Thorium Ore spawns in the overworld and is easily mined with an Iron Pickaxe. The ore can be smelted into ingots or doubled into dusts using a Manufactory or similar machine. Thorium is the first Fission Reactor fuel for most players.
Thorium can be put into an Isotope Separator to get Thorium-230 and a small amount of Thorium-232 (1 tiny clump, or 1/9th of a normal clump). Thorium-232 has two uses: You can put it next to a Decay Generator to produce a small amount of power and get a Lead Block, or put the clumps in a Decay Hastener to get Lead Dust. Thorium-230 can be put in a Decay Hastener to be turned into Lead Dust as well, but it's normally used to make TBU Fuel instead, the base Fission Reactor fuel (unless you get Uranium first.)
Time: 25 secs