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 Entered dateSiteRegionReactor typeEvent description
ENS 5413727 June 2019 16:06:00SusquehannaNRC Region 1At 0937 EDT on 6/27/19, Susquehanna Unit 2 had a control power fuse fail that caused a loss of power to one of two power distribution systems of the Reactor Protection System. This loss of power resulted in a valid isolation signal and actuation of the Primary Containment Isolation System that affected multiple systems, and is reportable per 10 CFR 50.72(b)(3)(iv)(A). The situation has been resolved and the plant is currently using an alternate power source. Offsite power and the Emergency Diesel Generators are still available. The licensee notified the NRC Resident Inspector.
ENS 541036 June 2019 12:02:00SusquehannaNRC Region 1This 60-day telephone notification is being made in accordance with the reporting requirements specified by 10 CFR 50.73(a)(1) and 10 CFR 50.73(a)(2)(iv)(A) to describe an invalid actuation of a general containment isolation signal affecting multiple Main Steam Isolation Valves (MSIVs). On April 18, 2019 at approximately 0110 EDT, during performance of an ASME reactor vessel leak check, all four inboard MSIVs closed as a result of actuation of the Main Steam Line (MSL) high flow instrumentation. The high flow signal was spurious on the 'D' channel with no flow in the MSLs. Since an actual high flow condition did not exist at the time of the actuation, the actuation was considered invalid. The MSIVs functioned as designed on actuation of the MSL high flow instrumentation. All outboard MSIVs were closed at the time of the actuation in accordance with the vessel leak check procedure. The NRC Resident Inspector has been notified."
ENS 5407822 May 2019 06:01:00SusquehannaNRC Region 1

On 5/22/2019, the 'A' Control Structure Chiller (Div I) tripped due to a loss of (motor control center) MCC 0B136. The 'B' Control Structure Chiller was already inoperable due to Div II (Emergency Service Water) ESW being out of service for planned maintenance. With the loss of Control Structure HVAC System the ability to maintain temperatures in various spaces including relay rooms, Control Room Floor Cooling and Emergency Switchgear rooms was lost. The 'B' Control Structure Chiller was restarted at 0251 EDT and cooling was reestablished to the required areas, however the 'B' chiller is not considered operable at this time. Units 1 and 2 entered (Technical Specification) TS 3.0.3 at 0256 EDT and a controlled shutdown of both units commenced, Unit 2 at 0340 EDT and Unit 1 0350 EDT. This constitutes a TS required shutdown and requires a 4 hour (Emergency Notification System) ENS notification in accordance with 10 CFR 50.72(b)(2)(i). The failure also requires an 8 hour ENS notification in accordance with 10 CFR 50.72(b)(3)(v) due to the loss of a safety function. The licensee needs to restore the 'B' loop of ESW to exit the Limiting Condition of Operation (LCO). The licensee is currently performing a flow surveillance, once complete and assuming the data is acceptable, the licensee will be able to exit the LCO. The units are in a normal electrical lineup. The licensee will be notifying the state of Pennsylvania FEMA Operations Center. The licensee has notified the NRC Resident Inspector.

  • * * UPDATE ON 05/22/2019 AT 1302 FROM SCOTT MYRTHEL TO THOMAS KENDZIA * * *

On 5/22/2019 at 0601 EDT Susquehanna Steam Electric Station reported a shutdown had been commenced at 0340 EDT for Unit 2 and 0350 EDT for Unit 1 due to inoperability of both control structure chillers. Power has been restored to MCC 0B136, and at 0901 EDT the 'A' control structure chiller was declared operable and LCO 3.0.3 was exited. Power reduction for both units was halted at 0901 EDT and preparations for power restoration initiated. As of 1255 EDT on 5/22/2019, Unit 1 power is 94% and Unit 2 power is 92%. Notified the R1DO (Arner).

