Secret Nuclear Warehouse Explained

By Kelsey Davenport


In November 2019, the head of the U.N. nuclear watchdog urged Iran to explain uranium traces found at an undeclared site. Reuters reported that the site was a warehouse in Tehran’s Turquzabad district. What is known about the site? 

In his 2018 address to the U.N. General Assembly, Israeli Prime Minister Benjamin Netanyahu alleged that there was a “secret atomic warehouse for storing massive amounts of equipment and materiel from Iran’s secret nuclear weapons program” in the Turquzabad district of Tehran. He revealed a photo of the building in question and claimed that Iran stored “300 tons” of equipment at the site, including 15 kilograms of unspecified radioactive materials. Netanyahu said Israel shared intelligence about the site with the International Atomic Energy Agency (IAEA) and urged it to investigate the warehouse.

The IAEA’s efforts to seek clarification from Iran about the site began in January 2019. Inspectors reportedly visited the warehouse in the spring and took environmental samples. Test results leaked in June indicated that uranium was found at the site, but the agency did not publicly confirm the presence of uranium until November.

On November 7, 2019, Acting-Director General Cornel Feruta convened a special meeting of the IAEA’s Board of Governors and reported that the agency “detected natural uranium particles of anthropogenic origin at a location in Iran not declared to the agency.” Diplomats present at the meeting confirmed to reporters that the samples were taken from Turquzabad and that the uranium detected was processed, but not enriched. The acting IAEA chief said that the composition of the particles indicated that they may have been produced through uranium conversion activities, according to U.S. Ambassador to the IAEA Jackie Wolcott.


What explanation has Iran offered? 

Iranian officials publicly denied that the warehouse was used to store materials and equipment from its nuclear program. Even after the IAEA’s disclosure, the Atomic Energy Organization of Iran (AEOI) said that the warehouse was owned by a private company and could have been used to store old equipment from Iran’s uranium mine. The AEOI said that particles of uranium could “fly anywhere.” Iran’s Foreign Ministry has also accused Israel of setting a “trap” at the site and called on the IAEA to “maintain its vigilance.”

Besides its public denials, Iran does not appear to be fully cooperating with the IAEA’s investigation into the site. In his address to the IAEA Board of Governors on November 21, Feruta said that the investigation “remains unresolved” and urged Iran to comply with the agency’s inquiries. Rafeal Grossi, who took over from Feruta in December, said that the IAEA continues to question Iran about the site. But as of December 3, the agency had “not received an entirely satisfactory reply.” 

Press TV, Iran's state-run English-language outlet, claimed that the warehouse had been used as a carpet cleaning facility and was vacant for three years.


What do outside nuclear specialists believe Turquzabad was doing?

Most specialists believe that the Turquzabad warehouse was used to store documents, equipment and materials that were part of the nuclear weapons program that Iran abandoned in 2003. There are no indications that the warehouse was used for ongoing, illicit, nuclear activities.


To what extent could Iran have cleaned up the warehouse before U.N. inspectors took soil samples in April 2019?

Satellite imagery suggests that Iran removed materials from the site after Israel announced in May 2018 that it had stolen archived documents detailing Iran’s past nuclear weapons program. Israel also alleged that Iran disposed of the radioactive material stored there and engaged in sanitization efforts.

It is not clear what specific steps Iran may have taken to sanitize the warehouse or if the steps were taken deliberately to prevent the IAEA from detecting what was stored at the site. It would have been extremely difficult for Iran to remove all evidence of radioactive materials at the site.


What does the Turquzabad case indicate about Iran’s deviation from commitments under the 2015 nuclear deal. Is or was it cheating?

The monitoring and verification measures of the 2015 Joint Comprehensive Plan of Action (JCPOA) – brokered with the world’s six major powers – require Iran to declare all nuclear materials and any facility that contains nuclear material to the IAEA. Under those rules, it appears that Iran was obligated to declare the material at the warehouse but failed to do so.

The origin of the material and when it was processed is unclear. The processed uranium may have been part of a clandestine operation that was subsequently stored at the warehouse after Tehran abandoned its nuclear weapons program in 2003. Iran was required to answer IAEA questions about its past nuclear weapons program before the JCPOA was fully implemented, but Tehran was not required to make a full disclosure about its illicit activities or destroy documentation of the program. Iran’s decision to retain documents and materials is not proof that it intends to pursue nuclear weapons.

However, if Iran processed any of the uranium found at the site after the JCPOA entered into effect in January 2016, it would have violated a requirement that the agency verify uranium ore produced and processed in Iran and monitor it.

In either case, the uranium raised questions about Iran’s conversion activities and full disclosure to the IAEA. Iran is required to cooperate fully with the IAEA’s investigation. Failure to comply will increase speculation that Iran is conducting illicit activities and intends to pursue nuclear weapons. 


What are the implications if Iran conducted nuclear activities at this or any other undeclared sites since the 2015 nuclear deal?

It would be a violation of the JCPOA as well as Iran’s commitment under the 1967 Nuclear Nonproliferation Treaty (NPT) to subject its nuclear program to international safeguards. At the same time, illicit nuclear activity would not necessarily indicate that Tehran intended to pursue nuclear weapons, but it would raise legitimate questions about Iran’s commitment to a peaceful nuclear program. 

Iran could face referral to the U.N. Security Council for conducting undeclared nuclear activities. If any of the remaining parties to the JCPOA believe Iran has not addressed a dispute, it could go to the Security Council and snap back the U.N. sanctions lifted by the JCPOA.  

