You don't use metal in advanced research reactors. Alloys yes, pure metal no. It swells a LOT under irradiation You use it to cast into hemispheres, slugs or Oralloy tampers. Metallic uranium is for for bombs. They're very close if they are doing this.https://www.theguardian.com/world/2021/jan/17/grave-military-implications-iran-making-uranium-metal-alarms-europe …
Iran already can make Zircaloy tubing for reactors. That's civilian, but those metals can be used to make a superstable uranium metal alloy for bombs: Mulberry DPRK believed to have developed Mulberry alloy for its bomb program. Could DPRK + Iran swap material? UK and USA did