Old school nuclear ractor config: Pretty much just the old 1.2.5 or earlier reactor functionalities for those who really want it.
Completely rewrite Nuclear Reactors again, just to add back in (optionally) OP ice cooling? How can you even feed that much ice to them anymore without EE2?
The ice cooling made absolutely no sense anyway.
In reactors, heat is roughly equal to the energy output, so cooling it down is stupid.
Okay, I meant external water cooling from th old reactors. Oops 
Anyways, it would be a minor heat reduction.
In the future you will need to pump water into it, and steam will be outputed.
Control rods: Redstone no longer affects the Reactor. You will need a control rod to turn off the reactor, but it only works if the control rod touches the reactor. (moar nerfs to da reactor!!!1!)
Old school nuclear ractor config: Pretty much just the old 1.2.5 or earlier reactor functionalities for those who really want it.
Control rods: Although you can not see them it can be assumed that the control rods already exist inside a reactor block. without control rods a reactor would not be able to be moderated, controlled and "Turned off" effectively. The main control factor for a reactor is literally how far the control rods are pulled out of the nuclear pile. In minecraft this can be seen as a redstone signal activating the reactor.
Old school nuclear reactor config: Absolutely not, the reactor was changed for a reason. While I am usually a big fan of "Config all the things!" such a large feature should not have a config in my opinion.
