Iran’s nukesLooking for Evidence of the Construction of Iran’s New Centrifuge Assembly Plant: New Possible Preparations Identified

By David Albright, Sarah Burkhard, and Frank Pabian

Published 29 October 2020

This summer, Iran decided to construct a new underground centrifuge assembly plant, following the destruction of the above ground one at the Natanz enrichment site on 2 July 2020. So far, Iran has undertaken little visible work in the mountains adjacent to the Natanz enrichment site with the exception of possible construction preparations. A nearby gunnery range appears to have been converted to a construction support and staging area in the first half of September. Because of the added difficulties of building an underground site, the completion of a new centrifuge assembly plant able to assemble thousands of advanced centrifuges per year is unlikely in 2021.

In early September 2020, Iran announced its earlier decision to replace its Iran Centrifuge Assembly Center (ICAC), destroyed in early July of this year,1 with a new facility in a mountain near the Natanz uranium enrichment site. According to Ali Akbar Salehi, head of the Atomic Energy Organization of Iran (AEOI); “It was decided to establish a more modern, wider and more comprehensive hall in all dimensions in the heart of the mountain near Natanz. Of course, the work has begun.”2 The destroyed site was designed to assemble thousands of advanced centrifuges each year. Its destruction set back Iran’s plans to expand its centrifuge program by at least a year and perhaps longer. Exactly how long will depend on Iran’s ability to rebuild the new facility, outfit it with sensitive equipment, and bring it into operation.

It is hard to envision that Iran could quickly replace its assembly plant able to churn out thousands of centrifuges in a year. The above ground center at the Natanz enrichment site took years to finish and bring into operation, although some of that delay was caused by restrictions in the Joint Comprehensive Plan of Action (JCPOA). Nonetheless, absent the JCPOA, Iran would have needed more than a few years to build and operate a production scale plant.

Building the new plant in a mountain would further complicate its construction. The tunnel must include clean rooms necessary for assembling advanced centrifuges. Some of the replacement equipment is controlled internationally and highly sophisticated, likely requiring Iran to try to obtain it from abroad. Since Iran is banned from buying it, it will need to activate its illicit procurement networks, potentially causing further delays.