Iran's Growing Stockpiles of Enriched Uranium

As of November 2020, Iran had amassed 12 times the amount of enriched uranium – the fuel for a nuclear bomb – that was permitted by the 2015 nuclear deal negotiated by the world’s six major powers. The deal stipulated that Tehran was limited to producing a maximum of 203 kg (or 447 pounds) of low-enriched uranium to only 3.6 percent. Generating fuel is one of three steps required to make a viable bomb; the others are designing the weapon and marrying it to a delivery system, such as a missile or a gravity bomb dropped by a warplane. As of November 2, Tehran had stockpiled 2,443 kg (or 5,386 pounds) of uranium enriched to 4.5 percent, the International Atomic Energy Agency (IAEA) reported.

Past Report: IAEA Rebukes Iran for Nuclear Violations

Centrifuges at the Fordow Nuclear Site
Centrifuges at the Fordow Nuclear Site

If Iran enriched its entire stockpile to 90 percent, it would have enough enriched uranium for two nuclear weapons. By November, Tehran’s so-called breakout timeline—or the time needed to highly enrich enough uranium for one nuclear bomb —had decreased from more than a year (under the terms of the nuclear deal) to about three months, the Institute for Science and International Security, a nuclear nonproliferation group, reported. Iran also installed 174 advanced centrifuges—the IR-2M — to enrich a larger quantity of uranium, shrinking the breakout time even further.

Yet Iran also appeared to limit its breaches of the deal originally brokered by the Britain, China, France, Germany, Russia and the United States, according to nuclear experts also outside the U.N. watchdog agency. The rate of enrichment actually slowed between September and early November 2020. The slower growth — and the lull in new violations—suggested that Tehran “is showing restraint so as not to cross any red lines that might imperil a U.S. re-entry into the nuclear deal and return to full compliance by all parties down the road,” the Arms Control Association wrote in an analysis of the November IAEA report. 

The Trump administration was sufficiently concerned about the IAEA report that the president reportedly considered military options before leaving office. Iran, in turn, threatened retaliation for a U.S. military strike. “Any action against the Iranian nation would certainly face a crushing response,” Ali Rabei, the government spokesperson, said. The IAEA also warned that a military strike would undermine its ability to inspect nuclear sites. 

Past Analysis: Iran's Breaches of the Nuclear Deal

The assassination of Mohsen Fakhrizadeh, a prominent nuclear scientist, led Iran to take more dramatic steps. On December 1, the conservative-dominated parliament passed a bill demanding that the government immediately resume enriching uranium to 20 percent, a step that could bring Tehran closer to attaining fuel for a bomb. On December 3, Iran told the IAEA it would quadruple the number of IR-2M centrifuges at the underground Natanz facility, violating the JCPOA's limits on advanced centrifuges. 

Britain, France and Germany warned that these breaches could "jeopardize" European efforts to revive the JCPOA under a Biden administration. "If Iran is serious about preserving a space for diplomacy, it must not implement these steps," the E3 said in a joint statement on December 7. 

Iran has breached the nuclear deal at least five times since President Donald Trump withdrew from the agreement in May 2018.  Tehran first exceeded the deal’s limits on its uranium stockpile in July 2019 and on advanced centrifuges in September 2019. Foreign Minister Javad Zarif has said that all steps are “reversible,” if the U.S. returned to the deal and lifted all sanctions on Iran. The following are excerpts from the IAEA report.


Enriched Uranium Stockpile

“As of 2 November 2020, the Agency verified that, based on the JCPOA and decisions of the Joint Commission, Iran’s total enriched uranium stockpile, comprising enriched uranium produced at FEP, PFEP and FFEP47 was 2442.9 kg (+337.5 kg since the previous quarterly report). The stockpile comprised 2408.5 kg of uranium in the form of UF6; 15.5 kg of uranium in the form of uranium oxides and their intermediate products; 8.2 kg of uranium in fuel assemblies and rods; and 10.7 kg of uranium in liquid and solid scrap."

“The total enriched uranium stockpile comprises 215.1 kg of uranium enriched up to 3.67% U-23548, produced prior to 8 July 2019, and 2227.8 kg of uranium enriched up to 4.5% U-235, produced since 8 July 2019. The latter, which is entirely in the form of UF6, includes 692.7 kg of uranium enriched up to 2% U-235 produced in R&D lines 2 and 3 at PFEP.”


Advanced Centrifuges

“On 2 September 2020, the Agency verified that Iran had installed the headers and sub-headers of one unit at FEP where these three cascades were to be installed. On 11 October 2020, the Agency verified that Iran had installed the cascade of IR-2m centrifuges and, on 9 November 2020, verified that this cascade was connected to the feed and withdrawal stations, but was not being fed with UF6. On the same date, the Agency also verified that Iran had begun installing the cascade of IR-4 centrifuges but had not begun installing the cascade of IR-6 centrifuges.”

“On 10 November 2020, the Agency verified that Iran was continuing to accumulate enriched uranium from R&D lines 2 and 3 (paras 32–42) through feeding UF6 into cascades of up to: nine IR-4 centrifuges; eight IR-5 centrifuges; six IR-6 centrifuges and another cascade of 20 IR-6 centrifuges; 10 IR-6s centrifuges; and 10 IR-s centrifuges. The following single centrifuges were being tested with UF6 but not accumulating enriched uranium: one IR-1 centrifuge; four IR-2m centrifuges; one IR-4 centrifuge; two IR-5 centrifuges; two IR-6s centrifuges; one IR-8 centrifuge; one IR-8B centrifuge; one IR-s centrifuge; and one IR-9 centrifuge. On 27 September 2020, the Agency verified that Iran had dismantled the cascade of IR-2m centrifuges in R&D line 5 (see paragraph 13 above). On 10 November 2020, the Agency verified that Iran was continuing to accumulate enriched uranium from R&D lines 4 and 6 (paras 32–42) through feeding UF6 into a cascade of 152 IR-4 centrifuges and a cascade of 110 IR-6 centrifuges, respectively.”

