What is the vital element used in nuclear fuel?

The primary element used in nuclear fuel is Uranium-235. This isotope of uranium is significant because it is one of the few materials that can sustain a nuclear chain reaction, which is essential for producing the energy in nuclear reactors.

Uranium-235 is fissile, meaning it can easily undergo fission when it absorbs a neutron, splitting its nucleus and releasing a considerable amount of energy, as well as more neutrons that can then induce fission in other Uranium-235 nuclei, leading to a self-sustaining reaction. This property makes it the most common choice for nuclear energy production.

While Uranium-238 and Plutonium-239 also play roles in the nuclear fuel cycle, especially in certain types of reactors or applications, they are not as commonly used as Uranium-235 for traditional nuclear fission reactors. Thorium-232, on the other hand, is not fissile itself and requires conversion into Uranium-233 before it can be used as fuel, thus it does not directly serve as a nuclear fuel in its initial form.

Hence, Uranium-235's ability to effectively sustain controlled nuclear reactions positions it as a vital element in the realm of nuclear fuel.