By Fredrik Dahl
VIENNA (Reuters) - The U.N. nuclear watchdog says it is prepared to verify the implementation of any agreement to curb Iran's atomic activities that negotiators for Tehran and six major powers may reach in Geneva this week.
Iran and the United States, Russia, China, France, Britain and Germany are due to resume negotiations in the Swiss city on Wednesday with officials signalling that a breakthrough is within reach after years of deadlock.
With inspectors present in Iran virtually around the clock - in effect the outside world's eyes on the ground - the International Atomic Energy Agency (IAEA) would have a crucial role in ensuring that Iran fulfils its end of such a deal.
The powers want Iran to halt its most sensitive nuclear fuel-making activity and take other measures - for example, permitting more inspections - as part of an interim confidence-building accord that would buy time for talks on a more far-reaching settlement of the decade-old dispute.
If "we are requested to implement some verification measures, we are prepared to implement them," IAEA Director General Yukiya Amano said.
His inspectors regularly visit Iran's declared nuclear facilities to check that no material there is diverted for military uses. But Iran has so far not granted them the more far-reaching, unfettered access they say is needed to provide assurances that it does not have any secret nuclear activity.
Following is an overview of the IAEA's current and potential future involvement in Iran if the Islamic Republic and the powers agree on how to start resolving the impasse over its nuclear project - which Tehran says is peaceful but the West fears may be aimed at developing a warhead capability.
WHAT DOES THE IAEA DO IN IRAN TODAY?
The IAEA's anti-proliferation inspectors currently may visit 17 declared nuclear sites, as well as nine so-called "locations outside facilities" where nuclear material is usually stored.
Inspectors are believed to visit Iran's most disputed sites - the underground enrichment plants at Natanz and Fordow - about once a week, but the others less often. Refined uranium can, if processed to 90 percent of fissile purity, provide the core of an atomic bomb. Western experts say Iran could draw on uranium enriched at Natanz or Fordow if it opted to produce nuclear weapons. Iran says that it refines uranium only to fuel a planned network of nuclear power plants.
In its latest quarterly report on Iran issued in mid-November, the IAEA said it "continues to verify the non-diversion" of declared nuclear material. But, it again underlined, inspectors were in no position to provide "credible assurance" about the absence of undeclared nuclear activity.
Amano told Reuters in a November 13 interview that the IAEA has staff in Iran virtually every day of the year. "We do not have inspectors permanently stationed in Iran. But as they have many facilities, in reality we have one or two inspectors on the ground all the time," the veteran Japanese diplomat said.
Despite often strained ties between the IAEA and Iran in the past, agency officials say these regular inspections are usually conducted smoothly and with good cooperation by Tehran.
Relations seem to have improved since the election of a relative moderate, Hassan Rouhani, as Iranian president in June on a platform to try to defuse the nuclear stalemate and secure an easing of sanctions on the major oil producer.
Iran agreed this month to grant the IAEA access to a uranium mine and another nuclear-related site as part of an agreement meant to resolving outstanding issues between them, including suspicions that Iran has researched how to make an atomic bomb, a charge it denies.
WHAT WOULD THE IAEA WANT TO DO?
The agency says it needs to be able to carry out snap - or short-notice - inspections beyond declared sites to verify that Iran is not hiding any work with weapons applications.
As part of any final settlement, the powers would almost certainly demand that Iran observe the IAEA's Additional Protocol endowing it with wider inspection authority.
The Additional Protocol grants broader access to all relevant facilities, including those where nuclear material is not customarily used. Iran signed it in late 2003 and implemented it provisionally until 2006. Iran renounced the protocol that year after the IAEA's 35-nation Board of Governors reported Tehran to the U.N. Security Council.
"The agency will not be in a position to provide credible assurance about the absence of undeclared nuclear material and activities in Iran unless and until Iran provides the necessary cooperation with the agency, including by implementing its Additional Protocol," the IAEA's latest report said.
At present, roughly 20 IAEA staff are believed to travel to Iran regularly, even though the number of people on an agreed list of designated inspectors for the country is much higher.
Amano suggested the IAEA, in the short run at least, would be able to cope with an increased workload in verifying a nuclear agreement: "We can mobilise the existing staff. We have very capable inspectors with good knowledge of the nuclear fuel cycle."
WOULD INSPECTORS DETECT ANY BOMB BREAKOUT BID?
IAEA officials voice confidence that they are inspecting Iranian nuclear facilities often enough to spot any attempt to divert any material there for nuclear arms.
"As far as declared facilities are concerned we have the capacity to detect any change in a timely manner," Amano said.
But a U.S. think-tank said Iran should be pressed to increase the frequency of inspections of its enrichment plants.
The Institute for Science and International Security (ISIS) argued in a report last month that the time Iran would need to make enough weapons-grade uranium for one bomb has steadily shortened, to as little as 1-1.6 months.
ISIS has estimated that if Iran expanded its enrichment plants it could reach "critical capability" in 2014 - being able to produce highly-enriched uranium for a weapon so fast that the IAEA may not notice before it was a fait accompli.
However, any deal between Iran and the powers would likely be designed to lengthen the timeline required for any nuclear weapons breakout by Tehran. The IAEA's latest report showed that Iran had stopped expanding its nuclear programme since Rouhani took office in early August.
Apart from more inspections and implementation of the Additional Protocol, Iran should allow the IAEA to install remote camera monitoring of its enrichment plants and provide early notification of plans to build nuclear sites, ISIS said.
(Editing by Mark Heinrich)