IAEA cites advances in Iran nuclear program

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.

Enriched uranium and plutonium both can be used for the fissile cores of nuclear warheads.

The letter, signed by IAEA Deputy Director General Olli Heinonen and dated April 18, says Iran has provided information to the agency that it has put the centrifuges into operation.

The letter also cites Iranian information to the agency that “some UF6 is being fed” into the centrifuges at the underground Natanz facility, referring to the uranium gas.

Iran says it wants to enrich uranium only to lower levels suitable for generating electricity. But suspicions about its intentions have led to demands that it freeze its enrichment program. Its refusal has resulted in U.N. Security Council sanctions.

Last week, Iran said it had begun operating 3,000 centrifuges at Natanz -- nearly 10 times the previously known number. The United States, Britain, France and others criticized the announcement, but experts -- and several world powers -- expressed skepticism of the claims.

Still, the IAEA letter reflects a swift advance in the program. A little more than two weeks ago, diplomats had said Tehran was running slightly more than 600 centrifuges and had not introduced uranium gas into them.

A diplomat accredited to the IAEA, who demanded anonymity, said the new operation appeared to be geared to preparing the centrifuges for producing enriched uranium and was not yet part of the direct process, although traces of low-enriched uranium were being produced.