LINK TO REPORT Based on documents in the Iran Nuclear Archive, seized by Israel in early 2018, Iran’s Amad Plan created the Shahid Mahallati Uranium Metals Workshop near Tehran to research and develop uranium metallurgy related to building nuclear weapons. Figure 1 shows this site as it looked in 2002 and 2003, when an existing workshop was renovated and brought into operation. The facility was intended as a pilot plant, aimed at developing and making uranium components for nuclear weapons, in particular components from weapon-grade uranium, the key nuclear explosive material in Iranian nuclear weapon cores. The site was meant to be temporary, until the production-scale Shahid Boroujerdi facility at Parchin was completed.1 However, the Shahid Mahallati facility was capable of making the first cores of weapon-grade uranium, in case Shahid Boroujerdi was unfinished when weapon-grade uranium would have had become available.