Seven centrifuge models are shown on the guide. Five of these models have been previously identified by experts from images made available by Iran: the IR-1, IR-2, IR-2m, IR-3 and IR-4. Based on the IAEA's most recent report on Iran's nuclear programme, there are 15,420 IR-1 centrifuges and 1008 IR-2m centrifuges curretntly installed at the below-ground Natanz Fuel Enrichment Plant (FEP). There are also an additional 356 IR-1 centrifuges installed at the Natanz facility’s above-ground Pilot Fuel Enrichment Plant (PFEP), along with 172 IR-2m centrifuges and 177 IR-4 centrifuges. The IR-2 and IR-3 variants, shown in 2008 during former Iranian president Ahmadinejad’s visit to the Natanz facility, were never installed in great numbers and have presumably been discontinued or superseded.
A 'third-generation' centrifuge publicly unveiled by Iran in 2010 is also pictured in the guide. It is identified as a possible IR-6, although this nomenclature is uncertain. According to IAEA reporting, there are currently 19 IR-6 centrifuges installed in the Natanz PFEP.
Project Alpha has also located in a 2010 PressTV video footage of what may be Iran's controversial IR-5 centrifuge. In November, Iran was accused of possibly violating the Joint Plan of Action when it fed uranium hexafluoride (UF6) into an IR-5 at the Natanz PFEP. (Iran subsequently pledged to stop the practice.) The IR-5 is not known to have been visually identified in the public domain before now, although it remains unclear as to whether the centrifuge shown in this video footage is actually an IR-5. According to IAEA reporting, there is currently only one IR-5 installed in the Natanz PFEP.
There are two other types of Iranian centrifuges which are not shown in the guide: the IR-6s and the IR-8, both of which Project Alpha has been unable to find images of in open sources.
The IR6s - presumably a variant of the IR-6, given its name - has been tested intermittently with UF6 in the Natanz PFEP since 2013. An incomplete prototype of the IR-8 centrifuge has been in the PFEP since late 2013, but has not yet been fed with UF6. The Institute for Science and International Security has conducted an analysis of the reported technical specifications of the IR-8, which is available here.
Under the terms of the seven-month extension of the Joint Plan of Action, Iran has reportedly agreed to refrain from pursuing 'semi-industrial-scale operation' of the IR-2m; to not feed the IR-5 centrifuge with UF6; to not pursue cascade testing of the IR-6; and to not install the IR-8, according to Al-Monitor.
Project Alpha's centrifuge field guide can be downloaded as a PDF document at the link below.