LEU

LEU (Low Enriched Uranium) is uranium which contents from 2 to 5% of uranium-235. Generally used in Atomic Reactors as the main source of energy. It can be obtained from the first Hexavalent Uranium Fluoride load into Gas Uranium Centrifuge. In real life, any metallic uranium with <20% of uranium-235 is called as LEU, but 5-20% 235U is generally used for experiments, so it won't be added to the game.

To obtain LEU Rods you should add LEU to iron tube. After that combine 6 LEU Tubes in one and place it into graphite box.