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At 2312 EDT, on August 3, 2020, Brunswick Unit 1 declared an Unusual Event due to a loss of offsite power. The unit was at approximately 20 percent power and was not synced to the grid when the unit automatically scrammed. All control rods fully inserted. Emergency Diesel Generators started and began powering the safety buses. Safety systems actuated as expected. The Unit also experienced a loss of Fuel Pool Cooling and Cleanup System, but one pump was returned to service. Unit 2 remains at 100 percent power and is unaffected. The licensee notified State and local governments, as well as the NRC Resident Inspector. Notified DHS SWO, FEMA Operations Center, CISA IOCC, FEMA NWC (email), DHS Nuclear SSA (email), and FEMA NRCC SASC (email).

• * * UPDATE FROM MARK TURKAL TO DONALD NORWOOD AT 0120 EDT ON 8/4/2020 * * *

At approximately 2302 EDT, a loss of offsite power occurred on Unit 1. This resulted in a Reactor Protection System (RPS) actuation. Per design, emergency diesel generators 1 and 2 properly started and loaded to their respective emergency buses. The Reactor Core Isolation Cooling (RCIC) system was manually started and is being used to control reactor water level. The High Pressure Coolant Injection (HPCI) system was manually started and is being used for pressure control. As previously reported, an Unusual Event was declared at 2312 EDT due to the loss of offsite power. At the time of the event, Unit 1 was in the process of shutting down for maintenance associated with a ground on the main generator. Due to the RPS actuation while critical, this event is being reported as a four-hour, nonemergency notification per 10 CFR 50.72(b)(2)(iv)(B). As a result of the reactor trip, reactor water level reached low level 1 (LL1). The LL1 signal causes a Group 2 (i.e., floor and equipment drain isolation valves), Group 6 (i.e., monitoring and sample isolation valves) and Group 8 (i.e., shutdown cooling isolation valves) isolations. The LL1 isolations occurred as designed; the Group 8 valves were closed at the time of the event. Per design, the loss of offsite power also caused a Group 1 (i.e., main steam isolation valve) isolations. Due to the Emergency Diesel Generator and Primary Containment Isolation System (PCIS) actuations, this event is also being reported as an eight-hour, nonemergency notification in accordance with 10 CFR 50.72(b)(3)(iv)(A). Unit 2 was not affected. There was no impact to the health and safety of the public or plant personnel. The safety significance of the event is minimal. All safety related systems operated as designed. Investigation of the cause of the loss of offsite power is in progress. The licensee notified the NRC Resident Inspector. Notified R2DO (Inverso).

• * * UPDATE ON 8/4/2020 AT 1534 EDT FROM JOSEPH ELKINS TO ANDREW WAUGH * * *

At 1454 EDT on August 4, 2020, the Unusual Event was exited when offsite power was restored to Unit 1. Per design, when the loss of offsite power to Unit 1 occurred, all four emergency diesel generators (EDGs) started and EDGs 1 and 2 properly suppled emergency buses 1 and 2. Since Unit 2 was not affected by the loss of power, EDGs 3 and 4 ran unloaded. With restoration of offsite power to Unit 1, EDG 2 has been secured. EDGs 1, 3, and 4 are being secured as required by plant operating procedure. Notified R2DO (Inverso), NRR EO (Miller), IRD MOC (Grant), DHS SWO, FEMA OC, DHS NICC WO, CISA IOCC (email), DHS SWO (email), FEMA NWC (email), FEMA Ops Center (email), FEMA-NRCC-sasc (email), NRCC THD Desk (email), NuclearSSA (email). ********************************************************************************************************************************

At 2204 EDT on 5/6/19, a Notification of Unusual Event (NOUE) was declared due to a fire lasting greater than 15 minutes. The fire occurred in the '2B' Heater Drain Pump motor located in the turbine building. The fire was extinguished following initial Emergency Declaration. There were no releases to the environment. Unit 1 was unaffected by the event and remains in Mode 1 at 100 percent power. The licensee notified the NRC Resident Inspector. Notified DHS SWO, FEMA Operations Center, DHS NICC, FEMA NWC (email), DHS Nuclear SSA (email), and FEMA NRCC SASC (email).

