system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Nuclear powered submarines. How do they work and manage the nuclear waste and why don't we have more nuclear "stuff" like nuclear trains or nuclear Google headquarters?
gpt
Nuclear submarines are electric submarines with a built-in nuclear power plant. The nuclear reactor powers everything on board, from desk lamps to propulsion to water desalination.

Nuclear fuel lasts a *long* time! Every 20 years, or so, they take out the spent fuel and loads in new fuel. The spent fuel (nuclear waste) is brought to a facility for temporary storage before it can be put in permanent storage (I don't think anyone have built a permanent storage for nuclear waste yet).