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May 19, 2021
Iran's Nuclear Efforts, Capabilities Still Murky

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Paul Kerr

Even as the UN Security Council has begun considering potential responses to Iran’s controversial nuclear program, Tehran’s nuclear capabilities and intentions remain shrouded in ambiguity.

The International Atomic Energy Agency (IAEA) is not “in a position to conclude that there are no undeclared nuclear materials or activities in Iran,” Director-General Mohamed ElBaradei wrote in a Feb. 27 report to the agency’s Board of Governors.

Largely because of Iran’s lack of full cooperation with the investigation, the report adds, there remain “uncertainties related to the scope and nature” of Iran’s nuclear efforts, particularly its uranium-enrichment program. An IAEA investigation, which began more than three years ago, has discovered a variety of clandestine Iranian nuclear activities, some of which violate the country’s safeguards agreement with the agency. Such agreements, which are required under the nuclear Nonproliferation Treaty (NPT), allow the IAEA to monitor NPT states-parties’ declared civilian nuclear activities to ensure they are not used for military purposes.

Iran ’s secret nuclear activities, laggard cooperation with the IAEA, and evidence of military ties to its ostensibly peaceful nuclear program have fueled concerns that Iran is attempting to acquire nuclear weapons.

Nevertheless, the evidence of an Iranian nuclear weapons program remains largely circumstantial. The IAEA has not recently discovered evidence of any undeclared Iranian nuclear programs. There is also no direct evidence that Iran is pursuing nuclear weapons.

U.S. officials, however, continue to insist that Iran is intent on acquiring such weapons, although they acknowledge that it would take Tehran some time to do so, even if the programs continue.

Robert Joseph, undersecretary of state for arms control and international security, told the House International Relations Commit tee March 8 that the U.S. intelligence community estimates Iran to be approximately five to 10 years away from a nuclear weapons capability, a time frame consistent with previously reported U.S. estimates. (See ACT, September 2005.)

Joseph explained that Iran faces technical obstacles to developing its uranium- enrichment program but has the ability to overcome those problems over time. Washington, however, may not have a good sense of how much longer Iran needs, he said, adding that several “wildcards,” including potential assistance from foreign entities, could “accelerate that timeline.”

Uranium-Enrichment Program

U.S. officials’ most immediate concern is Tehran ’s development of a gas centrifuge-based uranium-enrichment program. Gas centrifuges enrich uranium by spinning uranium hexafluoride gas at very high speeds in order to increase the concentration of the uranium-235 isotope. They can produce both low-enriched uranium, which can be used in nuclear power reactors, and highly enriched uranium, which can be used in certain types of nuclear reactors and as fissile material in nuclear weapons.

Iran has a pilot centrifuge facility and is constructing a much larger commercial facility. Tehran has told the IAEA that the pilot and commercial facilities will eventually contain approximately 1,000 and 50,000 centrifuges, respectively.

Although Iran has made progress on its enrichment program during the past several months, its ability to produce centrifuges currently appears to be limited. Iran has told the IAEA that it plans to install 3,000 centrifuges in the commercial facility beginning in the last quarter of this year. But a Department of State official told Arms Control Today March 17 that Washington is uncertain that Iran will be able to manufacture enough centrifuge components in time. In addition, Iran is still dependent on foreign suppliers for some key components, the official said.

A diplomatic source had previously indicated that Tehran can build large numbers of P-1 centrifuges but not enough to meet the commercial centrifuge facility’s planned capacity. Tehran lacks the expertise to pro duce more advanced P-2 centrifuges, the source said. (See ACT, March 2006).

Tehran resumed work on the conversion facility in August 2005 and began work on the centrifuge program several months later. Iran had agreed to suspend the program in November 2004 as part of an agreement governing Tehran’s negotiations with France, Germany, and the United Kingdom . Tehran terminated the suspension completely in February.

According to ElBaradei’s report, Iran has begun testing both a 10-centrifuge cascade and a 20-centrifuge cascade in the pilot facility. Only the 10-centrifuge cascade tests have involved uranium hexafluoride.

The pilot facility also contains a cascade of 164 centrifuges that Iran has never operated with nuclear material, according to the IAEA. Learning to operate cascades with at least that number of centrifuges is considered critical in developing the skills necessary to operate larger cascades, the State Department official said.

A diplomatic source in Vienna indicated to Arms Control Today in February that Iran is “months away” from producing enriched uranium. Asked about press reports that Tehran is on the verge of operating the cascade, the source said March 22 that Iran “is not there yet.”

Iran also has a uranium-conversion facility, which converts lightly processed uranium ore into several compounds, including uranium tetrafluoride and uranium hexafluoride.

Iran has had difficulty producing uranium hexafluoride of sufficient purity, but its con version capabilities appear to be improving, said both the Vienna diplomat and the State Department official. Uranium hexafluoride with high levels of contaminants can corrode centrifuges when used as feedstock.

The United States assesses that Iran’s uranium hexafluoride is now of high enough quality that it will not damage the centrifuge, the State Department source said.

