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Start date | Reporting criterion | Title | Event description | System | LER | |
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ENS 50597 | 6 November 2014 01:38:00 | 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor | Six Unit 2 Control Rod Drive Hydraulic Control Units Inoperable | Six (6) U2 CRD (Control Rod Drive) HCU (Hydraulic Control Unit) accumulators were identified with riser brackets that were installed incorrectly. This issue impacts U2 CRD HCU accumulators only. The incorrect riser bracket installation could challenge the ability of the CRD hydraulic control unit to perform its design function during a seismic event. Identified U2 control rods associated with HCU accumulators that had riser brackets installed incorrectly were declared inoperable. This condition has been corrected since initial identification, restoring all control rods to operable status. Reference IR 2407342. This notification is made pursuant to 10CFR 50.72(b)(3)(v) regarding the reportability of multiple failures that could have prevented fulfillment of a safety function. The NRC Resident Inspector will be notified.
The purpose of this notification is to retract the ENS notification made on November 6, 2014 (ENS 50597). An Engineering Evaluation has determined that the function of the affected U2 CRD HCU Accumulators was not affected as discussed in Chapters 6 and 15 of the Updated Final Safety Analysis Report. Therefore, the threshold for reporting the issue as an event or condition that could have prevented the fulfillment of a safety function was not met (NUREG 1022, Revision 3, Event Report Guidelines Section 3.2.7). The NRC Resident Inspector has been notified. Notified R3DO (Dickson). | Control Rod |