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?
I can't answer that - I'm not that closely tuned to the nuclear process. I'm more familiar with them from the outside, viewing each plant as an asset in a portfolio of power sources meant to meet load. I have to know their availability and the reasoning behind their not being available, but I don't need to know anything that specific.
I spent a few years in a couple of coal-fired plants back in the '80's, but I avoided nuclear like the plague.
Boron shim is NOT used in BWR’s. Power is controled with rods only. The nly boron in a boiler is the no-$h_t emergency shutdown bron injection system using a squib valve.