By Fredrik Dahl
GENEVA (Reuters) - The U.N. nuclear watchdog is to play a major role in verifying the implementation of a landmark deal to curb Iran's atomic activities that negotiators for Tehran and six major powers reached in Geneva on Sunday.
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) will be crucial in ensuring that Iran fulfils its end of the agreement.
Under the interim accord designed to pave the way for talks on a final settlement of the decade-old dispute, Iran will halt its most sensitive enrichment of uranium, stop expanding other nuclear activity and agree to more intrusive U.N. surveillance.
It remains to be seen how Iran carries out these steps: Western diplomats have often accused it in the past of stonewalling the Vienna-based IAEA to buy time for its nuclear program, especially regarding a long-stalled investigation into suspected atomic bomb research by Tehran.
This time, however, any lack of compliance could jeopardize the rewards for Tehran under the agreement in terms of sanctions easing for its ailing economy. The West has made it clear that the limited sanctions relief on offer can be reversed.
"Iran has agreed to submit its program to unprecedented monitoring," U.S. Secretary of State John Kerry said. "For the international community, this first step will provide the most far-reaching insight and view of Iran's nuclear program that the international community has ever had."
IAEA Director General Yukiya Amano called the agreement struck in Geneva an important step forward.
Amano's 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 planned involvement in Iran under the deal to start resolving the standoff over a nuclear project Tehran says is peaceful but the West fears may be aimed at building bomb making capability. Some terms of the deal are taken from a U.S. fact sheet as the official text itself has yet to be published.
WHAT DOES THE IAEA DO IN IRAN TODAY?
* In its latest quarterly report on Iran issued in mid-November, the IAEA said it is able to verify that Iran's declared nuclear material is not being diverted, but its inspectors are in no position to provide "credible assurance" that Iran is not conducting other activity it has not declared.
* The IAEA already 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," Amano told Reuters in a November 13 interview.
* Roughly 20 IAEA staff are believed to travel to Iran regularly, with a much larger number of people included on a list of designated inspectors for the country. Amano said his staff could handle a bigger workload if needed. "We can mobilize the existing staff. We have very capable inspectors with good knowledge of the nuclear fuel cycle."
* The IAEA's anti-proliferation inspectors have access to 17 declared nuclear sites, as well as nine other locations where nuclear material is usually stored. Inspectors are believed to go to Iran's most disputed sites, the underground uranium enrichment facilities at Natanz and Fordow, about once a week, and visit the other sites less often.
* 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 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 a lifting of sanctions on the major OPEC country.
* Iran agreed this month to grant the IAEA access to a uranium mine and another nuclear-related site as part of a deal meant to resolve outstanding issues between them. This is separate from the latest deal with the great powers.
HOW WOULD IAEA'S ROLE EXPAND UNDER THE NEW DEAL?
* Iran has now agreed to give IAEA inspectors daily access to Natanz and Fordow: "This daily access will permit inspectors to review surveillance camera footage to ensure comprehensive monitoring," the U.S. fact sheet said.
* Iran has agreed to limit production of centrifuges used to refine uranium. To monitor this, the U.N. nuclear agency will gain access to centrifuge assembly facilities and centrifuge rotor component production and storage facilities. It will also inspect uranium mines and mills.
* Apart from uranium, a nuclear bomb can also be derived from plutonium, which could one day be produced at Arak, a heavy-water reactor Iran is building. According to the fact sheet, Iran has committed to halting advances of its activities there. Inspectors will be able to visit the site more often.
* The six powers and Iran have further agreed to establish a joint commission to work with the IAEA to monitor implementation of the agreement.
"This will require a level of cooperation and information sharing between the IAEA, the powers and Iran which is probably unprecedented concerning one country's nuclear program," said Mark Hibbs of the Carnegie Endowment think-tank.
"Until now, the information-sharing has been strictly between Iran and the IAEA."
WHAT MORE 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 confirm 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 giving it greater inspection authority, which Iran signed in 2003 but renounced in 2006 as tensions with the West worsened. The protocol gives inspectors access to all relevant facilities, including those where nuclear material is not customarily used.
"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.
WOULD INSPECTORS DETECT ANY BOMB BREAKOUT BID?
* The new agreement is designed to lengthen the timeline required for any nuclear weapons "breakout" by Tehran, so that the powers would have warning if Tehran should seek an atomic bomb.
* The Institute for Science and International Security (ISIS) think-tank 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 around 30-50 days. It said on Sunday the agreement would lengthen that time.
* Proliferation expert Mark Fitzpatrick of the International Institute for Strategic Studies (IISS) in London said the deal "significantly sets back" Iran's ability to produce a nuclear weapon without being detected and stopped.
"Just a few weeks ago analysts were projecting that by next summer Iran might be able to produce a weapon's worth of uranium within a week or so," Fitzpatrick said. "Now it will be months. Yes, enrichment will continue - that was inevitable - but it will be more tightly inspected."
(Editing by Mark Heinrich)
(This Factbox was refiled to testore dropped word "relief" in the fifth paragraph)