• * * UPDATE ON 5/7/19 AT 0002 EDT FROM MICHAEL BRADEN TO BETHANY CECERE * * *

The NOUE was terminated as of 2359 EDT on 5/6/19. No off-site resources were required to extinguish the fire. The turbine building is now free of smoke. The licensee will notify the NRC Resident Inspector, State of North Carolina, Brunswick County, New Hanover County, and the Coast Guard. Notified R2DO (Heisserer), NRR EO (Miller), and IRD (Gott). Notified DHS SWO, FEMA Operations Center, DHS NICC, FEMA NWC (email), DHS Nuclear SSA (email), and FEMA NRCC SASC (email).

EN Revision Text: UNUSUAL EVENT DUE TO SITE CONDITIONS PREVENTING PLANT ACCESS A hazardous event has resulted in on site conditions sufficient to prohibit the plant staff from accessing the site via personal vehicles due to flooding of local roads by Tropical Storm Florence. Notified DHS SWO, FEMA OPS, and DHS NICC. Notified FEMA NWC, NuclearSSA, and FEMA NRCC via email.

• * * UPDATE FROM BRUCE HARTSCOK TO VINCE KLCO ON 9/28/2018 AT 1414 EDT * * *

On 9/18/2018 at 1400 EDT, the Unusual Event at Brunswick was terminated due to the ability to transport personnel to the site. The licensee will notify the NRC Resident Inspectors. Notified the R2DO (Guthrie), NRR EO (Miller) and the IRD MOC (Grant). Notified DHS SWO, FEMA OPS, and DHS NICC. Notified FEMA NWC, NuclearSSA, and FEMA NRCC via email.

At 1346 EST the licensee reported that at 1326, Brunswick Unit 1 declared an Alert under EAL HA 2.1 due to an explosion/fire in the Balance of Plant 4 kV switchgear bus area. Prior to the Alert declaration, the operators initiated a manual SCRAM due to an unexpected power decrease from 88% to 40%. The licensee has visually verified that there is no ongoing fire and is investigating the initial cause of the event. Offsite power is available to the site, but EDGs 1 and 2 are running and supplying Unit 1 loads. The MSIVs shut and HPCI/RCIC are being used to maintain vessel level. At 1412 EST, NRC decided to remain in Normal Mode. At 1704 EST the licensee reported the following: At 1313 hours Eastern Standard Time (EST) a manual reactor scram was initiated due to loss of both recirculation system variable speed drives as a result of an electrical fault. At this time, a Startup Auxiliary Transformer (SAT) experienced a lockout fault; interrupting offsite power to emergency buses 1 and 2. Emergency Diesel Generators (EDGs) 1, 2, 3, and 4 automatically started and EDGs 1 and 2 synchronized to emergency buses 1 and 2 per design. The power interruption resulted in closure of the Main Steam Isolation Valves, per design. The manual scram also resulted in closure of Group 2, 6, and 6 Containment Isolation Valves. The Reactor Core Isolation Cooling (RCIC) system was manually started and is being used to control reactor water level. The High Pressure Coolant Injection (HPCI) system was manually started and is being used for pressure control. The Plant response to the event was per design. Unit 2 is not directly affected by the event, however, due to the shared electrical distribution system is in a Technical Specification Action statement due to the Inoperable Unit 1 SAT. The public health and safety is not impacted by this event. At 1751 EST, the licensee reported that the emergency declaration had been downgraded to an Unusual Event at 1730 because the plant no longer meets the criteria for an Alert, but does meet the criteria for an Unusual Event due to a "loss of all offsite power to Emergency 4 kV buses E1 (E3) and E2 (E4) for greater than or equal to 15 minutes." The NRC Resident Inspector has been notified. The licensee has notified the State and Local governments. Notified DHS, FEMA, USDA, HHS, DOE, DHS NICC, EPA EOC, FEMA NWC (via email), FDA EOC (via email) and Nuclear SSA (via email).

