VIENNA — Key restrictions on Iran’s nuclear program will start to ease in slightly more than a decade, years before the 15-year international nuclear accord agreed on last year expires, advancing Tehran’s ability to build a bomb even before the end the pact, according to a document obtained Monday by The Associated Press.
The document is the only secret text linked to last year’s agreement between Iran and six foreign powers. It says that after a period between 11 to 13 years, Iran can replace its 5,060 inefficient centrifuges with up to 3,500 advanced machines.
But because the newer models are up to five-times as efficient, they will allow Iran to enrich at more than twice the rate it is doing now, meaning the time Iran would need to make a weapon would drop from a year to six months.
The U.S. says the Iran nuclear agreement is tailored to ensure that Iran would need at least 12 months to “break out” and make enough weapons-grade uranium for at least one weapon.
Details published earlier outline most restraints on Iran’s nuclear program meant to reduce the threat that Tehran will turn nuclear activities it says are peaceful to making weapons.
But while some of the constraints extend for 15 years, documents in the public domain are short on details of what happens with Iran’s most proliferation-prone nuclear activity — its uranium enrichment — beyond the first 10 years of the agreement.
The document obtained by the AP fills in the gap. It says that as of January 2027 — 11 years after the deal was implemented — Iran can start replacing its mainstay centrifuges with thousands of advanced machines.
The document also allows Iran to greatly expand its work with centrifuges that are even more advanced, including large-scale testing in preparation for the deal’s expiration 15 years after its implementation on Jan. 18.
A senior U.S. official noted, however, that the limit on the amount of enriched uranium Iran will be allowed to store will remain at 300 kilograms (660 pounds) for the full 15 years, significantly below the amount needed for a bomb. As well, it will remain restricted to a level used for reactor fuel that is well below weapons grade. Like the diplomats, the official demanded anonymity in exchange for discussing the document.
“We have ensured that Iran’s breakout time comes down gradually after year 10 in large part because of restrictions on its uranium stockpile until year 15,” the official said. “As for breakout times after the initial 10 years of the deal, the breakout time does not go off a cliff nor do we believe that it would be immediately cut in half, to six months.”
Still the easing of restrictions on the number and kind of centrifuges means that once the deal expires, Tehran will be positioned to quickly make enough highly enriched uranium to bring up its stockpile to a level that would allow it to make a bomb in half a year, should it choose to do so.
The document doesn’t say what happens with enrichment past year 13. That indicates a possible end to all restrictions on the number and kind of centrifuges even while constraints on other, less-proliferation prone nuclear activities remain until year 15.
While the secret document hasn’t been made public, U.S. officials say members of Congress have been able to see it. It was given to the AP by a diplomat whose work has focused on Iran’s nuclear program for more than a decade, and its authenticity was confirmed by another diplomat who possesses the same document.
The diplomat who shared the document described it as an add-on agreement to the nuclear deal. But while formally separate from that accord, he said that it was in effect an integral part of the deal and had been approved by the U.S., Russia, China, Britain, France and Germany.