“On 18 October 2020, the Agency verified that Iran had conducted mechanical testing of three IR-4 centrifuges simultaneously for 42 days at the Tehran Research Centre (para. 40). As of 20 October 2020, Iran had not started using a new location, beyond those specified in the JCPOA, for mechanical testing of centrifuges.”


Undeclared Sites

“As previously reported, in February 2019, the Agency detected natural uranium particles of anthropogenic origin at a location in Iran not declared to the Agency. Based on subsequent information provided by Iran, the Agency took environmental samples at two declared nuclear facilities in Iran. The Agency’s assessment of the analyses of these samples was that some findings were not inconsistent with information provided by Iran, but that there were a number of other findings for which further clarifications and information needed to be provided and questions needed to be answered by Iran."

"These other findings included the presence, at the location in Iran not declared to the Agency, of isotopically altered particles of low enriched uranium, with a detectable presence of U-236, and of slightly depleted uranium."

“On 21 October 2020, Iran provided the Agency with additional information and explanations. In relation to the low enriched uranium particles, Iran said that ‘the evidence of such contamination is under investigation.’"

“The Agency considered Iran’s response to be unsatisfactory because it was not technically credible and, therefore, sought further clarifications and information from Iran. The Agency also noted the amount of time that had elapsed in addressing these issues. On 5 November 2020, Iran provided the Agency with some more information related to its explanations. In a letter dated 9 November 2020, following an assessment of this new information, the Agency informed Iran that it continues to consider Iran’s response to be not technically credible. A full and prompt explanation from Iran regarding the presence of uranium particles of anthropogenic origin, including isotopically altered particles, at a location in Iran not declared to the Agency, is needed.”



Statement by the E3 on Iran at the IAEA Board of Governors Meeting on November 18

"As participants to the JCPoA, we reiterate our continued commitment to the preservation and full implementation of the nuclear agreement. We E3 have worked hard to preserve the agreement. We have been consistently clear that we regret the US withdrawal from the JCPoA and re-imposition of US sanctions. We have lifted sanctions as foreseen by the JCPoA and taken additional efforts to allow Iran to pursue legitimate trade, by developing the financial mechanism INSTEX.

"However, despite these good faith efforts, Iran has engaged, for a year and a half now, in numerous, serious violations of its nuclear commitments. We continue to be extremely concerned by Iran’s actions, which are hollowing out the core non-proliferation benefits of the deal. Advancements on Research & Development have irreversible consequences.

"We are concerned at Iran enriching uranium above the 3.67% JCPoA limit, and the continued growth of its low-enriched uranium stockpile, which is now 2443 kg. This is a dozen times the JCPOA limit. Contrary to the JCPoA, Iran is using advanced centrifuges for the production of low-enriched uranium (LEU). Contrary to the JCPoA, Iran is also enriching at Fordow: this facility has no credible civilian use.

"Iran also continues to conduct research and development on several types of advanced centrifuges not permitted under the JCPoA and the JCPoA’s R&D Plan. This includes the operation of hundreds of IR-2m, IR-4 and IR-6 centrifuges. Iran has also introduced new types of centrifuges not authorized under the JCPoA. Iran must cease undertaking any research and development of advanced centrifuges contrary to the provisions of the JCPoA.

"On top of this, Iran has announced that it intends to install advanced centrifuges at the Fuel Enrichment Plant at Natanz. The IAEA report confirms this process has already started: one full cascade of IR2m centrifuges is now installed at the FEP, as well as some IR4 centrifuges. The report also indicates that these cascades will continue to accumulate uranium. The IAEA reported on 17 November that the process of feeding the IR2m cascade with UF6 has now been initiated.

"The JCPoA is clear that all centrifuge research and development should be undertaken at the PFEP. The JCPoA is also clear that only IR-1 centrifuges may be installed at the FEP for enrichment purposes and that their number is limited to no more than 5060. Iran’s latest decision to change the location of its research and development activities, which are already being conducted in ways that are inconsistent with the JCPoA, as well as increasing the overall number of centrifuges installed at the FEP, is a matter of deep concern. It makes it easier for Iran to expand its activities with advanced centrifuges in the future should it decide to do so. The FEP has space for thousands of additional centrifuges, therefore moving advanced centrifuges to a larger space raises serious concerns about Iranian intent. We urge Iran not to proceed with the installation of advanced centrifuges at the Fuel Enrichment Plant, and its plans to move its R&D facility to the FEP. These activities constitute a further violation of the JCPoA and send an unacceptable signal to the broader international community that has rallied in support of preserving the JCPoA.

"It is now critical that Iran immediately reverses its steps and returns to full compliance with the JCPoA without further delay. We remain committed to working with all JCPoA participants to find a diplomatic way forward and we intend to pursue these discussions within the framework of the JCPoA."

Photo credits: Tasnim News Agency (CC BY 4.0)
Some of the information in this article was originally published on November 18, 2020.