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The query [[Category:ENS Notification]] [[Site.Company::Cleveland Electric]] [[Scram::+]] was answered by the SMWSQLStore3 in 0.4567 seconds.


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 Entered dateSiteScramRegionReactor typeEvent description
ENS 5223210 September 2016 07:23:00Davis BesseAutomatic ScramNRC Region 3B&W-R-LPAt 0343 EDT, with the unit operating at approximately 100% full power, an automatic reactor trip occurred due to a Main Generator lock-out. The cause of the generator lock-out is being investigated at this time. All control rods fully inserted. Post trip, the Steam Feedwater Rupture Control System was actuated due to high Steam Generator 1 level. The cause of the high Steam Generator 1 level is being investigated at this time. The unit is currently in Mode 3 (Hot Standby) and stable, at approximately 550 degrees F and 2155 psig. Steam is being discharged through the Atmospheric Vent Valves for decay heat removal. There is no known primary to secondary leakage, and all safety systems functioned as expected. The NRC Resident Inspector has been notified of the event. The licensee notified the State of Ohio, Ottawa and Lucas County.
ENS 5169629 January 2016 16:43:00Davis BesseAutomatic ScramNRC Region 3B&W-R-LPAt 1322 EST, with the unit operating at approximately 100% full power, an automatic reactor trip occurred due to actuation of Reactor Protection System (RPS) Channel 4. The cause of the RPS actuation is being investigated at this time. Nuclear Instrumentation calibration for RPS Channel 2 was in progress at the time of the trip, with Channel 2 in bypass and Channel 1 in trip. All control rods fully inserted. Immediately post trip, the Steam Feedwater Rupture Control System actuated due to high Steam Generator 1 level due to unknown causes. The Main Steam Isolation Valves closed and Auxiliary Feedwater started as expected. Secondary side relief valves lifted in response to the trip, with two of the relief valves (one on each header) not properly reseating until operators manually lowered Main Steam Header pressure. The Bayshore 345 kV Offsite Electrical Distribution Circuit automatically isolated at the time of the unit trip. This was unexpected. The remaining offsite circuits remain in service. The unit is currently in Mode 3 (Hot Standby) and stable, at approximately 550 degrees F and 2155 psig. Steam is being discharged through the Atmospheric Vent Valves for decay heat removal. There is no known primary to secondary leakage, and all safety systems functioned as expected. Both primary Source Range nuclear instruments automatically energized, however, they were previously declared inoperable due to an administrative issue. Both Source Range instruments are functional and indicating properly. Both alternate Source Range instruments are operable, and all required Technical Specification actions have been completed. The NRC Resident Inspector has been notified of the event.
ENS 510619 May 2015 19:45:00Davis BesseManual ScramNRC Region 3B&W-R-LP

At 1855 EDT, a steam leak from the #1 moisture separator reheater in the turbine building was reported to the control room. Operators performed a rapid down power to approximately 30% at which time the reactor was manually tripped. At 1910 EDT an Unusual Event was declared. The steam feed rupture control system was manually initiated (this includes actuation of both turbine-driven Auxiliary Feedwater Pumps) and the steam leak was isolated. Station air compressor #2 (non-safety related) tripped. Station air compressor #1 automatically started. The unit is currently in mode 3 (Hot Standby) and stable. Steam is being discharged through the atmospheric dumps as a means of decay heat removal. There is no known primary to secondary leakage. All systems functioned as expected. There were no reported injuries and personnel accountability is in progress.

The licensee notified state and local agencies and informed the NRC Resident Inspector. Notified DHS SWO, FEMA Ops Center, NICC Watch Officer and FEMA NWC and NuclearSSA via email.

