For a submarine, nuclear propulsion removes the recurring need to surface for battery charging and extends endurance far beyond conventional fuel limits. It also reduces the space devoted to fuel and associated piping, an important gain inside a pressure hull where volume is scarce. Abundant electrical power supports sensors and the energy-intensive work of sustaining air and other life-support services underwater. A long-range submarine is expensive with either propulsion system, which makes the nuclear premium easier to justify when persistent underwater presence matters.
Chapter · 27:38-29:28
Nautilus and the submarine case for nuclear power
Nautilus demonstrates why submarines were the most persuasive early case for nuclear propulsion: sustained underwater endurance, range, and electrical power solve immediate operational limits.