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Natanz explosion: Timeline and details on possible scenarios


An incident at the Natanz nuclear enrichment facility on July 2 led to speculation over whether the incident was as serious setback for Iran's nuclear program and what was affected. It also leads to questions over whether it was, as Iran asserts, an accident or intentional sabotage.


The incident was the third of three myserous incidents in a week. On June 25 a massive explosion, seen many miles away in Tehran, burned a hillside near a missile complex at Khojir. On June 30 a medical center suffered a fire in Tehran, killing more than a dozen people. On July 2 an incident at Iran’s Natanz enrichment facility was initially mentioned by Iran’s official media, without elaboration.

It comes in the wake of a cyber attack. Iran alleged a cyber attack harmed Shahid Rajaee port in May.

In historical terms Natanz is important and has been sabotaged before. The Natanz facility was last impacted by the Stuxnet malicious computer worm in 2010. Stuxnet was developed by Israel and the US according to the New York Times and may have destroyed up to 1,000 centrifuges at the Natanz facility.

The Associated Press noted that the US National Oceanographic and Atmospheric Administration has data from a satellite tracking fires that shows a fire at around 2am. This corresponds with someone on the ground who allegedly heard an explosion.

What is the Natanz facility?

The Natanz consists of a fuel enrichment plant and is Iran’s largest gas centrifuge uranium enrichment facility, according to the BBC. It began functioning in 2007. It was part of the Joint Comprehensive Plan of Action, or Iran Deal, of 2015. BBC notes: "Before 2015, the country had two enrichment facilities - Natanz and Fordo - where uranium hexafluoride gas was fed into centrifuges to separate out the most fissile isotope, U-235. The deal saw Iran agree to only produce low-enriched uranium, which has a 3-4% concentration of U-235, and can be used to produce fuel for nuclear power plants. Weapons-grade uranium is 90% enriched or more...Iran also agreed to install no more than 5,060 of the oldest and least efficient centrifuges at Natanz until 2026, and not to carry out any enrichment at Fordo until 2031. The 1,044 centrifuges there were supposed to spin without uranium hexafluoride gas being injected."

In November 2019 the Atomic Energy Organization of Iran said it had doubled the number of advanced centrifuges at the site. This was part of Iran's decision to increase enrichment and move away from the 2015 deal. An inspector of the site was denied entry in 2019. Iran was progressing with enrichment at Natanz. According to reports at the end of 2019 Iran had unveiled 30 IR-6 centrifuges for Natanz and there were 60 of these spinning at Natanz at the time.

The first reports in Iranian media on July 2

The incident: Official statements

Iran’s Behrouz Kamalvandi (بهروز کمالوندی), spokesman for the Iranian Atomic Energy Organization, said no casualties had occurred at Natanz and that the incident was being investigated on July 2. Read his statement at this link.

It was not widely reported in Iranian media until some eight hours after the initial explosion and fire took place. IRIB news gave a tour of the area that was burned in the afternoon.

The tour of the facility on the afternoon of July 2.

On July 3 Iran highlighted an IAEA statement that also appeared to downplay the impact of the explosion. "According to the International GroupTheInternational Atomic Energy Agency (IAEA) said on Thursday in response to news of the incident in one of the sheds under construction in the open area of ​​the Natanz nuclear site that the incident was likely to affect the agency's oversight activities at the Natanz nuclear site."

The Iranian media reiterated: "The incident was in one of the sheds under construction in the open area of ​​Natanz website, Behrouz Kamalvandi, the spokesman of the Atomic Energy Organization, said: In fact, there is no pollution. Kamalvandi pointed out: "Unfortunately, some rumors have been spread by the opposition media regarding the issue of pollution, which is not true at all." Expert teams are at the scene and are investigating the cause of the accident."

This was one of three reports provided to media such as Tasnim, read the others here and here and here. This was an attempt by Tehran to control the narrative.

The incident: Claims of responsibility and other statements

Throughout July 2 details emerged about the incident. An analysis piece at IRNA news said the “Zionist regime and the US” were crossing red lines.

Head of Iran's Passive Defense Organization Brigadier General Gholamreza Jalali on Friday July 3 said that very limited cyberattacks waged against facilities of the country since the start of the current Iranian year

A group called the “Homeland Panthers (Cheetahs of the Homeland)” claimed responsibility, according to emails allegedly sent to BBC Persian. The emails arrived “hours before any news of the incident had emerged,” according to Radio Farda. The emails however claimed something more complex. They asserted there was an attack and then a coverup. They appeared to want to blow the lid on the coverup they assumed would happen.

