Which of the following is a main fuel material used in nuclear reactors?

Uranium-235 is a primary fuel material used in nuclear reactors due to its ability to undergo fission, releasing a significant amount of energy. In a nuclear fission process, the nuclei of Uranium-235 can absorb neutrons and become unstable, leading to their splitting into smaller nuclei. This reaction releases a large quantity of energy, which is harnessed for power generation.

Uranium-235 is favored in most light water reactors, where it serves as the main fissile material. The concentration of Uranium-235 in natural uranium is approximately 0.7%, and it is often enriched to increase the percentage of this isotope for more efficient nuclear reactions.

In contrast, the other elements listed do not fulfill the criteria for use as fuel in nuclear reactors. Carbon-12 is stable and does not participate in fission, making it unsuitable as a nuclear fuel. Oxygen-16, while a crucial element in many chemical processes and compounds, does not undergo fission and is not used in reactors. Hydrogen-1, or protium, is also not a fissionable material and is typically associated with fusion processes rather than fission-based nuclear power generation. Thus, Uranium-235 stands out as the correct answer, being the