ENS 540559 May 2019 13:51:00SusquehannaNRC Region 1A non-licensed employee supervisor had a confirmed positive for alcohol during a random fitness-for-duty test. The employee's access to the site has been terminated. The NRC Resident Inspector has been informed.
ENS 5335220 April 2018 16:05:00SusquehannaNRC Region 1GE-4A non-licensed supervisory contract worker was found in violation of the Fitness for Duty Program. The individual's access to the plant has been terminated. The licensee notified the NRC Resident Inspector.
ENS 533103 April 2018 02:53:00SusquehannaNRC Region 1GE-4On April 3, 2018 at 0019 (EDT), the Susquehanna control room received indication that a loss of Secondary Containment Zone 3 differential pressure had occurred. Control room operators noted the loss following completion of surveillance testing. The cause is under investigation. Zone 3 differential pressure was restored to greater than 0.25 inches WC (water column) at 0145 (EDT). Zone 3 differential pressures being less than 0.25 inches WC constitutes a loss of Secondary Containment based on not meeting requirements of SR (Surveillance Requirement) 3.6.4.1.1. This event is being reported under 10 CFR 50.72(b)(3)(v)(C) and per the guidance of NUREG-1022, Revision 3, Section 3.2.7, as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system. The NRC Resident Inspector has been notified.
ENS 5325612 March 2018 14:34:00SusquehannaNRC Region 1GE-4A non-licensed supervisor tested positive for alcohol during pre-access screening. The individual's access to the plant was denied. The NRC Resident Inspector has been notified.
ENS 5320211 February 2018 23:36:00SusquehannaNRC Region 1GE-4On February 11, 2018 at 2203 (EST), the Susquehanna Control Room received indication that a loss of Secondary Containment Zone 2 differential pressure (DP) had occurred. Control Room operators noted a differential pressure of <.25" WC (inches Water Column) for several seconds. System DP was restored to normal in 1 minute. The cause of the pressure swings is under investigation. Zone 2 differential pressures being less than 0.25" WC constitutes a loss of Secondary Containment based on not meeting requirements of SR 3.6.4.1.1. This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022 Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system. The licensee notified the NRC Resident Inspector.
ENS 5309830 November 2017 16:02:00SusquehannaNRC Region 1GE-4On November 30, 2017 at 1026 EST, the Susquehanna Control Room received indication that a loss of Secondary Containment Zone 2 differential pressure had occurred. Control Room operators noted a differential pressure of 0.0 inch WC (water column) for several seconds, followed by a high DP of 0.5 inch WC. System DP was restored to normal in 3 minutes. The cause of the pressure swings is under investigation. Zone 2 differential pressures being less than 0.25 inch WC constitutes a loss of Secondary Containment based on not meeting requirements of SR 3.6.4.1.1. This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022, Rev. 3, Section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system. The licensee notified the NRC Resident Inspector.
ENS 530036 October 2017 21:46:00SusquehannaNRC Region 1GE-4On October 6, 2017 at 1945 EDT, a loss of Control Room Habitability Envelope (CRE) was declared due to failing to meet the requirements of SR 3.7.3.4 during 72 month surveillance testing. Measured in-leakage exceeded the SR acceptance value. The CRE is required to be maintained such that occupants can control the reactor safely under normal conditions and maintain it in a safe condition following a radiological event, hazardous chemical release, or a smoke challenge. The station remains in compliance with Technical Specification required action statements. This event is being reported under 10 CFR 50.72(b)(3)(v)(D) and per the guidance of NUREG 1022, Rev. 3, Section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Control Room Habitability Envelope. The licensee notified the NRC Resident Inspector.
ENS 5297316 September 2017 15:53:00SusquehannaNRC Region 1GE-4On September 16th, 2017 at 1330 hrs. (EDT), a loss of secondary containment differential pressure (D/P) occurred due to an equipment failure. This caused a reduction in Reactor Building Zone 2 (Unit 2) D/P to less than the required 0.25 inches WC per SR (Surveillance Requirement) 3.6.4.1.1. 2V206B, Reactor Building Zone 2 Equipment Compartment Exhaust Fan, was manually started and Reactor Building Zone 2 D/P was restored to greater than 0.25 inches WC by 1333 hrs. Reactor Building Zone 1 (Unit 1) and Zone 3 (Units 1&2) ventilation remained in service and stable. This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022, Rev. 3, section 3.2.7, as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system. The licensee has notified the NRC Resident Inspector.
ENS 528928 August 2017 22:33:00SusquehannaNRC Region 1GE-4On August 8th, 2017 at 2044 hrs. (EDT) a loss of secondary containment differential pressure (D/P) occurred due to an apparent equipment failure. This caused a reduction in Reactor Building Zone II (Unit 2) D/P to less than the required 0.25 inch WC (water column) per SR (Surveillance Requirement) 3.6.4.1.1. Reactor Building Zone II Exhaust Fans were manually swapped and Reactor Building Zone II D/P was restored to greater than 0.25 inch WC by 2112 hrs. Reactor Building Zone 1 (Unit 1) and Zone 3 (Units 1&2) ventilation remained in service and stable. This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022 Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system. The licensee notified the NRC Resident Inspector.
ENS 5284410 July 2017 07:35:00SusquehannaNRC Region 1GE-4On July 10th, 2017 at 0250 hrs. (EDT) a loss of secondary containment differential pressure (D/P) occurred due to failure of a non-safety related discharge damper associated with 2V205B Reactor Building Zone II Exhaust Fan. This caused a reduction in Reactor Building Zone II (Unit 2) D/P to less than the required 0.25 inches WC (Water Column). 2V205A Reactor Building Zone II Exhaust Fan was manually started and Reactor Building Zone II D/P was restored to greater than 0.25 inches WC by 0301 hrs. Reactor Building Zone 1 (Unit 1) and Zone 3 (Units 1&2) ventilation remained in service and stable. This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022, Rev. 3, section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system. The licensee notified the NRC Resident Inspector.
