I couldn't find an explanation on here (forum, wiki, bug tracker) so I tried a bunch of stuff in creative until I found something that works:
1. Run Uranium Ore through the Macerator to get Crushed Uranium Ore.
2. Run that through the Ore Washing Plant to get Purified Crushed Uranium Ore.
3. Run that through the Thermal Centrifuge to get Uranium 238 and Tiny Pile of Uranium 235.
4. Craft 6 U-238's and 3 U-235 piles into Enriched Uranium Nuclear Fuel.
5. Extrude an Iron Plate in the Metal Former to get Fuel Rod (Empty).
6. Run the uranium and the rod through the Solid Canning Machine to get Fuel Rod (Uranium).
Most of this stuff is radioactive, you'll want a full hazmat suit. Also the Thermal Centrifuge needs 48 EU/t, so you'll need a lot of energy.