Nuclear propulsion includes a wide variety of propulsion methods that use some form of nuclear reaction as their primary power source. Many military submarines and a growing figure - with crude prices and emission in mind - of large surface ships, especially icebreakers, use nuclear reactors as their power plants (see nuclear marine propulsion for civil use and nuclear navy for naval use). In addition, various types of nuclear propulsion have been proposed, and some of them tested, for spacecraft applications:

• Antimatter catalyzed nuclear pulse propulsion
• Bussard ramjet
• Fission-fragment rocket
• Fission sail
• Fusion rocket
• Gas core reactor rocket
• Nuclear electric rocket
• Nuclear photonic rocket
• Nuclear pulse propulsion
• Nuclear salt-water rocket
• Nuclear thermal rocket
• Radioisotope rocket