Uranium is a heavy, silvery-white metal that is naturally found in the Earth's crust. It is primarily used as fuel in nuclear reactors, where it undergoes a process called nuclear fission to produce energy. Uranium is also a key component in the development of nuclear weapons. This element has several isotopes, with Uranium-235 and Uranium-238 being the most significant. Uranium-235 is the isotope that can sustain a nuclear chain reaction, making it crucial for both energy production and military applications. Due to its radioactive properties, uranium must be handled with care to ensure safety and environmental protection.