ElBaradei reported that Iran’s current uranium-conversion “campaign,” which began last November, is scheduled to end this month. Iran has produced about 85 metric tons of uranium hexafluoride since September 2005.

Centrifuge Acquisitions

ElBaradei reported that the IAEA has not yet been able to verify the “correctness and completeness” of Iran’s statements regarding its P-1 and P-2 centrifuge programs.

Iran acquired its centrifuge materials and equipment in the 1980s and 1990s from a clandestine supply network run by Abdul Qadeer Khan, then a high-level Pakistani nuclear official.

Tehran has provided the IAEA with some information regarding these acquisitions as well as related offers from foreign suppliers, but it has not been fully forthcoming.

ElBaradei reported that Iran clarified during a February meeting some information regarding its P-1 procurement efforts. But the agency still thinks, partly because of information provided by members of the network, that Iran may be withholding relevant documentation and other information about its centrifuge acquisitions. The agency is concerned that Tehran may have conducted undisclosed work on both types of centrifuges and may also have an ongoing clandestine centrifuge program.


The IAEA appears to have found more evidence that calls into question Tehran’s past claims regarding experiments to separate plutonium, which can also be used as fissile material. Iran has in the past misled the agency about the duration of its experiments, but the new evidence suggests that Iran may have separated more plutonium that it had previously acknowledged.

Iran allowed the IAEA to take samples of the plutonium solution produced in a Tehran research reactor and also provided the agency with plutonium disks Tehran said were produced from the solution.

According to ElBaradei’s report, the IAEA has determined that the isotopic composition of the disks differs from the isotopic composition of the solution. This discrepancy suggests that the disks were made with plutonium that Iran has not disclosed to the IAEA, the State Department official said.

Iran has provided the IAEA with some additional information regarding the matter, which the agency is currently assessing.

The IAEA is concerned that Iran may intend to use a heavy-water reactor under construction at Arak to produce plutonium for fissile material. But Iran does not have a known dedicated plutonium-separation facility and has not announced plans to build one.

Possible Nuclear Weapons Research

Uranium-Casting Document

ElBaradei reported to the IAEA board in November that Iran possesses a document containing instructions for reducing uranium hexafluoride to metal, as well as casting uranium metal into hemispheres. Uranium cast in such a manner is used in explosive cores of nuclear weapons. (See ACT, December 2005.)

ElBaradei noted that “there is no indication” Iran has actually used the information in the document, but he also suggested that Iran may possess additional related documents. The report indicates that the Khan network provided the same document, along with “other similar documents,” to a country now known to be Libya.

According to the State Department official, IAEA Deputy Director-General Olli Heinonen told diplomats March 3 that members of the Khan network revealed that Iran requested the document. Tehran had earlier maintained that its suppliers initiated the document transaction.

Other Possible Military Projects

The IAEA also continues to investigate other possible nuclear weapons-related projects that were described in documents found in an Iranian laptop computer.

IAEA officials met with their Iranian counterparts in January and February to discuss the discovery of documents relating to a “Green Salt Project.” Specifically, the documents disclosed designs for a “small-scale” facility to produce “green salt,” another name for uranium tetrafluoride. A former State Department official confirmed in February that the computer contained designs for a “small-scale” facility to produce green salt. However, Tehran denies that the project exists and has declined to discuss the matter.

The IAEA also is investigating intelligence that Iran has conducted “tests related to high explosives” and has produced a “design of a missile re-entry vehicle.” According to the State Department official, the “tests” refer to evidence also reportedly found on the laptop, which indicates that Iran has conducted research on electronically driven detonators used to ignite conventional explosives at high speeds. This research is applicable for building an implosion-type nuclear device.

Whether and to what extent a re-entry vehicle design would improve Tehran’s ability to deliver a nuclear weapon is unclear. A State Department official confirmed information first reported in the March 13 edition of Time magazine describing what U.S. officials believe is an Iranian nuclear-weapon design. The intelligence, which was found on the laptop, describes a sphere about 0.6 meters in diameter with a mass of 200 kilograms.

The former State Department official said that there is insufficient information to determine Iran’s weapons-making capability. But it is generally believed that explosive nuclear tests are required to develop a reliable nuclear warhead of that size. Iran has never conducted such a test.

The IAEA is investigating evidence indicating that some Iranian officials involved in the re-entry vehicle project are also associated with Iran’s nuclear program. For example, the State Department official said that there is a “paper trail” connecting at least one such official with a research center that has been the subject of IAEA scrutiny.

Located at a site called Lavizan-Shian, the Physics Research Center has attracted the agency’s attention because it was involved in nuclear research and had been connected to the Iranian Ministry of Defense.

ElBaradei reported that Iran recently fulfilled a long-standing agency request by allowing IAEA inspectors Feb. 26 to interview the former head of the research center about the center’s efforts to obtain equipment potentially related to uranium enrichment. The IAEA still wishes to interview another official involved in the center’s procurement efforts, his report says.