Nuclearcraft guide to make HECF-251-Oxide-fuel for the Philosopher's Stone. Use this reactor setup. Feel free to make it higher if you want to use up the fuel faster. Required Items/Machines: 10 stacks of either Yellorium or Uranium ingots (doesnt matter which). 1x Isotope Separator 1x Decay Hastener 1x Fuel Reprocessor 1x Fluid Infuser 1x 5x5x5 Fission Reactor (or bigger). Put 10 stacks of Uranium/Yellorium in the isotope separator. Producing Uranium-238, and tiny bits of Uranium-235. Craft the tiny Uranium-235 into 57x Uranium-235, and combine one of those with 8 of the Uranium-238 to make LEU-235-Fuel. Make a total of 57 LEU-235-Fuel. Throw those into your reactor to deplete them. Put the 57 depleted LEU-235 in your Fuel reprocessor to get neptunium-237, plutonium-239, Plutonium-241 and some uranium-238. Craft the tiny bits of neptunium-237 into 22x neptunium-237. Put the 22x Neptunium-237 in your Decay Hastener to get Uranium-233. Combine those with Uranium-238 to make LEU-233-Fuel. Throw that in the reactor, deplete it, and fuel reprocess it to get Plutonium-242 and some other stuff. Craft 15 HEP-241 fuel from the items you got. Once again, throw it in the reactor and reprocess to get a bunch of Curium-246 and Curium-247. Craft 8 HECm-247. One more round of reactor and reprocessing, and you will have enough Califorium-251 and Califorium-252 to create 4 HECf-251. Throw that in the fluid infuser with some oxygen and you will get the 4x HECf-251 Oxide you need! Source I've made the original guide on Reddit shorter for readability.
