At Duke, our safety analyses have an allowance for a small amount of B-10 depletion. Our B-10 surveillance program ensures B-10 in safety-related sources stay above the allowed value. We don't measure B-10 in all tanks, but we measure B-10 in the source for makeup to those tanks. If B-10 at source gets close to allowed value we stop boron recycle and make up with fresh boron.

Dan Wellbaum Reactor Engineering Catawba Nuclear Station

From: pwrrm@retaqs.com [mailto:pwrrm@retaqs.com] On Behalf Of Kenneth R Pike Sent: Wednesday, July 08, 2009 10:16 AM To: pwrrm@retaqs.com Subject: [Pwrrm] RCS B10 depletion impact on Boron Inj Safety Systems?

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?

Thanks in advance

Ken Pike Retaqs, Inc. 610.277.8991 x 253