Sanctions
Iran wanted immediate removal of all UN sanctions and relief from the American and European economic and financial curbs that have throttled its economy. In the event the deal lifts all economic and financial sanctions against Iran - but only after it has been shown to have complied with its obligations on reducing centrifuges and uranium stockpiles. That process is likely to take six months to a year, according to John Kerry, the US secretary of state; waiting until 2016 for tangible economic benefits may seem too long for some in Tehran.
UN resolutions against Iran will eventually be lifted in unison once Iran has addressed “all key concerns”, including potential military dimensions to its programme, a process that could take years. Even then restrictions on access to sensitive technologies and ballistic missiles will be maintained in a new resolution.
Some measures to monitor and assess compliance - and handle disputes - are sketched out but key details remain unresolved. Judging what "compliance" entails will be highly contentious. Should there be a violation, sanctions are restored through a "snap back" mechanism. That is easy enough for US sanctions, but diplomats have struggled to design a mechanism for reimposing UN sanctions that would be immune from political vetoes from Russia or China.
Uranium enrichment
Debate about the deal has often focused on one issue: how many centrifuges will Iran keep. Iran currently has 19,000 centrifuges and wanted to keep them all. The US initially said it would accept only 1,000-2,000. In the end, the agreement allows Iran to use 5,060 of its oldest centrifuges over the next decade to enrich uranium. In addition, Iran will only be permitted to enrich uranium to 3.67 per cent, well below the level needed for a weapon, according to the US.
Iran also appeared to give more on the issue of Fordow, the underground enrichment facility carved into a mountain. Fordow will not be destroyed, as some had urged, but it will not be used to enrich uranium during the life of the deal. An AP report earlier in the week said that centrifuges at Fordow would be fed other elements, such as germanium, which could produce material used in medicine. James Acton, a nuclear expert at the Carnegie Endowment, said it would be difficult to later convert the same machines back to enrich uranium.
The big questions in the US and Israel will be about how quickly Iran could start to rebuild its nuclear infrastructure if it complies with the terms of an agreement. The general restrictions on enriching uranium last for 10 years, while on Fordow they last for 15 years. Strict limits on enrichment research will be phased out after 10 years according to an unspecified plan.
Plutonium
Diplomats long feared that Iran’s Arak heavy water research reactor would be used to produce enough plutonium for a nuclear bomb, creating another route to a weapon. Under the deal, Iran promised not to use the facility for weapons-grade plutonium production - a pledge it backs up by removing from the country or destroying the original core of the reactor. Such a significant change would take years to reverse. Any heavy water beyond the needs of the reactor will be sold on the international market for the next 15 years. Iran also promises not to build any additional heavy water reactors through that period.
Inspections
Under the agreement, international inspectors will have access to the complete supply chain of Iran's nuclear complex - not just the facilities that enrich uranium, but also the uranium mines, the plants that produce centrifuge machinery and its storage facilities. The inspection regime will last from between 20 to 25 years. In addition, Iran has agreed to sign the Additional Protocol of the International Atomic Energy Agency, which grants inspectors access to declared and undeclared sites.
However, the access that inspectors will have to Iranian facilities that have conducted research on the military applications of nuclear research remains unclear from the announcements so far, although the US said that UN nuclear sanctions on Iran would only be lifted once Tehran had addressed questions about the research.
What is left to be decided?
As the parties delve into the fine-print, the remaining technical issues could still be deal-breakers. The conditions and timing for removing sanctions remain a potential stumbling block. Judging from the vague answers about the treatment of Iran's stockpile of enriched uranium, it appears that there is still considerable disagreement about the way that it will be reduced. Big questions also remain about Iranian weapons research. The biggest potential obstacles, however, are domestic politics in Washington and Tehran, where Congress or Iranian hardliners could yet find ways to block the diplomacy.
Geoff Dyer in Washington and Alex Barker in Lausanne
The Financial Times Limited 2015.