DUBAI, United Arab Emirates — Moments after Iran and world powers signed a landmark nuclear deal on Sunday, U.S. Secretary of State John Kerry was already looking ahead to the "even more difficult" efforts to probe Tehran's atomic capabilities and try to ease international concerns that they cannot be diverted for weapons development. Iran's President Hassan Rouhani, meanwhile, said his country is ready to "remove created doubts" about Iran's nuclear program, which Tehran insists is fully peaceful.
Both Kerry's predictions and Rouhani's promises will shape the next six months in the first step of an accord that could help redefine the politics of the region and reset relations between the U.S. and Iran after nearly 35 years of mutual recriminations and suspicions. Tough and expansive U.N. inspections are ahead. Iran also must keep up its end of the bargain with measures such as curbing uranium enrichment and halting work on a new reactor.
Here is a look at the demands, the details and the political ripples from the deal hammered out in Geneva:
IRAN STEPS BACK
From a pure number-crunching standpoint, Iranian compliance would make enrichment levels and stockpiles insufficient to create a nuclear weapon or move quickly toward warhead capacity.
The centerpiece of the agreement is the degree of Iran's uranium enrichment, which is the process of converting concentrated uranium into nuclear fuel.
Iran has pledged to keep its enrichment at no higher than 5 percent. This is well below what's needed for weapons-grade material at more than 90 percent enrichment. It would allow Iran to make fuel for its lone energy-producing reactor, a Russian-built plant in Bushehr on the Persian Gulf coast. But it would keep the levels too low for a weapon or even a fast-track effort at so-called "breakout" toward warhead strength.
Iran already has a significant stockpile of higher-enriched uranium: an estimated 185 kilograms (407 pounds) of 20 percent-enriched uranium. This is the highest level acknowledged by Tehran. The Geneva deal calls for Iran, over the next six months, to either "dilute" the material below 5 percent or have it repurposed into powder — which makes it useable as nuclear fuel but very difficult to be further boosted. In recent years, Iran has repurposed an amount of 20 percent enrichment similar to its current stockpile.
Specialized centrifuges are needed in the enrichment process. The deal blocks the installation of any new centrifuges for the next six months. This means Iran could not significantly accelerate production of even the 5 percent enriched uranium.
Beyond enrichment, Iran also agreed to halt work on a planned heavy water reactor in Arak, about 255 kilometers (152 miles) southwest of Tehran. Heavy water is a compound used to cool nuclear reactors, which do not need enriched uranium to operate. Heavy water reactors also produce a greater amount of plutonium as a byproduct, which could be used to make warhead material. Iran does not currently possess the technology to extract the plutonium, and promised in Geneva not to seek it.
THE UN STEPS IN
Inspectors for the U.N.'s nuclear watchdog agency have made frequent visits to Iranian facilities for years. The Geneva deal gives them faster and broader access as the linchpin of monitoring and enforcement.
Iran agreed to provide "daily access" to International Atomic Energy Agency teams at the two main enrichment sites: Natanz and Fordo. Natanz, about 160 miles (260 kilometers) southeast of Tehran, is the main enrichment facility. Fordo, built into the side of a mountain about 100 kilometers (60 miles) south of Tehran, was disclosed by Iran in 2009. The area is heavily protected by the Revolutionary Guard.
U.N. nuclear inspectors have toured both sites, but the Geneva pact would allow everyday access to review U.N. surveillance video.
The expanded U.N. reach also stretches to centrifuge construction and storage sites, uranium mines and mills and closer scrutiny of all aspects of the planned Arak reactor.
Another important concession by Iran is its pledge to address all concerns in U.N. Security Council resolutions on Tehran's nuclear ambitions. One key site is the Parchin military compound outside Tehran. Parchin has been suspected of housing a secret underground facility used for Iran's nuclear program, a claim denied by Iran. U.N. nuclear inspectors twice visited the site, but seek a third tour.
Before the deal was reached, Iran's president often said settling the nuclear standoff was a "win-win" proposition. In the short-term, it may turn out an easier ride for Rouhani than President Barack Obama, who faces conservative critics calling the deal an appeasement and America's main Mideast ally Israel denouncing it from every angle. A "historic mistake," complained Israel Prime Minister Benjamin Netanyahu.
Rouhani has his own hard-line opposition, which is increasingly uneasy about Iran's outreach to Washington. But Rouhani has the backing of Iran's top authority, Supreme Leader Ayatollah Ali Khamenei, and the deal is likely to elevate his government's image.
That's because Iran did not give up the basic elements of its enrichment program, which is seen as a symbol of Iran's self-promoted image as a technological leader in the Islamic world. Khamenei had set this as a "red line" in the talks. The decision of world powers to allow Iran's enrichment program to continue — while concentrating on output levels — gave Rouhani a major credibility boost at home and permitted the first-step accord to move forward.
CARROTS, STICKS AND SANCTIONS
For the West, the deal does not mark a major roll back of sanctions. Iran still faces widespread blocks from international banking networks and oil sales, which have cut the country's main currency source by more than half.
The deal does, however, offer some sanctions easing on gold and other precious metals, Iran's automobile and aviation industries and petrochemical exports. The world powers at the talks — the five permanent Security Council members plus Germany — further agreed to hold off any new nuclear-related sanctions for at least six months in exchange for Iranian adherence to the deal.
It also opens up $4.2 billion from oil sales to be transferred in installments over the next six months as various compliance stages are reached. That's still a very small sum in a country that was once one of OPEC's top exporters.
The White House estimated the total benefit for Iran at about $7 billion, which was described as a "fraction" of the financial hit from sanctions over the half-year period.
But the deal's first stage appeared structured more with reputation than relief in mind.
If Iran fails to abide by the guidelines, its international profile is left in tatters and chances for further sanctions' easing is lost. It also would likely escalate calls from Israel, Gulf Arab states and elsewhere for possible military action against Iran's nuclear facilities.