Uranium is a nuclear material

Uranium is a chemical element in the periodic table that has the symbol U and atomic number 92. It is a silvery-white metal included in the actinide series of periodic tables. Uranium has 92 protons and 92 electrons, and valence electrons 6. The uranium nucleus binds 141 to 146 neutrons, so there are 6 uranium isotopes. The most common isotopes are uranium-238 (146 neutrons) and uranium-235 (143 neutrons). All uranium isotope is unstable and radioactive is weak. Uranium has the second largest atomic weights among all the chemical elements that can be found naturally. [3] The uranium-type mass is about 70% larger than lead, but it is not as dense as gold or tungsten. Uranium can be found naturally in low concentrations (several parts per million (ppm)) in soil, rocks, and water.

Uranium that can be found naturally is uranium-238 (99.2442%), uranium-235 (0.7204%), and some uranium-234 (0.0054%). Uranium decays slowly by emitting alpha particles. The life span of uranium-238 is about 4.47 billion years, while for uranium-235 is 704 million years. [4] Therefore, uranium can be used for dating the Earth's age.
Uranium-235 is the only fissile natural chemical element isotope (ie it can maintain chain reaction in nuclear fusion), whereas uranium-238 can be fissile using fast neutrons. In addition, uranium-238 can also be transmuted into fissionable plutonium-239 in nuclear reactors. Another uranium isotope that is also fissile is uranium-233, which can be produced from thorium.