Semantic search
| Entered date | Site | Region | Reactor type | Event description | |
|---|---|---|---|---|---|
| ENS 40179 | 19 September 2003 11:25:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | At 0930 on September 19, 2003 it was identified that there was a major loss of offsite response capability. 43 out of 63 early warning sirens were determined inoperable due to loss of power as a result of Hurricane Isabel. The State and NRC Resident Inspector will be notified of this event.
On September 24, 2003, at 0715 hours, a siren poll test was conducted to verify availability of the early warning sirens (EWS). The test identified that 57 of 63 (90%) sirens were available. The current availability of the EWS no longer constitutes a major loss of emergency assessment capability, offsite response capability, or offsite communication capability pursuant to 10CFR50.72(b)(3)(xiii) The NRC Resident Inspector was informed. Notified R2DO (C. Julian) |
| ENS 40328 | 18 November 2003 10:03:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | This is notification of a Special Report in accordance with Technical Requirement 7.1.1 of the North Anna Technical Requirements Manual. On November 17, 2003, at 1150 hours, the Main Control Room observed the start of all fire pumps and receipt of associated alarms. An investigation determined that a significant leak in the fire protection header occurred outside the protected area. The cause for the fire protection header leak has not been determined. In an effort to isolate the leak, two of the three fire pumps had to be shut down and the third pump was isolated. The leaking portion of the fire protection header was isolated by 1313 hours. The running fire pump was then used to refill and pressurize the fire protection header. By 1420 hours, the fire protection system had been returned to normal. The licensee notified the NRC Resident Inspector. |
| ENS 40379 | 9 December 2003 17:12:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | At 1559 EST on 12/09/03, Seismic activity was felt at North Anna Power Station (NAPS). Both units continue to operate at 100 percent power with no problems. Seismic monitoring systems did not pick up the event. The earthquake was centered 15 miles Southeast of Colombia, VA (29 miles from NAPS) and registered 4.5 on the Richter Scale. Initial plant walk downs have identified no issues. Operations and engineering are continuing to walk down the units to identify problems that are undetectable from the control room. The licensee notified the NRC Resident Inspector. |
| ENS 40497 | 2 February 2004 16:41:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | A licensed operator was determined to be under the influence of alcohol during a random test. However, it was below the 10CFR26 cut-off level but could have resulted in the individual being unfit for scheduled work activities. The employee's access to the plant has been put on fitness-for-duty hold pending resolution. Contact the HOO for additional details. The licensee notified the NRC Resident Inspector. |
| ENS 40637 | 3 April 2004 13:17:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | Notification made to State Department of Environmental Quality (DEQ) for a chemical spill of Calgon H-901-g going into onsite waters." Approximately 500 gallons of chemicals containing Bromine used to treat service water spilled onsite. A portion of the spill entered the drainage system and was released offsite. The licensee attributes the spill to a mechanical failure on their brominator system and is in the process of cleaning up the material onsite. The licensee informed the NRC Resident Inspector. |
| ENS 40739 | 10 May 2004 00:11:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | 2-EE-EG-2H was out of service for scheduled maintenance. During an inspection, 4 shims on the exhaust stack seismic support on the south wall were found missing. The shims provide baseplate bearing on the concrete wall near each anchor bolt and had fallen to the floor. In addition, both lower anchor bolt nuts had worked loose and had fallen to the floor and one of the upper anchor bolt nuts had worked loose and was partially disengaged. Following this discovery 2-EE-EG-2J was inspected and 3 of the 4 supports were not properly fastened. 2J EDG was declared inoperable based on this discovery. Due to both U-2 Emergency Diesel Generators being in operable the safety functions needed to maintain the reactor in a safe shutdown condition and remove residual heat would have been imparted in the event of a loss of off site power 2-EE-EG-2J was repaired and returned to operable at 2313 EST on May 09, 2004. The NRC Resident Inspector was notified of this event by the licensee. |
| ENS 40784 | 29 May 2004 09:55:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | During performance of Hot Rod Drop Testing (and) when withdrawing 'D' Control banks, a failure of Group 1 Position Indication was identified. Entered action of Technical Requirement Manual (TRM) 3.1.3 and opened the Reactor Trip Breakers within 15 minutes per action (statement) of TRM 3.1.3. After the Reactor Trip Breakers were opened all Group 1 "D" Control Rods fully inserted into the core. There were no reactivity concerns since the reactor was borated with adequate shutdown margin. The failure of the position indicator has been identified and repaired. There were no other issues associated with this incident and the licensee will proceed with Hot Rod Drop Testing while at 0% reactor power and Mode 3. The licensee will notify the NRC Resident Inspector. |
| ENS 40804 | 10 June 2004 16:11:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | A Unit 2 automatic reactor trip occurred while the licensee was performing planned periodic testing on train "A" solid state protection. All control rods fully inserted into the reactor core. The Auxiliary Feedwater Pumps automatically started as expected immediately following the reactor trip due to low-low level in the steam generators. The unit is being maintained stable in mode 3 and heat sink is being performed via steam dump to the condensers. All other systems functioned as required. The cause of the reactor trip is under investigation. The licensee notified the NRC Resident Inspector.
This is an update to event notification 40804. At 1313 hours on June 10, 2004, North Anna Unit 2 experienced an automatic trip from 100 percent during the performance of 2-PT-36.1A (Train 'A' Reactor Protection and ESF Logic Actuation Logic Test). The cause of the reactor trip, was determined to be an incorrect configuration of the cell switch (52h contract) on 'A' Reactor Bypass Breaker, 2-EP-BKR-BYA. The incorrect cell switch configuration resulted in a turbine trip signal being generated during testing which resulted in a reactor trip signal being generated in the 'B' train Reactor Protection System. The Auxiliary Feedwater System actuated in response to the event. Control room personnel responded to the event in accordance with emergency procedure E-0, Reactor Trip or Safety Injection. The control room team stabilized the plant using ES-0.1 Reactor Trip recovery. The lowest Reactor Coolant System (RCS) pressure during the event was 1988 psig and the lowest RCS temperature was 549 degrees. No human performance issues were identified during this event. A non-emergency four-hour report was made to the NRC operations center at 1611 hours pursuant to 10CFR50.72(b)(2)(iv)(B) for an actuation of the Reactor Protection System while critical. An eight-hour report was also made to the NRC in accordance with 10CFR 50.72(b)(3)(iv)(A) due to the Auxiliary Feedwater Pump starts (Engineering Safety Features Actuation). The Reactor Protection System, AMSAC (ATWAS Mitigating System Actuation Circuit), and the Auxiliary Feedwater System operated properly in response to the event. During the Unit 2 reactor trip, a blown output fuse on a logic card (that feeds the permissive for arming the Steam Dumps from loss of load) prevented the Main Steam Dump Valves from opening in Tavg Mode as expected. The Steam Generator Power Operated Relief Valves (PORVs) lifted and operated to control RCS temperature until transferring Steam Dump control to the Steam Pressure Mode. The fuse was replaced. A post trip review was conducted at 1500 hours on June 10, 2004. The cell switches on the Reactor Trip Bypass breakers have been repaired and post maintenance testing has been completed. Management approval was granted to start-up Unit 2. North Anna Unit 2 is currently in Mode 1 and is preparing to be placed on-line. The licensee notified the NRC Resident Inspector. Notified R2DO (Lesser) and NRR EO (Bateman). |
| ENS 40820 | 16 June 2004 10:11:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | At 0945 on 6/16/04, the uninterruptible power supply to the Technical Support Center was removed from service for pre-planned maintenance. As a result, the plant Safety Parameter Display System (SPDS) and the Technical Support Center (TSC) computer system are inoperable. This event is a major loss of emergency assessment capability and is reportable under 10CFR50.72(b)(3)(xiii). The expected duration of the maintenance is between 4 and 8 hours. This pre-planned maintenance also made the ERDS inoperable. The Licensee has notified the NRC Resident Inspector.
