VIENNA (Reuters) - Iran's launch of uranium enrichment in an underground bunker, defying the United Nations, is a test-scale operation not producing nuclear fuel in meaningful amounts, diplomats said on Thursday.
They said Iran remains well short of the ``industrial-scale'' capacity to refine uranium it announced on April 9.
Iran has been upping the ante in a standoff with the
Iran, the world's fourth largest oil exporter, says it wants the fuel for generating electricity and to allow it to export more of its valuable oil and gas.
Iran has doubled the number of operating centrifuges in recent weeks in its new Natanz plant. But it has not shown it can run them nonstop for extended periods, the key to enriching enough uranium for electricity or the core of an atom bomb.
A note by the International Atomic Energy Agency's chief inspector obtained by Reuters said Iran has begun feeding ``UF6'' uranium gas into centrifuges in the vast Natanz bunker.
Iran, brushing aside two sets of U.N. sanctions slapped on it since December, had started up more than 1,300 centrifuges in an accelerating campaign to lay a foundation for ``industrial scale'' enrichment involving more than 50,000, the note said.
But diplomats familiar with the IAEA's findings in Natanz characterized Iran's activity as test-scale.
``The current feeding is at a very, very low level, only to condition the new centrifuges. No enriched product is being made now,'' said a Vienna-based diplomat close to the IAEA.
Another diplomat accredited to the agency said: ``It's not productive activity. We understand that they are just doing stress tests on the cascades to see if they will run smoothly.''
PROGRESS NOT DECISIVE
Responding to the IAEA report, the U.S. warned on Wednesday that Iran could face further U.S. sanctions if it continued to defy the U.N.
The Institute for Science and International Security (ISIS), a Washington think-tank that closely tracks Iran cautioned that Tehran's nuclear progress was not yet decisive.
``The quantity of UF6 (uranium feedstock) introduced at this time is small and the cascades are operating under low pressure, indicating that Iran is at an early stage of enrichment in the cascades,'' ISIS said in an email reacting to the IAEA note.
Iran aims to have 3,000 centrifuges running at Natanz by the end of May. That could be enough to refine uranium for one bomb within a year, if the machines ran for long periods.
But an above-ground, research facility at Natanz was dogged by glitches with a number of centrifuges overheating or exploding in experimental runs over the past year.
Centrifuges, tubular devices that are tricky to calibrate, spin at supersonic speed to refine fuel for power plants or, if it is enriched to high levels, nuclear explosives.
Many observers believe Iran is playing up its progress in the main underground plant for political reasons before it has genuinely mastered enrichment technology.
``Tehran is trying to say they can do it, crossing a certain threshold. It's more a political message than a technical achievement, to raise the price the big powers will have to pay in any future negotiations,'' said one senior diplomat.
The IAEA note said Tehran had agreed after months of haggling to allow ``a combination of unannounced inspections and containment and surveillance measures'' to improve transparency at Natanz. It urged Iran to honor the deal.