ENS 5282624 June 2017 15:42:00SusquehannaNRC Region 1GE-4On June 24, 2017 at 1028 (EDT), a loss of secondary containment occurred due to trip of 2V217A Zone III Filtered Exhaust Fan causing a reduction in D/P (differential pressure) to less than the required 0.25 WC (water column). 2V217B Zone III Filtered Exhaust Fan started on low flow in AUTO as designed and secondary containment D/P was restored to greater than 0.25 WC by 1029 hours. This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022, Rev. 3, section 3.2.7 as a loss of a safety function. There is no redundant Susquehanna secondary containment system. The licensee notified the NRC Resident Inspector.
ENS 527979 June 2017 12:51:00SusquehannaNRC Region 1GE-4On June 9, 2017 at 0509 (EDT), Secondary Containment Zone 3 (Unit 1 and 2 Reactor Building) differential pressure lowered to 0 (inches) WG (water gauge) during a routine restoration due to equipment failure. One of the two Unit 1 Zone 3 exhaust fan breakers experienced a failure that during procedural restoration caused Secondary Containment Zone 3 to experience a positive differential pressure. Required differential pressure per SR 3.6.4.1.1 could not be maintained. Zone 3 differential pressure was recovered to (greater than) 0.25 (inches) WG following restart of Unit 2 Zone 3 Secondary Containment fans. All other Zones of Secondary Containment were unaffected by this event. This event is being reported under 10 CFR 50.72(b)(3)(v)(C) and per the guidance of NUREG 1022 Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment System. The NRC Resident Inspector has been notified.
ENS 527958 June 2017 19:10:00SusquehannaNRC Region 1GE-4At 1527 hrs (EDT) on June 8, 2017, Susquehanna Steam Electric Station Unit 1 reactor automatically scrammed due to a loss of Main Turbine Electro-Hydraulic Control (EHC) logic power causing a High Flux Reactor Power RPS (Reactor Protection System) trip. All control rods (fully) inserted and both reactor recirculation pumps tripped due to reaching reactor water level 2. Reactor water level lowered to -49 inches causing Level 3 (+13 inches) and Level 2 (-38 inches) isolations. HPCI (High Pressure Coolant Injection) and RCIC (Reactor Core Isolation Cooling) automatically initiated and were overridden by control room operators after RPV (Reactor Pressure Vessel) water level was restored to the normal band with feedwater. HPCI and RCIC injected to the Reactor Coolant System during reactor level stabilization. All isolations and initiations occurred as expected. No main steam relief valves opened. Pressure was controlled via main turbine bypass valve operation. All safety systems operated as expected. Secondary Containment Zone 1, 2, and 3 differential pressure lowered to 0 inch WG (Water Gauge) due to a trip of the Reactor Building Ventilation system that resulted from Unit 1 Level 2 isolation. Differential pressure was restored to Zones 1, 2, and 3 by the initiation of Standby Gas Treatment System on the Unit 1 Level 2 initiation. Unit 1 reactor is currently stable in Mode 3. Investigation into the loss of Main Turbine EHC logic power is underway. The NRC Resident Inspector has been notified. A voluntary notification to PEMA and press release will occur. The suspected cause of the loss of power to the EHC logic circuit is ongoing maintenance on the system.
ENS 5277226 May 2017 13:22:00SusquehannaNRC Region 1GE-4This 60-day telephone notification is being made in accordance with the reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe an invalid actuation of a general containment isolation signal affecting multiple Main Steam Isolation Valves (MSIVs). On April 2, 2017 at approximately 2127 Eastern Daylight Time, during performance of a reactor vessel leak check, all four inboard MSIVs closed as a result of actuation of the Main Steam Line (MSL) high flow instrumentation. The high flow signal was spurious on two channels with no flow in the MSLs. Since an actual high flow condition did not exist at the time of the actuation, the actuation was considered invalid. The MSIVs functioned as designed on actuation of the MSL high flow instrumentation. All outboard MSIVs were closed at the time of the actuation. The NRC Resident Inspector has been notified.
ENS 526583 April 2017 11:37:00SusquehannaNRC Region 1GE-4This is being reported under 10CFR20.1906(d)(1,2). At 1045 hours (EDT), the SSES (Susquehanna Steam Electric Station) Radwaste shipper was notified by the RP (Radiation Protection) shipping technician performing a receipt survey of an open transport vehicle shipped exclusive use carrying an empty radwaste liner exceeded the 10CFR71.47(b)(1) vehicle contact dose rates of 200 mR/hr. Per NDAP-QA-0720 (Nuclear Department Administrative Procedure) Attachment E, contaminated /radioactive shipments this is a 1 hour notification for exceeding the radiological receipt survey requirements of 200 mR/hr at any point on the outer surface of the vehicle. The vehicle was from Energy Solutions. The licensee will be using the vehicle to transport radwaste from the facility. The licensee has notified the Pennsylvania Emergency Management Agency and the NRC Resident Inspector.
ENS 525998 March 2017 08:49:00SusquehannaNRC Region 1GE-4On March 08, 2017 at 0239 hours (EST), Secondary Containment Zone 3 (Unit 1 and 2 Reactor Building) differential pressure lowered to 0 (inches) WG due to a trip of the running Zone 3 Secondary Containment fans. The fan trip was caused by a human performance error during a Unit 2 outage related activity. Required differential pressure per SR 3.6.4.1.1 could not be maintained. Zone 3 differential pressure recovered to (greater than) 0.25 (inches) WG at 0255 hours after restart of Zone 3 Secondary Containment fans. All other Zones of Secondary Containment were unaffected by this event. This event is being reported under 10 CFR 50.72(b)(3)(v)(C) and per the guidance of NUREG 1022 Rev. 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment System. The licensee informed the NRC Resident Inspector.
ENS 5255215 February 2017 18:10:00SusquehannaNRC Region 1GE-4