SPDS and the TSC computer were returned to service at 17:04 on 06/16/04. The NRC Resident Inspector will be returned to service. |
| ENS 41104 | 8 October 2004 14:14:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | The licensee experienced an apparently spurious actuation of the CO2 (carbon dioxide) suppression system in the North Anna Unit 1 turbine building (specifically the main turbine, low pressure turbine, and exciter area). The licensee responded and determined there was no fire and secured the CO2 release within two minutes. The event was classified as an unusual event per item K.13 of the emergency action levels due to onsite release of a toxic gas. The licensee has pulled the actuation fuses on the system, isolated the CO2 storage tank, and is in the process of ventilating the area. A fire watch has been posted and the licensee is checking CO2 levels throughout the area. There were no injuries as a result of the discharge and no significant operational impairment. The licensee has notified appropriate state and local authorities as required due to the declaration of an unusual event. The licensee will also notify the NRC resident inspector.
The licensee terminated the unusual event at 14:45 EDT following inspection of the turbine building and confirmation that CO2 levels did not represent a personnel hazard. R2DO (Ogle); NRR EO (Reis); NSIR IRD (Wilson); FEMA (Dunker); and the DHS senior watch officer have been notified. |
| ENS 41322 | 10 January 2005 14:57:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | At 1345 on 1-10-2005, the Federal Energy Regulatory Commission (FERC) Local Engineer was notified by voice mail message of a failure of the North Anna Spillway Emergency Diesel (1-EE-EG-4) during a surveillance PT. 1-EE-EG-4's voltage regulator would not control voltage. The cause of the failure is unknown at this time. This failure only affects the hydro project and there is no impact on station operation. The FERC notification was made per 18CFR12.10(a). The licensee has notified the NRC Resident Inspector.
The following information was provided by licensee via facsimile: At 1457 hours on January 10, 2005, a 4 hour non-emergency notification was made to the NRC Operation Center as a result of an Offsite Notification to other government agency (i.e- FERC due to an inoperable spillway diesel) in accordance with 10 CFR 50.72 (b)(2)(xi). NRC guidance in NUREG -1022, Event Reporting Guidelines 10 CFR 50.72 and 50.73, provides discussion and notification examples intended to set a threshold that ensures reporting when an issue is safety significant. Some notifications to other government agencies may have little or no significance and may not be reportable to the NRC. Although the project safety device was inoperable and therefore reportable to FERC there was no safety significance since normal power was available throughout the time the device was out of service. Based on the discussions in NUREG - 1022, Section 3.2.12 for the notification in question, the North Anna Station Nuclear Safety Operating Committee has determined a NRC Notification was not required because there was no safety significance and is therefore being retracted. The licensee notified the NRC Resident Inspector. Notified R2RDO (Charlie Payne). |
| ENS 41426 | 21 February 2005 09:37:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | On February 21, 2005, at 0250 hours (EST), the Unit 1 Plant Computer System (PCS) failed rendering the Safety Parameter Display System (SPDS) inoperable. The PCS and SPDS were restored at 0650 hours. This event is a major loss of emergency assessment capability for greater than one hour and is reportable under 10 CFR 50.72(b)(3)(xiii). The licensee will notify the NRC Resident Inspector. |
| ENS 41456 | 2 March 2005 17:49:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | The following information was provided by the licensee via facsimile (licensee text in quotes): On March 2, 2005, at approximately 1239 hours (EST), the transmitter antenna that provides the signal that activates the emergency sirens was determined to be inoperable during testing activities. This affected the system's ability to automatically activate the emergency sirens. The antenna system was restored to service at 1249 hours on March 2, 2005. All sirens re-tested satisfactorily. This event is a loss of the Emergency Notification System and is reportable under 10 CFR 50.72(b)(3)(xiii). The equipment was repaired by replacing faulty components. Troubleshooting the failure is in progress. Sirens were last tested satisfactorily on 02/23/05. The licensee will notify the NRC Resident Inspector. |
| ENS 41898 | 6 August 2005 00:20:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | The Unit 2 reactor automatically tripped due to an overpower-delta temperature (OpDeltaT) trip signal. The licensee states that an actual OpDeltaT condition did not exist at the time of the trip. The trip signal is believed to have been generated by lightning strikes from an electrical storm that was passing through the area at the time. The trip was uncomplicated and all systems functioned as required. All control rods fully inserted; no safety relief valves lifted; decay heat is being discharged to the main condenser using normal feedwater to supply the steam generators; the reactor temperature and pressure are at normal hot standby range. No obvious grid disturbance was seen during the trip and Unit 1 was not impacted (Unit 1 was being ramped offline at the time for secondary side maintenance work). The licensee noted that Auxiliary Feedwater did auto-start as expected due to a trip from full power and was subsequently secured. The licensee is still investigating the cause of the OpDeltaT trip signal but noted that other Unit 2 instrumentation was found failed after the transient including the Unit 2, A-loop, wide range T-hot and T-cold indications and the Unit 2, B-loop, T-cold indication. The licensee plans to remain in Mode 3 until the investigation is complete and instrument repairs completed. The licensee notified the NRC Resident Inspector. |
| ENS 41900 | 7 August 2005 20:06:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | Unit SPDS was unavailable for greater than 60 minutes due to a plant computer system failure. SPDS was unavailable from 1507 on 08/07/05 until 1900 on 08/07/05. The licensee notified the NRC Resident Inspector. |
| ENS 42097 | 30 October 2005 03:05:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | The Unit 2 SPDS (Safety Parameter Display System) was unavailable from 0050 EDT to 0300 EST on 10/30/05. The cause of the unavailability is believe to have been related to software updates. The condition has been corrected and the system is back in service. This item is reportable per the licensee's procedures whenever SPDS is out of service for more than one hour. The licensee notified the NRC Resident Inspector. |
| ENS 42443 | 22 March 2006 18:16:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | On March 22, 2006, an unscheduled poll of the North Anna sirens was initiated. During the period from 1251 to 1303 hours, actuation signals were not received at the transmitter and no outgoing signal was transmitted to the sirens. This event is a loss of the Emergency Notification System and is reportable per 10 CFR 50.72 (b)(3)(xiii). At 1303 hours, telecommunications notified (the plant staff) that the siren system was operational. The cause of the failure is being investigated. The licensee will notify the NRC Resident Inspector. |
