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 Kenneth R Pike
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?