• * * UPDATE FROM MARTY IRWIN TO DANIEL MILLS AT 1825 ON 2/07/16 * * *

At 1814 EST the emergency declaration was terminated because offsite power was restored. The NRC Resident Inspector has been notified. The licensee has notified the State and Local governments. Notified R2DO (Musser), NRR EO (Morris), IRD MOC (Stapleton), R2RA (Haney), NRR ET (Lubinski), NRR ET (Dean), DHS, FEMA, USDA, HHS, DOE, DHS NICC, EPA EOC, FEMA NWC (via email), FDA EOC (via email) and Nuclear SSA (via email).

The licensee declared an Unusual Event because of a halon discharge in the simulator. This potentially affects access and habitability of the Technical Support Center (TSC) and the Emergency Operations Facility (EOF). The Unusual Event was declared under HU3.1 "toxic, corrosive, asphyxiate, or flammable gases in amounts that have or could have adversely affected normal plant operations." The fire brigade has been dispatched to determine whether a fire actually exists. The licensee informed State and local agencies and the NRC Resident Inspector. Notified other FEDS (FEMA Ops Center, DHS NICC Watch Officer, DHS SWO) and (Nuclear SSA, FEMA NWC) via email.

• * * UPDATE AT 0707 EDT ON 8/12/2014 FROM DAVID FASCHER TO MARK ABRAMOVITZ * * *

The Unusual Event was terminated at 0700 EDT. Halon discharged into the plant simulator. There was no actual fire. Offsite assistance was requested. Local fire department and ambulance are on site. The TSC and EOF have been activated. The halon discharge into the simulator building is not impacting normal plant operations where the ERO (Emergency Response Organization) capabilities and staffing are still required. Therefore, activation for UE (Unusual Event) is being terminated. The Incident Commander released the building for normal access at 0717 EDT. The licensee informed State and local agencies and the NRC Resident Inspector. Notified the R2DO (Nease), IRD (Gott), and NRR (Thomas). Notified other FEDS (FEMA Ops Center, DHS NICC Watch Officer, DHS SWO) and (Nuclear SSA, FEMA NWC) via email.

• * * UPDATE AT 1218 EDT ON 8/12/14 FROM CRAIG OLIVER TO JOHN SHOEMAKER * * *

EVENT DESCRIPTION: This is an update of a previous notification which was made by telephone to the (NRC) Operations Center at approximately 0504 EDT per Event Number 50355. At approximately 0421 EDT on 08/12/2014, the Halon fire suppression system in the Plant Simulator actuated by releasing the Halon. A Notification of Unusual Event (NOUE) was declared at 0432 EDT on the basis that a release of toxic or asphyxiating gas had occurred on site (Emergency Action Level HU3.1). Emergency response personnel reported to the site and prepared to perform emergency response activities. The site fire brigade was dispatched. The local fire department was called and emergency personnel were dispatched to the site. The reason for the Halon discharge is not known at this time and is under investigation. No actual fire was observed. The Plant Simulator is located in the same building with the primary Technical Support Center (TSC) and primary Emergency Operations Facility (EOF). Since the Halon discharge occurred in this building, the site incident commander restricted access to these two primary Emergency Response Facilities, rendering them unavailable for use. The NOUE was terminated at 0700 EDT. Normal access to the TSC and EOF was restored at 0717 EDT. INITIAL SAFETY SIGNIFICANCE EVALUATION: This event had no effect on the operating units, and there was no adverse impact on nuclear safety or on the health and safety of the public. The NRC Resident Inspector has been notified. CORRECTIVE ACTIONS: Offsite fire department personnel assisted by on site fire brigade have validated that no fire condition existed. The building has been ventilated and normal access restored. The failure of the Halon System is being tracked for restoration in accordance with station fire protection documents. Notified R2DO (Hopper) and NRR Daytime EO (Thomas).