| ENS 42483 | 8 April 2006 01:11:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | While in Mode 3 at 547 degrees and 2235 psig in the Reactor Coolant System, during Rod Control System rod drop testing, the group 2, 'A' shutdown bank step counter failed. The step counter is required to be operable in Modes 3, 4 and 5 per (Technical Requirements Manual requirement) 3.1.3 or the reactor trip breakers must be opened within 15 minutes. The step counter failed at 2217 and at 2231 the reactor trip breakers were opened. This was considered a valid actuation of the (Reactor Protection System) due to the (Technical Requirements Manual) requirements and due to the equipment malfunction. Shutdown margin is adequate and all emergency buses are on offsite power. Emergency Diesel Generators are available. The licensee notified the NRC Resident Inspector. |
| ENS 42996 | 16 November 2006 03:57:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | At 0226, North Anna Power Station Unit 2 automatically tripped on steam flow greater than feed flow with low steam generator water level on 'B' Steam Generator. This was caused by a Steam Flow Channel (Channel 3) Low failure. After the reactor trip, Auxiliary Feedwater Pumps automatically started on Low-Low Steam Generator Level. All control rods fully inserted. RCPs are in operation transferring decay heat to the steam generators. The steam generators are discharging steam to the main condenser using the condenser steam dumps. Main feedwater pumps are running to maintain steam generator water levels. Unit 1 was not affected. The licensee will notify the NRC Resident Inspector. |
| ENS 43072 | 3 January 2007 19:32:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | A Unit-1 reactor trip was initiated by a Process Rock card failure that caused the 'B' main feed regulation valve to fail closed. The closure of the 'B' main feed regulation valve caused a reactor trip due to a steam flow - feed flow mismatch with a low steam generator water level. The auxiliary feed water system actuated as expected due to the reactor trip. The plant was stabilized with no other issues using the appropriate emergency procedures. All control rods fully inserted on the trip and no relief or safety valves lifted in either the primary or secondary systems. Auxiliary feed water pumps automatically started and injected into the steam generators on a low water level signal. The operators restored normal feedwater flow to the steam generators. Decay heat is via the condenser steam dumps. The plant is aligned to the normal shut down electrical alignment. Card replacement is expected tonight and reactor startup is expected tomorrow. The licensee notified the NRC Resident Inspector. |
| ENS 43195 | 27 February 2007 22:15:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | Both Trains of Emergency Core Cooling System (ECCS) Pump Room Exhaust Air Cleanup System (PREACS) were declared inoperable at 1620 when dampers 2-HV-AOD-228-1 and -2, Safeguards Area Exhaust Bypass Dampers, failed surveillance testing. A ramp down was initiated at 1947 as required by Technical Specification 3.0.3. Temporary repairs to the dampers were completed at approximately 2125 and the ramp down was terminated. Temporary repair was made to the bypass damper seating surface. The licensee notified the NRC Resident Inspector. |
| ENS 43217 | 7 March 2007 06:11:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | The Unit-2 H Emergency Diesel Generator (EDG) automatically started on a Degraded Voltage/Under Voltage (DV/UV) signal due to the loss of the 'B' Reserve Station Service Transformer (RSST). The Unit-2 H Emergency Diesel Generator is supplying the Unit-2 H 4160 Volt Bus. Both Unit 1 and Unit 2 were stabilized using the appropriate abnormal procedures. During the event, the Unit 2 'B' Main Feed Water Pump motor, 2-FW-P-1B1, was noted to be running with the other motor, 2-FW-P-1B2, not running. The Unit 2 'B' Main Feed Water Pump was subsequently placed in Pull-to-Lock. Investigation continues as to the cause of the loss of the 'B' Reserve Station Service Transformer and the start of the Unit 2 'B' Main Feed Water Pump motor. The licensee notified the NRC Resident Inspector. |
| ENS 43462 | 29 June 2007 20:45:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | At 1752 hours EDT Unit 2 received a 'B' train safety injection (SI). This spurious SI on 'B' train caused a trip of the main feedwater pumps and a turbine trip. The Unit 2 reactor tripped due to the turbine trip. The single train SI resulted in ECCS flow to the RCS. Both trains of SI were manually initiated per station procedures. The 'B' train of SI could not be reset and this resulted in RCS inventory increasing and lifting of the pressurizer PORV's. The pressurizer relief tank rupture disc ruptured and released water to the containment sump. SI flow to the core has been secured. Normal charging has been returned to service. This event is reportable per 10CFR50.72(b)(2)(iv)(A) for ECCS flow to the RCS. 10CFR50.72(b)(2)(iv)(B) for RCS Actuation (Rx/Turbine Trip). 10 CFR50.72(b)(3)(iv)(A) for AFW pump start, containment phase 'A' isolation, ECCS pumps actuation, and EDG starts. The AFW pump auto started during the event and operated as expected. Cause of the 'B' train SI is unknown at this time. All rods fully inserted. All systems functioned as required with the exception of the 'B' train SI which spuriously actuated and then could not be reset. All equipment started as expected from the SI actuation. AFW is still supplying cooling water to the steam generators at this time and decay heat is being discharged via steam dumps to the condenser. The licensee does not yet know how much water was discharged to the containment sump. The reactor is currently stable at no-load temperature and pressure with the level in the pressurizer a little high but tracking down to normal. The licensee notified the NRC Resident Inspector. |
| ENS 43527 | 27 July 2007 09:05:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | In March 2005, battery cell internal resistance for an EDG battery bank revealed five cells with abnormal resistance. "There was one cell for which no reading could be obtained and was replaced immediately. A second cell had a reading that was nearly four times the average of the associated string and was subsequently replaced as a proactive measure during the EDG maintenance outage. Three (3) other cells were noted with higher than average readings that are not considered to be operability concerns. In total, five (5) cells out of a total of 240 were found with higher than expected internal resistance values. The failed battery was destructively tested revealing significant corrosion within the battery. The unit-2 batteries have been replaced. The unit-1 batteries will be replaced in the fall 2007 outage. Manufacturer: Enersys (Exide) Model: 3CA-5 Serial Number: beginning with 05 The licensee notified the NRC Resident Inspector. |
| ENS 43546 | 3 August 2007 10:18:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | Loss of (SPDS) for greater than 8 hours (is expected) because of a failed plant computer system. Troubleshooting to resolve computer issues is in progress." The licensee entered established contingency procedures to compensate. The licensee notified the NRC Resident Inspector.
