It's basically how many million EU you get from each uran element on average. A single one (or 10, as long as they don't connect) is eff 1.
Now, having multiple uran adjacent to each other make each produce more energy (one more million per)
So putting 4 uran in a square is 3 efficiency (1+2 mil Eu for each)
Too tired to explain better 
http://test.vendaria.net/index…CHCHCCHCHXHCCCCHCCXHCCCHC
Should cool 3 elements at *almost* full speed (24 heat/t)
A coolant cell would go from 9999 heat to zero in under seven minutes! 
I'm pretty sure you need a transformer to go HV -> MV for it to work. Otherwise, just use an MFSU.
depends on the reactor, if it's 20 eu/t it's LV and 40/t is MV. You need like 512 eu/t for it to be HV
Or, just use the uran to craft nukes. I believe that would give more boom for your buck 
If you really mean 0 chambers, I think it's impossible to make it mk.2. Best I can find:
http://test.vendaria.net/index…XXXXXXXXXXXXXXXXXXXXXXXXX
With one chamber it's like mk2-3
http://test.vendaria.net/index…XXXXXXXXXXXXXXXXXXXXXXXXX
Edit: Accidentally made mk.1 30eu/t 1.5 eff (only 4 HDs!)
http://test.vendaria.net/index…XXXXXXXXXXXXXXXXXXXXXXXXX
Yeah, the 40 block max thing sucks. I mean, just make it have a (configurable) output face, either up/down or to a pole at one side...
2 more heat than mine, but I've seen worse 
As far as I got it he's using EE to HAAAX! make ice.
I have been theorycrafting a bit about this.
http://test.vendaria.net/index…XXXXXXXXXXXXXXXXXXXXXXXXX
This reactor hooked to a 1/7 clock is mk.1, with only 1 chamber and 20 eu/t at 3.5 efficiency. To compare a full-blown 6-chamberer mk.2 with square setup is barely cheaper, with same eu/t but worse efficiency.
And yes, I have accounted for the fact that either redstone of cable has to interfere with external cooling. Putting the power line trough the water and it still works 
I don't understand how this designs have perfect heat balance, can you explain to me what do you mean and how this result is obtained? from what I can see they are bulding up heat.
If the reactor hull (and right top HD) has a lot of heat in them, the two HDs with coolants will suck up all heat generation. So if you keep swapping those coolants (And HDs) it won't change temperature
So you get both power AND scrap from your trash 
Also wouldn't work since nether unloads when you enter normal world and vice-verca.
Reinforced pictures
Dang, I was looking forward to nerdraging at him
Although it's arguable that the basic concept of nuclear fission/fusion is common knowledge...
Edit: Also funny how he called STEAM turbines "rocket science"
Edit2: Outb4 steam rocket
Nils .... First of all coolants will die quickly, secondly using ice makes it either -SUC or -CASUC.
Also it's mk.4 at least
More uran = Bigger boom.
To get perfect heat balance, so it won't cool down. A cold breeder is a slow breeder
Where will the fire spawn? Under the wood? 
Lol nargon, that totally looks like this reactor!
http://test.vendaria.net/index…HCCCCUCHCHCCHCCUUCCCHCCHC
Didn't copy it, I swear
