What is used as fuel in nuclear reactors?

Nuclear fuel – uranium-235 and its isotopes: tritium, plutonium. Free neutrons split uranium atoms, and a gigantic energy is released, many orders of magnitude greater than the energy of a chemical reaction, for example, an explosion of TNT. This energy is utilized, i.e. are used, converted first into water vapor energy, and then through a generator into electrical energy, which is supplied to cities and villages. For example, France gets most of its electricity from nuclear power plants.