The agreement tabled by Iran in its negotiations with the European Union (EU) falls far short of a permanent suspension of the gas centrifuge program, and would allow Iran to move significantly closer to a large uranium enrichment capability.
In their proposal, Iran offers a deal that involves installing 3,000 gas centrifuges at Natanz, which would give Iran a significant uranium enrichment capability. Because the installation of 3,000 centrifuges is far too large for the pilot plant, it would likely involve installing gas centrifuges in the large underground cascade halls for the first time. Subsequent phases of the proposed deal would involve the commissioning of the 3,000 centrifuges and the installation and commissioning of thousands more centrifuges at the underground site. For a newly annotated image of the Natanz site showing the location of the underground cascade halls, click here.
Iran has pledged that the installed centrifuges would be solely dedicated to making low enriched uranium (LEU) for nuclear reactor fuel. The 3,000 centrifuges would be sufficient to produce about 2-3 tonnes of LEU per year, but this is far less than the 25 tonnes of LEU that will be required annually for the nuclear power reactor under construction at Bushehr.
LEU cannot be used directly to make nuclear weapons, however Iran could decide in the future to use these same centrifuges to quickly make highly enriched uranium (HEU) for nuclear weapons. As long as international safeguards are in place, the International Atomic Energy Agency (IAEA) would know if such an increase in enrichment level occurs but would not be able to prevent it. The 3,000 centrifuges would be able to produce enough HEU for about 2-3 nuclear weapons per year.
The 3,000 proposed centrifuges are identical to the number of machines in a "block" of the underground enrichment plant designed to hold 50,000 centrifuges. A block is a predetermined module which is designed to be the basic unit of the full-scale fuel enrichment plant. If Iran is able to operate one complete block of centrifuges, they would gain the expertise in centrifuge installation and operation that they have not yet been able to acquire, and which is a necessary hurdle to overcome in order to operate the complete, 50,000 machine uranium enrichment plant that Iran plans to complete.
This offer from Iran would also mean that Iran would have to resume operations at the uranium conversion facility to produce uranium hexafluoride (UF6), the feed material that flows through the centrifuges in the enrichment process.
The deal proposed by Iran is not adequate to end the threat posed by the Iranian uranium enrichment program. The fundamental goal of the negotiations between the EU and Iran remains the permanent suspension of Iran's uranium enrichment program, while facilitating Iran's access to nuclear power and a guaranteed fuel supply. Iran must understand that the likely alternative to reaching agreement is for the issue to be referred to the UN Security Council. Given Iran's past violations of its IAEA safeguards agreements, and strong suspicions that it seeks nuclear weapons, the European Union negotiators are right to pursue a better deal than the one offered by Iran.