In developing a B10 depletion lesson recently I discovered a concern that I have not seen raised before. Does your Safety Analysis for your boron injection or S/D systems (Accumulators, Boron Injection Tank or RWST) consider anything less than nominal B10 abundance (19.9 a/o) in the boron ppm requirement? If the analysis assumes nominal B10 and there is some B10 depletion then the negative reactivity assumed could be more than that actually available (non-conservative) upon injection. Is this accounted for in some fashion?