Reactor vessels

Light-water reactor - Includes the pressurized water reactor and the boiling water reactor. Most nuclear power reactors are of this type.

Grate-moderated reactor - Includes the Chernobyl reactor (RBMK), which has a highly unusual reactor configuration compared to the vast majority of nuclear power plants in Russia and around the world.

Gas cooled thermal reactor - Includes the Advanced Gas-cooled Reactor, the gas cooled fast breeder reactor, and the high temperature gas cooled reactor. An example of a gas cooled reactor is the British Magnox.

Pressurized heavy-water reactor - utilizes heavy water, or water with a higher than normal proportion of the hydrogen isotope deuterium, in some manner. However, D2O (heavy water) is more expensive and may be used as a main component, but not necessarily as a coolant in this case. An example of a heavy water reactor is Canada's CANDU reactor.

Liquid metal cooled reactor - utilizes a liquid metal, such as sodium or a lead-bismuth alloy to cool the reactor core.

Molten salt reactor - salts, typically fluorides of the alkali metals and of the alkali earth metals, are used as the coolant. Operation is similar to metal-cooled reactors with high temperatures and low pressures, reducing pressure exerted on the reactor vessel versus water or steam-cooled designs.