On February 15, 2017 at 1337 (EST), Secondary Containment Zone 1 (Unit 1 Reactor Building) differential pressure lowered to 0 inches WG (Water Gauge) due to a trip of the running Unit 1 B Filtered Exhaust Fan. Required differential pressure per SR (Surveillance Requirement) 3.6.4.1.1 could not be maintained. Zone 1 differential pressure recovered to greater than 0.25 inches WG less than one minute later after start of the standby Zone 1 Filtered Exhaust Fan. Zone 2 (Unit 2 Reactor Building) and Zone 3 (Common Areas of Unit 1&2 Reactor Buildings) ventilation remained in service and stable. This event is being reported under 10 CFR 50.72(b)(3)(v)(C) and per the guidance of NUREG-1022, Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment System. Post-maintenance testing was underway when the fan tripped. While the investigation is on-going to determine the cause, the licensee does not believe the maintenance or testing caused the fan to trip The licensee has notified the NRC Resident Inspector.

  • * * RETRACTION FROM RONALD FRY TO DONALD NORWOOD AT 0833 EDT ON 4/12/2017 * * *

The Unit 1 B Filtered Exhaust Fan trip that resulted in loss of secondary containment differential pressure occurred during post maintenance testing (PMT). The PMT was being performed following replacement of a flow controller associated with the Unit 1 B Filtered Exhaust Fan. In support of the PMT, Technical Specification (TS) 3.6.4.1 Condition A had been entered and was in effect at the time of the fan trip. The maintenance and the associated PMT were performed in accordance with approved work instructions/procedure. Subsequent to the initial report, Susquehanna troubleshooting determined that the fan trip was the result of an internal leak in the newly installed controller that prevented the new controller from functioning properly. The condition was therefore determined to have been the result of the completed maintenance. NUREG-1022, Section 3.2.7, includes the following guidance: '...reports are not required when systems are declared inoperable as part of a planned evolution for maintenance or surveillance testing when done in accordance with an approved procedure and the plant's TS (unless a condition is discovered that would have resulted in the system being declared inoperable).' Following completion of the troubleshooting, Susquehanna determined that, per NUREG-1022, Section 3.2.7, the event was not reportable. Secondary Containment was declared inoperable as a part of a planned evolution for maintenance which was done in accordance with an approved procedure and the Susquehanna TS. The discovered condition was not a pre-existing condition that would have resulted in the system being declared inoperable prior to the planned maintenance activity. The licensee notified the NRC Resident Inspector. Notified R1DO (Jackson).

ENS 5236916 November 2016 17:13:00SusquehannaNRC Region 1GE-4On November 16, 2016 at 1045 (EST), Unit 2 B ESS (Engineered Safeguards System) Bus Sync Selector switch failed and was unable to be switched out of the ON position. The failure rendered all other sync selector switches associated with Emergency Diesel Generators and Off-Site supplies to the ESS buses unable to fulfill their intended function of allowing manual transfer between power supplies to the ESS buses. This resulted in the inability of Unit 1 and Unit 2 to comply with SR (Surveillance Requirements) 3.8.1.8 and 3.8.1.16 thus requiring declaration of Operating AC Sources inoperable. This condition could have prevented the fulfillment of the safety function of systems required to maintain the reactor in a safe shutdown condition, remove residual heat, control the release of radioactive material, and mitigate the consequences of an accident. Subsequent actions were taken in accordance with station procedures to remove fuses for the affected sync circuit, restoring the manual transfer function to all but the Unit 2 B ESS bus. One Emergency Diesel and one offsite source remain inoperable with the fuses removed. At no time were any ESS buses disconnected from offsite power. All ESS buses remained capable of being automatically energized from their respective emergency diesel in an emergency. The licensee has notified the NRC Resident Inspector.
ENS 5226627 September 2016 22:27:00SusquehannaNRC Region 1GE-4

On September 27, 2016 at 1644 (EDT), damaged ductwork was identified in the secondary containment boundary associated with reactor building zone 3 (Units 1 and 2) recirculation plenum. The size of the hole in the secondary containment boundary was determined to be 22.5 square inches. Due to exceeding allowable total leakage in the current secondary containment isolation configuration, a violation of SR 3.6.4.1.5 (occurred). Action to establish a tested configuration with sufficient inleakage margin to restore compliance with SR 3.6.4.1.5 was completed September 27, 2016 at 2115 hrs. This event is being reported under 10 CFR 50.72(b)(3)(v)(C) and per the guidance of NUREG 1022, Rev 3, Section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment System. The licensee notified the NRC Resident Inspector.

  • * * RETRACTION AT 1444 EST ON 11/23/2016 FROM MANU SIVARAMAN TO MARK ABRAMOVITZ * * *

Following the 8 hour 10 CFR 50.72 notification made on September 27, 2016 (EN 52266), further engineering analysis determined that the as-found tear in the Zone 3 ductwork did not impact the ability of Secondary Containment to perform its safety function and that Secondary Containment was not inoperable as a result of the condition. To support the determination, a drawdown test was conducted in a limiting configuration (i.e. least inleakage margin). No substantial change in drawdown testing results were observed over the last three tests. These tests spanned over seven years. Additionally, repairs were promptly made to the affected area. As a result, this event notification is being retracted as it is not reportable pursuant to 10 CFR 50.72(b)(3)(v)(C). The licensee notified the NRC Resident Inspector. Notified the R1DO (Dwyer).