At 1205 hours, the Unit 2 SPDS was returned to operable. The licensee notified the NRC Resident Inspector. Notified R2DO (Moorman) |
| ENS 43866 | 25 December 2007 23:22:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | On 12/25/07 at 2110 hours EST, Unit 2 tripped from 100% power due to a trip of the 'B' Reactor Coolant Pump. The reactor trip 1st out annunciator was 'Loss of flow, power >30%'. All control rods fully inserted. This event is reportable per 10 CFR 50.72(b)(2)(iv)(B). The Auxiliary Feedwater (AFW) pumps auto started due to the event and the steam driven AFW pump subsequently tripped on overspeed. The steam driven AFW pump was reset and placed in service. The ESF (Engineered Safety Function) actuation is reportable per 10 CFR 50.72(b)(3)(iv)(A). The unit is currently in mode 3 and (the licensee is) investigating the cause of the ground on the 'B' reactor coolant pump. The plant is at normal operating pressure and temperature. The electrical grid is stable and supplying plant loads through the startup transformer. Decay heat is being removed via the steam dumps to the condenser with feedwater being supplied via the normal path. The licensee has notified the NRC Resident Inspector. |
| ENS 43972 | 8 February 2008 19:59:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | While withdrawing shutdown bank rods in preparation for a North Anna Unit 2 startup, a Rod Control system Urgent Failure alarm was received in the main control room. Further investigation revealed group step counters for Shutdown Bank 'A' deviated by 3 steps from demand. TRM 3.1.3 was entered and the Reactor Trip breakers were opened within the 15 minute requirement. The licensee notified the NRC Resident Inspector. |
| ENS 44393 | 7 August 2008 17:26:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | At 1430 hours on 8-7-08, approximately 20 individuals from a group identified as the Southeast Convergence for Climate Action arrived at the North Anna Nuclear Information Center (NANIC) and initiated a civil disturbance within the center. (The NANIC is located just inside the Owner Controlled Area). When the NANIC closed at 1600 hours, 8 of the individuals refused to leave the building. Local Law enforcement informed the individuals that they would be placed under arrest, and 2 individuals exited the area. The remaining 6 individuals were detained by Local Law Enforcement Officers and removed from Dominion property. Licensee has notified the NRC Resident Inspector. |
| ENS 44581 | 18 October 2008 16:43:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | At 11:25 on 10/18/08 it was identified that 2-SI-MOV-2867A and 2-SI�MOV-2867B, Boron Injection Tank (BIT) Inlet valves were both inoperable. This resulted In less than 100% of the equivalent to a single operable ECCS train being available (TS 3.5.2.C). 2-SI-MOV-2867A was made inoperable on 10/17/08 at 23:26 for troubleshooting. Subsequently 2-SI-MOV-2867B became inoperable on 10/18/08 at 03:26 because its emergency power supply was inoperable for maintenance. At that time TS 3.0.3 was applicable with 13 hours to reach MODE 4 and 37 hours to reach MODE 5. On 10/18/08 at 12:05 2-SI-MOV-2867A was made available and TS 3.0.3 action was cleared. The emergency power supply for 2-SI-MOV-2867B was made operable on 10/18/08 at 13:35. NRC Resident Inspector will be notified. |
| ENS 44972 | 6 April 2009 14:18:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | At ~ 1230 EDT on 04/06/09, the Virginia DOT was notified that a truck shipment from North Anna to Surry Power Station containing radioactive contaminated equipment had caught on fire. The fire was contained to the truck tractor engine compartment, and was put out with no radioactive release having occurred. The trailer is on state route 522, approximately 1 mile from route 33 in Louisa County, Virginia, within 10 miles of North Anna. The truck is not drivable at this time. North Anna management and Health Physics personnel are at the site. The station NRC residents are also at the site. Media personnel are present. The shipment type is described by the state DOT as: 'Radioactive Material Surface Contaminated Objects, SCO-II, 7, UN 2913 Fissile Excepted'. Activity: 7.82 millicuries total in 2 containers, or 2.89 E2 MBq. The materials were GSI-191 support equipment and tools, grating covers, and herculite wrapped Styrofoam. |
| ENS 45013 | 23 April 2009 14:47:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | At 1410 hours on April 23, 2009, it was identified that an ALERT classification had not been declared on April 22, 2009 as required by EPIP-1.01. North Anna Emergency Plan, Emergency Action Level H2.1 requires the declaration of an ALERT for a fire or explosion in any safe shutdown area and either plant personnel report visible damage to any safety-related structure, system or component within the area or affected system parameter indications show degraded performance. A description of the event is provided below. On April 22, 2009, at approximately 0500 hours, Operations personnel identified a strong odor in the North Anna Unit 1 Cable Vault area. Subsequent investigation identified that the odor was coming from circuit breaker 01-EE-BKR-1J1-2S-J1 associated with the "D" Control Rod Drive Mechanism (CRDM) Fan (1-HV-F-37D). Operations personnel locally opened the circuit breaker to place it in a safe condition. 1-HV-F-37D had tripped approximately 30 minutes prior to the event. 1-HV-F-37D is not safety-related and not required for safe shutdown however; the supply breaker is safety-related since it is located on an emergency bus. Operation personnel then opened the circuit breaker cabinet and a small (6-inch) flame was observed. Operations personnel used a CO2 extinguisher on the internals of the circuit breaker to quickly extinguish the small fire. Appropriate levels of management were informed. The breaker has been quarantined. The cause of the circuit breaker failure has not been identified. A Root Cause Evaluation is in progress. There were no injuries. The plant continues to operate at full power. As a result of identifying that the criterion for the EAL was exceeded and no longer exists, a notification is being made to the NRC Operations Center in accordance with 10CFR50.72(a)(1)(i). The NRC Resident Inspector has been notified and the State and local governments will be notified.
