VIENNA (Reuters) - Iran has significantly expanded uranium enrichment with almost 5,000 centrifuges now operating and this has made it harder for UN inspectors to keep track of the disputed nuclear activity, an IAEA report has said.
Obtained by Reuters, the restricted International Atomic Energy Agency (IAEA) report said Iran had increased its rate of production of low-enriched uranium (LEU), boosting its stockpile by 500 kilograms to 1,339 kilogram in the past six months.
Iran's improved efficiency in turning out potential nuclear fuel is sure to fan Western fears of the Islamic Republic nearing the ability to make atomic bombs, if it chose to do so.
Oil giant Iran says it wants a uranium-enrichment industry solely to provide an alternative source of electricity.
But it has stonewalled an IAEA investigation into suspected past research into bomb-making, calling U.S. intelligence about it forged, and continues to limit the scope of IAEA inspections.
David Albright of Institute for Science and International Security, a Washington think tank that tracks proliferation issues, said Iran now had accumulated enough LEU to convert into high-enriched uranium (HEU) sufficient for one atom bomb.
This would require reconfiguring Iran's centrifuge network and miniaturising HEU to fit into a warhead -- technical hurdles that could take one to two years or more. "Weaponizing" enrichment would not escape IAEA notice unless done at a secret location.
There are no indications of any such covert diversion.
"[But] Iran could accomplish nuclear weapons 'breakout capability' within 3-6 months at Natanz or a clandestine... facility," Albright said in an email commentary on the report, citing a 20 percent rise in its daily LEU production rate.
"They haven't made a political decision to do that. Whether they [will] is unknown," he told Reuters. "But their lack of constraint is disappointing given [U.S. President Barack] Obama's effort to start negotiations," he said.
The UN nuclear-watchdog report said Iran had 4,920 centrifuges, cylinders that spin at supersonic speed, being fed with uranium hexafluoride gas (UF6) for enrichment nonstop as of May 31, a jump of about 25 percent since February.
Another 2,132 machines were installed and undergoing vacuum tests while a further 169 were being set up -- bringing Iran's total number of deployed centrifuges at its underground Natanz enrichment hall to 7,231 -- with 55,000 eventually planned.
The IAEA had told Iran that given the burgeoning numbers of centrifuges and increased pace of enrichment, "improvements to the containment and surveillance measures are required in order for the agency to continue to fully meet its safeguards objectives," the report said, referring to basic inspections.
Senior inspectors were discussing solutions with Iran.
"There is now a forest of 7,000 machines, that's quite a lot, it's a very impressive place, and they will be installing more which could mean 9,000 [soon]," said a senior UN official who asked for anonymity to discuss sensitive information.
"That makes it increasingly difficult to do the surveillance [to ensure no diversions for bombmaking purposes elsewhere]. We are reviewing [the angles] of our cameras, walking rules [for workers handling equipment], where things are being kept."
At a separate pilot plant in Natanz, Iran continues to test small numbers of a more sophisticated centrifuge than the 1970s vintage it is now using. These models could refine uranium two to three times as fast as the P-1, analysts say.
IAEA chief Mohammed ElBaradei has urged Iran to engage with the United States, "grasp the hand that Obama is extending to you," and negotiate over its nuclear program to ensure it remains civilian under effective monitoring.
But little progress in coaxing Iran to open up to IAEA investigators and grant more wide-ranging inspections is likely without a major thaw in Tehran's relations with Western powers.
"The Iran file has been on the table for six years. It's high time to sort it out. We hope Iran and international community get to the table and start to come up with solutions so we can do our [nonproliferation] job," said the senior UN official.
Obama has set a rough timetable for negotiating results with Iran, saying he wanted serious progress by the end of the year. He has underlined that any U.S. overtures will be accompanied by harsher sanctions if there is no cooperation.