Side note 2:
I am working on a realistic Nuclear Reactor mod - primarily intended to serve as the interface between IC2 and RotaryCraft, as that is otherwise nonexistent.
In that realism will be failure. If you fail to cool it down, or pull a Chernobyl and retract all the control rods, it will melt down, causing a possible reactor containment breach by way of hydrogen explosion and thus spewing radioactivity (as an ambient effect rooted to the location) over a large area. In the interest of gameplay, I do intend to either make it decay or be able to be cleaned up, however.
Welcome to the FTB Forums Reika

This reactor mod sound very intersting i'll stay tuned and watch your threads!