Main points of the nuclear agreement of the 5 + 1 with Iran

The participants at the final stage of the negotiations.

The 5 + 1 (US, Russia, China, France, Great Britain, + Germany) finally, after almost ten years of negotiations reached an agreement with Iran over ways to control Iran's nuclear program. The main issue, the French newspaper Le Monde writes, was to get a mechanism in place that would guarantee that Iran's breakout time, the time it would need to produce enough enriched uranium for the production of an atomic bomb, would be fixed at at least a year. The mechanism will stay in place during the next ten years.
The agreement reached in Vienna will reduce in ten years the number of centrifuges that enrich uranium from 19.000 to 5.060.
Only the oldest models may be used. The ones that are superfluous will be stocked away under seal and under supervision of the International Atomic Agency IAEA at the Natanz facility during a period of 15 years. Natanz is also the only place where in the coming 15 years uranium will be enriched and the grade of enrichment will not exceed 3,67 %. (For an atomic weapon 90% is needed).
The underground site in Fordow will be transformed in a research facility. The 1.044 centrifuges at this place will be placed under seal.
The amount of enriched uranium in Iran's possession will be strictly limited. All uranium that is enriched to a degree that surpasses the 3,67 % must be sent abroad or diluted, with the exception of the uranium already embedded in the system of the research reactor in Tehran. During 15 years Iran is not entitled to have more that 300 kilo's uranium enriched to a degree of 3,67 % on its territory. The surplus has to be exported or diluted.
The agreement also mentions plutonium, the other material that can be used for a bomb. It stipulates that the heavy water installation in Arak will be modified under supervision of the 5 + 1 and the IAEA so as to guarantee that it will not be able anymore to produce  plutonium. The fuel for this installation will sent abroad after it has been used up. Iran will not build any other heavy water installations during the next 15 years.
One sticky point during the negotiations was the issue of inspections. The 5 + 1 got their way on this point. There will be a reinforced system of inspections in place, and the IAEA has even got the right to inspect beyond the duration of the agreement itself:  during the next 20 years it will supervise the centrifuges. And the production of  yellow cake (concentrated uranium) will even be submitted to inspections during the next 25 years. Iran will sign the additional protocol (AP) of the IAEA that permits intrusive inspections, among which under certain conditions, military sites. Also it takes upon itself the obligation to inform the IAEA at least sicx months in advance about any new installation in which uranium is going to be used. Iran has also given the green light to investigate the program it has so far executed
What the Iranians get in return is the gradual lifting of the sanctions. The sanctions applied by the EU and the USA in the domain of finance, energy and transport will be lifted as soon as the IAEA has reported that Iran has executed the agreed measures. That will be,according to the expectations, at the beginning of the year 2016. The same applies to the resolutions that the United Nations adopted against Iran since 2006. 
However, the measures concerning non-proliferation (like the ban on certain imports) contained in these resolutions, will be maintained during ten years, or till the moment that the IAEA has reported that the Iranian nuclear program is exclusively peaceful.However, if Iran violations the terms of the agreement, the sanctions will be re-introduced according to a mechanism that is called « snap back », which will stay in place during ten years.
The sanctions concerning the import of offensive armaments and materials that can be used in ballistic missiles stay in place for a period of eight years, unless otherwise decided by the UN Security Council.  Also the sale or transfer of certain heavy weapons by or to Iran stays prohibited during a period of five years. The UN Security Council might confirm the validity of the agreement in a resolution in the coming week.