Of all the pressing issues in the volatile Middle East, the most pressing for the Biden administration will be Iran’s controversial nuclear program. Joe Biden pledged to rejoin the landmark nuclear deal negotiated between Iran and the six major world powers in 2015. “If Iran returns to strict compliance with the nuclear deal, the United States would rejoin the agreement as a starting point for follow-on negotiations,” he wrote in an op-ed for CNN in September 2020.
But rejoining the nuclear agreement will not be easy. The Islamic Republic continued to comply with its obligations for more than a year after President Donald Trump abandoned it in May 2018. In July 2019, Tehran began breaching the agreement. Iran’s breaches had been largely incremental and calibrated until the assassination of Mohsen Fakhrizadeh, a top nuclear scientist, on November 27.
- In July 2019, Iran surpassed limits on its stockpile of low-enriched uranium. A week later, it increased enrichment from 3.67 percent to 4.5 percent.
- In September 2019, it began using advanced centrifuges to enrich uranium.
- In November 2019, it began enriching uranium at the underground Fordo facility.
- In November 2019, it surpassed the limits on its stockpile of heavy water.
- In September 2020, its stockpile of low-enriched uranium reached 2,105 kilograms (2.3 tons), or about 10 times more than the limit set by the nuclear deal.
- In November 2020, its stockpile of low-enriched uranium reached 2,443 kilograms (2.7 tons), or about 12 times more than the limit set by the nuclear deal. A week later, it began enriching using 174 advanced centrifuges, the IR-2Ms.
Taken together, Iran’s so-called breakout time – the time needed to enrich enough uranium for one nuclear bomb – has shortened from one year to about three months, non-government nuclear experts estimated.
On December 1, three days after the Fakhrizadeh assassination, Iran's parliament, which is dominated by conservatives, enacted legislation demanding that the government immediately resume enriching uranium to 20 percent, a step that could bring Tehran closer to attaining fuel for a bomb. The nuclear deal stipulated that Tehran could only enrich uranium to 3.67 percent. On December 3, Iran told the International Atomic Energy Agency (IAEA) that it would quadruple the number of advanced centrifuges at an underground facility at Natanz.
In January 2021, Iran resumed enriching uranium to 20 percent at Fordo, an underground nuclear facility, and started research on metal-based fuels that could potentially be used as the core of a nuclear weapon. The IAEA warned that Iran was “quite rapidly” enriching uranium at 20 percent. “It is clear that we don’t have many months ahead of us,” IAEA director Rafael Grossi said on January 11. “We have weeks.” The following is a rundown of Iran’s breaches and assessments by the IAEA on Iran’s nuclear program.
Timeline of IAEA reports
Aug. 30, 2019: An IAEA safeguards report confirmed that Iran had begun to enrich uranium to 4.5 percent, beyond the 3.67 percent limit stipulated in the JCPOA. The agency also verified that Iran’s stockpile of low-enriched uranium exceeded the 300 kg limit. Iran continued to adhere to other aspects of the deal and allowed inspectors access to all sites that they needed to visit. But the report implied that Iran’s cooperation could use improvement. “Ongoing interactions between the Agency and Iran...require full and timely cooperation by Iran. The Agency continues to pursue this objective with Iran,” said the report.
Sept. 25, 2019: The IAEA found that Iran had breached the JCPOA again by using advanced centrifuges to enrich uranium. The watchdog “verified that all of the (centrifuge) cascades already installed in R&D lines 2 and 3 ... were accumulating, or had been prepared to accumulate, enriched uranium.” Each cascade could include up to 20 centrifuges. The JCPOA only allowed Iran to use some 5,000 of its first-generation IR-1 centrifuges to enrich uranium. Advanced centrifuges were supposed to only be used in small numbers for research purposes.
Nov. 11, 2019: In a quarterly report, the IAEA said that Iran had breached the 2015 nuclear deal by increasing its stockpile of enriched uranium. The watchdog also reported that its inspectors had found traces of uranium “at a location in Iran not declared to the agency.” The IAEA confirmed Iran had started enriching uranium at the underground Fordo facility. The JCPOA had banned uranium enrichment at the site until 2031.
