Nuclear Research

Senior Defense Department officials are becoming worried about the safety and reliability of U.S. nuclear weapons under the stewardship of Energy Secretary Hazel O'Leary and are concerned that they soon may be unable to meet the nation's potential military needs.

Iran has made steady progress toward producing nuclear fuel and could make significant quantities of enriched uranium in less than a year, according to new estimates by diplomats, scientists and intelligence officials. Mastering enrichment will move Tehran a big step closer to being able to build an atomic bomb. Iran's progress already has intensified its confrontation with the United States and other countries that fear it is trying to develop nuclear weapons.

European negotiators urged Iran's president-elect Monday to maintain a suspension of uranium enrichment activities, a day after he promised to restart the nation's controversial nuclear program. The call came as two inspectors from the International Atomic Energy Agency arrived in Iran for talks expected to include reports that Tehran worked secretly with plutonium, a possible component of nuclear bombs.

Egypt's nuclear experiments were small, basic and did not appear to be part of an attempt to make weapons, the International Atomic Energy Agency said, praising Cairo's cooperation with an investigation of the country's mothballed clandestine activities. The report, compiled by the Vienna-based International Atomic Energy Agency, made clear that investigations would continue. The atomic research reportedly stretched back four decades and ended as recently as five years ago.

Moscow told Iran it remained ready to build a joint-venture plant to enrich uranium in Russia, just days after a European Union diplomat said Tehran had dismissed the compromise plan at talks in Vienna. The idea, which would allow Tehran to establish a nuclear energy program but transfer enrichment to Russia, is aimed at ending a stalemate between Iran and the West. The West suspects Tehran of seeking to develop nuclear weapons under the cover of producing electricity.

An Iranian diplomat flew to Vienna on Wednesday with a letter for the International Atomic Energy Agency, and a Western diplomat said it was believed to be formal notification that Iran would resume conversion of uranium ore, the first step in a process that can produce reactor fuel or material for bombs.

Iran said Monday that it would resume activities related to uranium enrichment within days, a move the United States and the European Union have warned would lead to the case's being brought before the U.N. Security Council. Mohammed Saeedi, deputy chief of the Iranian Atomic Energy Organization, told a university conference that work would resume at a plant in Isfahan to convert raw uranium into a gas, the official IRNA news agency reported.

Iran is delivering small amounts of uranium gas to centrifuges that can enrich it to weapons-grade level and is running 1,312 of the machines, according to a confidential International Atomic Energy Agency document obtained Wednesday. The document -- a letter to Iranian officials from a senior IAEA staff member -- protests an Iranian decision to prevent inspectors from visiting the country's heavy-water facility, which will produce plutonium.

Iran's president stood at the dais, scolding his nation's enemies. "The army stands against any aggressor and will cut off its hand," Mahmoud Ahmadinejad declared to the television cameras as soldiers and tanks filed by on the avenue before him. The scene at Tehran's Army Day celebration this week was familiar. But the message was ambiguous.

The head of the United Nations nuclear inspection agency warned for the first time Thursday that Iran probably can enrich enough uranium to build a nuclear bomb in three to eight years, a judgment that sparked fresh concerns about Tehran's nuclear ambitions. Mohamed ElBaradei, director of the Vienna-based International Atomic Energy Agency, gave his assessment a day after a strongly worded IAEA report cautioned that Tehran had reduced its cooperation with U.N.