The Biden administration expects a restored nuclear deal would leave Iran capable of amassing enough nuclear fuel for a bomb in significantly less than a year, a shorter time frame than the one that underpinned the 2015 agreement, U.S. officials familiar with the matter said.
Administration officials concluded late last year that Iran’s nuclear program had advanced too far to re-create the roughly 12-month so-called breakout period of the 2015 pact, the U.S. officials said.
Despite the change, the U.S. is pushing ahead with talks. A revised deal needs to be reached soon, the officials said, to leave the U.S. and its allies with enough time to respond to an Iranian nuclear buildup.
How limited that breakout period will depend on the precise steps Iran agrees to take to dismantle, ship abroad, destroy or place under seal its stockpile of enriched uranium, machines for producing nuclear fuel and centrifuge manufacturing capacity
Reducing the breakout time in any revised pact raises fresh doubts about the Biden administration’s ability to negotiate what U.S. officials have called a longer, stronger deal that would further restrain Iran’s pathway to nuclear weapons and gain political support in Washington and among European allies.
U.S. officials have said Washington would lift the bulk of the sanctions imposed by the Trump administration if Iran rejoins the deal. There are ongoing negotiations in Vienna about what assurances Washington will provide to help Iran enjoy the economic benefits of a restored deal.
A State Department spokesperson declined to comment on the details of U.S. breakout assessments and said the administration is confident a deal “would address our urgent nonproliferation concerns.”
“As we have said, we have only a few weeks to conclude an understanding, after which the pace of Iran’s nuclear advances will make return to the JCPOA impossible,” the spokesperson said, referring to the formal name of the deal, the Joint Comprehensive Plan of Action.
The 12-month breakout time was a central tenet of the 2015 deal Iran reached with the U.S. and other powers, although it isn’t mentioned explicitly in the accord. The period was based on analyses that if Iran abrogated the restraints imposed by the pact, Tehran would still need a year to develop enough fuel for one bomb, giving the U.S. and its allies time to respond.
The Trump administration withdrew from the deal in 2018 and reimposed sweeping sanctions on Tehran, saying the agreement was insufficiently stringent. Since then, Iran has accelerated its nuclear program, reducing its breakout time to a few weeks, according to U.S. officials.
Some former U.S. officials warn that a deal with a breakout period of anything less than six months could weaken Washington’s ability to respond to a sudden ramp-up of Iran’s nuclear program.
Administration officials held internal deliberations last fall looking at breakout-time estimates under different scenarios, the officials familiar with the matter said. Those discussions made clear that the breakout time under any realistic deal would be significantly lower than 12 months, the officialssaid.
The breakout time is different from how long it would take Iran to attain a nuclear weapon because, according to Western officials, Iran is believed not to have mastered all the skills to build the core of a bomb and attach a warhead to a missile.