The Associated Press noted that the US National Oceanographic and Atmospheric Administration has data from a satellite tracking fires that recorded a fire at around 2am at the site. This corresponds with someone on the ground who allegedly heard an explosion.

The AP report quotes Fabian Hinz of the James Martin Center for Nonproliferation Studies claiming the fire took place at a new centrifuge production facility. David Albright of the Institute for Science and International Security also concurred that the fire was at a new production facility. This would be a set back for Iran’s production. Hinz said it could delay the advancement of centrifuge technology.

The New York Times reported that "a Middle Eastern intelligence official...said the blast was caused by an explosive device planted inside the facility. The explosion, he said, destroyed much of the aboveground parts of the facility.” This could be an area where new centrifuges are “balanced before they are put into operations.”

The July 3 Al-Jarida report

July 3: The claims grow

Al-Jarida media in Kuwait had a report on July 3 that Israeli "F-35 fighters bombed the Parchin site without the need for refueling" and then noted that "an Israeli electronic attack on 'Natanz' targeted computers controlling storage pressure devices...Tehran lost 80% of the UF6 gas stock necessary for uranium enrichment."

Al-Jarida referenced earlier reports about Israel being able to fly F-35s to Iran as proof that its source was correct this time. "The source also denied that Israel had bombed the Natanz site with an air strike, confirming that it had launched a cyber attack on the Iranian facility.

Tehran succeeded in hacking the Israeli Water Authority a few weeks ago, to respond to Tel Aviv with a cyber attack that targeted an Iranian port. It is noteworthy that the Natanz nuclear site, which is the main site for uranium enrichment and is located in the Isfahan province, was previously hacked through the Stuxnet virus, which caused the delay of Iran's nuclear program."

Al-Jarida's March 2019 reports on previous F-35 incidents can be read about here and here and here. The earlier reports were debated and considered of interest. Israeli media usually re-reports these findings or launders these accounts.

The July 3 report at Al-Jarida has some specifics. It says the sabotage targeted UF6 (uranium hexafluoride gas) gas storage that was used for uranium enrichment. This is linked to the November 2019 reports that Iran had begun production and injection of the gas into IR-6 centrifuges. These are the advanced centrifuges Iran has increased at Natanz. The Atomic Energy Organization of Iran (AEOI)’s Ali Akbar Salehi has spoken openly about the gas and the new centrifuges. The Kuwaiti paper asserts that Iran has now lost 80% of its stock of this gas. “This is likely to be an electronic attack on the computer network that controls the storage compression tanks. Iran will need about two months to compensate for the gas that was lost.” The Natanz explosion led to a “crack in the reactor building. Specialized groups went to the reactor to discover whether there was leakage in radioactive materials.”

The building where the fire appears to have taken place

Reports on July 3 assisted in locating the building at the Natanz facility where the incident took place. (approx. coordinates 33°43′N 51°43′E). Information now pointed to this building holding "equipment inside the workshop was used to take accurate measurements during the assembly of centrifuges that are sensitive and difficult to build."

VOA noted: “It took the Iranians a long time to build this workshop,” Washington-based Institute for Science and International Security researcher Sarah Burkhard told VOA Persian in an interview. “Its construction started in 2012 and they only got to a point where they could start operations there in 2018,” she said. Reports on July 3 pointed increasingly toward sabotage as the main factor behind the explosion, as opposed to an accident.

Iran moves towards a conclusion

Iran seeks to allay concerns to the IAEA that the fire or explosion resulted in damage or leaks that would lead to a finding against Iran. Iran told the IAEA that the cause was unknown as of Friday. Satellite images meanwhile confirmed the details of the damage. By Friday evening Iran officials were telling Reuters "they believed the fire at Natanz was the result of a cyber attack, but did not cite any evidence. One of the officials said the attack had targeted the centrifuge assembly building."

Reuters noted the following:

An article issued on Thursday by state news agency IRNA addressed what it called the possibility of sabotage by enemies such as Israel and the United States, although it stopped short of accusing either directly. "So far Iran has tried to prevent intensifying crises and the formation of unpredictable conditions and situations," IRNA said. "But the crossing of red lines of the Islamic Republic of Iran by hostile countries, especially the Zionist regime and the U.S., means that strategy...should be revised." Three Iranian officials who spoke to Reuters on condition of anonymity said they believed the fire was the result of a cyber attack, but did not cite any evidence.

This appeared to show Iran was weighing its options. If it says it was an attack it would need to respond. If it says it wasn't an attack, it must explain the accident to the IAEA.

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