The fate of the agreement remains uncertain after the Trump administration pulled out last year and reimposed sanctions on Iran. That move prompted Tehran to scale back its commitments under the pact.
Iran said this month it had breached a stockpile limit for low enriched uranium allowed under the deal and was enriching uranium at a higher level than permitted. Officials have said they will continue to reduce their obligations if the remaining parties to the deal do not help alleviate Iran’s economic isolation.
Earlier Sunday, the head of Iran’s nuclear agency was reported to have told lawmakers that Iran had enriched 24 metric tons of uranium since the nuclear deal was reached in 2015.
The remarks by Ali Akbar Salehi of Iran’s Atomic Energy Organization were reported widely by state-run and semiofficial media, which cited conservative lawmakers present at the closed-door meeting.
The claim, if confirmed, would suggest that Iran has produced far more enriched uranium than was previously known, exceeding the deal’s limit many times over.
But some analysts were skeptical. They suggested Salehi might have been talking about uranium that was enriched but subsequently diluted or “downblended” — a process that could be used to keep machines running while still ultimately yielding relatively low enriched uranium.
Salehi also said Iran was moving to restart activity at the heavy-water nuclear reactor at its Arak facility, according to the reports.
Iran’s uranium enrichment capabilities and its heavy-water nuclear reactor were restricted under the 2015 deal, formally known as the Joint Comprehensive Plan of Action, for fear that they could be used by Iran to pursue a nuclear weapons program.
To be used in nuclear weapons, uranium must be highly enriched. The JCPOA placed a limit on the amount of enriched uranium Iran could possess and the level to which it could be enriched.
The claim that Iran’s enriched-uranium stockpile had exceeded the 300-kilogram limit was subsequently confirmed by the International Atomic Energy Agency. But in Iranian media on Sunday, Salehi was reported to have said that it went further than this.
“After the JCPOA, Iran enriched 24 tons of uranium, not 300 kilograms,” Gholamali Jafarzadeh, a member of the Iranian parliament, quoted Salehi as saying, according to Mehr News.
Twenty-four metric tons is 24,000 kilograms.
The IAEA did not immediately respond to a request for comment.
Analysts see Arak’s heavy-water reactor as a risk for proliferation because it could allow Iran to produce weapons-grade plutonium. The nuclear deal required Iran to pour concrete into the pipes of the reactor’s core as part of a redesign.
Salehi said last week that the redesign, in partnership with China and Britain, was making progress. Britain replaced the United States in the project after the Trump administration pulled out of the nuclear deal.
In his meeting with lawmakers on Sunday, Salehi was reported to have said that the developments were not indicative of an intent to produce nuclear weapons.
“We do not intend to produce nuclear weapons because of religious reasons,” lawmaker Mehrdad Lahouti quoted Salehi as saying, according to the Iranian Students News Agency.
Though Iran and Britain are working together on the heavy-water reactor, relations between the countries have been tense in recent weeks, since British marines helped seize an Iranian-flagged tanker near Gibraltar and Iran seized a British-flagged tanker that was passing the Strait of Hormuz in the Persian Gulf.