The licensee declared a Notice of an Unusual Event per EAL HU2.2 "Explosion with Protected Area Boundary" following an apparent fault and explosion on the M29 transformer (a non-safety related transformer). This resulted in a loss of one electrical bus at the ocean discharge station; however, no safety-related electrical loads were effected and both units remained at 100 percent electrical power. Station personnel reported that there was no smoke in the area of the M29 transformer and the event may have been a flashover explosion in the area of the transformer. All safety systems remain available. Licensee is investigating the cause of the explosion, and no offsite assistance was required. The licensee has notified the NRC Resident Inspector, the State of North Carolina, and other local authorities. Notified DHS SWO, FEMA Operations Center, NICC Watch Officer, and NuclearSSA via e-mail.

• * * UPDATE ON 01/10/14 AT 2343 EST FROM MIKE MORRIS TO RYAN ALEXANDER * * *

Notification of an Unusual Event is being terminated (at 2320 EST) because the condition no longer exists. The source of the apparent explosion was a failed insulator on a breaker and is known to present no danger to public health and safety. Both Units are stable and a recovery organization is in place. The licensee has notified the NRC Resident Inspector regarding the termination of the event. Notified R2DO (Hopper), NRR EO (Lubinski), IRD Manager (Gott), DHS SWO, FEMA Operations Center, NICC Watch Officer, and Nuclear SSA via e-mail.

At 0900, the Brunswick Steam Electric Plant (BSEP) declared an Unusual Event due to a release of Freon from the 2A Turbine Building Chiller. The classification of the Unusual Event is based on Emergency Action Level (EAL) HU3.1, 'Toxic, corrosive, asphyxiant or flammable gases in amounts that have or could adversely affect normal plant operations.' Actions have been taken to secure the chiller and isolate the release of Freon; however, Freon continues to be released. The release is only affecting the area immediately surrounding the 2A Turbine Building Chiller. No other plant areas are being impacted. There is no impact on the health and safety of the public. The licensee notified Brunswick Warning Point, Hanover Warning Point, State Warning Point and the NRC Resident Inspector. Notified DHS, FEMA, DHS NICC and NuclearSSA (email).

• * * UPDATE AT 1555 EST ON 2/26/13 FROM ERIC WHITE TO S. SANDIN * * *

At 1545 EST on 2/26/13, Brunswick terminated their Unusual Event based on the fact that the entry conditions no longer existed. A temporary patch has been installed on the 2A Turbine Building Chiller and work is in progress to evacuate residual Freon from the chiller unit. The licensee notified state and local agencies and the NRC Resident Inspector. Notified R2DO (Musser), IRD (Kozal) and NRR (Chernoff). Notified DHS, FEMA, DHS NICC and NuclearSSA (email).

On 11/16/11 at 0208 EST, Brunswick Nuclear Plant, Unit 2 calculated a drywall floor drain 42 minute leak rate of 5.88 gpm, following several hours of gradually rising floor drain leakage during a plant startup. Tech Spec 3.4.4 A was entered, requiring floor drain leakage to be restored below 5 gpm within 8 hours. At 0253 EST, a 45 minute leak rate of 10.11 gpm was calculated. At 0301 EST, Unusual Event SU 6.1 was declared for unidentified leakage exceeding 10 gpm, and at 0309 EST, a manual reactor scram was inserted from approximately 7% power (10 CFR 50.72(b)(2)(iv)(B)). Following the scram, the reactor was depressurized at a maximum cooldown rate of 92.5 deg F/hr, and the unidentified leak rate fell less than 10 gpm within 1 hour and less than 5 gpm within 2 hours. Leak rate at 0614 EST on 11/16/11 is 3.82 gpm with reactor pressure at 228 psig. The exact nature of the leak is unknown at this time. The current plan is to continue to depressurize and cool down the reactor to Mode 4, such that a full drywall inspection can commence. At present, Brunswick has not terminated the Unusual Event. Level control is currently being maintained with control rod drives (CRD). The MSIVs were manually closed to control cooldown. The maximum cooldown was observed to be 92.5 F/hour. The plant plans to reopen MISIVs and depressurized to condensate booster pump injection pressure of 350 psig. The plan is to achieve Mode 4 for a leak inspection. The licensee has notified the NRC Resident Inspector.

