how are “nuclear powered” submarines and space probes powered?

Question

In other words, where do “nuclear powered” vehicles get their power from?

I imagine it’s not from fusion or fission, nor can it involve getting water to turn to steam, an in many other types of power generation.

So how does it work?

EDIT: it seems that nuclear submarines actually do use fission, so I’m switching my question to only focus on space vehicle power generation.

In: 3

Answer 1

Nuclear submarines are powered by a standard nuclear fission reactor that creates heat and turns a steam turbine.

Nuclear spacecraft are powered by something called a Thermo Electric Generator which is a device that uses a gradient in heat to create electrical power with no moving parts (sorta like a solar panel, except it uses heat instead of light) and a lump of naturally decaying radioactive material provides the heat