Ultronium is an ultra-radioactive isotope that does not occur naturally. You cannot mine, obtain, or craft it directly - only as a side product. It is one of the key ingredients in creating a Neutronium Rod. While Ultronium Rods can be used as fuel, it is highly unpractical.
At least 40 Ultronium Rods are required in order to craft an Atom Smasher. You will need to refine/centrifuge an approximate of 450 Solarium Stars, more than 3000 Neptunium Rods or Thorium Rods, or 600 Raw Nocxium to get that amount.
How to obtain
Used for
Reactor fuel
Crafting
