Semantic search
| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 50143 | 26 May 2014 06:52:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Control Room Overhead Annunciator Malfunction | At time 0252 EDT, the control room overhead annunciators malfunctioned resulting in the inability to receive more than one station alarm input and could not be acknowledged using the normal station alarm acknowledge pushbutton. This condition existed from time 0252 EDT until time 0516 EDT on 5/26/2014 at which time the system was restored. During the entire period, backup assessment capability was functional, dependent upon redundant assets as described in existing station documentation and/or functionality of the control room alarm typer. Additionally, the station computer alarms and Safety Parameter Display System remained functional during the entire time period. The licensee will continue to investigate the annunciator system. The licensee notified the NRC Resident Inspector. The licensee will also notify State and local government agencies. | Safety Parameter Display System | |
| ENS 50252 | 21 May 2014 07:36:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Control Room Overhead Annunciator Malfunction | At 0336 (CDT) on 5/21/14, during activities to isolate the preferred power supply for wiring modification, all control room annunciators cleared and lost power due to a disconnect switch failure associated with the alternate power supply. The normal power supply was restored at 0349 (CDT) to restore the annunciators to functional status. During the brief period of time the annunciators were unavailable, redundant assets as described in existing station documentation and/or the control room alarm typer remained functional along with the station computer alarms and Safety Parameter Display System to provide backup assessment capability. This event was previously determined to not be reportable, however, following additional review of the significance this is reportable. The NRC Resident has been notified of the event. The late reporting of this event has been entered into the Corrective Action Program. The licensee notified the State of Ohio as well as Lucas and Ottawa counties. | Safety Parameter Display System | |
| ENS 49546 | 17 November 2013 17:33:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | All Control Room Annunciators in Alarm | 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 47670 | 16 February 2012 18:42:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Spds Greater than Eight (8) Hours Due to Hard Drive Failure | At approximately 0542 hours (EST), the Safety Parameter Display System (SPDS) became non-functional, and therefore was not available in the Control Room or in the emergency response facilities. Efforts are underway to restore the system, but as of 1342 hours (EST) these efforts have not been successful. The loss of SPDS for more than 8 hours is being reported in accordance with 10 CFR 50.72(b)(3)(xiii). Troubleshooting efforts continue to restore the SPDS. The Emergency Response Data System (ERDS) remains functional, and the station remains capable of performing dose assessment using manual inputs per site procedures. The Control Room also continues to have the capability to retrieve plant data inputs to assess plant conditions and perform core damage assessments. The NRC Senior Resident Inspector has been notified, and the State of Ohio Emergency Management Agency will be notified.
As of 2100 EST on 02/16/12 the SPDS has been restored to service and is functioning properly. The licensee will inform the NRC Resident Inspector. Notified R3DO (Passehl). | Emergency Response Data System Safety Parameter Display System | |
| ENS 43292 | 9 April 2007 11:30:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Seismic Monitoring System Out of Service | 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. | ||
| ENS 43164 | 14 February 2007 01:12:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Offsite Communications Capability Due to a Power Outage in Toledo, Ohio | Due to a power outage offsite, the Davis-Besse Nuclear Power Station has experienced a loss of offsite communications capability, which is reportable within eight hours under 10 CFR 50.72(b)(3)(xiii). A loss of a minimum of two of three available telephone system pathways constitutes a loss of offsite communications capability under Davis-Besse site specific requirements (DBRM-RC-0001 R01 Attachment 10). As of 2012 on February 13, 2007, two of the three telephone pathways were unavailable. Full telephone service was restored at 2214 on February 13, 2007. Due to the loss of the telephone systems, the site also lost the capability to page the Emergency Response Organization via the Computerized Automated Notification System (CANS) in the event of an emergency declaration. However, the site retained the ability to group page the Emergency Response Organization via alternate means. In addition, due to an ongoing snow storm, the site has elected to augment on-shift personnel with selected key Emergency Response Organization personnel. The Emergency Notification System is currently available. The licensee informed the State of Ohio, local authorities and the NRC Resident Inspector. | ||
| ENS 41286 | 23 December 2004 11:14:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Response Capability | At 0614 hours on December 23, 2004, Davis-Besse activated station isolation procedures due to heavy snow and blowing snow. This is being reported as a loss of response capability under 10CFR 50.72 (b)(3)(xiii) due to the potential inability of local authorities to perform an evacuation. Minimum Emergency Response staffing is being maintained at the site. The state of Ohio and Ottawa and Lucas Counties have confirmed that they are currently capable of performing their emergency plan responsibilities. The licensee notified the NRC Resident Inspector. | ||
| ENS 40734 | 7 May 2004 16:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Emergency Preparedness Capability Due to Inability to Activate Sirens | The following information was obtained by the licensee via facsimile: During the May 7, 2004 monthly siren test, it was determined that the Ottawa County Sheriff dispatcher did not have the capability to activate the EPZ (Emergency Preparedness Zone) Sirens. Follow-up investigation determined that a time difference between the control station in the Emergency Operations Facility (EOF) and the sheriff's dispatch control station caused the sheriff's control station to be unable to activate the sirens. This condition was corrected within minutes of discovery, however it appears that the Sheriff's dispatcher had lost capability to activate the sirens when the EOF computer clock was reset due to daylight savings time (reset manually on April 5, 2004). All 54 sirens were successfully tested using the vendors control station. The ability to (activate) the sirens from the Sheriff's control station was restored. The EOF control station retained the ability to activate the sirens throughout this time period. Because the sirens could not be sounded from a 24-hour manned station, in accordance with station procedures, this event represents a Loss of Emergency Preparedness Capability. Therefore, this event is reportable within 8 hours of discovery in accordance with 10CFR50.72(b)(3)(xiii). The Ottawa County Sheriff's Office was notified of this event. The licensee has notified the NRC Resident Inspector. |