Its still Beta, but I highly recommend NuclearCraft as a dedicated nuclear alternative to Extreme Reactors.
Picture Extreme Reactors, but with more
varied fuel types, such that you're incentivized to have multiple types of reactors (I personally love turning off all Plutonium worldgen so that I can only get it via nuclear processing).
Also, the reactors explode if you design them poorly (too much heat), but unlike with, say, IC2, its really easy to see if your reactor is safe: you just need to look at the GUI and ensure your heat-per-tick rating isn't positive.
The turbine stuff is still incomplete: you're going to need to run your reactors similar to ER passive mode.
It also has Fusion power. And some silly stuff (like nuclear monsters) that you can turn off in configs (I do)
@turbodiesel4598 is the dev and he releases occassional youtube videos highlighting all recent changes, which is a really nice touch