Brazil's new Resende nuclear plant has the potential to produce enough enriched uranium for six nuclear bombs every year, U.S. researchers said Friday. Brazil denied the claim.

The commentary by the Wisconsin Project on Nuclear Arms Control, published in Friday's issue of the journal Science, came three days after U.N. experts visited the plant to resolve a dispute over inspections.

"At its announced capacity, Brazil's new facility located at Resende will have the potential to produce enough uranium to make five to six . . . warheads per year," according to the article by Gary Milhollin, director of the Wisconsin Project, and research associate Liz Palmer.

Brazil has disputed for nearly a year the level of access that U.N. inspectors say they need. The International Atomic Energy Agency, the United Nations' nuclear watchdog, wants full access to Resende to ensure that no uranium is diverted for weapons, but Brazil will not allow complete access to the plant's centrifuges, saying it fears industrial espionage.

The United Nations and the United States have pressed Brazil to resolve the impasse to avoid setting an example for countries, such as Iran and North Korea, that the United States suspects of developing bombs in defiance of the IAEA.

Brazil says that it plans to use its enriched uranium only for energy and that its constitution bans nuclear weapons research.

Milhollin and Palmer said in the journal article that upgrades planned for Resende would raise its capacity to 26 to 31 warheads a year by 2010 and 53 to 63 by 2014.

The Wisconsin Project is a private, nonprofit research organization in Washington, funded by foundations and the U.S. government. It aims to stop the spread of nuclear weapons and operates under the auspices of the University of Wisconsin.