• * * UPDATE FROM DAVID FASHCHER TO CHARLES TEAL AT 0550 EST ON 11/16/11 * * *

The leakage rate is currently 3.73 gpm. The decrease is due to lower pressure which is currently at 258 psig. There are no additional changes. The leakage source is not identified at this time. The licensee has notified the NRC Resident Inspector. Notified R2DO (Vias).

• * * UPDATE FROM DUSTIN LUPTON TO JOHN SHOEMAKER AT 0648 EST ON 11/16/11 * * *

The leakage rate is currently below the T.S. limit due to lower pressure which is currently at 210 psig. There are no additional changes. The plant will remain in an Unusual Event (UE) until further notice. The licensee has notified the NRC Resident Inspector. Notified R2DO (Vias).

• * * UPDATE FROM DUSTIN LUPTON TO CHARLES TEAL AT 0749 EST ON 11/16/11 * * *

The leakage rate is stable. The leak rate is calculated at 3.04 gpm at 183 psig at 0708 EST. The current reactor pressure is 162 psig. The licensee has notified the NRC Resident Inspector. Notified R2DO (Vias).

• * * UPDATE FROM DUSTIN LUPTON TO JOHN KNOKE AT 0832 EST ON 11/16/11 * * *

The licensee terminated from their Unusual Event at 0815 EST. The leakage is still unidentified. The licensee has notified the NRC Resident Inspector. Notified R2DO (Vias).

At 1137 EDT, Brunswick Units 1 & 2 declared an Alert condition due to a discharge of Halon gas into the basement of the emergency diesel generator building (EAL H.A.3.1 for toxic gas discharge into a vital area). Initial inspection indicates that there is no fire. No offsite assistance was required and no personnel injuries as a result of the discharge. Both reactors continue to operate at 100% power. The licensee is investigating the cause of the discharge and will terminate the Alert when the area is ventilated and can be reoccupied. The licensee has notified State and local authorities and the NRC Resident Inspector.

• * * UPDATE TO ABRAMOVITZ FROM CINDRIC AT 1616 EDT ON 6/6/10 * * *

The licensee terminated the Alert at 1614 EDT based on restoring normal atmosphere conditions in the emergency diesel generator building. The initiating cause of this event is still being investigated. State and local authorities have been notified and the Resident Inspector will be notified. The NRC Operations Center has notified the Federal Agencies initially notified of this event. R2DO (Vias), NRR EO (Galloway) and IRD (Grant) notified.

The licensee reported that a CO2 discharge has occurred in the Unit 1 HPCI room. The cause and amount of CO2 released is not specifically known but the licensee judged that the room was not currently habitable based on the CO2. The licensee consequently declared an Unusual Event (UE) under EAL HU3.1 - "Toxic, Corrosive, Asphyxiant, or Flammable Material in Amounts That Could Adversely Impact Plant Operations. The licensee stated that activities were in progress in the room at the time of the discharge. There is no indication of a fire in the room and there were no personnel injuries as a result of the discharge. The discharge also had no impact on plant operation. The licensee at this point plans to terminate the UE when the room is properly ventilated. The licensee has notified State and local authorities and the NRC Resident Inspector and does not plan a press release.