The IAEA’s Board of Governors could also refer Iran to the Security Council for violating its legal safeguards obligations under the NPT. The board took a similar action in 2006 when Iran refused to cooperate with the IAEA’s investigation into Tehran’s illicit nuclear activities.


Iran has previously constructed secret nuclear facilities at Fordo and Natanz. How does the Turquzabad warehouse compare to those cases?

The Fordo and Natanz facilities were built to enrich uranium. The small size and limited enrichment capacity of Fordow indicates that it was probably part of a nuclear weapons program; it would be ill-suited to produce uranium for fueling a nuclear power reactor.

The warehouse in Turquzabad appears to have been used only as a storage facility.

It does not appear to have been used to produce nuclear material, so it has posed far less of a proliferation risk than the covert facilities at Natanz and Fordo did.


Under the 2015 nuclear deal, how difficult would it be for Iran to maintain a separate, clandestine nuclear program? 

No monitoring and verification regime can completely guarantee that a state is not engaging in illicit nuclear activities, but the measures put in place by the JCPOA are the most intrusive regime ever negotiated. Its provisions, along with foreign intelligence, ensure that clandestine operations could be quickly detected. States continue to use sophisticated national intelligence means to monitor and collect information about Iran’s nuclear program and look for evidence of illicit activity. For instance, U.S. intelligence detected Iran’s attempts to clandestinely build uranium enrichment facilities at Natanz and Fordo. States can also provide evidence of clandestine activity to the IAEA, which then determine if an inspection or follow-up is warranted.

The IAEA’s continuous surveillance of Iran’s fuel supply chain makes would make it difficult for Iran to divert materials from its declared peaceful program for illicit activities. Under the JCPOA, the international community would probably be able to detect any Iranian attempt to set up a clandestine supply chain and program. The nuclear deal requires Tehran to provide the IAEA with additional information and to allow IAEA inspectors to visit any site – within 24 days – to investigate evidence of illicit nuclear activities. The 24-day timeline was tested during the JCPOA negotiations to ensure that Iran could not sanitize a site to remove evidence of nuclear materials. Without the JCPOA, inspectors have no guarantee of timely access to an undeclared site.


What is the state of the 2015 JCPOA nuclear deal, given Iran’s latest breaches?

As of December 2019, Iran’s violations of the JCPOA did not constitute a near-term proliferation risk and were quickly reversible if Tehran chose to return to compliance with the JCPOA.

Since July 2019, Iran has:

  • enriched uranium to about 4.5 percent uranium-235, a level slightly above the 3.67 percent limit,
  • used additional centrifuges (including advanced machines) to enrich uranium,
  • resumed uranium enrichment at the Fordo site,
  • exceeded the 130 metric ton limit on heavy water,
  • and accumulated uranium beyond the 300-kilogram stockpile limit,

Cumulatively, Iran has slowly eroded its breakout time, which is the required to produce enough nuclear material for one bomb. The breakout time was about 12 months when the JCPOA was fully implemented in January 2016 – a significant increase from the two-to three-month breakout time before the JCPOA.

Iran has continued to adhere to the more intrusive monitoring and verification mechanisms under the deal. Its commitment to transparency aligns with President Hassan Rouhani’s vow that Tehran will fully comply with the JCPOA if sanctions are lifted as promised under the deal. (President Trump unilaterally withdrew from the deal and reimposed sanctions in May 2018 despite Iran’s compliance with the JCPOA. They went into effect after 90 day and 190 day wind-down periods.)

The remaining five parties to the JCPOA have condemned Iran’s breaches, but they also have committed to preserving the accord and resolving diplomatically Tehran’s violations. In November 2019, European parties to the deal (Germany, France, the United Kingdom and the European Union) warned Iran that its latest breach could lead them to invoke the JCPOA’s dispute resolution mechanism. If invoked, this process could lead the Security Council to reimpose sanctions on Iran.


How would international monitoring change if the 2015 nuclear deal were to collapse?

Irrespective of the JCPOA, Iran is required as a party to the 1967 Nuclear Nonproliferation Treaty (NPT) to implement a safeguards agreement with the IAEA. The NPT safeguards agreement gives inspectors access to nuclear sites in Iran to verify that Tehran’s activities are peaceful and that material is not being diverted for illicit purposes.

If the JCPOA collapses, Iran would no longer be required to adhere to monitoring and verification that go beyond its NPT safeguards agreement. The JCPOA includes continuous surveillance of Iran’s centrifuge production facilities and uranium mines and mills and real-time monitoring of enrichment levels.

It also requires Iran to build on its safeguards agreement, including implementing the additional protocol and what is known as Code 3.1. The additional protocol is a voluntary agreement that a state can enter into with the IAEA. It gives inspectors access to sites and facilities that support the country’s nuclear program but do not house nuclear materials. Code 3.1 requires a country to notify the IAEA when a decision is made to construct a nuclear facility. A standard safeguards agreement only requires notification 180 days before nuclear material is introduced.

If the deal falls apart, Iran could voluntarily accept any of these intrusive monitoring and verification mechanisms. Iran has provisionally implemented the additional protocol and Code 3.1 in the past. These measures are not required, but they are accepted best practices. Of the 175 states that have safeguards agreements with the IAEA, 136 have additional protocols that have entered into force.


Kelsey Davenport is the Director for Nonproliferation Policy at the Arms Control Association.