International Atomic Energy Agency Director-General Rafael Grossi is due to visit Tehran on Wednesday in parallel to the flurry of nuclear diplomacy between Iran and the US.
Grossi and his scientific team’s expertise in assessing the progress of Iran’s nuclear program – and how much it would need to be set back to prevent the development of a nuclear weapon – will be crucial to any potential nuclear deal and its verification measures.
On March 3, Grossi said, “My visit to Tehran last November and meetings with President Masoud Pezeshkian and Foreign Minister Abbas Araghchi indicate that there may be room for constructive compromises. I hope to see them again soon and pursue effective dialogue and tangible results.”
However, he cautioned that so far, there had been no progress.
Iran increasing its levels of enriched uranium
“Continued engagement and cooperation with the agency is essential at a time when diplomatic solutions are urgently needed,” the agency’s head said on X/Twitter on Monday.
Also in March, Grossi informed the IAEA Board of Governors that Iran’s 60% level enriched uranium had increased to 275 kilograms, an increase of approximately one full nuclear weapon’s worth per month since December.
“We need real answers,” he said, “and to stop [just] talking about the process,” which might later lead to answers.
The IAEA also found that Tehran had enough 60%-enriched uranium, which could be quickly converted to the 90% weaponized level, to make six nuclear weapons if it decided to do so.
This is without even taking into account the Islamic Republic’s uranium enriched to 20% and lower levels. Israeli and some US estimates are that Iran could potentially develop an even larger number of nuclear weapons than the IAEA estimates, especially if they made smaller nuclear bombs.
According to the Institute for Science and International Security, Tehran could develop close to 17 nuclear weapons in a period of only a few months.
Iran’s latest spike in uranium enrichment was in retaliation to the IAEA Board condemning it in November 2024 for nuclear violations. At the time, top Iranian officials had just forced out vice president Javad Zarif, one of the government’s top advocates for diplomacy with the West.
US-Iran nuclear talks taking place
Iran Supreme Leader Ayatollah Ali Khamenei had signaled zero willingness to trust and negotiate with the Trump administration over the nuclear deal and other issues, given the increased sanctions that it has placed on the Islamic Republic since US President Donald Trump took office on January 20.
However, since then, it appears that Pezeshkian has convinced Khamenei to at least play out nuclear talks with Washington, if for no other reason than to avoid what might otherwise be threats of an imminent Israeli airstrike.
Israel destroyed all of Iran’s most effective anti-aircraft systems, the five S-300 systems it bought from Russia, on October 26 in response to a second massive Iranian ballistic missile attack on the Jewish state on October 1.
Back in March, Grossi told the Board, “Following my last report, Iran’s stockpile of uranium enriched up to 60% U-235 has increased to 275 kg., up from 182 kg. in the past quarter. Iran is the only non-nuclear weapon state enriching to this level, causing me serious concern.
“It has been four years since Iran stopped implementing its nuclear-related commitments” under the nuclear deal, said the IAEA chief.
Lingering questions regarding details of Iran's nuclear program
Further, he said Iran’s claim that it has declared all of its nuclear materials “is inconsistent with the agency’s findings of uranium particles of anthropogenic origin at undeclared locations in Iran. The agency needs to know the current locations of the nuclear material and/or of contaminated equipment involved.”
“There is also a discrepancy in the material balance of uranium involved in uranium metal production experiments conducted at Jaber Ibn Hayan Multipurpose Laboratory, for which Iran has not accounted,” he warned.
Many of these question marks from the IAEA about Iran’s nuclear program stem from a 2018 Mossad operation that seized large volumes of the Islamic Republic’s nuclear secrets from the Shirobad area of Tehran.
In addition, Grossi stated in March, “I deeply regret that Iran, despite having indicated a willingness to consider accepting the designation of four additional experienced agency inspectors, did not accept their designation.”
Moreover, he said that he will “produce a comprehensive and updated assessment on the presence and use of undeclared nuclear material in connection with past and present outstanding issues regarding Iran’s nuclear program,” as instructed by the Board in November.
He did not give a deadline for filing the report but expressed hope that Trump had said he would prefer a diplomatic solution.
If Iran does decide to weaponize its uranium, it would still need to overcome certain special detonation and delivery issues if it wanted to target Israel.
There is an ongoing debate about whether overcoming those obstacles could take a few months or up to two years, depending on how many corners Tehran would cut along the way.
Reuters contributed to this report.