Best nuclear reactor setup?

[CitrusZ]

I'm about to set up a nuclear reactor and figured I would try to find the best set up, any builds you guys know that work really well?

 

[Omicron]

Define "the best setup".

Highest output?
Highest fuel efficiency?
Cheapest to build?
Most badass implementation?
Best fit for your needs?

You need to know what you want to find before you can start searching