I have a nuclear facility with three of these things, but right now ill tell you the model. its a "MARK-V-SUC, Hungry to the point of starving+Recycler" Reactor, but theres a catch (because coolant is supplies with buildcraft"
Through the use of redstone and a gate, if no ice traverses the pipe just before the reactor, a signal is sent to the reactor automatically shutting it down,
Excess ice that usually falls down is picked up by obsidian pipes. Ill give a more detailed pic but heres some info:
A very expensive one to buld.
Requires 14 full chests of ice to run 1/5-1/3 of a cycle. Thats 48384 cubes youll need to somehow come up with, friend
A recycler system will automatically catch excess ice and pipe it back to the iron pipe just before the gate. The gate will emit a redstone signal to stop the reactor if no ice goes through it.
Produces 1666 EU/T. Worth the cost. The consturction i have has three of these. Fills an MFSU in less than 2 minutes.
Still on MC 1.2.5 Uses Buildcraft, industrialcraft, and wireless redstone.
Ill put on more info as it comes.