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Category:NRC Preliminary Notification of Event/Occurrence
MONTHYEARML17165A4592017-06-14014 June 2017
PNO-III-2017-001: Braidwood Station, Units 1 and 2; Release of Circulating Water Containing Tritium Using an Unauthorized Release Path
PNO-III-11-005, Braidwood Unit 2 Unusual Event Due to Loss of All Control Room Annunciators2011-03-24024 March 2011
PNO-III-11-005, Braidwood Unit 2 Unusual Event Due to Loss of All Control Room Annunciators
PNO-III-10-014, A; Update - Shutdown of Braidwood Reactors Unit 1 & 22010-08-23023 August 2010
PNO-III-10-014A; Update - Shutdown of Braidwood Reactors Unit 1 & 2
ML1022902932010-08-17017 August 2010
PNO-III-10-014 - Shutdown of Braidwood Reactors Unit 1 & 2
PNO-III-10-001, Braidwood Station Declaration of Unusual Event Due to Fire within the Protected Area2010-01-11011 January 2010
PNO-III-10-001: Braidwood Station Declaration of Unusual Event Due to Fire within the Protected Area
PNO-III-09-007, A: Unusual Event at Braidwood Unit 2 Due to Loss of Offsite Power Unit Will Remain Shut Down for More than 72 Hours (Update)2009-08-0505 August 2009
PNO-III-09-007A: Unusual Event at Braidwood Unit 2 Due to Loss of Offsite Power Unit Will Remain Shut Down for More than 72 Hours (Update)
PNO-III-06-020, Braidwood, Nrc'S Review of Exelon'S Plans for Resuming Radioactive Discharges Through the Braidwood Blowdown Line2006-09-0808 September 2006
PNO-III-06-020: Braidwood, Nrc'S Review of Exelon'S Plans for Resuming Radioactive Discharges Through the Braidwood Blowdown Line
PNO-III-06-015, Braidwood Tritium Contamination Issues (Update)2006-06-13013 June 2006
PNO-III-06-015: Braidwood Tritium Contamination Issues (Update)
PNO-III-06-011, Braidwood: Tritiated Steam Released to the Environment2006-04-0707 April 2006
PNO-III-06-011, Braidwood: Tritiated Steam Released to the Environment
PNO-III-06-007, Braidwood 1 and 2 - Tritium Contamination Issues2006-03-30030 March 2006
PNO-III-06-007: Braidwood 1 and 2 - Tritium Contamination Issues
PNO-III-05-016, D Braidwood Tritium Contamination Issues (4th Upgrade)2006-03-15015 March 2006
PNO-III-05-016D Braidwood Tritium Contamination Issues (4th Upgrade)
ML0603405832006-02-0303 February 2006
PNO-III-05-016C Potential Off-Site Migration of Tritium Contamination (3rd Update)
ML0601806232006-01-18018 January 2006
PNO-III-05-016B: Braidwood Potential Off-Site Migration of Tritium Contamination (2nd Update)
ML0618400692005-12-0909 December 2005
E-mail from Habighorst to Lynch, Braidwood Tritium - Recent Contamination Contours, Etc
ML0609706112005-12-0707 December 2005
NRC Email from Justine Burza to Pn Recipients PNO-III-05-016A
ML1020302372005-12-0707 December 2005
Preliminary Notification of Event or Unusual Occurrence
ML0609700692005-12-0101 December 2005
NRC Email W/Att, from Jan Strasma to Richard Skokowski Et Al Draft Pn on Braidwood
ML0609700592005-12-0101 December 2005
NRC Email from Anne Boland to Geoffrey Grant and James Caldwell PNO-RII-05-016
ML0609700572005-12-0101 December 2005
Email for Dale Ambler to Steven Orth Attendees at Pn Debrief
ML0618401842005-12-0101 December 2005
E-mail from Boland to Shane, NRC Notification Braidwood
ML0533505122005-12-0101 December 2005
PNO-RIII-05-016 Braidwood Potential Off-site Migration of Tritium Contamination
PNO-III-05-013, ; Braidwood Forced Outage Due to Reactor Coolant Pump Leak-Off in Excess of Vendor Recommendations2005-09-13013 September 2005
PNO-III-05-013; Braidwood Forced Outage Due to Reactor Coolant Pump Leak-Off in Excess of Vendor Recommendations
2017-06-14
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PRELIMINARY NOTIFICATION- REGION III August 5, 2009 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-III-09-007A
This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region III staff on this date.
Facility Braidwood Nuclear Station Exelon Generation Co., LLC Braceville, IL Docket: 50-457 License: NPF-77 Licensee Emergency Classification X Notification of Unusual Event Alert Site Area Emergency General Emergency Not Applicable
SUBJECT:
UNUSUAL EVENT AT BRAIDWOOD UNIT 2 DUE TO LOSS OF OFFSITE POWER UNIT WILL REMAIN SHUT DOWN FOR MORE THAN 72 HOURS (UPDATE)
DESCRIPTION:
On July 30, at 8:59 p.m. CDT, Braidwood Unit 2 automatically tripped as a result of an electrical disturbance.
During the event, both auxiliary transformers, which supply offsite power to Unit 2 safety-related equipment, tripped off-line. The emergency diesel generators started supplying safety-related equipment with power.
All safety-related systems functioned as required. In accordance with plant procedures, the utility declared an Unusual Event (UE) because offsite power was unavailable for more than 15 minutes. The utility restored offsite power to Unit 2 at 12:36 a.m. CDT on August 2, 2009 and exited the Unusual Event.
The utility is trying to determine the cause of the electrical disturbance.
The transient also resulted in a loss of power to the non-safety related buses. This caused the condenser to become unavailable for cooling the steam generators. Instead, safety-related equipment, such as the auxiliary feedwater system, was used for cooling. As a result, steam was released to the environment where it quickly dissipated. The steam release contained a very low concentration of tritium. Preliminary analysis indicates the amount of tritium was less than one percent of the NRC limits. A more detailed evaluation will be completed as part of the NRC baseline inspection effort. No negative health impact to the public is expected as a result of the steam release.
Braidwood Unit 2 restarted and synchronized to the electrical grid on August 5, 2009, at 3:31 a.m. CDT.
The NRC resident inspectors responded to the reactor trip, and monitored the licensee's response to the incident.
Unit 1 continues to operate at full power.
State and Local officials have been informed.
The information presented in this Preliminary Notification has been discussed with licensee management and is current as of August 5, 2009, at 11:30 a.m.
CONTACTS: B. Dickson R.A. Skokowski 815/458-2853 630/829-9620
