Iran said to test advanced centrifuges with gas

VIENNA (Reuters) - Iran has introduced small amounts ofuranium gas into advanced centrifuges it is testing at its mainnuclear complex, diplomats said, in a further step towardsgaining the means to develop atom bombs if it chooses.

A European Union diplomat said the move was a "stunningrejection" of repeated U.N. Security Council demands that Iransuspend sensitive nuclear activity, and could hasten passage ofbroader sanctions drafted by six world powers.

Iran says it wants to enrich uranium only to produceelectricity so that it can export more oil. But it is undersanctions for hiding the programme until 2003, preventing U.N.inspectors since then from verifying it is wholly peaceful, andrefusing to suspend it.

Diplomats familiar with U.N. nuclear watchdog inspectionsdisclosed last week that Iran had begun "dry runs", withoutnuclear material, of a more efficient, durable centrifuge toreplace an erratic old model it now uses to enrich uranium.

They said Iran had now begun test-feeding token quantitiesof uranium "UF6" gas into a few of the "new generation"centrifuges in the pilot wing of the Natanz enrichment complex.No further details were immediately available.

International Atomic Energy Agency officials had nocomment, saying details would come in a report IAEA DirectorMohamed ElBaradei will deliver to the Vienna-based agency's35-nation Board of Governors and the U.N. Security Council nextweek.

The "IR-2" centrifuge, an adaptation of a Pakistani modelwhose design Iran obtained in the 1990s from the A.Q. Khannuclear smuggling network, could refine uranium 2-3 times asfast as the antiquated model Iran has used to date.

START-UP DIFFICULTIES

Tehran's quest to produce usable amounts of nuclear fuelhas been hampered by problems getting its existing "P-1" lineof centrifuges to spin non-stop at maximum speed. Iran had3,000 P-1s working by November, a basis for launchingindustrial-scale enrichment, but only at an estimated 10percent of capacity.

Three thousand P-1s could yield enough highly enricheduranium for one bomb in about a year if run at full capacity,but it would take only 1,200 of the IR2s to do so, U.S. nuclearanalyst David Albright said in a commentary last week.

Diplomats tracking the IAEA's Iran file said last week thatIran had decided to install no more P-1s in Natanz's vastunderground production hall and to expand capacity using onlytheir more advanced successor.

Iran revealed in 2006 that it was developing supposedlystate-of-the-art centrifuges at workshops put off-limits toIAEA inspectors in retaliation for steps by Western powers toimpose initial sanctions on Tehran.

The IAEA got a first, one-off look at the advancedcentrifuge effort when Iran allowed ElBaradei to visit aworkshop in Tehran last month in a gesture of transparency,diplomats close to the Vienna-based U.N. watchdog said.

A U.S. National Intelligence Estimate (NIE) said inDecember that Iran stopped trying to devise a nuclear warheadin 2003, shortly after Iranian exiles exposed secret enrichmentactivity.

But the NIE also said Iran would gradually acquire thelatent ability to assemble nuclear weapons through itsconsiderable expansion of enrichment infrastructure since then.

(Editing by Tim Pearce)