President Obama’s decision to permit Iran a “limited capacity” for enrichment meant the abandonment of his stated goal of denying Iran the capability to build a nuclear weapon. In its place, according to Secretary Kerry, the United States would seek the much more limited objective of strict limits on the numbers and types of centrifuges that would extend the time of breakout for Iran to acquire a nuclear weapon from two months to six–twelve months. But this new goal would be hard to enforce in practice — as it has been hard even to agree on the details of the agreement ahead of implementation.
The goal is unenforceable because the administration has never explained how the United States, the IAEA, or others would be able to detect with confidence any covert cheating that would erode the six-to-twelve-month barrier to breakout or, even if cheating were detected early, what we could do diplomatically in that period to stop Iran from moving forward. Experience has taught us that Iran is very adept at deception and denial and that the international community is both slow and reluctant to take firm action. In some cases, it has taken years to detect Iran’s violations of its safeguard agreements and additional years before the Security Council acted.
The revised goal has also proven to be unachievable in the negotiations. Abandoning the position of “no enrichment” was a huge concession made to secure an agreement. In fact, it served to complicate the negotiations by opening up many more questions than it resolved: What number of centrifuges would ultimately be agreed to? What about restrictions on replacing current-generation centrifuges with much more efficient models? What about restrictions on research and development of follow-on generations? What restrictions will prevent materials and equipment imported and manufactured by Iran from being used in a covert program, rather than the declared facilities? And, of course, how long will Iran be bound by the provisions? Not one of these issues has apparently been agreed upon in the talks. As for those issues on which administration officials have claimed progress, such as the Arak reactor, Iran has publicly denied any agreement on any issue.
Regarding the number of centrifuges to be allowed, the initial U.S. position reportedly was a ceiling of 1,000, but that quickly was raised to 6,000. If accurate, 6,000 centrifuges would probably position Iran for breakout in fewer than six months, because Iran has been permitted to undertake a number of “routine maintenance” procedures since the signing of the interim agreement that improved the efficiency of some of its centrifuges by as much as 25 percent. Presumably, this “maintenance” will be allowed to continue under any future agreement.
To break the impasse over centrifuges, the negotiators reportedly are considering a different metric to limit Iran’s uranium-enrichment capability: separative work units, or SWU, as the concept is known. SWU can be used to measure either the capacity of the enrichment process or the actual amount of enriched uranium produced. If SWU is used for the former, the calculation is based primarily on the number, efficiency, and configuration of the centrifuges in operation. This would require the parties to agree to a specific number of centrifuges and, therefore, would not break the negotiation logjam.
If, on the other hand, production is limited to a specified SWU level, the calculation is affected by other factors, including the amount of feedstock, the rate of spin, and the length of time that the centrifuges operate. Any of these, along with the number of centrifuges, can be altered while remaining under the permissible SWU level. Moving to this more complex and malleable SWU yardstick might be seen as a way forward, but only for those willing to accept a bad agreement.
On the surface, SWU provides a politically defensible means to measure output for enrichment. It is a unit of calculation used widely in the nuclear-energy industry, as well as by the IAEA in its quarterly reports on Iran’s nuclear program. But using SWU as a substitute for limiting the number of centrifuges is nothing more than sleight of hand. While it is necessary for any agreement to limit how much enriched material Iran can produce and stockpile, this is not the stated U.S. goal. That goal — to extend the time of breakout — requires strict and verifiable limits on centrifuges along with additional prohibitions on next-generation replacements and effective constraints on maintenance, research, and development.
Iran appears ready to take some steps that give the appearance of compromise, such as agreeing not to build a building for uranium conversion that doesn’t need to be built. It also seems willing to accept a limit on production of enriched material measured by SWU, although at a very high level. The motive is clear: Using SWU, instead of a low limit on centrifuge numbers, as the measure of production could permit Tehran to install any number of centrifuge cascades, including advanced models. Iran could, for example, operate multiple cascades for short periods of time and thereby stay within the permitted SWU limit. While operationally inefficient, this would permit Tehran to maintain a reserve capacity to enrich uranium far in excess of that suggested by the SWU allowance. Thus, when a decision is made to break out, there would be thousands of centrifuges ready to produce an abundance of material at a high level of enrichment in a short period of time.
Using SWU in this manner would make an agreement much more achievable as it would render moot the key differences not only on the number of centrifuges, but on next-generation replacements and on research and development. But the price tag is giving Iran what the Supreme Leader has always insisted on: a nuclear program that could quickly provide the regime with nuclear weapons.
It seems from the concessions made to date that the P5+1 negotiators might have already concluded that the choice before them is either a bad agreement that’s consistent with the Supreme Leader’s dictates or no agreement at all. If a limit on SWU is adopted in place of a limit on centrifuges, it would confirm that the P5+1 has chosen the former. It would mean the failure of even the limited goal of extending the time of breakout.
Moving away from a centrifuge limit to the SWU metric would represent the next step to a failed outcome. But whether SWU is adopted or not, if there are no restrictions on missiles, no effective constraints on R&D, only managed access on inspections, no tight controls on imports and manufacture of equipment, and other gaps that Iran can and will exploit (such as failing to come clean on past weaponization activities), the agreement will allow Iran to remain what it is today: a nuclear-weapons-threshold state. The result, as predicted by Secretary Clinton, will be a nuclear arms race in the region. Perhaps if diplomacy were practiced differently than it has been in Syria, in Ukraine, in the Iran negotiations, and elsewhere, there would be a greater chance of its success.
— Robert Joseph is a former undersecretary of state for arms control and international security.