The problem with reducing power that significantly is they they still use up the fuel at a rate similar to if they were running at 100%. Nuclear is different than fossil fuel in that regard - lowering output will still effect the longevity of the fuel rods just as if it was running at full output. So, it's more efficient to take one of 3 units off line and run the other two at or near full output than to run all 3 at a significantly reduced output.
Hopefully, they'll get some rain in eastern Tennessee - it's effecting their hydro generation as well as nuclear. I'm certain that it's effecting other plants along the river as well.
Yeah, I hadn’t really thought of the fuel depletion rate but now that you mention it, that makes sense. Does BFN (a BWR plant) typically run the same boron concentrations as do commercial PWR plants?