On April 22, 2009, at approximately 0500 hours, operations personnel identified a strong odor in the North Anna Unit 1 Cable Vault area. Subsequent investigation identified that the odor was coming from circuit breaker 01-EE-BKR-1J1-2S-J1 associated with the 'D' Control Rod Drive Mechanism (CRDM) Fan (1-HV-F-37D). Operations personnel locally opened the circuit breaker to place it in a safe condition. 1-HV-F-37D had tripped approximately 30 minutes prior to the event. 1-HV-F-37D is not safety-related and not required for safe shutdown however; the supply breaker is safety-related since it is located on an emergency bus. Operation personnel then opened the circuit breaker cabinet and a small (6-inch) flame was observed. Operations personnel used a C02 extinguisher on the internals of the circuit breaker to quickly extinguish the small fire. A root cause evaluation is in progress. At 1447 hours on April 23, 2009, a one hour notification was made to the NRC Operations Center in accordance with 10CFR50.72(a)(1)(i), which identified that the criterion for a ALERT EAL was exceeded due to the small fire in the circuit breaker and subsequent damage to the breaker internals. The notification also stated that the condition no longer exists. Subsequent reviews have determined that the 'Initiating Condition' for the Emergency Action Level was not met and the event was not required to be classified as an ALERT. The initiating condition states -Fire or explosion affecting the operability of plant safety-related structures, systems or components required to establish or maintain safe shutdown. The 'D' Control Rod Drive Mechanism is not required to establish or maintain safe shutdown and the emergency bus remained operable during the event. The notification made to the NRC on April 23, 2009 is being retracted. The NRC Resident Inspector has been notified. Notified the R2DO (Nease). |
| ENS 45026 | 28 April 2009 12:00:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | At 0953 hours on April 28, 2009, a loss of the 'B' Reserve Station Service Transformer resulted in a Degraded Voltage / Under Voltage automatic start of the Unit 2 'H' Emergency Diesel Generator. The Unit 2 'H' Emergency Diesel Generator is operating and supplying electrical power to the Unit 2 'H' 4160 Volt Bus. The Unit 2 'B' Charging Pump (2-CH-P-1B) and the Unit 2 'B' Component Cooling Water Pump (2-CC-P-1B) also auto started in response to the loss of power. (Procedure) 0-AP-10, 'Loss of Electrical Power', was entered to address the loss of the normal power source for the Unit 2 'H' Emergency Bus. Unit 2 is operating at 100% power and an investigation has been initiated to determine the cause of the event and appropriate corrective actions. The NRC Resident Inspector has been notified. There was no impact on Unit 1 operation. There was no loss of significant safety equipment as a result of the transformer loss. The licensee will continue to supply the 'H' 4160V bus with the 'H' Emergency Diesel Generator until compensatory measures are put in place. The loss of the 'H' bus places Unit 2 in a 72-hr shutdown action statement. |
| ENS 45460 | 23 October 2009 17:34:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | On 10/23/09 at 1633, North Anna Unit 1 was placing Excess Letdown in service per 1-OP-8.5 due to a small unquantifiable throughwall leak on 1-CH-TV-1204B. At 1634 (the licensee) entered action of TS 3.4.13 due to what appears to be an Excess Letdown Heat Exchanger tube leak. The Component Cooling Water Head Tank (level) increased from 59% to 79% and the VCT (Volume Control Tank) level dropped 20 % indicating approximately 260 gallons of RCS had flowed into the Component Cooling Water System. At 1638 Excess Letdown was removed from service and the leak was terminated. At 1718 (the licensee) commenced ramping Unit 1 from service (TS Required Shutdown) to comply with TS 3.6.1, 'Containment Integrity' due to the throughwall leak on 1-CH-TV-1204B. The licensee has placed the normal letdown system back in service while the plant is being shut down. The throughwall leak on 1-CH-TV-1204B is relatively small and unquantifiable compare to the tube leak on the excess letdown heat exchanger. The licensee plans to proceed to Mode 5 to repair both the Letdown valve and the Excess Letdown Heat Exchanger tube leak. The licensee will notify the NRC Resident Inspector.
The licensee determined that it exceeded EAL SU6.1, Unidentified or Pressure Boundary Leakage greater than 10 gpm, for 4 minutes but currently does not meet the EAL Criteria. This requires the licensee to make a 1-hour notification that it has classified the event after-the-fact as an unusual event but did not actually declare the unusual event . The licensee will notify the NRC Resident Inspector and has notified the Virginia Department of Emergency Management. |
| ENS 45556 | 9 December 2009 17:15:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | At 1423 hours on 12/9/2009, electrical supply breaker L102 was inadvertently opened which caused electrical Bus 3 and the 'C' Reserve Station Service Transformer to de-energize. This caused the loss of 'F' Transfer Bus which resulted in a loss of power to the 1H and 2J Emergency Busses and an automatic start of the 1H and the 2J Emergency Diesel Generators. Both emergency diesel generators started and re-energized their associated emergency bus as designed. The Unit 2 'G' Bus, which supplies power to the Unit 2 Circulating Water Pumps, did not automatically transfer to the 'B' Reserve Station Service Transformer in a sufficiently short time to prevent the loss of the Unit 2 Circulating Water pumps. The loss of the Unit 2 Circulating Water pumps resulted in an automatic low vacuum turbine trip and a subsequent (Unit 2) reactor trip due to the turbine trip. The 2 'G' Bus did automatically transfer to the 'B' Reserve Station Service Transformer and is currently energized. The Unit 2 Auxiliary Feedwater pumps automatically started and provided flow to the steam generators. There were no issues with the Auxiliary Feedwater System operation. The Unit 2 'A' Charging Pump and the Unit 2 'A' Component Cooling Water pump automatically started as designed due to the loss of power. The Unit 1 'B' Charging Pump and the Unit 1 'B' Component Cooling Water pump automatically started as designed due to the loss of power. The Unit 2 'C' Station Service Bus was lost following the trip when the electrical system automatically transferred to the Reserve Station Service transformers. With the 'C' Reserve Station Service Transformer de-energized the 'C' Station Service Bus was unable to transfer to an energized transformer. This resulted in the loss of the Unit 2 'C' Reactor Coolant Pump. The 'A' and 'B' Reactor Coolant Pumps remain in service at this time. The reactor trip is reportable per 10CFR50.72(b)(2)(iv)(B). The Auxiliary Feedwater system, Emergency Diesel Generator system, Charging system actuations are reportable per 10CFR50.72(b)(3)(iv)(A). The electrical system is being returned to a normal lineup. The condensate and feedwater system remained in service to provide flow to the steam generators. Steam Dump operation to the condenser is not available due to low condenser vacuum, therefore steam is being released to the atmosphere from the Steam Generator Power Operated Relief Valves. The licensee suspects that switchyard maintenance activities caused the L102 trip which initiated the chain of events. All rods inserted into the core during the trip. During the transient, some secondary relief valves lifted and properly reseated. There is no known primary to secondary leakage. During the event call, the licensee reported that the 'C' Reserve Station Service Transformer was returned to service. The licensee notified the NRC Resident Inspector and will be notifying the Louisa County Administrator. |
