Notice the word "legitimately" there?
Anyway, a quad plutonium cell surrounded by neutron reflectors generates over 1000 heat per second. You can't cool that with just internal vents, I'm afraid. You could use Shneekey's distributed coolant system (dumping the heat in coolant cells, swapping in fresh ones and pumping the depleted ones into cooling towers where they are restored), but I'm not sure you'd want to bother with that...
A good alternative are GregTech's hybrid reactors though. They run off single plutonium cells surrounded by quad thorium cells, which creates a sort of snowball effect between them that results in more pulses than conventionally possible. Thus you can get over efficiency 9 with them, and they are convenient in their fuel requirements because the same process you use to generate plutonium also gives you thorium.
There's even a crazy setup dubbed the "hybreeder", which is an efficiency 9.175, thorium-neutral hybrid reactor that pulls 367 EU/t and at the same time breeds almost three times its own fuel need out of depleted isotopes. However it is quite difficult to automate, since you not only need to constantly remove re-enriched isotopes and
insert depleted isotopes into that specific slot, but also occasionally replace the plutonium cells and
remove depleted isotopes from those specific slots. Off the top of my head, I wouldn't know how to do this - I know some GregTech machinery can target specific inventory slots, as can Factorization routers (but they require Factorization energy come the next update), but I've never even attempted doing anything like that.
Still, if you feel like tackling it - or running it manually - here's the layout:
http://www.talonfiremage.pwp.blueyo...4qbzfj7njhh1swr8v5nzsm9upgcbzzc239mx3b3o7pvr4
The thing was designed by Peppe with some help of Requia on the IC2 forums, if I recall correctly.
Also keep in mind that GregTech's 1.5 update will change how plutonium works a bit. I'm told hybrid reactors still work (Greg himself wants them as a buff to nuclear reactors), but the exact numbers and setups might change.