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| Report date | Site | Event description | |
|---|---|---|---|
| 05000280/LER-2017-001 | 11 October 2017 | Surry | On August 6, 2017, with Unit 1 at 100% power, a Reactor Coolant System (RCS) leak rate calculation determined the unidentified leak rate increased by 0.08 .gallons per minute. On August 8, a leak was obServed at an RCS hot leg.sample system valve,- and Unit 1 power level was reduced to investigate leakage indications. The. root isolation valve for the sample system valve was closed; however, leakage could not be verified as completely isolated. Further evaluation determined the leak to be through wall at the inlet of the sample system valve. Based upon the source of the leak and possible continued leakage, a Technical Specification shutdown clock was entered on August 9, at 13:38 hours. At 16:37 hours, Unit 1 was placed in Hot Shutdown. The cause of the event was the RCS pressure boundary leakage at the tubing/socket weld area of the hot leg sample system valve. With the unit in Hot Shutdown, the leak was isolated and repaired, and Unit 1 was returned to power operation on August 11, 2017. An apparent cause evaluation is being conducted. The event was reported as a plant shutdown required by Technical Specifications pursuant to 10 CFR 50.72(b)(2)(i) and degraded condition pursuant to 10 CFR 50.72(b)(3)(ii)(A). This report is being provided pursuant to 10 CFR 50.73(a)(2)(i)(A) and 10 CFR 50.73(a)(2)(ii)(A). |
| 05000281/LER-2016-001 | 8 December 2016 | Surry | On October 9, 2016 at 0254 hours, with Unit 1 and Unit 2 at 100 percent power, Unit 2 experienced an automatic reactor trip initiated by a turbine trip due to generator differential lockout relay actuation. At the time of the trip, high wind and heavy rain conditions existed due to the effects of Hurricane Matthew. All three auxiliary feedwater pumps automatically started on low-low steam generator water level as expected. All plant systems functioned as required, and Unit 2 was stabilized at hot shutdown. The trip response was not affected by any previously inoperable systems, structures, or components. The direct cause of the generator differential lockout was an electrical ground overcurrent initiated by water accumulation in the "A" phase of the "A" station service transformer leads termination enclosure. Affected electrical enclosures were drained, the system was tested, and modifications to the enclosures to prevent recurrence of water intrusion were completed prior to returning Unit 2 to power operation on October 13, 2016. This report is being submitted pursuant to 10CFR50.73(a)(2)(iv)(A) as an event that resulted in the automatic actuation of the Reactor Protection System' and the Auxiliary Feedwater System. |
| 05000280/LER-2015-003 | 11 December 2015 | Surry | On October 13, 2015 at 1815 hours, with Unit 1 at 100 percent power and Unit 2 at 93.5 percent power at the end of life coastdown, Unit 1 experienced a reactor trip initiated from a turbine trip by main generator trip. The main generator trip was due to a loss of the main generator field that caused a loss of field protection relay to trip. All three auxiliary feedwater pumps automatically started on low-low steam generator water level providing flow to the steam generators. Main steam trip valves were closed due to primary cooldown in accordance with emergency operating procedures and the plant was stabilized using steam generator power operated relief valves. The direct cause of the loss of main generator field of the Unit 1 generator was an electrical fault in the main generator exciter spacer coupling. Corrective actions to prevent recurrence will be implemented through the corrective action program when the root cause evaluation is completed. This report is being submitted pursuant to 10CFR50.73(a)(2)(iv)(A) as an event that resulted in the automatic actuation of the Reactor Protection System and the Auxiliary Feedwater System. |
| 05000281/LER-2015-002 | 4 November 2015 | Surry | On September 16, 2015, at 2014 hours with Units 1 and 2 operating at 100 percent power, Emergency Diesel Generator 2 automatically started and assumed power to the Unit 2 'H' emergency bus. The event occurred during quarterly performance of the Emergency Bus Undervoltage and Degraded Voltage Protection Test. The direct cause of the event was the defective "A" single phase relay sticking and preventing the relay contacts from changing state. The procedures for Emergency Bus Undervoltage and Degraded Voltage Protection Tests have been revised to physically validate the state of the emergency bus relays prior to testing additional relays. This report is being submitted pursuant to 10 CFR 50.73(a)(2)(iv)(A) for valid actuation of an Emergency Diesel Generator. |