| ENS 45558 | 10 December 2009 12:48:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | On December 9, 2009, at 1423 hours, Unit 2 tripped offline due to the loss of 'C' Reserve Station Service Transformer. This resulted in a loss of power to one of the bearing cooling system level control valves (LCV). The affected LCV failed open, which caused the bearing cooling tower basin to overflow and release bearing cooling water to Lake Anna. By approximately 1530 hours, plant personnel had manually isolated the bearing cooling water system and the flow to the lake stopped shortly afterwards. Based on the duration of the event (approximately 70 minutes) and the maximum discharge flow rate of a bearing cooling water make-up pump (850 gpm), no more than 59,500 gal. of water were discharged to the lake. Based on visual observation of the actual flow going to the lake, it was estimated that approximately 35,000 gal. were discharged. The bearing cooling water was sampled on 12/09/09 by the Chemistry Department as part of their routine chemistry surveillance. All chemical parameters analyzed were within VPDES (Virginia Pollutant Discharge Elimination System) permit limits. There was no violation of permit parameters from this discharge and no adverse impact to the environment was observed. Bearing cooling system chemistry is maintained to meet VPDES discharge limits. At 1035 hours on December 10, 2009, a 24-hour notification of the unusual discharge was made to the Virginia Department of Environmental Quality in accordance with the North Anna VPDES permit. This issue is being reported per 10CFR50.72(b)(2)(xi) as an event where notification of other government agencies has been made. The NRC resident inspector has been notified. |
| ENS 45623 | 11 January 2010 16:53:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | A verbal report was made to the Federal Energy Regulatory Commission (FERC) Engineer on January 11, 2010 at 1510 hours pursuant to 18CFR12.10(a) for a condition affecting the safety of a project or works. A new wet area has been identified on the slope of Dike 6, approximately 25 feet from the top of the structure. Dike 6 was designed and created during original plant construction to support electrical towers and provide isolation between Lake Anna and the proposed Unit 3 & 4 intake structures. The Unit 3 & 4 intake area is currently being used as a settling pond. The settling pond is used to process storm water and other secondary water before the liquid is discharged from the station. This minor seepage is located about half way down the slope to the settling pond. Water samples were obtained from the wet area and it was determined that the seepage was not ground water. The sample composition was similar to the water in Lake Anna. Currently, there is no threat to the public or North Anna Power Station. Engineering is investigating this issue and a corrective action plan will be developed to correct the minor seepage. This issue is being reported pursuant to 10CFR50.72(b)(2)(xi). The licensee has notified the NRC Resident Inspector and the local government. |
| ENS 45877 | 27 April 2010 18:44:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | On 4/27/2010 at 1637 hours, during recovery from a refueling outage when the main turbines and exciter were replaced, Unit 2 experienced a generator lockout which caused a turbine trip. The turbine trip resulted in a reactor trip when the reactor was at 74% power. The generator lockout occurred while automatic voltage regulator testing was being performed. This event is reportable per 10CFR50.72(b)(2)(iv)(B) due to actuation of the Reactor Protection System. The Auxiliary Feedwater Pumps (AFW) received an automatic start signal due to low/low level in the steam generators following the reactor trip. Steam Generator inventory was restored to normal operating level. The Steam Driven AFW pump experienced an issue with the lube oil system which resulted in some of the oil leaking onto the floor. An investigation into the oil leakage issue will be performed. The Steam Driven AFW pump was declared inoperable until this investigation is complete. The two motor driven AFW pumps automatically started and operated as designed. This event is reportable per 10CFR50.72(b)(3)(iv)(A) due to actuation of an ESF system. All control rods inserted into the core following the reactor trip and decay heat is being removed using the normal steam dump system. Several secondary (feedwater) relief valves lifted and resealed during the event. Unit 2 is stable in Mode 3 at normal operating temperature and pressure. Unit 2 is in a normal shutdown electrical lineup and there was no impact on Unit 1. The NRC Resident Inspector has been notified by the licensee. |
| ENS 45960 | 28 May 2010 03:43:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | A Unit-2 reactor trip was initiated by a loss of the Unit-2 'B' station service bus. The loss of the 'B' station service bus caused a reactor trip due to the loss of flow on one-of-three loops due to the loss of the 'B' Reactor Coolant Pump. The Auxiliary Feed Water system actuated as expected due to the reactor trip. The plant was stabilized in Mode 3 using the appropriate emergency procedure. During the transient, the 'B' Reserve Station Service Transformer de-energized and the Unit-2 'H' Emergency Diesel Generator was previously tagged out for planned maintenance. This resulted in the Unit-2 'H' emergency bus being de-energized. The alternate AC diesel generator has been placed in service and is providing power to the Unit-2 'H' emergency bus. The automatic tap changer for the 'C' reserve station service transformer did not work in automatic and had to be manually adjusted to control voltage. Unit-2 'C' Reactor Coolant Pump remains in service. All control rods fully inserted on the trip and no relief valves lifted or safety valves lifted in either the primary or secondary systems. The turbine drive and 'B' motor driven Auxiliary Feed Water pumps automatically started and injected into the 'A' and 'B' steam generators on a low level signal. The 'A' motor driven Auxiliary Feed Water pump failed to start due to the loss of the 'H' emergency bus. The 'C' steam generator is being controlled with main feed water though the 'C' main feed regulating valve bypass valve. Decay heat removal is via the condenser steam dumps. The licensee has notified the NRC Resident Inspector.
