Ken,
Callaway conducts periodic measurements of
B-10 content in applicable tanks and adjusts minimum Boron concentration limits
accordingly. An example from the site procedure is quoted below.
Jim McInvale
Operating limits and control
bands are set to compensate for depletion of B-10 due to use of
recycled boric acid. The lower
operating limit, 2030 ppm, compensates for a potential B-10
level in the RWST of 19.6%,
making it equivalent to 19.9 atom %. Yearly analyses of B-10
in the RWST will be performed
to verify and track the changes in B-10 level. This new
operating limit is more
conservative than the T/S requirement of 2000 ppm B.
From: pwrrm@retaqs.com
[mailto:pwrrm@retaqs.com] On Behalf Of
Sent: Wednesday, July 08, 2009
9:16 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