Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 52438 | 15 December 2016 13:50:00 | On 12/14/16 at 1206 (EST), 0-PT-89.9K (underground fuel-oil piping pressure test), was performed UNSAT after a failed attempt to maintain pressure in the supply line to the Unit 2 'H' Emergency Diesel Generator (EDG) Day Tank. The exact source of the leakage is unknown at this time but is reasonable to believe some fuel oil was released underground. The associated Fuel Oil line is currently tagged out and isolated. This condition is reportable to the Virginia Department of Environmental Quality (VA DEQ) as part of the Underground Storage Tank Program. Pressure tasting of the other EDG fuel oil supply lines has been previously completed satisfactorily. The 2H EDG remains Operable as the redundant fuel oil transfer pump and its fuel oil piping are Operable and capable of maintaining adequate day tank level. The VA DEQ was notified of this condition at 1130 (EST) on 12/15/16. This event is reportable in accordance with 10CFR50.72(b)(2)(xi) for 'Any event or situation, related to the health and safety of the public or onsite personnel, or protection of the environment, for which a news release is planned or notification to other government agencies has been or will be made.' The licensee has notified the NRC Resident Inspector and will notify Louisa County.
This is a follow-up report to Event Number 52438, made on 12/15/2016, regarding offsite notification to the Virginia Department of Environmental Quality for potential fuel oil leakage from the supply line to the Unit 2H Emergency Diesel Generator (EDG) Day Tank. During investigation of the potential fuel oil leak from the 2HB EDG Day Tank supply line (as previously reported in EN 52438), the 2HA fuel oil line, which runs close to the 2HB line, was disturbed and began to leak a mist of fuel oil. The fuel oil was contained in the area and was being cleaned via vacuum truck as it was leaking. Personnel at the scene noted the soil was not contaminated with fuel oil initially and saw the leak start on 2HA line. It has been estimated that less than one gallon of fuel oil was released to the surrounding soil during troubleshooting of the leak. The fuel oil was immediately vacuumed. The 2HA line was isolated and the leakage was stopped. The 2HA line is to be repaired and tested. The 2H EDG remains available, however, it is considered inoperable at this time. Investigation of the 2HB fuel oil line continues. The condition of the 2HA fuel oil line was reported to the Virginia Department of Environmental Quality (VA DEQ) as part of the Underground Storage Tank Program on 12/28/16. Therefore, this event is reportable in accordance with 10CFR50.72(b)(2)(xi) for 'Any event or situation, related to the health and safety of the public or onsite personnel, or protection of the environment, for which a news release is planned or notification to other government agencies has been or will be made.' The licensee has notified the NRC Resident Inspector and will notify Louisa County. Notified R2DO (Rose). |
| ENS 52137 | 30 July 2016 15:17:00 | On July 30, 2016 at 1152 hours (EDT) following a containment walkdown to investigate an increase in RCS unidentified leakage to 0.15 gpm, a leak was identified on the seal return line from 2-RC-P-1C, 'C' Reactor Coolant Pump. The source of the leakage cannot be isolated and is considered RCS pressure boundary leakage. (Technical Specification) LCO 3.4.13, RCS Operational Leakage, Condition B for the existence of pressure boundary leakage was entered. Technical Requirement TR 3.4.6, ASME Code Class 1, 2, and 3 Components is also applicable. Unit 2 is projected to be taken to Mode 5 for repair. This event is reportable in accordance with 10 CFR 50.72(b)(2) for 'the initiation of any nuclear plant shutdown required by the plant's Technical Specifications' and 10 CFR 50.72(b)(3)(ii)(A) for 'any event or condition that results in the condition of the nuclear plant including its principal safety barriers, being seriously degraded.' The licensee will be notifying the Louisa County Administrator and has notified the NRC Resident Inspector. |