EN#45960 reported the RPS Actuation (50.72(b)(2)(iv)(B)) and AFW System Actuation (50.72(b)(3)(iv)(A). The event occurred at 0003 EDT on May 28, 2010. Technical Specification (TS) 3.0.3 was entered at 0004 hours on May 28, 2010, for inoperable offsite power sources with the 2H emergency diesel generator (EDG) being inoperable per TS 3.8.1. M. Update: At the time of the event, the station was experiencing a severe lightning storm. The Auxiliary Feedwater System was returned to auto standby at 0558 hours. At approximately 0942 hours, RCS cooldown to Mode 4 was started on Unit 2. Mode 4 was entered at 1245 hours. The 'A' and 'B' RCPs remain secured in Mode 4. Following repairs and post maintenance testing the 'C' reserve station service transformer (RSST) was declared operable at 1324 hours. This restored two (2) qualified offsite circuits for Unit 1 and one (1) qualified offsite circuit for Unit 2. TS 3.0.3 was cleared at this time on Unit 2. The 'B' RSST remains out of service (OOS) pending repairs and testing. The Unit 2 'B' station service bus remains OOS. The 2H EDG previously reported OOS for scheduled maintenance is expected to be returned to service on Monday, May 31, 2010. The alternate AC diesel generator continues to supply power to the 2H emergency bus. Limiting action remains for one (1) offsite circuit for Unit 2 being inoperable along with the 2H EDG OOS. The licensee will be notifying the NRC Resident Inspector. Notified R2DO (Haag). |
| ENS 46013 | 16 June 2010 13:38:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | During performance of the Early Warning System (EWS) Polling Function Test the sirens did not respond. At 0859 hours (EDT) on June 16, 2010, the polling function test of the sirens was started. After four (4) sirens did not respond to the polling, the test was suspended and the Telecommunications group was notified. With Telecommunications monitoring the EWS primary base radio, the polling function test was run again. It was determined the audio signals from the status logger were being transmitted to the EWS primary base radio, however, the radio was not keying or transmitting the audio signal to the sirens. A check of the keying signal from the processor to the primary base radio was noted to be operating properly, however, the primary base radio was still not transmitting the audio signal to the sirens. Therefore, activation of the EWS by the state or local agencies would not have been possible. At 0925 hours, the EWS was switched to the back-up radio base station and tested satisfactory for proper radio function. The polling function test was performed with all 68 sirens responding as designed. All 68 sirens polled satisfactory during the last performance of the EWS Polling Function Test on June 2, 2010. The licensee has notified the State and the NRC Resident Inspector. Local agencies will also be informed. |
| ENS 46020 | 16 June 2010 21:08:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | On 6-16-2010 at 1920 hours, Unit 2 experienced an automatic reactor trip/turbine trip from 98% power. A severe lightning storm was in progress at the time of the trip and a lightning strike appears to be the cause of the event. The reactor trip was actuated from Channel 1 and Channel 2 Over Temperature Delta T. All control rods fully inserted into the core during the trip. The control room staff responded to the trip in accordance with plant procedures and the unit is stable in Mode 3. This event is reportable per 10CFR50.72(b)(2)(iv)(B). The Auxiliary Feedwater pumps started as designed following the reactor trip and steam generator inventory was restored to normal operating level. The Auxiliary Feedwater pumps have been secured and returned to automatic. This event is reportable per 10CFR50.72(b)(3)(iv)(A) due to the ESF actuation. Decay heat is being removed by the condenser steam dump system. The 'A' loop wide range hot and cold leg thermocouples remain failed high and the 'B' loop wide range cold leg thermocouple also failed high during the event. The plant is in a normal shutdown electrical lineup. The licensee has notified the NRC Resident Inspector and will notify the local authorities. See EN #41898 for similar occurrence. |
| ENS 46039 | 23 June 2010 15:19:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | North Anna experienced a severe storm the night of June 22, 2010. At 0910 hours on June 23, 2010, the telecommunications group polled the Early Warning System (EWS) sirens to check operability. The first siren did not respond. It was determined the back-up base radio was not transmitting the audio signal to the sirens. Therefore, activation of the EWS by the state or local agencies would not have been possible. It was possible to activate the EWS sirens locally from North Anna off a separate radio system. At 1040 hours the back-up radio was replaced and tested satisfactory for proper radio function. The primary base radio was also replaced and tested satisfactorily. The polling function test was performed with all 68 sirens responding as designed. The EWS sirens are currently operating off of the primary base radio with the back-up radio available for operation. The EWS was initially on the backup radio. This radio has been replaced. The licensee notified the NRC Resident Inspector, state government and will notify local government. The licensee will contact local media concerning this event. |
| ENS 46094 | 14 July 2010 19:53:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | At 1834 hours on 7/14/10, the Unit 1 'C' Reactor Coolant Loop was declared inoperable due to small unisolable leaks on the 'C' Steam Generator secondary side surface sample line. Two small through-wall flaws were identified in the piping upstream of 1 -SS-217, 'C' Steam Generator surface sample line manual isolation valve. The piping is Class 2 and the non-conforming condition could not be evaluated with the steam generator pressurized. Based on the condition of the piping and the inability to evaluate the flaw, the 'C' Steam Generator was declared inoperable per Technical Requirements Manual 3.4.6, ASME Code Class 1, 2 and 3 Components. Subsequently, Technical Specification 3.4.4 was entered to place Unit 1 in Mode 3 within 6 hours. At 1934 hours on 7/14/10, North Anna Unit 1 initiated a shutdown in accordance with Technical Specification 3.4.4. The unit will be shutdown and the line will be evaluated and repaired. The licensee is presently at 82% power and coasting down in power. All safety systems are fully operable. The licensee has notified the NRC Resident Inspector.
North Anna Unit 1 entered mode 3 at 2353 hrs. There were no complications during shutdown. One source range monitor failed downscale low. The other source range monitor is operating correctly. The failure of this source range monitor did not affect shutdown capabilities. Notified R2DO (Seymour). |
| ENS 46153 | 5 August 2010 14:53:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | At 1345 EDT, following maintenance on 1-CH�LCV-1115A, VCT divert valve, testing was commenced. At 1355 EDT, the valve failed to the full divert position and could not be repositioned from the normal control system, resulting in 75 gpm letdown flow being diverted to the gas stripper. At 1401 EDT, the normal letdown flowpath was isolated in accordance with plant procedures and the leakage isolated. The identified flow rate exceeded the threshold for entry into a Notice of Unusual Event under EAL tab SU6.1 due to identified leakage greater than 25 gpm. The licensee will inform State and local agencies and has notified the NRC Resident Inspector. |
| ENS 46294 | 30 September 2010 15:36:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | On September 12, North Anna Power Station Unit 1 entered a scheduled refueling outage. During the outage while performing reviews for a design change, it was determined that some uncontrolled plant drawings indicated that Microtherm insulation may have been installed on some piping locations inside the containment. The Microtherm insulation impacts the new containment sump strainers installed to address NRC GSI-191 requirements. It was subsequently confirmed via walk downs that the Unit 1 containment contained some Microtherm insulation. Based on conflicting information on the possible installation of Microtherm inside Unit 2 containment and the identification of Microtherm insulation on Unit 1, a conservative decision was made to shutdown Unit 2 on September 29, and the Unit was cooled down to Mode 5 to allow a detailed inspection to be performed. The areas where the Microtherm insulation was potentially installed could not be inspected with the Unit at power. Subsequent inspections have confirmed that the Microtherm insulation was installed in some areas of the Unit 2 containment. These locations include the reactor vessel nozzles and reactor coolant pump casings. Plans are being developed to remove this insulation on both units. The overall impact of the Microtherm insulation on the containment sump operation is being evaluated by engineering. The licensee has notified the NRC Resident Inspector and the Louisa County Administrator. |