Nov. 18, 2019: The IAEA confirmed that Iran had breached the 130 metric ton limit on heavy water set by the JCPOA. Heavy water allows unenriched uranium to be used as a fuel in specially designed nuclear reactors. Heavy water reactors also produce plutonium as a waste fuel, which can then be reprocessed for use in plutonium bombs.
March 3, 2020: The IAEA released two reports that criticized Iran for violations of the JCPOA. Iran had tripled its stockpile of low- enriched uranium over the previous three months, it said in one report. It shortened the breakout time to produce enough fissile material for a nuclear weapon, although the IAEA did not find evidence that Iran had taken steps to produce a bomb. In the second report, the IAEA condemned Iran’s refusal to grant inspectors access to three sites of interest. The report said that it found evidence from early July 2019 that was consistent with efforts to “sanitize” part of an unnamed location to obscure nuclear material.
March 3, 2020: The IAEA said that Iran had refused to grant inspectors access to three sites of interest. The sites were suspected to have been part of the Iran’s nuclear program in the early 2000s. The watchdog believed that Iran had tried “to sanitize part of the location” to obscure its past nuclear activities. “Iran is curtailing the ability of the agency to do its work,” IAEA Director General Rafael Grossi said.
June 5, 2020: The IAEA said that Iran’s stockpile of enriched uranium had grown far above the amount permitted by the JCPOA. Iran possessed 1,571.6 kg of low enriched uranium, a 50 percent increase since February. Its stockpile of heavy water remained slightly above the 130 metric ton limit set by the JCPOA.
June 5, 2020: Iran blocked IAEA inspectors from accessing two sites, the U.N. watchdog reported. The agency said that the sites may have been used for the storage and explosive testing of undeclared nuclear materials in the early 2000s. “The Agency notes with serious concern that, for over four months, Iran has denied access to the Agency…to two locations and, for almost a year, has not engaged in substantive discussions to clarify Agency questions related to possible undeclared nuclear material and nuclear-related activities in Iran,” the report said.
June 19, 2020: The IAEA Board of Governors passed a resolution—25 to two, with seven abstentions—calling on Iran to fully cooperate with an investigation into its past nuclear work after more than a year of stonewalling. Iran had denied inspectors access to two suspect sites where it was suspected of storing undeclared nuclear material The resolution was the first formal challenge of Iran in eight years from the IAEA Board of Governors.
Aug. 26, 2020: The IAEA and Iran released a joint statement which said that Iran agreed to provide the IAEA with access to the two suspect sites and facilitate verification activities.
Sept. 4, 2020: In a quarterly report, the IAEA said that Iran’s stockpile of low-enriched uranium reached 2,105 kilograms, or about 10 times more than the JCPOA limit. The stockpile had grown some 544 kilograms since the last quarterly report, released in June. Iran also began operating slightly more advanced centrifuges, but not enough shorten its breakout time, which remained three to four months. When Iran was in full compliance with the JCPOA, its breakout time had been 12 months.
In a separate safeguards report, the U.N. watchdog confirmed that it had visited one undeclared nuclear site to take environmental samples. The agency said it would visit another suspect site later in September.
Nov. 11, 2020: The IAEA reported that Iran’s stockpile of low-enriched uranium reached 2,443 kg (2.7 tons), or about 12 times more than the JCPOA limit. The stockpile had grown by 337.5 kg since the prior report released in September, a slower rate of growth than previously recorded. Iran installed 174 IR-2M centrifuges and conducted tests of three IR-4 advanced centrifuges.
The IAEA found Iran’s explanations for uranium particles detected at an undeclared nuclear site to be “unsatisfactory” and “not technically credible.”
Nov. 17, 2020: The IAEA reported that Iran began feeding uranium gas into 174 IR-2M advanced centrifuges at Natanz, the IAEA .
Dec. 4, 2020: Iran informed the IAEA that it would install three new cascades of advanced centrifuges. Each cascade was made up of more than 150 centrifuges.
Jan. 4, 2021: The IAEA confirmed that Iran had begun enriching uranium up to 20 percent at Fordo. The agency verified that centrifuges cascades at Fordo had been reconfigured to enrich levels of uranium from 4.1 percent to 20 percent.