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Accelerated Advanced Centrifuge Deployments
On October 10, 2022, the IAEA reported new advanced centrifuge deployments at the
underground enrichment facility at the Natanz FEP (see Annex). The IAEA report did not
contain any new information on advanced centrifuge deployments at the Fordow Fuel
Enrichment Plant (FFEP) or the Natanz Pilot Fuel Enrichment Plant (PFEP).
The new IAEA report shows a marked increase in Iran’s centrifuge deployments (see Figure 1).
As of October 10, 2022, Iran had a total of 4000 advanced centrifuges of varying types installed
at its three enrichment facilities.
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Over half of the installed advanced centrifuges are IR-2m
centrifuges. The FEP contains roughly 78 percent (3132 advanced centrifuges) of the total
number of advanced centrifuges Iran has deployed at all three facilities.
At the Natanz FEP, as of October 10, 2022, Iran had 3132 advanced centrifuges installed in 12
IR-2m cascades (2088 centrifuges), three IR-4 cascades (522 centrifuges), and three IR-6
cascades (522 centrifuges). Since late August 2022, the last month covered by the IAEA’s latest
quarterly Iran report, Iran installed 1218 advanced centrifuges in six IR-2m cascades and
completed one IR-4 cascade at the Natanz FEP.3 This buildup in just over five weeks signifies a
44 percent increase in the total number of Iran’s installed advanced centrifuges.
The workhorse: the IR-1
The IR-1, based on a design provided by Khan, is the most widely deployed centrifuge in Iran’s facilities. Research and design on the IR-1 began in earnest in the late 1990s, when Iran first successfully tested a centrifuge and made a decision to scale up its program. The output of a single IR-1 in a cascade is estimated to be about 0.8 SWU per year, which is low compared to Iran’s more advanced models.
As of November 2022, Iran was operating approximately 7,000 IR-1 centrifuges, with thousands more in storage. The rotors of the IR-1 are made from aluminum. Its bellows are made from maraging steel.
Second-generation: the IR-2m and IR-4
Iran experimented with a second generation of centrifuges based on drawings and components of Pakistan’s P-2 provided by Khan. Iran subsequently modified those designs to develop the IR-2m and the IR-4. The rotor assembly of the IR-2m is made of carbon fiber and maraging steel; the IR-4’s rotor assembly is made entirely from carbon fiber. The output of both the IR-2m and the IR-4 is estimated to be roughly 4 SWU to 5 SWU per year—or four to five times greater than an IR-1.
When Iran began breaching the accord in 2019, it scaled up enrichment using both machines. By November 2022, Iran was operating 1,044 IR-2m centrifuges and 348 IR-4 centrifuges to produce and stockpile low-enriched uranium at the FEP at Natanz. It was also using a single cascade of 164 IR-4 centrifuges in conjunction with a cascade of IR-6 machines to enrich uranium to 60 percent at the PFEP at Natanz.
Third generation: the IR-6
In 2021, Iran began using a cascade of IR-6 centrifuges to produce uranium enriched up to 60 percent at the PFEP at Natanz. For the first time, it also installed IR-6 machines at Fordow and used them in conjunction with IR-1 cascades to produce uranium enriched to 20 percent. A year later, Iran announced it was enriching uranium to 60 percent there. Iran has also installed 522 IR-6 centrifuges in three cascades at the FEP at Natanz since mied-2022.