  • * * UPDATE AT 2201 EDT ON 5/9/15 FROM GERRY WOLF TO S. SANDIN * * *

The licensee exited the Unusual Event at 2121 EDT based on the following: At 2121 hours EDT, the Unusual Event at the Davis-Besse Nuclear Power Station was terminated. The steam leak has been isolated and plant conditions are stable. Cooling continues to be maintained via the auxiliary feedwater system. The initiation of auxiliary feedwater at the start of the event is reportable as a Specified System Actuation per 10CFR50.72(b)(3)(iv)(A). The licensee notified state and local agencies and informed the NRC Resident Inspector. Notified R3DO (Skokowski), NRR EO (Morris) and IRD (Grant). Notified DHS SWO, FEMA Ops Center, NICC Watch Officer and FEMA NWC and NuclearSSA via email.

ENS 500978 May 2014 17:46:00Davis BesseManual ScramNRC Region 3B&W-R-LPOn 5/4/14 while the plant was in Mode 3 and the reactor not critical, unexpected position indications were observed on a Control Rod while withdrawing an Axial Power Shaping Rod (APSR). Due to the uncertainty of rod positions, the APSR was inserted into the core. The reactor trip breakers were then opened from the Control Room using the manual trip pushbuttons. All Control and Safety Rods were unlatched and fully inserted into the reactor core before the reactor trip breakers were opened. This manual initiation of the Reactor Protection System with the reactor not critical is being reported per 10 CFR 50.72(b)(3)(iv)(A). The reportability of this event was determined based on an extent of condition review for Event Number 50086 that occurred 5/5/14. The failure to meet the 8-hour reporting requirement has been entered into the Corrective Action Program. The licensee notified the NRC Resident Inspector, the State of Ohio, and Ottawa and Lucas Counties.
ENS 500865 May 2014 21:17:00Davis BesseManual ScramNRC Region 3B&W-R-LPDuring planned testing of the Control Rod Drive (CRD) system, the reactor trip breakers were opened via the manual reactor trip push buttons to de-energize a CRD motor in response to a high temperature. The partially withdrawn control rods fully inserted and all other rods remained in their initial positions. This manual Reactor Protection System (RPS) actuation while the reactor was not critical is reportable in accordance with 10 CFR 50.72(b)(3)(iv)(A). The licensee notified the NRC Resident Inspector, the State of Ohio, and Ottawa and Lucas Counties.
ENS 4915929 June 2013 22:48:00Davis BesseAutomatic ScramNRC Region 3B&W-R-LPAutomatic trip of Reactor Coolant Pump 1-2 due to an electrical differential current fault resulted in an RPS actuation on Flux/Delta Flux/Flow. Startup Feedwater Valve 1 did not respond as expected post-trip and has been placed in manual control. All secondary side steam reliefs initially re-seated following reactor trip. Subsequent Main Steam Line #1 Safety Valve leakage mitigated during post-trip recovery actions. All other systems have functioned as expected. The plant is stable in Mode 3 - Hot Standby. All rods inserted into the core during the trip. Decay heat is being removed via turbine bypass valves to the main condenser with normal feedwater to the steam generators. The plant is in its normal shutdown electrical lineup. The licensee characterized the trip as uncomplicated. The licensee will be notifying Lucas and Ottawa counties, the State of Ohio and will be issuing a press release. They have notified the NRC Resident Inspector.
ENS 428286 September 2006 05:33:00Davis BesseManual ScramNRC Region 3B&W-R-LPObserved degrading condenser pressure. Entered abnormal procedure DB-OP-02518, High Condenser Pressure and reduced reactor power. At <280 Mwe and > 5 inches Hg (mercury) A (absolute) , manually tripped the reactor at approximately 45% power in accordance with procedure. Normal post-trip response. Condenser pressure is slowly recovering. Still trying to determine the source of the condenser air in-leakage. Notified Ottawa County Sheriff of main steam safety / atmospheric vent valve operation at 0231 hours per procedure. All control rods fully inserted on the trip. Decay heat is being removed using the turbine bypass valves and the motor driven feed pump. There is no steam generator tube leakage. The atmospheric vent valves / main steam safety valves lifted for a few seconds following the trip and fully reseated after the initial lifting. Plant electrical power if from the grid backfeeding to the station. The electric grid is stable. The NRC Resident Inspector was notified of this event by the licensee.