| 05000280/LER-2015-002 | 12 October 2015 | Surry | On August 14, 2015 at approximately 0830 hours, with Surry Power Station Units 1 and 2 operating at 100% power, a Virginia Electric and Power Company (Dominion) Nuclear Security Officer was told by a truck driver that he had portions of a disassembled weapon inside his backpack with the rest of the weapon located inside of his delivery truck. The driver informed the Security Officer of the contraband during a routine delivery truck search in the vehicle sally port, which is the vehicle search area for entry into the station's protected area. The truck driver was denied protected area access and he and the delivery truck were escorted off-site. At 0850 hours on August 14, 2015, a one-hour notification was made to the NRC pursuant to 10CFR73, Appendix G, item 1(d), for an attempted introduction of contraband into a protected area. This Licensee Event Report is being submitted pursuant to 10CFR73.71(a)(4) for a 60 day follow-up written report. |
| 05000281/LER-2015-001 | 18 September 2015 | Surry | On July 21, 2015 at 05:05, with Unit 1 at Hot Shutdown and Unit 2 at approximately 6% power, Unit 2 experienced a reactor trip initiated from a turbine trip during performance of the Turbine Overspeed Protection Control system circuitry testing. The turbine trip was caused by governor valves rapidly opening due to a speed error which had accumulated between the turbine speed and reference setpoint resulting in a rapid increase in impulse pressure. The root cause of this event was inadequate instructions in the Overspeed Protection Control testing section of the operating procedure. The testing will be removed from operating procedures and placed in test procedures that are not performed as part of routine turbine startup. All systems functioned as required. Initiation of auxiliary or emergency systems was not required. Unit 2 was placed in hot shutdown and the health and safety of the public were not affected. This report is being submitted pursuant to 10CFR50.73(a)(2)(iv)(A) as an event that resulted in the automatic actuation of the Reactor Protection System. |
| 05000280/LER-2015-001 | 30 March 2015 | Surry | On January 27, 2015, with Units 1 and 2 operating at 100 percent power, it was identified that four sliding missile shields on the Main Steam Valve House (MSVH) were not included in the Abnormal Environmental Conditions procedure to be closed upon the threat of high winds. The shields are necessary to meet the design function of the MSVH for protection of the safety-related equipment and must be closed to perform their design function. A missile penetrating the MSVH could have prevented the MS and/or AFW systems from being able to mitigate the consequences of -an accident. Therefore, this event is reportable pursuant to 10 CFR 50.73(a)(2)(v). The shields were inappropriately excluded from the original revision of the procedure, which has now been revised to include the shields. This event posed no significant safety implications due to the low probability of missile damage inside the MSVH with the shields open. Therefore, the health and safety of the public were not affected by this event. |
| 05000281/LER-2014-001 | 23 June 2014 | Surry | On April 30, 2014, with Unit 2 in cold shut down for a refueling outage, the Unit 2A pressurizer safety valve failed its as-found test due to the lift setting being lower than the setpoint tolerance allowed by Technical Specifications. On May 6, 2014, the Unit 2C pressurizer safety valve also failed its as-found test due to the lift setting being lower than the setpoint tolerance allowed by Technical Specifications. The as-found pressurizer safety valve lift settings were evaluated and it was determined the valves were capable of performing their safety function with the low as-found lift settings. Therefore, the health and safety of the public were not affected. This report is being submitted, pursuant to 10 CFR 50.73(a)(2)(i)(B), for operation prohibited by Technical Specifications. |
| 05000280/LER-2014-001 | 27 May 2014 | Surry | At 11:40 on March 29, 2014, with both Unit 1 and Unit 2 operating at 100% power, the Unit 1D service water header was declared inoperable as a result of indications received during testing. The direct cause of the indications was due to a mostly closed service water header isolation valve for the Unit 1D service water header. In October 2013, following valve replacement, the valve handwheel was re- oriented causing the valve to become mostly closed while indicating open. Therefore, the Unit 1D service water header was inoperable from October 21, 2013 until March 29, 2014 and Technical Specification limiting conditions of operation were exceeded twice during timeframes when one of two other operable service water headers was tagged out for maintenance. Also, as a result of the restricted flow condition, a service water pump that supplies cooling to a charging pump was also determined to be inoperable beyond its Technical Specification limiting conditions of operation.
