Strike at Natanz nuclear enrichment facility in Iran: what kind of retaliation to expect?

Former Junior Research Fellow, Nuclear Nonproliferation and Russia Program
July 13, 2020

In July a large explosion caused extensive damage to a building at the nuclear complex at Natanz, Iran’s largest uranium-enrichment facility. The next day, another explosion was reported at a power station in the southern Iranian region of Ahvzaz, close to the Iraqi border[1].

Just since Thursday, explosions occurred at two power plants in Iran, and there was a chlorine gas leak at a chemical plant, all of which the government described as accidents. The previous week, an explosion hit a missile production facility at the Khojir military complex in eastern Tehran, which officials said was caused by a gas tank’s detonating.

The damage caused to Natanz enrichment facility is estimated to be far more extensive that was previously reported. Satellite images beefed up the photos from ground level that slowly led Iranian officials to switch from calling the damage at the facility “limited” to “significant”[2]. High-resolution commercial satellite imagery from July 4 and 5, 2020, shows that the Iran Centrifuge Assembly Center (ICAC) at the Natanz Enrichment Site has suffered significant, extensive, and likely irreparable, damage to its main assembly hall section. The facility was essential to the mass production of advanced centrifuges, in particular the assembly of rotor assemblies, the rapidly spinning part of the centrifuge and its most crucial component. An annex to the building was intended to assemble electrical components of centrifuges, including motors, another important component of centrifuges[3].

The restoration works might take 1 year or more to rebuild the entire facility from the scratch, so severe was the damage caused. It is extremely likely that much of the sensitive equipment, including balancing machines, specialized rotor assembly equipment, measuring equipment, and centrifuge test stands, are also largely unsalvageable. The explosion may have destroyed any contents of what must be a large storeroom for sensitive centrifuge components and many rotor assemblies; the latter would await deployment in enrichment plants[4].

Iranian R&D facilities are not likely to be affected by the explosion. Iran has near-term research and development of centrifuges at the nearby Natanz Pilot Fuel Enrichment Plant (PFEP). Iran has other facilities that assemble advanced centrifuges for R&D, such as Kalaye Electric, a facility in north Tehran which assembles the IR-8 centrifuge and perhaps other ones as well. This all proves the notion that the attack clearly had political component provided with a series of short-of-war clandestine strikes aimed at eliminating any chance of Iran producing highly-enriched uranium (HEU) for military purposes.

Iran’s facilities monitored 24/7 prior to the accident It is noteworthy that Iran continued its international obligations and allowed International Atomic Energy Agency (IAEA) to monitor its critical facilities. Iran permitted the Agency to use on-line enrichment monitors and electronic seals, said the latest IAEA report. For instance, prior to the implementation of the Iran agreement (formally known as the Joint Comprehensive Plan of Action, or JCPOA) on January 16 of 2016, the IAEA had installed what is known as an Online Enrichment Monitor[5] or OLEM, a new high-tech device that monitors Iran’s uranium enrichment activities at the Natanz Fuel Enrichment Plant 24 hours per day, seven days a week. It measures the characteristics of gaseous uranium, in each unit of the equipment, the main connection node—a gamma ray detector based on a sodium iodide crystal—measures the amount of uranium 235 in the pipe, while pressure and temperature sensors enable the machine to determine the total quantity of gaseous uranium. From the two, the device can calculate the enrichment level, which can be checked by inspectors on the site. The device is non-intrusive and does not use a radioactive source, it is safe to maintain and can work autonomously All its components are contained in sealed boxes that are connected by special tubing and all enclosures are under IAEA seal. A special paint is used to ensure that any attempt to tamper with the system will be detected[6].

Responsible State Party for the attack? A Middle Eastern intelligence official said Israel planted a bomb in a building where advanced centrifuges were being developed. Meanwhile, Israeli Defense Minister Benny Gantz denied that Israel was behind a number of mysterious blasts in Iran, saying that not everything that happens there could be blamed on the Jewish state[7]. However, the Israeli intentions are “ to act on all fronts to reduce the possibility that Iran will become a nuclear power – and we will continue to do this part of protecting our security”- a part of a Gantz citation on his interview to Army Radio.

Retaliation to be? It was quite clear that American-Israeli alliance is most likely connected to the fire attacks on Iranian critical facilities, especially concerning the fact Now the World is expecting retaliatory actions form Iranian defense agency. Western officials anticipate some type of cyberattacks, perhaps against American or allied forces in Iraq. In the past, those have been directed against American financial institutions, a major Las Vegas casino and a dam in the New York suburbs or, more recently, the water supply system in Israel, which its government considers “critical infrastructure[8].”

The main idea that Iranians may not do significant vengeance is that Iran does not want to do much for the administration that due in November. The same happened with the assassination of General Suleimani in January. This incident did not lead to reciprocal actions form Iran which makes it quite likely that Iran will limit its actions to cyberattacks. Many hopes are put to the new U.S administration and initiatives to resurrect Joint Comprehensive Plan of Action with U.S. active participation.

[1] Gantz: Not everything that happens in Iran is connected to us. The Jerusalem Post, 5 july 2020. URL:

[2] Mystery fire at Iranian nuclear facility is the latest in a series of unexplained incidents. CNN July 6, 2020. URL:

[3] Damage to the Iran Centrifuge Assembly Center (ICAC) at Natanz Is Far More Severe and Extensive Than Previously Reported. Institute for Science and International Security, 8 July 2020. URL:

[4] Damage to the Iran Centrifuge Assembly Center (ICAC) at Natanz Is Far More Severe and Extensive Than Previously Reported. Institute for Science and International Security, 8 July 2020. URL:

[5] New IAEA Uranium Enrichment Monitor to Verify Iran’s Commitments under JCPOA. International Atomic Energy Agency official website. URL:

[6] Round-the-clock surveillance of Iran’s uranium-enrichment sites continues, despite coronavirus. Bulletin of the Atomic Scientists, 25 March 2020. URL:

[7] Gantz: Not everything that happens in Iran is connected to us. The Jerusalem Post, 5 July 2020. URL:

[8] Israel Hack of Iran Port Is Latest Salvo in Exchange of Cyberattacks. New York Times, 19 May 2020. URL: