I'm having the same problem. It's not a waste heat problem or a control problem. For whatever reason, the right-click menu just plain isn't loading actions. Can't turn reactors on and off, can't deploy the deployable heat radiators, can't deploy the unfolding microwave transmitter thing. And reactors aren't defaulting to being turned on; they're not generating any waste heat or thermal power, and thus not generating any electricity. I only have KIWI reactors so far on my game, but I can't get them to work no matter what the configuration. I'm just getting to the point where I'd be deploying an orbital power network, if I could get any of the pieces to work :\