ENS 5225522 September 2016 10:58:00SusquehannaNRC Region 1GE-4On September 22, 2016, at 0320 (EDT), Secondary Containment Zone 2 (Unit 2 Reactor Building) differential pressure lowered to 0.15 (inch) WG due to a stuck non-safety related exhaust damper on the in service Zone 2 exhaust fan. Required differential pressure per SR 3.6.4.1.1 could not be maintained. Zone 2 differential pressure recovered to greater than 0.25 (inch) WG on September 22, 2016 at 0342 (EDT) by starting the standby Zone 2 exhaust fan. Zone 1 (Unit 1 Reactor Building) and Zone 3 (Unit 1&2 Reactor Buildings) ventilation remained in service and stable. This event is being reported under 10 CFR 50.72(b)(3)(v)(C) and per the guidance of NUREG 1022 Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment System. The Licensee notified the NRC Resident Inspector.
ENS 519878 June 2016 07:01:00SusquehannaNRC Region 1GE-4Susquehanna Unit 1 identified RPV (reactor pressure vessel) pressure boundary leakage from (local power range monitor) LPRM 24-09 housing above the flange during an under vessel leak inspection on 06/08/2016 at 0226 EDT. The leakage point is a through wall indication on the ASME Class 1 LPRM stub tube. The leakage is not isolable from the reactor vessel. The reactor was in Mode 4 at the time of discovery. This event is being reported as a degraded condition pursuant to 10CFR50.72(b)(3)(ii)(A). A repair plan is being formulated. The licensee has notified the NRC Resident Inspector.
ENS 519836 June 2016 08:13:00SusquehannaNRC Region 1GE-4Susquehanna Unit 1 commenced a manual shutdown on 06/05/2016 for a maintenance outage. At 2202 hours (EDT) on 06/05/2016, operators began reducing power in accordance with plant procedures. At 0352 hours on 06/06/2016, the Main Turbine was tripped with reactor power at approximately 15%. The Mode switch was taken to 'STARTUP/HOT STANDBY' (Mode 2) at 0515 hours on 06/06/2016. Manual insertion of control rods was paused as scheduled for entry into the drywell for inspections. There were no ESF actuations. At 0556, the licensee identified leakage from a weld on seal water line piping connected to the 1B reactor recirculation pump seal area. The location is within the reactor recirculation loop isolation valves, therefore is isolable from the reactor vessel. The piping is ASME Class 2 and is reactor coolant pressure boundary. The reactor was in Mode 2 at the time of discovery. This event is being reported as a plant shutdown required by technical specifications pursuant to 10CFR50.72(b)(2)(i) and degraded condition pursuant to 10CFR50.72(b)(3)(ii)(A). Activities are continuing to achieve cold shutdown. The licensee informed the Commonwealth of Pennsylvania and the NRC Resident Inspector.
ENS 5192513 May 2016 05:00:00SusquehannaNRC Region 1GE-4At approximately 0110 hours (EDT) on May 13, 2016, Susquehanna Steam Electric Station Unit Two reactor was manually scrammed by plant operators due to a sustained loss of AC power to essential plant loads. Power to MCC 2B246 was lost at 2355 on May 12, 2016, resulting in a loss of Drywell cooling. Drywell pressure increased to 1.3 psig when operators placed the mode switch to the shutdown position to manually SCRAM the reactor. All rods inserted as expected. Reactor water level lowered to -27 inches and was immediately restored by normal feedwater level control. Level 3 (+13 inch) PCIS isolations occurred, along with an initiation of the RCIC system (-30 inches). Once adequate level was verified, RCIC was overridden. Pressure was controlled with turbine bypass valves, and subsequently main steam line drains. All safety systems functioned as expected. The power loss also tripped Reactor Building HVAC, causing a loss of secondary containment differential pressure resulting in a loss of safety function. Due to the loss of drywell cooling, high drywell pressure actuations and a second reactor SCRAM signal, this signal was automatic, occurred at 0314 hours. HPCI (which automatically initiated on high drywell pressure) was subsequently overridden and declared inoperable, resulting in a loss of safety function. (HPCI did not inject into the vessel). The reactor is currently stable in Mode 3. Initial reports from the field indicate a phase to phase fault on the MCC 2B246 bus bars. The licensee has notified the NRC Resident Inspector and will be issuing a press release.
ENS 5187220 April 2016 01:52:00SusquehannaNRC Region 1GE-4On April 19th, 2016 at 2159 (EDT), Secondary Containment became inoperable due to failure to meet Surveillance Requirement (SR 3.6.4.1.1) on Unit 1 and Unit 2. The inoperability was caused when Reactor Building differential pressure was discovered to be less than Technical Specification requirements (-0.25 inches of water gauge). Secondary Containment was restored April 19, 2016 at 2222 by adjusting intake louvers in accordance with off normal operating procedure ON-RBHVAC-201. This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022 Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system. The licensee notified the NRC Resident Inspector.
ENS 518516 April 2016 17:27:00SusquehannaNRC Region 1GE-4On April 6th, 2016 at 1337 (EDT) and 1343 (EDT) Secondary Containment became inoperable due to failure to meet a Surveillance Requirement (SR 3.6.4.1.3) on Unit 1 and Unit 2. The inoperability was caused when two separate sets of Reactor Building airlock doors were sequentially opened during a medical emergency to transport an individual. Each set of airlock doors was opened momentarily to allow passage. Secondary Containment was restored April 6, 2016 at 1344 (EDT) when the transport evolution was complete. This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022 Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system. The NRC Resident Inspector has been notified.
ENS 5183831 March 2016 12:45:00SusquehannaNRC Region 1GE-4On March 31, 2016 at 0603 (EDT), with Susquehanna Unit 1 in its 19th Refueling and Inspection Outage, Unit 1 received a valid isolation signal. Preliminary investigation indicates the isolation signal was the result of a human performance error. The systems affected by the isolation signal responded as designed for the current shutdown plant conditions. This isolation of multiple primary containment isolation systems is being reported under 10CFR50.72(b)(3)(iv)(A) and per the guidance of NUREG 1022, Rev. 3, section 3.2.6 as a system actuation. The licensee notified the NRC Resident Inspector.
ENS 5183030 March 2016 02:13:00SusquehannaNRC Region 1GE-4On March 29, 2016 at 2256 (EDT), Secondary Containment Zone 2 (Unit 2 Reactor Building) differential pressure lowered to 0.0 (inches) WG (water gauge) due to a failed closed discharge damper on the in service Zone 2 exhaust fan. Required differential pressure per SR 3.6.4.1.1 could not be maintained. Zone 2 ventilation was restored by starting the standby Zone 2 exhaust fan. Zone 2 differential pressure recovered to (greater than) 0.25 (inches) WG at 2321 hours. Zone 3 (Unit 1&2 Reactor Buildings) ventilation remained in service and stable. Zone 1(Unit 1 Reactor Building) ventilation remained in service however it is not required in this mode of Operation. This event is being reported under 10 CFR 50.72(b)(3)(v)(C) and per the guidance of NUREG 1022 Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment System. The licensee has notified the NRC Resident Inspector.
ENS 517778 March 2016 09:37:00SusquehannaNRC Region 1GE-4On March 8, 2016 at 0232 hours (EST), Secondary Containment Zone 3 (Unit 1&2 Reactor Building) differential pressure lowered to 0.16 inches water gauge when securing Unit 1 Zone 3 HVAC for planned maintenance. Required differential pressure per SR 3.6.4.1.1 could not be maintained in the intended alignment. Zone 3 ventilation was restored to the original alignment and Zone 3 differential pressure recovered to greater than 0.25 inches water gauge at 0335 hours. Zone I (Unit 1 Reactor Building) and Zone II (Unit 2 Reactor Building) ventilation remained in service and stable. Station engineering and maintenance are investigating the Zone 3 HVAC system to determine the cause. This event is being reported under 10 CFR 50.72(b)(3)(v)(C) and per the guidance of NUREG 1022, Rev. 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment System. The NRC Resident Inspector has been notified.
ENS 517642 March 2016 17:20:00SusquehannaNRC Region 1GE-4On March 2, 2016 at 1330 hrs. (EST), Secondary Containment became inoperable due to failure to meet a Surveillance Requirement (SR 3.6.4.1.3). The inoperability was caused when Unit 2 Reactor Building Airlock doors were inadvertently opened simultaneously. Secondary Containment was restored March 2, 2016 at 1331 hrs. when the doors were closed. This event is being reported under 10 CFR 50.72(b)(3)(v)(C) and per the guidance of NUREG 1022, Rev. 3, section 3.2.7, as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system. The licensee has notified the NRC Resident Inspector.
ENS 5175022 February 2016 18:47:00SusquehannaNRC Region 1GE-4On February 22, 2016 at 1345 (EST). Secondary Containment became inoperable due to failure to meet a Surveillance Requirement (SR 3.6.4.1.3) on Unit 1. The inoperability was caused when Unit 1 Reactor Building Airlock doors were inadvertently opened simultaneously. Secondary Containment was restored February 22, 2016 at 1346 when the doors were closed. This event is being reported under 10 CFR 50.72(b)(3)(v)(C) and per the guidance of NUREG 1022, Rev. 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system. The licensee informed the NRC Resident Inspector.
ENS 515886 December 2015 09:58:00SusquehannaNRC Region 1GE-4

