Just sneak while right-clicking the reactor with a wire in hand, being able to build such a good circuit you should know that. I just don't know if directly on it placed isolated wire will work, if not just use bare.
Also both of your circuits are really nice, makes you almost wanna try to make such a 5 sec reactor of doom :3
Yeah I believe placing a bare wire directly on the reactor works, but if you're using a six chamber setup it has to be basic redstone feeding directly to one of the chambers, unless of course this has already been fixed?
My timer for the reactor of doom, one lagspike though and you're screwed.
Runtime: 5 secs
Cooldown time: 7 mins 15 secs
Effective EU/t: 33.03
Total output: 480,000,000 EU