Chemistry of the uranium U-235/238 isotopic enrichment: prior to the enrichment itself (gas diffusion, centrifuge, laser, nuzzle), uranium must be brought to UF₆ form, the only utilizable uranium species in this process:

- Why the uranium hexafluoride UF₆ is the only uranium compound utilizable in the gas diffusion and centrifugal enrichment processes?

- Uranium concentrate contains only 75-90 % - what procedure is used to purify it prior to conversion to hexafluoride?

- Purified product of separation, uranyl nitrate is converted to trioxide, then reduced with hydrogen to uranium dioxide, which then undergoes through 2-step fluoridation. Write the chemical reactions for these two steps.

- At the fuel fabrication plants, the isotopically enriched UF₆ is converted back to UO₂ . Write the chemical reactions for the deconversion of UF₆ back to UO₂ (this time 99.999% pure and isotopically enriched).