• * * UPDATE FROM GARY ROBERTS TO DONG PARK @ 1354 EST ON 02/19/10 * * *

At 1330 EST on 2/19/10, the Unusual Event was terminated. The atmosphere in the HPCI room is back to normal. The CO2 source was from cylinders located in the HPCI room which is part of the fire suppression system. The licensee has notified the NRC Resident Inspector. Notified IRD (Grant), R2DO (Bartley), NRR EO (Thorp), DHS (Vestal) and FEMA (Fuller).

At 1823 EST, Unit 2 was manually scrammed due to a loss of offsite power from the Startup Auxiliary Transformer to both 4KV Emergency (E) buses. Both Emergency Diesel Generators (EDGs) 3&4 autostarted and re-energized the affected electrical buses. At 1823 EST, an Unusual Event was declared based on EAL 06.01.01, "Inability to power either 4KV E bus from offsite power." Unit 2 is currently stable in mode 3, Hot Shutdown, with MSIVs closed and HPCI controlling pressure and RPV Water Level. All control rods fully inserted following the manual reactor scram. The licensee determined that no emergency facilities will be activated and that no offsite assistance is needed at this time. The licensee informed both state and local agencies and will inform the NRC Resident Inspector.

• * * UPDATE PROVIDED BY JOEL LEVINER TO JEFF ROTTON AT 2214 EST ON 11/01/06 * * *

On 11/01/06 at approximately 18:23 (EST) Brunswick Unit 2 experienced a loss of the unit's Startup Auxiliary Transformer and a loss of reactor forced circulation. A manual reactor scram was performed as required by station Abnormal Operating Procedures. Due to the loss of the Startup Auxiliary Transformer and subsequent manual reactor scram, a loss of Offsite Power resulted to the unit's power buses when unit shutdown was completed. All control rods properly inserted when the manual reactor scram was performed. All four site emergency diesels started and diesels 3 and 4 are supplying the Unit 2 emergency buses. Reactor water level reached low level 1 (LL1) and low level 2 (LL2) as result of the reactor scram and loss of offsite power. The LL1 signal resulted in Group 2 (floor and equipment drain isolation valves), Group 6 (monitoring and sampling isolation valves) and Group 8 (shutdown cooling isolation valves) isolation signals. All low level 1 isolations occurred as designed. The LL2 resulted in a Reactor Core Isolation Cooling (RCIC) system actuation, High Pressure Coolant Injection (HPCI) system actuation, Group 3 (reactor water cleanup valves) isolation signal, a secondary containment isolation signal, a Standby Gas Treatment (SBGT) initiation signal, a Control Room Emergency Ventilation (CREV) initiation signal, and an Alternate Rod Insertion (ARI) actuation signal. All isolation and actuations occurred as designed with the exception the CREV initiation and ARI actuation. CREV initiation and ARI actuations were performed by manual actions. The failure of the CREV and ARI initiation/actuations are under investigation. The RCIC and HPCI systems were used to restore reactor water level to the normal operation band. Reactor vessel pressure is being controlled in the normal band with manual operation of Safety Relief Valves (SRV), and HPCI/RCIC in pressure control mode. The Main Steam Isolation Valves (MSIVs) (Group 1) and the drywell pneumatic isolation valves (Group 10) closed on the loss of power. The plant is a stable condition. Troubleshooting activities are in progress to determine the cause of the event. At 1910, the NRC was previously notified of the Unusual Event declaration. Initial Safety Significance Evaluation: The safety significance of this event is minimal and Unit 2 is in a stable condition. All control rods properly inserted when the manual scram was performed. Plant safety systems responded as required with the exception of the CREV and ARI systems which did not automatically initiate but functioned properly when manually actuated. All four emergency diesels started and Unit 2 diesels 3 and 4 are supplying the Unit 2 emergency buses. Reactor pressure and level are being controlled per procedure, with HPCI and RCIC. Actions are in progress to re-establish off site power supply to emergency buses 3 and 4 via backfeed through the Unit Auxiliary Transformer (UAT). Corrective Actions: Actions are in progress to re-establish offsite power supply to emergency buses 3 and 4 via backfeed through the UAT. Investigations are in progress to determine the cause of the SAT failure and the failure of CREV and ARI to auto-initiate. The licensee has notified the NRC Resident Inspector and the State and local emergency agencies. Update provided also added the following reportable notifications due to the event: 10CFR50.72(b)(2) (iv)(A) and(iv)(B) and 10CFR50.72(b)(3)(iv)(A). Notified R2DO (Evans).

