A series of Brazilian statements about nuclear matters raised worries in Washington and Vienna about Brazil's intentions, however. During his winning campaign, leftist Workers' Party presidential candidate Luiz Inacio Lula da Silva criticized the 1970 Non-Proliferation Treaty as unfair. "If someone asks me to disarm and keep a slingshot while he comes at me with a cannon, what good does that do?" da Silva asked in a speech. He later said Brazil has no intention to develop nuclear arms.

Suspicions rose anew after da Silva's science and technology minister, Roberto Amaral, said Brazil would not renounce its knowledge of nuclear fission, the principle behind the atomic bomb. Brazilian officials quickly said Amaral was out of line, and he later resigned.

The da Silva government announced it will expand its uranium enrichment capability not only for its own power plants but also to sell low-enriched uranium for use in energy production in other countries. The program is to begin this year. Only a half-dozen countries now have such a capability...

A separate issue facing Bush is where to draw the line on Brazil and other countries seeking a uranium enrichment capability. Such projects are permitted under the Non-Proliferation Treaty when the purposes are peaceful, but Bush has proposed a change.

Under his plan, announced in a Feb. 11 speech, countries that do not already produce uranium would not be allowed to do so. Rather, they would be provided nuclear fuel at a reasonable cost -- and only if they also agreed to rigorous IAEA inspections.

For governments that already considered the treaty unfair, Bush's proposal seemed only to reaffirm the bias in favor of countries that already possessed atomic technology when the treaty was crafted in the 1960s. Three countries that later built nuclear weapons -- India, Pakistan and Israel -- did not sign.

"We don't like treaties that are discriminatory in their intent," said the Brazilian official, who described Bush's nuclear fuel proposal as "unacceptable to Brazil, precisely because we see ourselves as so strictly committed to nonproliferation, to disarmament, to the peaceful uses of nuclear energy."

Iran has made similar statements, as has North Korea, which U.S. intelligence experts believe has built one or two nuclear weapons. Iran and North Korea had secret enrichment programs, with Iran's hidden for 18 years. North Korea evicted U.N. inspectors and withdrew from the Non-Proliferation Treaty.

In Brazil, by contrast, one U.S. official said, "we don't have any reason to think there are problems." A diplomat in Vienna said: "It's not Iran, it's just not."

Yet permitting Brazil to proceed with the kind of enrichment program that Bush wants to limit, several analysts said, would threaten to weaken efforts to make common rules. Lawrence Scheinman of the Center for Nonproliferation Studies said: "Brazil going forward could give cause to countries like Iran to do the same."

"It makes mincemeat of the president's speech," said Henry Sokolski, director of the Nonproliferation Policy Education Center, a Washington think tank. He noted that Bush said countries must agree to rigorous IAEA inspection to get international help. "It sets a hell of a precedent if they go through with an enrichment facility."