Answer: -
Extensively processed to clean, purify, and concentrate it.
Uranium (U235), naturally occurring at 0.7%, must undergo a series of processes to become a useable fuel before it can be put into a reactor.
The process include converting uranium oxide to uranium hexafluoride allowing it to be enriched to 3%.
After enrichment, the gas is converted to uranium dioxide fuel pellets. These are placed inside thin metal tubes which are assembled in bundles to become the fuel elements for the core of the reactor.