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| 05000281/LER-2014-002 | 2 January 2014 | Surry | On October 13, 2014 at 07:58, with Units 1 and 2 at 100% power, Unit 2 experienced a reactor trip due to a spurious opening of the Unit 2 "B" reactor trip breaker due to a loose screw on a reactor protection trip relay for the reactor trip breaker. All three auxiliary feedwater pumps automatically started on low-low steam generator water level providing flow to the steam generators. The rapid increase in steam generator pressure on the relief valve setpoints resulted in the lifting of all three steam generator power operated relief valves. Unit 2 was placed in hot shutdown and the health and safety of the public were not affected. The loose screw on the reactor protection trip breaker relay was tightened and the breaker was closed successfully. Remaining connections on the Unit 2 relay control circuitry were checked for tightness. Unit 1 reactor trip breaker relay control circuitry will be checked for tightness at the next available opportunity. Torque requirements for terminal screws will be incorporated into the Surry Electrical Installation Specification and applicable procedures will be revised to include the torque requirements. This report is being submitted pursuant to 10CFR50.73(a)(2)(iv)(A) as an event that resulted in the automatic actuation of the Reactor Protection System and the Auxiliary Feedwater System. |
| 05000280/LER-2010-001 | 15 July 2010 | Surry | On May 21, 2010, with Surry Power Station (SPS) Units 1 and 2 at 100% reactor power, a Virginia Electric and Power Company (Dominion) Nuclear Security Officer detected contraband in the bag of a Dominion Employee at the SPS security access control building, which is outside the protected area.5 Security noted that the employee was cooperative when stopped and unaware that the contraband was in the bag. The employee stated that the day before he had taken the contraband out of his vehicle and placed it in the side pocket of his bag. The employee stated that he packed his lunch for the next day and had forgotten to take the contraband out. There was no evidence collected in the investigation of this incident to suggest that the employee was untruthful when he stated that his acts on May 21, 2010 were unintentional and without malice. An evaluation was performed which determined that the cause of this incident was a human error due to less than adequate self-checking. This event meets the criteria specified in 10 CFR 73, Appendix G, item 1(d), as an attempted introduction of contraband into a protected area. A one-hour report Event Notification# EN45941 was made to the NRC. This Licensee Event Report is being submitted pursuant to 10 CFR 73.71(a)(4) for a 60 day follow-up written report. |
| 05000280/LER-2009-002 | 23 November 2009 | Surry | On September 24, 2009, with Units 1 and 2 at 100% reactor power, it was discovered that the three emergency service water (ESW) pump oil cooler outlet lines, which penetrate the pump base plates, were not sealed to prevent pump house water intrusion. The ESW pump house is designed to withstand flooding from hurricane driven tidal surges of 22.7 feet. With the pump base plates at approximately 18 feet above sea level, potential pump inoperability would occur if the water level rises above 18 feet. The cause evaluation identified that in the 1990's, the threaded interface seals on the outlet lines were no longer utilized.DThe evaluation also found the apparent cause to be inadequate procedural guidance for sealing the outlet lines.DFollowing discovery, seals were installed.DThe maintenance procedure has been strengthened to prevent recurrence.DAn evaluation determined this issue to be of very low risk significance, therefore, the health and safety of the public was not affected. This report is being submitted pursuant to 10 CFR 50.73(a)(2)(i)(B), any event or condition which was prohibited by Technical Specifications. D |