I just found IC2 and the wonders it holds, and began thinking "man I freaking love fusion power, I wonder..." and found this mod. I have a question about being able to add Rocket Science to IC2 and being able to keep my old world. I put a lot of time into my nuclear power plant and fairly sprawling workshop and transformer substations and I really don't want to lose those. Being able to decommission my constantly angry NPP and move into the ~FUUUUUTUUURE~ with fusion would rock so hard. Sorry if this had just been asked and I missed it!
It should work with an existing world if you get your block IDs right, but I have had some weird bugs with chunk resets and with some of the missiles f.e. them getting stuck at the old max height of 128, which forced me to load an older save. If you really want to get it, backup your .minecraft somewhere and then install it, but I would recommend what RealEyesRealLies said, the APS mod is much more stabile and the tokamak is awesome, although really expensive to build.