Last week, the United States uttered the clearest statement so far of its aims for a nuclear deal with Iran.  In an interview on October 30, U.S. Secretary of State John Kerry specified what he saw as “four present pathways to a bomb for Iran – the hidden so-called secret facility in a mountain called Fordow, the open Natanz enrichment facility, the plutonium heavy-water reactor called Arak, and then, of course, covert activities.”  Kerry said “our goal is to shut off each pathway sufficient that we know we have a breakout time of a minimum of a year [...]”

If any final deal emerges from the present talks, these four criteria will probably be used to judge it.  Clearing three of the four hurdles will be difficult. 

The first two, which are concerned with uranium enrichment, have attracted the most attention.  At issue for both Natanz and Fordow is the number and type of centrifuge Iran will be allowed to operate.  To have a year’s breakout time (that is, to make it impossible for Iran to fuel a bomb in less than a year) there could not be many.  The United States reportedly had been seeking 1,300 first-generation centrifuges, while Iran insisted on maintaining at least the roughly 9,000 currently operating.  More recently, the number 4,000 has been mentioned.  Unfortunately, 4,000 first-generation  centrifuges could theoretically produce a bomb’s worth of weapon grade uranium in less than six months, assuming Iran fed the centrifuges with the low-enriched uranium gas it has already produced.  To prevent that, Iran would have to get rid of most of the low-enriched gas it has on hand, and keep its overall stockpile small.  In this case, Iran would be left with natural uranium gas to feed the centrifuges.  Only then would the 4,000 centrifuges need more than a year to fuel a bomb.  Any final deal would probably have to cut the number of operating centrifuges below 4,000, or cut the supply of low-enriched uranium gas, or both. 

In his Washington Post column on October 30, David Ignatius wrote that such a compromise is under discussion, with the United States reportedly ready to accept a cap of 4,000 centrifuges alongside “a few hundred” kilograms of low enriched uranium gas.

The fourth criterion too seems a high hurdle.  To shut off the pathway of “covert activities,” that is, to ensure that Iran is not building a “bomb in the basement,” Iran would have to explain its suspicious research in the past – research that appears to be for the components of an actual atomic bomb.  Iran also would have to be more transparent with nuclear inspections by the International Atomic Energy Agency.  So far, neither has been the case.  The IAEA’s investigation of “possible military dimensions” to Iran’s nuclear work made no progress until last November, and only limited progress since then, with a drop off since August, according to IAEA Director General Yukiya Amano.  Speaking at the Brookings Institution on October 31, Director General Amano called the allegations of weapon work “broadly credible” and said that “Iran has a case to answer.”

This failure to cooperate leaves the world uncertain about how soon Iran might be able to field a weapon.  It also raises the question of how much “covert activity” Iran still might be hiding.  A final deal would have to furnish assurance on these points.

According to Reuters, Secretary Kerry will meet Iran’s foreign minister in Oman on November 9-10 to continue searching for a deal.  That meeting will be followed by others with all the negotiating parties in advance of November 24, when the talks are due to end.