Had a similar problem, try NOT using TE3 fluiducts/AE fluid export as they simply can't handle the ludicrous of water amounts required and the fact that its not supposed to be run that way.
The reactor+turbine should be a closed system(aka recycling same water) so except for the initial water you shouldn't need to input more water once it starts looping.
The fluiducts when interacting with fluidports can only handle like 60~120mb/t, direct tesseract connection or direct fluiddport connection between the reactor and turbine should recycle the water, simply set a few(1~3 should be enough) aqueous accumulators to input into the water tesseract/additional fluidport to get it running and it should become a closed system
Thanks for the help. I moved it to a closed system using tesseracts and it works fine with the reactor flow rate identical to the max rate on the turbine.