Refining

Uranium Ore can be found naturally below the surface in small clusters but if you are in old chunks or you just want to craft some their is a recipe. But be careful because it will hurt you when mining it unless you have a radiation suit.

If you are planning on mining some uranium you will want an Anti-Radiation Suit so you won't take any damage while working with it.

Once you have your Uranium ore you will want to get the ore from it by smelting the ore.

Uranium ingots only use is to refine it into Refined Uranium. Refined Uranium will come in handy later.

Now using that Refined Uranium you can create Plutonium Ingots again which will be used later.

Like Uranium Ingots, Plutonium's only use is to be refined into Refined Plutonium.

You now have your unstable materials ready for creating a reactor core which is used for the creation of a Nuclear Reactor.