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| Entered date | Event description | |
|---|---|---|
| ENS 49546 | 17 November 2013 19:27:00 | A station annunciator system malfunction caused all Control Room annunciator indications to be in alarm status. This condition resulted in a loss of normal audible and visual plant condition assessment capabilities and was assessed as being a significant loss of assessment capabilities. Backup assessment capability existed and was dependent upon redundant assets as described in existing station documentation and/or functionality of the Control Room Alarm Typer. At 1659 EST full annunciator capability was restored following cleaning of a disconnect switch. The NRC Resident Inspector has been notified." State and local officials will be notified. |
| ENS 43292 | 9 April 2007 15:17:00 | On April 9, 2007, at approximately 0730 hours, the keyswitch for the Seismic Monitoring System was discovered in the off position, rendering the Seismic Monitoring System unavailable. The system has apparently been in this configuration since March 29, 2007, when deficiencies were found during routine calibration checks. The ability to declare an Unusual Event per Emergency Action Level 8.A.1 would not be significantly hampered by this event, because this declaration would be based on either personnel feeling an earthquake, or detection via the Seismic Monitoring System. However, the unavailability of the Seismic Monitoring System could potentially hamper the operators in determining the magnitude of an earthquake in order to determine if it reached Operating Basis Earthquake levels or Safe Shutdown Earthquake levels. Therefore, this could potentially hamper the declaration of an Alert or Site Area Emergency, respectively, per Emergency Action Levels 8.A.2 or 8.A.3. Therefore, this event is being considered reportable per 10 CFR 50.72(b)(3)(xiii), as it results in a loss of emergency assessment capability. Compensatory measures are being established to obtain an off-site source of this information in a timeframe that can support timely declaration of an emergency. The licensee will notify the NRC Resident Inspector.
At time 0639 on 4/10/2007 the Seismic Monitoring System Instrumentation was reset. The Seismic Monitoring System is now FUNCTIONAL. With the SMA-3 Key Switch in the OPERATE position and the system RESET, the Seismic signal processing system and output devices are functioning to provide a STA SEISMIC INSTR ON alarm and to indicate if an OBE or SSE threshold has been exceeded. Therefore, the emergency assessment capability to declare an ALERT for EAL 8.A.2 or a Site Area Emergency for EAL 8.A.3 is restored. The Seismic Monitoring System remains INOPERABLE pending completion of DB-MI-04222, Seismic Instrumentation Calibration." R3DO (S. Burgess) notified. NRC Resident Inspector will be notified of this update by the licensee. |