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The most recent reports from the International Atomic Energy Agency (IAEA) detailing Tehran’s failure to declare illicit nuclear activities from its pre-2003 weapons development effort and the continued growth of Iran’s nuclear program underscores the urgency and importance of restoring the mutual U.S. and Iranian compliance with the 2015 nuclear deal, known as the Joint Comprehensive Plan of Action (JCPOA). Full implementation of the JCPOA would roll back Iran’s nuclear advances, restore intrusive monitoring, and provide the best possible assurance that Tehran’s nuclear activities are peaceful.
According to the IAEA’s May 30 report on Iran’s current nuclear program, Tehran has stockpiled enough material enriched to 60 percent uranium-235 that could, if enriched to weapons-grade material, give it enough uranium for one bomb (25 kg) in under 10 days.
While the 10-day “breakout” is a worst-case scenario estimate, the timeframe is dangerously close to the point where Iran could breakout between regular IAEA inspections. Weaponization would still take 1-2 years, but that process would be more difficult to detect and disrupt once Iran moved the weapons-grade uranium from its declared enrichment facilities. Iran could also use the 43 kilograms of 60 percent enriched uranium to fashion a bomb, although such a device would be bulky and inconsistent with the weapons design Iran pursued during its pre-2003 organized weapons program. Growth in the stockpile of 20 percent enriched uranium gas—now at 238 kilograms —and Iran’s continued use of more advanced centrifuge machines would give Tehran the technical capacity to produce enough weapons-grade material for an additional bomb in another four weeks.
This drop in breakout significantly increases the proliferation risk posed by Iran’s nuclear program and underscores the urgent need to reimpose limits on Tehran’s nuclear activities, reduce its stockpiles of enriched uranium, and roll back its enrichment capacity. The quickest route to decreasing breakout and restoring more intrusive monitoring is by closing the deal to restore full compliance with the JCPOA.
According to May 25 testimony from U.S. Special Envoy for Iran Robert Malley, restoring the JCPOA would push the breakout back up to about 6 months. This would give the international community time to respond if Tehran were to make a move toward weaponization in the future.
The IAEA report does note that Iran has moved an additional 20 percent and 60 percent uranium gas to its fuel production plant. In total, Iran transferred 38 kilograms of uranium gas enriched to 60 percent to the Fuel Plate Fabrication Plant (23 kilograms in January and 15 kilograms in April) and converted 2 kilograms into uranium powder in March, to produce HEU targets for the Tehran Research Reactor. The IAEA reports no further conversion of 60 percent gas to powder. The stockpile of 20 percent enriched uranium transferred to the fabrication plant is about 209 kilograms (33 kilograms transferred in November, 147.8 kilograms transferred in January, 11.7 kilograms in April, and 16.6 kilograms in May).
Transferring this material—which poses a more significant proliferation risk than the stockpile enriched up to five percent—does suggest that Iran is still interested in restoring the JCPOA and has no immediate intention to produce weapons-grade uranium, as it would need to bring the uranium gas back to its enrichment facilities for further enrichment, adding time and increasing the likelihood of detection.
However, while Iran’s actions might be intended to signal that it remains serious about reaching an agreement to return to compliance with the JCPOA alongside the United States, the risk posed by Tehran’s advancing nuclear program is growing. The United States, and more particularly Israel, is unlikely to tolerate the threat of an undetectable Iranian nuclear weapons breakout capability in the long term. This increases the likelihood of sabotage or military attacks on Iran’s nuclear facilities to try to roll back its program and lengthen the breakout timeline. While this may work in the short term, it is counterproductive as a nonproliferation strategy, as Iran typically responds to such acts by hardening its nuclear facilities and ratcheting up its program.
The Agency’s Safeguards Report on Iran
The IAEA’s second report, which details the agency’s investigation into past illicit nuclear activities, further highlights the imperative of restoring the JCPOA. This report concludes that Iran conducted uranium metal activities that should have been declared to the IAEA under Tehran’s legally required safeguards agreement. It also notes that Iran has still not provided technically credible explanations for the presence of processed uranium at three undeclared locations. All these activities date back to the pre-2003 period and do not pose an immediate risk, but Iran’s failure to provide the IAEA with credible information is very concerning and undermines its safeguards obligations—particularly after Iran and the IAEA reached an agreement on March 5 to try and conclude the investigation by the IAEA’s June 6-10 Board of Governors meeting.
According to the report, Iran did provide the agency with some information in response to the IAEA’s queries as part of the March 5 joint statement. Iran’s responses, however, have not been “technically credible.” Iran has also tried to claim that the presence of processed uranium at the three locations still under investigation may be a result of “third party sabotage” that contaminated the sites. Iranian officials have never admitted to pursuing nuclear weapons in the past and they are highly unlikely to fully admit to having done so in formal responses to IAEA questions. Nevertheless, Iran’s claim of third-party interference strains credulity and Tehran’s failure to cooperate more fully undermines confidence in the peaceful nature of its current nuclear program.
Critics of the JCPOA argue that Iran’s failure to answer the IAEA’s questions about past work is reason to walk away from the year-long negotiations to restore the accord. On the contrary, it is precisely because Iran had an illicit nuclear weapons program prior to 2003 and lied about it that restoring the JCPOA is necessary.
An agreement that leads to the prompt restoration of mutual compliance with the JCPOA would put back in place the most intrusive monitoring regime ever negotiated and provide the IAEA with increased access to Iran’s nuclear sites and facilities. Greater access to sites and information gives the agency a better picture of Iran’s nuclear program and more tools to investigate evidence of illicit nuclear activities and materials. When Iran’s nuclear program is strictly limited, quick detection of nuclear activities that breach the JCPOA’s restrictions and/or Iran’s legally binding commitment under the nuclear Nonproliferation Treaty (NPT) then provides the international community with time to respond – time that it does not currently have given Tehran’s expanding nuclear activities.
