Here is my next design:
http://www.2shared.com/file/-xse6MAU/Uranumator.html
Its pretty much a fully completed reactor with a nice control room. Its has 3 floors. The bottom floor is where the cooling system is housed the middle floor is where the redstone circuits are housed and the top floor is the control room and acces to the reactor for refueling. I made is so that you can acces all floors easily. The control room got a nice system with lights :). Most of the building is supposed to be underground and only the top floor will be above ground.
Whole reactor fits in 1 chunk easily. The detector system is very sensitive. At the first signs that less buckets are coming out it will shutdown. If you want to run it with less uranium just change the redstone repeater which is directly wired to the detector. Longer delays means it will keep running with less buckets that pass the detector block. Through dont expect it to run with like 4 uranium.
Tell me what you think about this one :).