VIENNA -- The U.N. nuclear agency has told member nations that Iran is poised for a major technological upgrade of its uranium enrichment program, in a document seen Thursday by The Associated Press. The move would vastly speed up Tehran's ability to make material that can be used for both reactor fuel and nuclear warheads.
In an internal note to member nations, the International Atomic Energy Agency said it received notice last week from Iran's nuclear agency of plans to install high-technology enriching centrifuges at its main enriching site at Natanz, in central Iran. The machines are estimated to be able to enrich up to five times faster than the present equipment.
The brief note quoted Iran as saying new-generation IR2m "centrifuge machines ... will be used" to populate a new "unit" -- a technical term for an assembly that can consist of as many as 3,132 centrifuges.
It gave no time frame and a senior diplomat familiar with the issue said work had not started, adding it would take weeks, if not months, to have the new machines running once technicians started putting them in. He demanded anonymity because he was not authorized to divulge confidential information.
Phone calls to Ali Asghar Soltanieh, Iran's chief IAEA delegate, for comment went to his voice mail.
Iran insists it does not want nuclear arms and argues it has a right to enrich for a civilian nuclear power program. But suspicion persists that the real aim is nuclear weapons, because Iran hid much of its program until it was revealed from the outside more than a decade ago and because of what the IAEA says are indications that it worked secretly on weapons development.
Defying U.N. Security Council demands that it halt enrichment, Iran has instead expanded it. Experts say Tehran already has enough enriched material for several nuclear weapons.
Nonproliferation expert Mark Fitzpatrick described the planned upgrade as a potential "game-changer."
"If thousands of the more efficient machines are introduced, the timeline for being able to produce a weapons worth of fissile material will significantly shorten," said Fitzpatrick, of the International Institute for Strategic Studies.
"This won't change the several months it would take to make actual weapons out of the fissile material or the two years or more that it would take to be able to mount a nuclear warhead on a missile, so there is no need to start beating the war drums," he said. "But it will certainly escalate concerns".
A Western diplomat accredited to the U.N. agency said IAEA delegation heads from the United States and its allies planned to discuss Iran's plans later in the day. He too demanded anonymity because he was not authorized to talk about the issue.
The planned upgrade deals a further blow to international efforts to coax Tehran to restore confidence in its aims by scaling back its nuclear activities and cooperating with agency attempts to investigate allegations of secret weapons work.
It comes ahead of planned talks next month where the United States, Russia, China, Britain, France and Germany will press Tehran to cut back on enrichment. Separately, IAEA experts are scheduled to visit Tehran Feb. 13 in their more than yearlong effort to restart a probe of the weapons allegations.
Iran says it is enriching only to power reactors and for scientific and medical purposes. But because of its nuclear secrecy, many countries fear that Iran may break out from its present production that is below the weapons-grade threshold and start enriching to levels of over 90 percent, used to arm nuclear weapons.
Tehran now has more than 10,000 centrifuges enriching uranium at its main plant at Natanz, 225 kilometers (140 miles) southeast of Tehran, to fuel grade at below 4 percent. Its separate Fordo facility, southwest of Tehran, has close to 3,000 centrifuges -- most of them active and producing material enriched to 20 percent, which can be turned into weapons-grade uranium much more quickly.
Iran has depended on domestically made and breakdown-prone IR-1 centrifuges whose design is decades old at both locations up to now, but started testing more sophisticated prototypes in the summer of 2010.
David Albright, whose Washington-based Institute for Science and International Technology serves as a resource for some U.S. government branches, estimated in a 2011 report that 1,000 of the advanced machines "would be equivalent to about 4,000-5,000 IR-1 centrifuges" in production speed.