On December 06, 2015 at 0546 (EST), Reactor Building Zone 1 Secondary Containment differential pressure lowered to less than 0.25 inch Water Column (WC) (degrading vacuum) when the running Reactor Building Zone 1 exhaust fan tripped. This required a TS 3.6.4.1 entry for failure to meet SR 3.6.4.1.1 on Unit 1 and Unit 2.

The standby fan automatically started, restoring of Reactor Building Zone 1 Secondary Containment differential pressure to greater than -0.25 inch WC. Field operators confirmed proper system response at 0553 (EST) December 06, 2015. This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022 Rev 3 section 3.2.7 as a loss of a Safety Function. " The licensee has notified the NRC Resident Inspector.

ENS 515876 December 2015 05:28:00SusquehannaNRC Region 1GE-4

On December 06, 2015 at 0350 (EST), Reactor Building Zone 1 Secondary Containment differential pressure lowered to less than 0.25 inch Water Column (WC) (degrading vacuum) when the intake supply plenum screens were found to be iced over. This required a TS 3.6.4.1 entry for failure to meet SR 3.6.4.1.1 on Unit 1 and Unit 2.

Snow melt heaters were manually started to melt the ice allowing restoration of Reactor Building Zone 1 Secondary Containment differential pressure to greater than 0.25 inch WC at 0434 on December 06, 2015. This event is being reported under 10 CFR 50.72 (b)(3)(c) and per the guidance of NUREG 1022 Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system. The licensee has notified the NRC Resident Inspector.

ENS 515761 December 2015 16:07:00SusquehannaNRC Region 1GE-4On December 1, 2015 at 1245 EST, Secondary Containment became inoperable due to the failure to meet a Surveillance Requirement (SR 3.6.4.1.3) on Unit 2. The inoperability was caused when RB (Reactor Building) airlock doors were inadvertently opened simultaneously. Secondary Containment was restored December 1, 2015 at 1246 EST when the doors were closed. This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022, Rev 3, section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system. The licensee notified the NRC Resident Inspector.
ENS 5153814 November 2015 00:22:00SusquehannaNRC Region 1GE-4On 11/13/15 at 1745 EST, Unit 1 drywell entry was performed during an unplanned Unit 1 outage. The licensee identified leakage from a weld on the 3/4 inch lower seal vent piping connected to the 1B reactor recirculation pump lower seal area. The location is within the reactor recirculation loop isolation valves, therefore isolable from the reactor vessel. The piping is ASME Class 2 and is a reactor coolant pressure boundary. The reactor was in mode 3 at the time of discovery. Control Room determined at 2110 EST on 11/13/15, that requirements for 10CFR50.72(b)(3)(ii)(A) were not met. This event is being reported as a degraded condition pursuant to 10CFR50.72(b)(3)(ii)(A). The Licensee notified the NRC Resident Inspector.
ENS 5153312 November 2015 17:47:00SusquehannaNRC Region 1GE-4

On November 12, 2015 at 1132 hrs. (EST), Secondary Containment became inoperable due to failure to meet SR 3.6.4.1.1 requirements on Unit 2.

The inoperability was caused when RB (Reactor Building) Zone II differential pressure (D/P) oscillated between 0.23 and 0.43 inches WG (water gauge) (less than SR 3.6.4.1.1 requirement of greater than or equal to 0.25 inches WG). The oscillations subsided at 1501 (EST) and RB Zone II D/P continues to be maintained at approximately 0.35 inches WG. This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022 Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system. The licensee notified the NRC Resident Inspector.