| ENS 46352 | 22 October 2010 09:46:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | On 10/22/2010 at 0636 hours, North Anna Unit-1 reactor was manually tripped during physics testing and 1-E-0 was entered due to problems with the Rod Control In Hold Out Switch. The out direction of the switch was not functioning properly and the reactor was tripped to put the plant in a condition to perform maintenance. All control rods fully inserted into the reactor core. This was an uncomplicated reactor trip with no automatic ESF actuation required. Unit 1 is currently stable at normal operating temperature and pressure in MODE 3 (Hot Standby). The plant electrical line-up is normal. Decay heat removal is via the steam dumps. Notification will be made to the local county administrator's office. The NRC Resident Inspector has been notified. |
| ENS 46377 | 29 October 2010 14:11:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | This report is being made pursuant to 10 CFR 50.72(b)(2)(xi) for notification to other government agencies. Dominion North Anna Power Station intends to voluntarily notify state and local agencies regarding an increase in tritium levels in one (1) onsite ground water monitoring sample point. This increase in tritium levels has not exceeded any NRC regulatory dose limits nor has it exceeded the voluntary reporting limits (i.e., 20,000 picoCuries per liter) specified in NEI 07-07 Industry Ground Water Protection - Final Guidance Document. Two (2) adjacent onsite ground water monitoring sample points have not shown a similar increase. None of the eight (8) ground water monitoring sample points surrounding the station have shown any detectable levels of tritium. All indications show that the tritium in the one (1) onsite ground water monitoring sample point has not migrated to the lake or any drinking water sources. The station continues to monitor, sample and investigate the source of the tritium anomaly. This condition does not present a health hazard to station employees or the general public. Normal tritium levels at the particular sample point are 3-4000 picoCuries per liter. One sample read 16,500 picoCuries per liter. Samples afterwards have return to normal readings. The NRC Resident Inspector has been notified. |
| ENS 46676 | 15 March 2011 17:38:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | On 03/15/2011 at 1131 EDT, the Technical Support Center (TSC) ventilation system was rendered nonfunctional as a result of loss of power to the system. System power was lost approximately one hour after returning the normal power supply to service following maintenance. This condition has the potential to render the TSC unavailable due to the inability of the ventilation and filtration system to maintain a habitable atmosphere. Compensatory measures exist to relocate the TSC to alternate locations. On 03/15/2011 at 1545 EDT, after verifying the bus supplying the TSC ventilation was satisfactory for return to service, power was restored using an alternate feed. This notification is being made in accordance with 10CFR50.72(b)(3)(xiii) due to the potential loss of an emergency response facility. The NRC Senior Resident Inspector was notified. |
| ENS 46697 | 25 March 2011 11:14:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | This 24-hour report is being issued in accordance with the requirements of NRC Certificate of Compliance 1030, Amendment 0, for the NUHOMS Storage System, Technical Specification (TS) 2.2, Functional Operating Limit Violations. During a review of historical North Anna NUHOMS dry storage canister (DSC) loading certification documents, a discrepancy was identified. The NUHOMS Certificate of Compliance 1030 Amendment 0 Technical Specifications include a Figure 2, "Heat Load Zones" which specifies the maximum decay heat load for each of the 32 assembly locations in a DSC. The figure includes limits for two zone '1b' locations and two zone '1a' locations in the four center locations of the DSC. The zone '1b' decay heat limit of 0.8 kw is specified for the two 'upper compartments' and zone '1a' decay heat limit of 1.05 kw is specified for the two 'lower compartments' on the figure. Contrary to this, the loading certifications for 7 of 10 DSCs already loaded at NAPS (North Anna Power Station) were not developed to maintain this orientation when loaded in the horizontal storage module (HSM). As a result, the DSC zone '1b' heat load limits were exceeded in some cases for these 7 DSCs. The heat load limit for all other zones in the DSCs are symmetric, and those assemblies were verified to the correct limit and are unaffected by this error. In addition the total heat load limit for the sum of the center assemblies was met for all DSCs. The maximum heat load of any zone '1b' assembly at the time of loading was 0.859 kw, which is slightly higher than the 0.8 kw limit. The lower heat load of assemblies in the other compartments offset the slightly higher heat load effects, and it is expected that the thermal analysis acceptance criteria would still have been met at the time of loading. The decay heat of the assemblies has continued to decrease since their initial loading and it was confirmed that 12 of the 13 assemblies that initially exceeded the 0.8 kw limit currently meet the zone '1b' heat load limits. The current decay heat of the remaining assembly is slightly above the 0.8 kw limit. Based on the offsetting margins identified above all of the affected DSCs are currently in a safe condition as loaded in the HSMs. The NRC Resident Inspector has been informed. |
| ENS 46751 | 13 April 2011 16:15:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | This is a voluntary notification for planned maintenance that affects the TSC ventilation system. At approximately 0400 EDT an April 14, 2011 the North Anna TSC (Technical Support Center) air conditioning and filtration systems will be rendered non-functional to perform preventive maintenance on electrical buses supplying power. This condition has the potential to render the TSC unavailable due to the inability of the ventilation and filtration system to maintain a habitable atmosphere. Temporary ventilation is being established for the TSC computer room. The maintenance is expected to last less than 24 hours. Compensatory measures exist to relocate the TSC to alternate locations, if needed. The NRC Resident Inspector has been notified.
The maintenance on the TSC ventilation system has been completed and the TSC has been returned to service. The licensee will be notifying the NRC Resident Inspector. Notified R2DO (O'Donohue). |
| ENS 47181 | 23 August 2011 14:24:00 | North Anna | NRC Region 2 | Westinghouse PWR 3-Loop | At 1403 hrs. EDT, North Anna Power Station declared an Alert due to significant seismic activity onsite. The Alert was declared under EAL HA6.1. Both units experienced automatic reactor trips from 100% power and are currently stable in Mode 3. All offsite electrical power to the site was lost. All four emergency diesel generators (EDG) automatically started and loaded and provided power to the emergency buses. While operating, the 2H EDG developed a coolant leak and was shutdown. As a result, the licensee added EAL SA1.1 to their declaration. All control rods inserted into the core. Decay heat is being removed via the steam dumps to atmosphere. No personnel injuries were reported.
The licensee has downgraded the Alert to a Notification of Unusual Event based on equipment alignments and inspection results. The licensee notified R2 IRC. Notified IRD (Marshall), NRR (Thorp), FEMA (Hollis), DHS (Inzer), USDA (Ferezan), HHS (Willis) and DOE (Parsons).
The licensee has exited the Notification of Unusual Event at 1315 EDT. The exit criteria was that all inspections and walkdowns were completed and plant conditions no longer meet the criteria for a NOUE. Notified R2DO (Widmann), IRD (Marshall), NRR (Thorp), FEMA (Hollis), DHS (Inzer), USDA (Ferezan), HHS (Willis) and DOE (Jackson).
This notification is to report new information identified post event that a condition existed which met the emergency plan criteria but was not declared. On August 23 at 1403 EDT, North Anna Power Station declared an Alert due to seismic activity onsite. The Alert was declared under Emergency Action Level (EAL) HA6.1 "Other conditions existing which in the judgment of the SM warrant declaration of an alert. Initial review of seismic response data from the earthquake on 8/23/11 (1348 hours) indicates that design spectrum input assumptions (i.e. Design Basis Earthquake (DBE) limits) may have been exceeded above 5 HZ. This would have resulted in classification of an Alert under EAL HA1.1. No significant equipment damage to safety related systems (including class I structures) has been identified through site walk-downs nor has equipment degradation been detected through plant performance and surveillance testing following the earthquake. The licensee notified the NRC Resident Inspector. The licensee also plans on notifying the State Emergency Operations Center and the Louisa County County Administrator. Notified R2DO (Widmann) and NRR EO (Bahadur). |