April 12, 2022 | Policy Brief

Iran’s Centrifuge Manufacturing Goes Underground

The International Atomic Energy Agency (IAEA) reported last week that Iran is concentrating its centrifuge production equipment at two centrifuge manufacturing facilities — both likely located beneath mountains — that are highly fortified against sabotage or military strikes. Since the Islamic Republic has not permitted daily international monitoring of those underground sites for more than one year, the IAEA cannot ascertain whether the regime is diverting key nuclear equipment to quickly produce atomic weapons.

Iran previously built its fastest, most advanced centrifuges at the Iran Centrifuge Assembly Center (ICAC), an aboveground plant located at the Natanz nuclear complex. In July 2020, however, an internal explosion destroyed more than half of the ICAC, likely reducing Tehran’s advanced centrifuge production for several months. Iran blamed the incident on foreign sabotage.

In April 2021, Iran announced it would rebuild the ICAC facility underground. Ali Akbar Salehi, then-head of Iran’s Atomic Energy Organization, stated at the time, “We are working 24/7 to move all our sensitive halls into the heart of the mountain near Natanz.” The location of the site is not publicly known, but it could be buried beneath one of the mountains south of the former ICAC building and the Natanz enrichment plants. In October 2020, the IAEA’s director general, Rafael Grossi, stated that he was aware of the new facility.

A second centrifuge plant, located near Karaj, was the target of an alleged drone strike in June 2021. Iran produced delicate centrifuge equipment at the site, such as rotor tubes, bellows, and rotor assemblies. Following the incident, Iran’s production of advanced centrifuges declined further but reportedly rebounded by November 2021 at the latest.

In January 2022, Tehran relocated the Karaj facility to a mountainous area near the Esfahan uranium conversion facility and complex. For more than one year, Tehran has not permitted the IAEA to review video of daily activities at nuclear sites, including the centrifuge production facilities, thus inhibiting the agency’s ability to ascertain whether Iran is diverting centrifuge equipment to clandestine locations. The IAEA reported last week that although it has visited both sites to install cameras and place seals on equipment, it cannot confirm whether Iran is producing new centrifuge components.

Iran claims it is continuing to collect video footage on IAEA cameras and will turn over the data once it receives sanctions relief. Yet between June 2021, when the alleged sabotage occurred at the Karaj facility, and December 2021, Tehran refused to permit the IAEA to re-install cameras, meaning that the agency is missing footage of six months of activities and can never reconstruct events at the site. It will rely instead on estimates of Iran’s centrifuge production to determine whether Tehran may have diverted any nuclear equipment.

Iran’s advanced centrifuge program requires intensive, continuous monitoring, since diverting just 650 of its most advanced machines to a clandestine facility would be enough to facilitate a breakout to nuclear weapons.

Since entering office, however, the Biden administration has failed at each quarterly IAEA Board of Governors meeting to recommend that the body censure Iran for its restrictions on IAEA monitoring, non-cooperation with a separate IAEA investigation into Tehran’s undeclared nuclear activities, and flagrant nuclear escalations — the majority of which have occurred on the Biden administration’s watch.

Instead, President Joe Biden is determined to return to the 2015 nuclear deal, formally known as the Joint Comprehensive Plan of Action (JCPOA). In less than two years, the accord would allow Iran to bolster its capability to dash to nuclear weapons while limiting the IAEA’s ability to detect covert atomic weapons work.

Instead of reviving a further weakened version of the JCPOA, Washington must reverse course and rebuild a multilateral pressure campaign against Iran in coordination with its European allies. Any nuclear deal with Iran must require that Tehran verifiably eliminate its uranium enrichment program and account for all clandestine nuclear work to date.

Andrea Stricker is a research fellow at the Foundation for Defense of Democracies (FDD), where Anthony Ruggiero is a senior fellow. Anthony previously served in the U.S. government for more than 19 years, including as senior director for counterproliferation and biodefense (2019-2021) on the National Security Council. They both contribute to FDD’s Iran Program, International Organizations Program, and Center on Military and Political Power (CMPP). For more analysis from the authors, the Iran Program, the International Organizations Program, and CMPP, please subscribe HERE. Follow Andrea and Anthony on Twitter @StrickerNonpro and @NatSecAnthony. Follow FDD on Twitter @FDD and @FDD_Iran and @FDD_CMPP. FDD is a Washington, DC-based, nonpartisan research institute focused on national security and foreign policy.


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