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