Damon, we have exactly the same
problem. We have a recorder and alarm for all control banks. The
setpoints change every cycle based on our fully withdrawn rod position
for that cycle. The setpoints for CBA and CBB are around 213 for
Lo-Lo and 223 for Lo. The setpoints for CBC and CBD very with power.
We've tried to clarify to the operators that the alarm indicates that you
need to check your shutdown margin.
We also have a statement in TS that
says the control banks will not be inserted beyond the insertion limit
specified in the COLR. If it is then restore the bank within 2 hours
or reduce power to the power specified in the COLR or be in HSD within
6 hours. Well the COLR says the insertion limit for Shutdown A and
B is fully withdrawn. The same applies for Control A and B. Only
C&D vary with power.
So basically we have in our annunciator
response procedures if you get the alarm to do a shutdown margin and if
you don't have adequate SDM then reduce power until you do. Otherwise
I think the recorders for CBA and CBB are useless as are the alarms.
Michael J. Fanguy
Nuclear Analysis & Fuel
Lead Reactor Engineer
Surry Power Station
Email: Michael.Fanguy@Dom.com
Phone: 757-365-2155
Pager #: 3453
"BRYSON, DAMON V"
<DBRYSON@scana.com>
Sent by: pwrrm-bounces@retaqs.com
10/02/2007 05:23 PM
|
Please respond to
PWR Reactivity Management <pwrrm@retaqs.com> |
|
|
To
| "PWR Reactivity Management"
<pwrrm@retaqs.com>
|
|
cc
|
|
|
Subject
| [Pwrrm] Rod Insertion Limits vs. Shutdown
Margin |
|
This question is for the Westinghouse crowd.
We at VC Summer have recently found some inconsistencies between
our Rod Insertion Limit (RIL) Lo-Lo alarm and our RIL in the Core Operating
Limits Report (COLR). For all control banks besides the lead bank,
the installed RIL alarm setpoint is at 213 steps, while our COLR limit
is 230 steps. The COLR limit is consistent with our reload shutdown
margin analysis, which assumes all rods except the lead bank at 230 steps
(the all rods out position).
As far as we can tell, our alarm has always
been set to 213 for all previous cycles. In previous cycles the COLR
only listed the lead bank limit, but no limits for other banks. We
placed that limit in the COLR based on our analysis assumptions.
Do other plants use similar setpoints? I
know many plants have repositioning strategies that require rod motion
during the cycle, but our plant does not. I also haven't found any
mention of the RIL alarm in the Westinghouse reload design process checklists.
My control room operators want some justification for this discrepancy,
since I just taught them in our last requal session that the purpose of
the RIL alarm is to verify you have shutdown margin. Thanks for any
help you can give...
Damon Bryson
dbryson@scana.com
803-345-4814
_______________________________________________
PWRRM mailing list
PWRRM@retaqs.com
http://www.keffective.com/mailman/listinfo/pwrrm
CONFIDENTIALITY NOTICE: This
electronic message contains information which may be legally
confidential and/or privileged and does not in any case represent a
firm ENERGY COMMODITY bid or offer relating thereto which binds the
sender without an additional express written confirmation to that
effect. The information is intended solely for the individual or
entity named above and access by anyone else is unauthorized. If
you are not the intended recipient, any disclosure, copying,
distribution, or use of the contents of this information is
prohibited and may be unlawful. If you have received this
electronic transmission in error, please reply immediately to the
sender that you have received the message in error, and delete it.
Thank you.