ENS 5153212 November 2015 15:15:00SusquehannaNRC Region 1GE-4At 1132 hours (EST) on November 12, 2015, Susquehanna Steam Electric Station Unit 1 reactor automatically scrammed due to one Main Steam Isolation Valve (MSIV) unanticipated closure causing a High Pressure RPS (Reactor Protection System) trip. All control rods inserted and both reactor recirculation pumps tripped due to reactor water level 2. Reactor water level lowered to -37 inches causing Level 3 (+13 inches) and level 2 (-38 inches) (Division 2 only) isolations. RCIC (Reactor Core Isolation Cooling) automatically initiated and was overridden by control room operators after RPV (Reactor Pressure Vessel) water level was restored to the normal band with feedwater. All isolations and initiations occurred as expected. No main steam relief valves opened. Pressure was controlled via main turbine bypass valve operation. All safety systems operated as expected. The Unit 1 reactor is currently stable in Mode 3. Investigation into the cause of the MSIV closure is underway. Unit 2 was unaffected and continues power operation. The NRC Resident Inspector has been notified. A voluntary notification to PEMA (Pennsylvania Emergency Management Agency) and press release will occur. The plant is in its normal shutdown electrical lineup.
ENS 5143229 September 2015 14:56:00SusquehannaNRC Region 1GE-4On 9/29/15 at 1020 EDT, the 'B' train of Standby Gas Treatment System was declared inoperable for planned testing. On 9/29/15 at 1030 EDT, during performance of a surveillance on Unit 1 Reactor Pressure Vessel water level instrumentation, one channel was found to not meet acceptance criteria. The failed level channel is part of the initiation logic for the 'A' train of Standby Gas Treatment. This resulted in a loss of safety function for the Standby Gas Treatment System. On 9/29/15 at 1145 EDT, the 'B' train of Standby Gas Treatment was restored to operable by restoring from the planned testing. This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022 Rev 3 section 3.2.7 as a loss of a Safety Function. The NRC Resident Inspector has been informed.
ENS 513757 September 2015 11:32:00SusquehannaNRC Region 1GE-4This report is made due to notification from Susquehanna to Pennsylvania Department of Environmental Protection (DEP) regarding a bypass of the sewage treatment plant at the plant property. The notification was approved at 0925 (EDT) and completed at 0940 (EDT) hours on 09/07/15. The sewage treatment plant operator reported excessive influent which led to an unanticipated bypass of the sewage treatment plant. The influent was returned to normal values by isolating the domestic water filter backwash line. No bypass leakage is occurring at this time. The licensee has notified the NRC Resident Inspector.
ENS 5135527 August 2015 20:39:00SusquehannaNRC Region 1GE-4

On 8/27/2015 at 1347 (EDT), a cart and personnel were being traversed through an airlock in the Unit 2 reactor building and both airlock doors were inadvertently opened at the same time for a brief period of time (approximately one minute). Secondary Containment differential pressure was maintained throughout the time period that the doors were opened. The doors serve as a Secondary Containment boundary and at least one in series is required to be closed at all times for Secondary Containment Operability. This event is being reported under 10 CFR 50.72(b)(3)(v) and per the guidance of NUREG 1022 Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment System. The licensee notified the NRC Resident Inspector.

  • * * RETRACTED ON 10/22/15 AT 1645 EDT FROM ALEX MCLELLAN TO DONG PARK * * *

NUREG-1022, Revision 3, Section 3.2.7, 'Event or Condition that Could Have Prevented Fulfillment of a Safety Function,' states, in part, that 'events covered in paragraph (b)(3)(v) of this section may include one or more procedural errors, equipment failures, and/or discovery of design, analysis, fabrication, construction, and/or procedural inadequacies.' The level of judgment for reporting an event or condition under this criterion is a reasonable expectation of preventing fulfillment of a safety function. A SSC (System, Structure, and/or Component) that has been declared inoperable is one in which the SSC capability has been degraded to the point where it cannot perform with reasonable expectation or reliability. For SSCs within the scope of this criterion, a report is required when: - There is a determination that the SSC is inoperable in a required mode or other specified condition in the TS (Technical Specification) applicability, -The inoperability is due to one of more personnel errors, including procedure violations; equipment failures; inadequate maintenance; or design, analysis, fabrication, equipment qualification, construction, or procedural deficiencies, and -No redundant equipment in the same system was operable. Subsequent to the reporting of this condition, Susquehanna Nuclear, LLC performed an investigation of the event. Below are the results. When the airlock doors were opened at the same time, they were being operated as designed. Each individual had a 'green' light, which allowed them to open each door. Based on the investigation, the doors were open at the same time for approximately one second. In summary, the inoperability of Secondary Containment was not due to personnel error or a procedure violation. At the time of the event, both airlock doors were operable. No equipment failures, inadequate maintenance, or design, analysis, fabrication, equipment qualification, construction, or procedural deficiencies were identified. In summary, based on the above, the identified condition is not reportable in accordance with 10 CFR 50.72(b)(3)(v), for an event or condition, that at the time of discovery, could have prevented the fulfillment of a safety function. As such, this 8-hour event notification is being retracted. The licensee has notified the NRC Resident Inspector. Notified R1DO (Gray).

ENS 5126927 July 2015 17:50:00SusquehannaNRC Region 1GE-4

On July 27, 2015 at 1118 (EDT), Secondary Containment became inoperable requiring a Technical Specification 3.6.4.1 entry for failure to meet SR (Surveillance Requirement) 3.6.4.1.1 on Unit 1 and Unit 2.

The inoperability was caused by Zone 2 differential pressure lowering to less than 0.25 inches WC when a secondary containment door was opened without appropriate authorization. The secondary containment door was closed at 1149 and secondary containment D/P verified greater than 0.25 inches WC at 1205. This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022 Rev. 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system. The loss of secondary containment occurred due to multiple openings of Door 104R which provides access to area of the building that provides alternate access to the building roof, but this door is not the normal access to the building roof The licensee notified the NRC Resident Inspector.

