Reactor designs. version 2-2.2.751 and above.

Have you looked at the below thread?
How i learned to stop worrying and love the bomb - Nuclear power guide and reactor designs

The "V3" planner is now over 3 years old, so I suggest using this one instead:
IC2 Experimental Reactor Planner open beta

Also, you seem to have made two almost-identical threads about this.

The second post of the "How I learned to stop worrying..." thread has reactor designs, including several that don't require GregTech components.

As far as how to open my reactor planner, it's an executable jar, so as long as you've got Java installed (which most PC Minecraft players already have done to be able to play Minecraft), you should be able to download it and double-click the file.