What's the energy source in nuclear reactors?

The energy source in nuclear reactors is the nuclear fission of heavy elements, primarily uranium or plutonium.

Nuclear reactors harness the energy produced by nuclear fission, a process in which the nucleus of a heavy atom, such as uranium-235 or plutonium-239, is split into two or more smaller nuclei along with a few neutrons. This process releases a significant amount of energy, which is the primary source of power in a nuclear reactor.

The fission process begins when a neutron strikes the nucleus of a heavy atom, causing it to become unstable and split. The resulting smaller nuclei, known as fission products, are highly radioactive. The neutrons released during fission can then go on to cause further fissions, creating a chain reaction. This chain reaction is carefully controlled in a nuclear reactor to ensure a steady rate of fission, and thus a steady output of energy.

The energy released during fission is primarily in the form of kinetic energy of the fission products and neutrons. This kinetic energy is converted into thermal energy as the particles collide with other atoms in the reactor. The thermal energy is then used to heat water, producing steam which drives a turbine connected to an electricity generator.

The fuel used in nuclear reactors is typically in the form of solid pellets, often made of uranium dioxide. These pellets are stacked into fuel rods, which are then grouped together to form a fuel assembly. The reactor core, where the fission takes place, contains many such assemblies.

In summary, the energy source in nuclear reactors is the nuclear fission of heavy elements, primarily uranium or plutonium. The energy released during fission is converted into thermal energy, which is then used to generate electricity.