Submarines: How They Work - Archimedes' Principle
In 1954, the U.S. commissioned the first nuclear-powered submarine, the USS Nautilus. Because nuclear-powered engines
required no air, the submarine could stay submerged indefinitely,
surfacing only when in need of supplies. The Nautilus could
travel at speeds of 23 knots surfaced and submerged.
A nuclear-powered engine works because heat is generated by the fissioning of the nuclear fuel. Two systems of
pressurized water are sent through the nuclear engine. The first,
or primary, system circulates water through the reactor, piping
loops, pumps and finally to the steam generators, where the heat
from the reactor is transferred to the secondary water system. The
water from the primary system is then directed back to the reactor
to be heated again. The heat transferred to the secondary system
creates steam. This steam supplies the ship with electricity and
propulsion when it moves through the turbine generators and propulsion
turbines, respectively. The steam, condensed back to water, returns
to the steam generators to be reheated.