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
803-345-4814