Nuclear reactors are versatile devices that can be used for a variety of purposes, including generating electricity, producing radioactive isotopes, and propelling ships and submarines.

Pressurized water reactors (PWRs) are the most common type of nuclear reactor in the world. They use ordinary water as both the coolant and the moderator.

Nuclear fuel serves multiple purposes in a nuclear reactor. It provides energy for the reactor, controls the rate of the nuclear reaction, and absorbs neutrons.

Uranium-235 is the most common type of nuclear fuel. It is a fissile isotope of uranium that can be used to sustain a chain reaction.

Nuclear reactors generate electricity through the process of nuclear fission. In nuclear fission, a heavy nucleus is split into two or more lighter nuclei, releasing a great amount of energy.

The primary purpose of a nuclear moderator is to slow down neutrons. This is necessary because neutrons produced by nuclear fission are too fast to cause further fissions.

Ordinary water is the most common type of nuclear moderator. It is used in pressurized water reactors (PWRs) and boiling water reactors (BWRs).

Nuclear control rods serve multiple purposes in a nuclear reactor. They control the rate of the nuclear reaction, absorb neutrons, and prevent the reactor from going critical.

Boron carbide is the most common type of nuclear control rod. It is a compound of boron and carbon that is very effective at absorbing neutrons.

Nuclear shielding materials serve multiple purposes. They protect personnel from radiation, prevent the spread of radioactive contamination, and reduce the amount of radiation released into the environment.

Lead, concrete, and water are all commonly used nuclear shielding materials. Lead is very effective at absorbing gamma radiation, while concrete and water are effective at absorbing both gamma radiation and neutrons.

Nuclear waste disposal facilities serve multiple purposes. They safely store nuclear waste, prevent the spread of radioactive contamination, and reduce the amount of radiation released into the environment.

Deep geological repositories are the most common type of nuclear waste disposal facility. They are located deep underground in stable geological formations.

Nuclear decommissioning projects serve multiple purposes. They safely dismantle a nuclear facility, clean up radioactive contamination, and restore the site to its original condition.

Reactor decommissioning is the most common type of nuclear decommissioning project. It involves the safe dismantling of a nuclear reactor and its associated facilities.