Well. Peter Crail has a “piece”:http://www.armscontrol.org/act/2011_10/IAEA_to_Detail_Iran_Alleged_Warhead_Work in ACT which states that Iran, despite earlier claims from Iranian officials, has begun installing IR-1 centrifuges at Fordow, rather than more advanced models.

Writes Peter:

bq.. Last June, Iran announced that it would soon begin using the plant to produce uranium enriched to 20 percent uranium-235 to produce fuel for research reactors and that it would triple such production through the use of more-advanced centrifuge designs it has been developing. The Sept. 2 IAEA “report”:http://isis-online.org/uploads/isis-reports/documents/IAEA_Iran_2Sept2011.pdf said that as of Aug. 20, Iran had installed one of two centrifuge cascades designated for the production of 20 percent-enriched uranium.

*snip*

Although the report did not specify the type of machine being installed, *diplomatic sources confirmed that the centrifuges are IR-1 machines, a crash-prone design Iran currently uses at its commercial-scale Natanz enrichment plant.* The improved designs Iran has been developing, called the IR-2m and IR-4, are believed to enrich uranium three times faster than the IR-1.

p. ISIS analysts David Albright, Paul Brannan, Andrea Stricker, and Christina Walrond “confirmed”:http://isis-online.org/uploads/isis-reports/documents/IAEA_Iran_Report_ISIS_analysis_2Sept2011.pdf the IR-1 installation with their own sources:

bq.. The IAEA reports that Iran has installed one cascade of centrifuges at the Fordow site to be designated for production of 19.75 percent enriched uranium. *ISIS has learned that these machines are new IR-1 centrifuges, not existing ones transferred from Natanz.*

Earlier this summer, the Vice President of Iran and head of Iran’s Atomic Energy Organization of Iran (AEOI), Fereydoun Abbasi-Davani, implied that Iran would soon deploy advanced centrifuges at Fordow, stating that these machines would be installed in 164-machine cascades.