"On 7 March 2021, the Agency verified... that: Iran had begun feeding natural UF6 into the third cascade of 174 IR-2m centrifuges," the UN nuclear agency said in a Monday report obtained by Reuters, referring to uranium hexafluoride, the feedstock for centrifuges.
"The fourth cascade of 174 IR-2m centrifuges was installed but had yet to be fed with natural UF6; installation of a fifth cascade of IR-2m centrifuges was ongoing; and installation of a sixth cascade of IR-2m centrifuges had yet to begin," it added.
Iran’s representative to the Vienna-based international organizations said in February that the country had installed new cascades of advanced centrifuges at two nuclear sites in Natanz and Fordow to increase enrichment capacity.
“Thanks to our diligent nuclear scientists, two cascades of 348 IR2m centrifuges with almost 4 times the capacity of IR1 are now running with UF6 successfully in Natanz,” Kazem Gharibabadi had announced in a post on his Twitter account.