| ENS 47682 | 21 February 2012 13:57:00 | On February 17, 2012, North Anna Power Station (NAPS) was notified by its vendor laboratory that a water sample, taken from an onsite ground water sample point, was confirmed to contain tritium above the voluntary reporting threshold of 20,000 picocuries per liter(pCi/L). The water sample, measuring 53,300 pCi/L, was obtained as a part of ongoing activities to determine the source of tritium previously reported to the state and NRC on October 29, 2010 (Event Notification - 46377). Current hydrological studies have determined the ground water in the area migrates to the station power block which is in the opposite direction from the lake. The ground water at the power block is collected in building subsurface drains and transported to a clarifier for processing. Clarifier discharge is accounted for as a monitored liquid effluent release pathway under the radiological effluent control program in accordance with the station's Offsite Dose Calculation Manual. As such, there is no increase to the projected annual dose to a member of the public. There are also no sources of drinking water in this area. Sampling of eight (8) ground water sample points outside the station protected area show no detectable levels of tritium confirming there is no migration offsite. The NRC Resident Inspector has been notified. A 30 day written report will be submitted to the NRC in accordance with NEI 07-07, Industry Ground Water Protection Initiative - Final Guidance Document. The licensee will inform both state and local agencies. |
| ENS 47665 | 15 February 2012 15:33:00 | At 12:44 on 2/15/2012, the Virginia Department of Environmental Quality was notified of a sewage system release that had the potential to reach state waters. On 2/14/2012, it was identified that water was flowing from a manhole cover near the North Anna training building. Further review identified the training building sewage lift station had lost power and that the water line in the manhole discharges to the lift station. It was estimated that approximately 120-200 gallons of untreated water reached the ground around the manhole before power was restored to the lift station. Upon further investigation, the station could not confirm whether untreated water reached Lake Anna. The NRC Resident Inspector has been notified. |
| ENS 47497 | 5 December 2011 09:35:00 | At approximately 0847 EST, Unit 1 Letdown Pressure Control Valve, 1-CH-PCV-1145, began acting erratically which resulted in the Letdown Relief Valve, 1-CH-RV-1203, lifting and flowing to the Pressurizer Relief Tank. At 0848 EST, the relief valve reseated and the leakage stopped. Approximately 42 gpm leakage resulted from the relief valve lifting. This 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 is troubleshooting the Letdown Pressure Control Valve. The licensee notified the NRC Resident Inspector and will notify State and local agencies. |
| ENS 47345 | 14 October 2011 15:30:00 | On 10/14/2011 at 0322 (EDT), Operations identified during operator rounds that the bearing cooling tower basin was overflowing. Earlier in the night the control room had received a bearing cooling basin high level alarm, verified that the bearing cooling tower basin was not overflowing and was monitoring the level from control room indications. The Control Room indications of bearing cooling basin level had remained steady. The overflow condition was due to leak by from a motor operated valve (MOV) which had been used earlier to add water to the bearing cooling basin. The leaking MOV was manually torqued shut which isolated the overflow discharge. Investigation of the inaccurate level indication is ongoing. Samples of the bearing cooling water were analyzed by Chemistry. All chemical parameters analyzed were within VPDES (Virginia Pollutant Discharge Elimination System) limits. Bearing Cooling chemistry is maintained to ensure compliance with the North Anna VPDES permit. It is estimated that 272 gallons may have been discharged to the lake. At 1440 hours on October 14, 2011, 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 licensee informed the NRC Resident Inspector. |
| ENS 47198 | 25 August 2011 17:14:00 | At 1610 EDT on August 25, 2011 the Virginia Department of Environmental Quality was notified of an oil spill that occurred at 1900 EDT on August 24, 2011. The spill was approximately 150 gallons to the gravel outside the North Anna Unit 2 Turbine Building. The event occurred while purging CO2 from the Unit 2 Main Generator with air. Standing oil from the gravel was pumped to barrels and oil soaks were applied to the remaining oil. Clean up of the gravel areas continued. The NRC Resident Inspector has been notified in addition to the state and local authorities. |
| ENS 46751 | 13 April 2011 16:15:00 | 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 46697 | 25 March 2011 11:14:00 | 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 46676 | 15 March 2011 17:38:00 | 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 46352 | 22 October 2010 09:46:00 | 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 44581 | 18 October 2008 16:43:00 | 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 42097 | 30 October 2005 03:05:00 | 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. |