Fuel rods in the reactor vessel are made of uranium-235. Uranium is one of the most common elements that can be found on earth and can be mined on areas where it is mostly concentrated. The uranium has to be taken from the rocks where it is found and then it will be combined with the uranium 235 isotope. After enriching the uranium with uranium 235 isotope it will be made into pellets that will be used and loaded into the nuclear fuel assembly.