As a party to the JCPOA, the United States also has more leverage to ensure that Iran provides adequate access for the IAEA in the event of future investigations. Iran stalled the IAEA’s inquiries into possible weaponization activities for more than a decade because there are no timebound requirements for addressing IAEA queries about illicit activities in an NPT-required safeguards agreement. It was not until the JCPOA was negotiated and Iran was required to respond to IAEA inquiries before receiving sanctions relief that Tehran provided information that allowed the IAEA to close its investigation.
The JCPOA sought to prevent Iran from stonewalling future investigations by allowing the Joint Commission, the body set up to oversee the JCPOA’s implementation, to vote to require Iran to provide the IAEA with the access necessary to address any concerns within 24 days. This includes access to military sites. Unlike other provisions in the JCPOA that require consensus, a vote on IAEA access needs only majority support. So, if JCPOA is restored, the United States, along with its European partners, could ensure the IAEA has the necessary tools and access to resolve outstanding questions.
While Iran is not going to come clean and own up to its past illegal nuclear weapons-related work, providing the agency with information that would allow the IAEA to close its investigation would have given an impetus to negotiations to restore the JCPOA and supported Tehran’s assertion that it has no interest in nuclear weapons. Iran’s lack of cooperation, however, ensures that this issue will remain a contentious topic during the agency’s upcoming Board of Governors meeting and increases the likelihood that the Board will censure Iran for failing to meet its safeguards obligations. Reuters reported June 1 that the United States, France, Germany, and the United Kingdom are circulating a draft resolution rebuking Iran for its failure to cooperate with the IAEA inquiry.
While a resolution of censure from the Board may complicated efforts to restore the JCPOA, the May 30 IAEA report provides the clearest indictment to date that Tehran violated its IAEA safeguards agreement by failing to declare materials and activities from the pre-2003 period. It is necessary and appropriate for the Board to take action to support the IAEA and send a clear signal to Iran that there are consequences for violating its safeguards obligations and failing to cooperate with the agency.
At the same time, given the growing proliferation risk posed by Iran's nuclear program, the United States and its European partners should take care to emphasize the critical importance of restoring the JCPOA and ratchet up efforts to conclude negotiations on an agreement to restore the accord.
Summary of the IAEA’s safeguards investigation into four locations where evidence suggests undeclared nuclear activities:
Location 1: Turquzabad
The IAEA had evidence that Iran used the Turuazabad site, previously referred to in IAEA reports as Location 1, to store nuclear material and equipment. The IAEA requested that Iran clarify whether the site was used for such purposes. Iran informed the agency in November 2019 that there were no undeclared nuclear materials or activities at the site. IAEA inspectors visited the location in February 2019; samples taken indicated the presence of processed uranium. Iran’s initial responses to the IAEA were not deemed technically credible. As a result of the March 5 agreement between the IAEA and Iran, Tehran provided further explanation for the presence of the uranium, saying that there was “the possibility of an act of sabotage by a third party to contaminate the area” but provided no evidence to support that claim, according to the May 30 IAEA report. Iran also said it could not identify where containers removed from sites in 2018 are currently located. The IAEA report concluded that the presence of uranium particles at the site “is not clarified.”
Location 2: Lavisan-Shian
The IAEA reported evidence of an undeclared uranium metal disc that had undergone drilling and processing at Lavisan-Shian, previously identified as Location 2. As part of its investigation, the IAEA visited a declared facility in Iran where uranium metal discs had been produced but was unable to determine if the Lavisan-Shian disc was at that site. The IAEA informed Iran in January 2022 that it “could not exclude that the disc had been melted, recast and was not part of the declared nuclear material inventory.” In the May 2022 report, the IAEA assess that the activities at Lavisan-Shian “were not declared by Iran to the Agency as required under the Safeguards Agreement.” The IAEA has no further questions about this location.
Location 3: Varamin
IAEA information suggests that Iran used Varamin for fuel-cycle-related activities, including an “undeclared pilot-scale facility for the processing and milling of uranium ore and conversion into uranium oxide” and possible UF4 to UF6 from 1999-2003. The IAEA’s evidence suggests that materials and equipment from the site were moved to Location 1, Turquazabad, for storage. In the May 2022 report, the IAEA noted that Iran stated in March 2022 that the location was used for the production of sodium sulphate. The IAEA stated that this explanation does not match the satellite imagery taken from the site and the results of the environmental samples that were collected during an August 2020 visit to the site. Specifically, it does not explain the presence of the uranium particles. The IAEA reported that Iran offered the additional explanation of third-party sabotage to contaminate the area but provided no evidence to support that claim.
Location 4: Marivan
The IAEA reported that safeguards relevant information suggests that Iran conducted “explosive experiments with protective shielding in preparation for the use of neutron detectors” at one of the areas under investigation at Marivan, previously referred to as Location 4 by the IAEA. In August 2021, Iran provided the agency with some documentation about Marivan and said that one of the areas in question was built to support a mine managed by another IAEA member state until it was abandoned in 1994 and that the bunkers at the site were used for deactivating munitions. The IAEA assessed that some of this documentation was inconsistent with its evidence. As part of the process initiated by the March 5 process, Iran informed the IAEA that it had never produced the type of material found at the site and that the presence might be accounted for by an act of third party sabotage to contaminate the site. Iran, however, provided no evidence for this claim. During the consultations, Iran also said that some of the photographs of the bunkers were fabricated. The IAEA said in its May 30 report that the presence of the uranium “is not clarified.”