Ive been having some problem with the stability of the steam generators actually. Sometimes they stop working for some reason when at 221 bar and 2 mb at 400 Hu. The strange thing is that it is only when working with the hot coolant. My lava setup works like a charm and ive never had any problem with it. To get it running i usuall have to get stable operation at 1 mb per tick and then increase it to 2 mb per tick or it just produces steam even when it has all the hot coolant it needs.
Lava setup 300 eu/tick with ender io and buildcraft
http://prntscr.com/4q9fcj
Mementh: I think its an optimal setup using only ic2. If you use some other mod that is good at moving fluids you can make setups that inputs 400 HU per steam generator. which makes the setup a lot cheaper since you need only about half the equipment (still need as many liquid heat exchangers). Ive used both ender io fluid pipes and steve's factory manager to great sucess.
My current setup looks like this using steve's factory manager:
http://prntscr.com/4qgu4o
I i use 1200 Hu in 3 steam generators and the remaining 144 heat is used in stirling engines. At first i had 6 steam cycles with 200 Hu per steamcycle but this is A LOT better as there is a large difference in running cost and initial investment. its also a lot cleaner.
I prefer moving the coolant away from the reactor as i can then make a smaller reactor room out of reinforced stone and build the turbines outside. However if you like putting the turbines on the sides of the 5x5 you can also make a simular setup as you have done but with 400 Hu per side of the 5x5. Iv'e tested it in creative and it works just fine using ender io.
Edit: Scratch the stability thing, there is now nothing left of my poor reactor, lucky i enclosed it in reinforced stone, only the reactor broke and not my base. The reason for the breakdown was this
http://prntscr.com/4qj4yx
For some unknown reason the turbine stopped processing the overheated steam and boom went my reactor. Anyone else having similar problems? Im leaning more and more towards using stirlings for 5x5. Both kinetic steam turbines and steam generators are highly unstable and unless you have a safety system on your reactor it might just go boom. I wont make the same misstake again.
I also found another bug. As long as the steam generator is pumping water into blocks besides it (for instance 1 mb/tick of distilled water that is instantly put back) it will never loose heat. My steam generators stay at 375 degrees forever as long as i keep recycling distilled water.