• * * UPDATE PROVIDED BY MARK SCHALL TO JEFF ROTTON AT 1805 EST ON 11/02/06 * * *

Licensee reported that the Unusual Event was terminated at 1745 EST on 11/02/06 after Offsite power was restored to both 4 KV E Buses from the Unit Auxiliary Transformer (UAT) on Unit 2. The #3 and #4 EDGs have been secured and are in Standby. #1 EDG remains inoperable and #2 EDG is presently being Load Tested. The licensee will be notifying the NRC Resident Inspector and the State and local emergency agencies. Notified R2DO (Evans), NRREO (Richards), IRD Manager (Leach), DHS (Barnes), and FEMA (Kuzia).

Event reportability is in accordance with 10 CFR 50.72(b)(3)(v)(D), 'Accident Mitigation,' and 10 CFR 50.72(b)(2)(i), 'TS Required Shutdown,' due to potential COMMON CAUSE FAILURE of all four Emergency Diesel Generators. On 05 August 2005, at 14:31 hrs, DG2 was started for data gathering purposes, and it experienced a trip and lockout on differential current. Investigation revealed that set points for the installed DG differential current protective devices may be set too conservatively. Since each DG has the same relay with the same set point, all DGs were declared inoperable. Preparations are in progress to place both units in Cold Shutdown. The site has insufficient operable backup AC sources. The current effect on the plant is minimal due to all normal AC sources being available and operable. However, due to the potential for losing a normal AC source resulting in insufficient power being available to some emergency systems, both units will be placed in cold shutdown until all emergency diesel generators can be restored to operable. Corrective actions are in progress to correct differential current protective device problem in order to restore availability of DG2 and operability of all four DGs. The licensee plans on commencing a down power on both units (Unit 2 first) within several hours. Technical Specifications require both units to be in Hot Shutdown within 12 hours (approximately 0700 on 08/06/05) and Cold Shutdown within 36 hours. Neither unit has any other significant systems LCOs. The licensee notified the NRC Resident Inspector.

• * * UPDATE FROM LICENSEE (BAIN) TO NRC (HUFFMAN) AT 10:38 EDT ON 8/06/05 * * *

This is a follow up message to the initial event reported in accordance with 10 CFR 50.72(b)(3)(v)(D), 'Accident Mitigation' and 10 CFR 50.72(b)(2)(i), 'TS Required Shutdown' due to the potential COMMON CAUSE FAILURE of all four Emergency Diesel Generators. Unit 2 entered Mode 3 (Hot Shutdown) at 04:46. Unit 1 entered Mode 3 (Hot Shutdown) at 05:31. Both units are continuing to cool down in preparation for entering Mode 4 (Cold Shutdown)." The licensee notified the NRC Resident Inspector. Notified R2DO(Landis), NRR EO (Haney), and IRD (McGinty).

Licensee declared an Unusual Event at 1308 EDT on 08/14/04. Unusual Event was declared due to a Loss of Offsite Power which occurred due to a Lockout trip of the Station Auxiliary Transformer. All four emergency diesel generators started and loaded properly. On the reactor trip, all rods fully inserted. They received Group II, VI, and VIII PCIS isolations due to the loss of power. The MSIVs are closed and the licensee manually started RCIC for reactor level control and HPCI for reactor pressure control. The licensee in activating the Emergency Response Organizations. No offsite assistance required. The licensee notified the NRC Resident Inspector, State and local Emergency response organizations.

