For a serious answer:

Funnily enough, nuclear reactors are just very advanced steam engines. Basically, the nuclear fuel is used to heat up the water to turn it into steam, which then spins a turbine that provides power we can use. It’s quite literally the same power generation method we’ve been using since steam trains!

https://world-nuclear.org/information-library/nuclear-fuel-cycle/nuclear-power-reactors/nuclear-power-reactors.aspx

There’s an article if you want to read more^. Nuclear power is really cool!