IRAN’S NUKESIranian Breakout Timelines Under JCPOA-Type Limits
The 2015 nuclear deal (JCPOA) made it impossible for Iran, if it withdrew from the deal, to produce enough weapon-grade uranium (WGU) for a nuclear weapon in less than 12 months. The U.S unilateral withdrawal from JCPOA in 2018 has changed the situation so fundamentally in favor of Iran and its nuclear weapons program, that new limits are needed, the most important of which is that Iran destroy centrifuges and related equipment, rather than store them. A focus on only limiting enriched uranium stocks will not provide sufficient breakout timelines.
Breakout timelines were fundamental to negotiating the Joint Comprehensive Plan of Action (JCPOA). The United States insisted on setting limits on Iran’s centrifuge program that, if reversed, would require 12 months to produce enough weapon-grade uranium (WGU) for a nuclear weapon. Re-imposing those same limits today could not achieve a 12-month breakout timeline, only about a four-to-five-month timeline. Worse, in subsequent months, Iran could more rapidly accumulate significant quantities of WGU than under the original deal.
The situation has changed so fundamentally that new limits are needed, the most important of which is that Iran destroy centrifuges and related equipment, rather than store them. A focus on only limiting enriched uranium stocks will not provide sufficient breakout timelines. Even proposals that essentially eliminate all stocks of enriched uranium would lead to breakout timelines that are just too short to provide a worthwhile agreement. A proposal only eliminating Iran’s 20 and 60 percent uranium stocks is essentially worthless.
Re-imposing the JCPOA’s Initial Enrichment Limits
The key JCPOA limits on Iran’s gas centrifuges that extended the breakout timeline during the first ten years of JCPOA implementation were:
· No enrichment above 3.67 percent
· A total enriched uranium stockpile of no more than 300 kg of up to 3.67% enriched uranium hexafluoride (or the equivalent in different chemical forms) (202.8 kg, uranium mass)
· An active enrichment output that was limited by the numbers and type of installed centrifuges: 5060 IR-1 centrifuges at the Natanz Fuel Enrichment Plant and 1044 non-enriching IR-1 centrifuges at Fordow. This limitation translates into a capacity of about 5000 separative work units (swu) per year.
· Centrifuge cascades above this limit at the time of agreement were dismantled and stored under monitoring.
· Manufacturing of new centrifuge rotor assemblies capped at no more than several tens of centrifuges per year. 1
At the time of the negotiation of the JCPOA, the vast bulk of centrifuges were relatively poorly performing IR-1 centrifuges, with about 1000 more advanced IR-2m centrifuges in six cascades.
