Nuclear submarine

A nuclear submarine is a submarine powered by a nuclear reactor, but not necessarily nuclear-armed.

Nuclear submarines have considerable performance advantages over "conventional" (typically diesel-electric) submarines. Nuclear propulsion, being completely independent of air, frees the submarine from the need to surface frequently, as is necessary for conventional submarines. The large amount of power generated by a nuclear reactor allows nuclear submarines to operate at high speed for long periods, and the long interval between refuelings grants a virtually unlimited range, making the only limits on voyage times factors such as the need to restock food or other consumables. Thus nuclear propulsion solves the problem of limited mission duration that all electric (battery or fuel cell powered) submarines face. Furthermore nuclear submarines can regenerate consumables to a certain extent, producing oxygen and fresh water from seawater via electrolysis and desalination.

The high cost of nuclear technology means that relatively few of the world's military powers have fielded nuclear submarines. Radiation incidents have occurred within the Soviet submarines, including serious nuclear and radiation accidents, but American naval reactors starting with the S1W and subsequent designs have operated without incident since the launch of USS Nautilus (SSN-571) in 1954.