That is not currently an option. I wouldn't use it, but perhaps others would. For me destroying the reactors is hard enough as it is. Especially once you get to the higher reactors and you need multiple critical shots. Starting over with reheating the reactor would make it damn near impossible for me. Keep in mind that each reactor is already harder and harder to destroy.
One change I have considered would be having the option of eliminating the randomness of the critical shot(s). I wouldn't mind having it be a progression with each reactor. Ex. Reactor 1: Destroy (left), Reactor 2: Destroy (left), Destroy (right), Reactor 3: Destroy (left), Destroy (right), Pop, etc. Perhaps have this as a tournament mode. Sorry, I haven't played with the settings too, but much I don't think this is an existing option.
PS: When I say "higher reactors" I'm talking about 4 and 5 for myself. I play the game quite a bit and I have never seen reactor 6.