• * * UPDATE PROVIDED TO JEFF ROTTON FROM KEITH HANZ AT 1727 EDT ON 08/14/04 * * *

Licensee declared termination of the Unusual Event at 1713 EDT on 08/14/04 after restoring offsite power to the Station Auxiliary Transformer, BOP and Emergency Buses. The licensee notified the NRC Resident Inspector. Notified R2DO (Julian), R4DO (Smith), IRD (Nieh), NRR EO (Carpenter), DHS (Doyle), and FEMA (Sullivan)

On July 29, 2004, at approximately 0351 hours, testing of Suppression Chamber-to-Drywell vacuum breakers commenced in accordance with Periodic Test 0PT02.3.1, "Suppression Chamber-to-Drywell Vacuum Breaker Operability Test." At 0357 hours, it was determined that vacuum breaker 2-CAC-X18D had an open indication. Technical Specifications (TS) Limiting Condition for Operation (LCO) 3.6.1.6, "Suppression Chamber-to-Drywell Vacuum Breakers," Condition B was entered for one suppression chamber-to-drywell vacuum breaker (2-CAC-X18D) not indicating closed. Required Action B.1 of TS LCO 3.6.1.6 provides 4 hours to verify the vacuum breaker closed. Attempts to confirm the vacuum breaker closed were unsuccessful and at 0757 hours, TS LCO 3.6.1.6 Condition C was entered. Required Action C.1 is to be in Mode 3 (Hot Shutdown) in 12 hours and Required Action C.2 is to be in Mode 4 (Cold Shutdown) in 36 hours. Initiation of the plant shutdown required by TS LCO 3.6.1.6 commenced at 0942 hours. This condition is being reported in accordance with 10 CFR 50.72(b)(2)(i) as the initiation of any nuclear plant shutdown required by the plant's TS. INITIAL SAFETY SIGNIFICANCE EVALUATION The initial safety significance of this condition is considered to be minimal. The actual position of the vacuum breaker cannot be confirmed, however if one vacuum breaker was not closed, communication between the drywell and suppression chamber air space could occur, and as a result, there is a potential, for primary containment overpressurization due to this bypass leakage if a loss of coolant accident were to occur. The plant is currently proceeding to hot shutdown with all Emergency Core Cooling systems operable. CORRECTIVE ACTIONS Determine the required corrective actions after entry into the drywell following shutdown. The safety significance of the event will be reviewed when the actual condition of the vacuum breaker is known. The NRC Resident Inspector has been notified.

• * * UPDATE ON 07/29/04 @ 1654 FROM KEN CHISM TO CHAUNCEY GOULD * * *

On July 29, 2004, at 1517 hours, a manual scram was inserted to shut down the Unit 2 reactor from approximately 23 percent of rated thermal power. The reactor shutdown was implemented to meet the requirements of Technical Specification (TS) Limiting Condition for Operation (LCO) 3.6.1.6 Required Action C.1 to be in Mode 3 in 12 hours. All control rods fully inserted into the core and no ECCS actuation occurred or relief valves lifted. Following the scram, an expected reactor vessel coolant level shrink occurred causing coolant level to decrease below the Low Level 1 setpoint. This coolant level decrease resulted in a Primary Containment Isolation Valve isolation signal to Group 2 (Drywell Equipment and Floor Drain, Traversing In-core Probe, Residual Heat Removal (RHR) Discharge to Radwaste, and RHR Process Sample), Group 6 (Containment Atmosphere Control/Dilution, Containment Atmosphere Monitoring, and Post Accident Sampling System), and Group 8 (RHR Shutdown Cooling Suction and RHR Inboard Injection) isolation valves. The isolation signal closed all of the valves that were open at the time of the expected initiation. The plant is currently in mode 3 and proceeding with a normal cooldown to Mode 4. The NRC Resident Inspection was informed. Notified Reg 2 RDO (Tom Decker).