ENS 510404 May 2015 21:44:00SusquehannaNRC Region 1GE-4On May 4, 2015 at 1439 (EDT), during maintenance activities on Unit 2 Zone 3 fan discharge exhaust dampers, the control room received a low DP (Differential Pressure) alarm and other confirmatory indications of a loss of building DP. Secondary Containment DP was restored after approximately 2 minutes. The fan exhaust dampers are outside the isolation dampers, therefore, there was no impact on the SGTS (Standby Gas Treatment System) ability to drawdown secondary containment. This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022 Rev 3. section 3.2.7, as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment System. The licensee has notified the NRC Resident Inspector.
ENS 5101727 April 2015 15:46:00SusquehannaNRC Region 1GE-4On 4/27/2015 at 0850 (EDT), Secondary Containment (Unit 1 Reactor Building) Boundary Door-721 was found ajar. The door was closed by operators. A status walkdown was performed and no other doors were found in this condition. Although, Secondary Containment differential pressure was maintained throughout the time period that the door was not fully closed and latched. The door serves as a Secondary Containment boundary and is required to be closed for Secondary Containment Operability. This event is being reported under 10 CFR 50.72(b)(3)(v) and per the guidance of NUREG 1022 Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment System. This door is in the railroad bay and was posted as a containment boundary door. Investigation into why this door was not closed and latched is continuing. The licensee notified the NRC Resident Inspector.
ENS 5101426 April 2015 01:37:00SusquehannaNRC Region 1GE-4At 2125 (EDT) on 4/25/15 the control room was notified of a medical emergency in the Radiologically Controlled Area (RCA). The individual was considered potentially contaminated since a complete frisk could not be performed prior to transport. An ambulance entered the Susquehanna Owner Controlled Area and the Protected Area at 2154 and exited at 2210 to transport the individual to the hospital. Radiological survey performed during transport by an SSES (Susquehanna Steam Electric Station) RP (Radiation Protection) Technician verified at 2255 the individual was not contaminated. The ambulance was verified not contaminated at 2303. This event is reportable under 10CFR50.72(b)(3)(xii). An Event of Potential Public Interest (EPPI) was made to the Pennsylvania Emergency Management Agency (PEMA) due to an emergency vehicle accessing company property. The licensee informed the NRC Resident Inspector.
ENS 5100122 April 2015 01:58:00SusquehannaNRC Region 1GE-4On April 21, 2015 at 2258 (EDT), Secondary Containment became inoperable requiring a Technical Specification 3.6.4.1 entry for failure to meet SR 3.6.4.1.1 on Unit 1 and Unit 2. The inoperability was caused by Zone 3 differential pressure lowering to less than 0.25 (inches Water Column) when Zone III fans tripped during 30mph wind gusts. Fans were restarted and differential pressure restored to greater than 0.25 (inches Water Column) at 2314 hrs. April 21, 2015. This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022 Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system. The licensee notified the NRC Resident Inspector.
ENS 5097611 April 2015 11:23:00SusquehannaNRC Region 1GE-4On 4/11/15, Unit 2 drywell entry was performed during a planned Unit 2 refueling inspection outage. At 0958 EDT, the licensee identified leakage from a weld on the 3/4 inch seal vent piping connected to the 2A reactor recirculation pump seal area. The location is within the reactor recirculation loop isolation valves, therefore it is isolable from the reactor vessel. The piping is ASME Class 2 and is a reactor coolant pressure boundary. The reactor was in mode 3 at the time of discovery. This event is being reported as a degraded condition pursuant to 10CFR50.72(b)(3)(ii)(A). The licensee notified the NRC Resident Inspector.
ENS 5097411 April 2015 05:22:00SusquehannaNRC Region 1GE-4

On April 11, 2015 at 0051 EDT, Secondary Containment became inoperable requiring a Technical Specification 3.6.4.1 entry for failure to meet SR (Surveillance Requirement) 3.6.4.1.1 on Unit 1 and Unit 2, loss of required differential pressure.

The inoperability was caused by a loss of normal Zone 2 differential pressure due to loss of running fans and failure to start of standby fans. The cause is being investigated. Engineering and maintenance personnel implemented a Temporary Engineering Change, which allowed restoration of one set of fans and dampers. Normal secondary containment differential pressure was restored. Technical Specification 3.6.4.1 was exited at 0320 EDT. This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022 Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system. The NRC Resident Inspector was notified. Temporary Engineering Change consisted of removing air to a previously running fan discharge damper so it would close and allow standby fans to start.

ENS 5097311 April 2015 01:52:00SusquehannaNRC Region 1GE-4At 2346 EDT on April 10, 2015, Susquehanna Steam Electric Station Unit 2 reactor automatically scrammed due to a main turbine trip caused by loss of turbine steam seals and degrading main condenser vacuum. Unit 2 reactor was being shutdown for a refueling outage. At approximately 37 percent power, turbine steam seals were lost resulting in a degrading vacuum. The vacuum degraded quickly, resulting in a main turbine trip before the reactor operator could insert a manual scram. At 37 percent power, the turbine trip caused an automatic scram. This occurred during a transfer from normal steam seal supply to the auxiliary boiler supply. All control rods (fully) inserted. Reactor water level lowered to +2 inches causing Level 3 (+13 inches) isolation. No ECCS actuations occurred. The Operations crew subsequently maintained reactor water level at the normal operating band using RCIC (Reactor Core Isolation Cooling). No steam relief valves opened. The reactor recirculation pumps tripped on EOC-RPT due to the turbine trip at power. The reactor is currently stable in Mode 3. Investigation into the cause of the loss of turbine steam seals is underway. The NRC Resident Inspector was notified. A voluntary notification to PEMA (Pennsylvania Emergency Management Agency) and press release will occur. Unit 2 is in a normal shutdown electrical lineup. Turbine steam seals were restored to the normal steam supply and condenser vacuum was restored. Decay heat is being removed via the steam bypass valves to the condenser. Unit 2 is proceeding with their cooldown to support the scheduled refueling outage.