Iran’s semi-official Fars news agency reported Monday that the country’s stockpile of 3.67 percent enriched uranium has now passed the 300-kilogram limit set by the 2015 nuclear deal.
Citing what it said was an “informed source,” Fars reported that the stockpile was measured and found to have exceeded the agreed limit laid out in the so-called Joint Comprehensive Plan of Action.
On June 17, a spokesperson for Iran’s Atomic Energy Organization said Iran would breach the limit within 10 days.
Speaking at the Arak heavy water production facility, Behrouz Kamalvandi acknowledged that the country had already quadrupled its production of low-enriched uranium and said Tehran would increase uranium enrichment levels “based on the country’s needs.”
That increase, he said, could be to any level, from 3.67%, which is the current limit set by the nuclear deal.
Iran needs 5% enrichment for its nuclear power plant in the southern port of Bushehr and 20% enrichment for a Tehran research reactor, the spokesman said.
When uranium is mined, it typically has about 140 atoms of the unwanted U-238 isotope for every atom of U-235. Refining it to a purity of 3.67%, the level now allowed by the nuclear deal, means removing 114 unwanted atoms of U-238 for every atom of U-235.
Boosting its purity to 20% would mean removing 22 more unwanted isotopes per atom of U-235, while going from there to 90% purity means removing just four more per atom of U-235, Kamalvandi noted at the time. Ninety percent is considered weapons-grade material.
That means going from 20% to 90% is a relatively quick process, something that worries nuclear nonproliferation experts.
The move was part of Iran’s recent 60-day ultimatum to the European Union for renegotiating the pact after the US withdrawal.
The Trump administration pulled America out of the deal in May 2018, saying it did not sufficiently rein in Iran’s nuclear program and did nothing to stop it from developing missiles or destabilizing the Middle East. The Europeans insist that the pact is an important pillar of regional and global security and was never meant to address those other issues.
In May Iran formally dropped the limitations on uranium enrichment and the production of heavy water that were laid down in the deal, citing its ultimatum to the EU, which it accuses of failing to protect Iran against the renewed US sanctions.
Under the terms of the nuclear deal, Iran can keep a stockpile of no more than 300 kilograms (660 pounds) of low-enriched uranium. That’s compared to the 10,000 kilograms (22,046 pounds) of higher-enriched uranium it once had. It is also capped at storing 300 tons of heavy water, which it sells to Oman for use as a coolant in nuclear reactors.