military has said nothing.
A fourth expert, Leonard Spector of the Carnegie Endowment for International Peace, said the Tuwaitha facility may have contained just enough high-grade uranium to make one bomb, but he added that no evidence was made public that the nuclear fuel was in the facility when it was bombed.
Maj. Gen. Martin L. Brandtner of the Marine Corps said last Thursday that the United States had "detected no perceptible radiation" in the vicinity of the plant. He said military authorities had planned the attack in such a way as to avoid fallout.
Mr. Spector, however, said, "If they [the military] have looked [for radiation] and found nothing, that would suggest they haven't destroyed the uranium.
"If the fuel was there when the facility was bombed, that would imply that Saddam didn't give a damn and wasn't going to make a bomb out of it in any case."
Mr. Spector said that officials of the International Atomic Energy Agency had seen 45 pounds of enriched uranium at the Tuwaitha facility when they inspected it in November. Slightly more than 17.5 pounds -- given to Iraq by the Soviet Union -- had been 80 percent enriched, and an additional 27.5 pounds -- originally from France -- was 93 percent enriched, the level generally accepted for use in weapons.
Ideally, Mr. Spector said, a bomb would require 55 pounds of 93 percent enriched uranium, although he acknowledged that a bomb probably could be constructed with somewhat less uranium and lower enrichment.
"The question is whether Saddam Hussein left it there or whether he moved it in anticipation of the war," he said.
Mr. Spector agreed with other nuclear specialists who said that even if the uranium had been in the plant, the radiological contamination would not have been significant beyond the
immediate area of the facility.
The two reactors were rated at 5 megawatt and 0.8 megawatt thermal capacity, compared with nuclear reactors generally used for power generation that average about 3,000 megawatts -- the size of Chernobyl in the Soviet Union.
"Those reactors did not contribute at all to the Iraqis' nuclear weapons potential," said Bennett Ramberg, a research associate the University of Southern California's Center for International and Strategic Affairs. "And their destruction did not contribute to the destruction of Saddam Hussein's ability to make nuclear weapons."
Mr. Ramberg, author of a 1980 book, "The Destruction of Nuclear Energy Facilities in War," agreed with other experts that the bombing of an operating nuclear reactor set a "dangerous precedent," especially since the Tuwaitha plant was too small to release radiation much beyond its immediate location.
"Unfortunately, other countries may conclude that bombing a reactor holds little or no radiological risk, when quite the opposite is true," he said.
Mr. Spector said the U.S. bombing in Iraq marked the first time an operating nuclear reactor had been bombed. When Israeli jets destroyed the Osirak reactor, near Tuwaitha, in 1981, it was not yet operating.
"I don't think the relatively small release of contaminants [from Tuwaitha] will add any unique and striking new levels of grief to that already caused by the bombing in Iraq," said Henry Kendall of the Massachusetts Institute of Technology, co-winner of the 1990 Nobel Prize for physics.
If a large electric power reactor had been bombed, however, the nuclear fallout "could have led to a very major catastrophe -- worse, possibly, than Chernobyl," he said.
Dr. Kendall said he hoped that when the gulf war was over, it would prompt international action -- "not just tactics, but actions and control" -- to stop the spread of nuclear weapons.