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The query [[Category:ENS Notification]] [[Site::Susquehanna]] [[Scram::+]] was answered by the SMWSQLStore3 in 0.4113 seconds.


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 Entered dateSiteRegionScramReactor typeEvent description
ENS 527958 June 2017 19:10:00SusquehannaNRC Region 1Automatic ScramGE-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 5192513 May 2016 05:00:00SusquehannaNRC Region 1Manual ScramGE-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 5097311 April 2015 01:52:00SusquehannaNRC Region 1Manual Scram
Automatic Scram
GE-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.
ENS 4934415 September 2013 11:52:00SusquehannaNRC Region 1Manual ScramGE-4

At 1123 EDT, (on 9/15/13), Susquehanna Unit 2 received a Division 2 RHR (Residual Heat Removal) room Flooded alarm. Plant operators reported 3 inches of water in the room with water coming from the 2B RHR pump suction relief valve. The Suppression Pool Isolation valve was closed to isolate the leaking relief valve from the Suppression Pool. This action stopped Suppression Pool level from lowering. The Leak is isolated at this time. Further water is being added to the room as the system piping is being drained. The cause of the relief valve lifting is unknown at this time and is under investigation. At the time of the event, Division 2 RHR system had been declared inoperable for unrelated equipment issues. At 1222 EDT, the licensee confirmed that leakage from the 2B RHR pump suction relief valve had stopped. Susquehanna Unit 2 remains stable and there was no impact on Susquehanna Unit 1. The licensee notified the NRC Resident Inspector, State, and Local authorities. Notified DHS SWO, FEMA, DHS NICC, and Nuclear SSA (email only).

  • * * UPDATE FROM MARTIN LICHTNER TO JOHN SHOEMAKER AT 1641 EDT ON 9/15/13 * * *

U2 SSES (Susquehanna Steam Electric Station) has exited the Unusual Event for Division 2 RHR room flooded as of 1552 EDT. The leak has been isolated, water removed from the room and Division 1 RHR is operating in shutdown cooling proceeding to Mode 4 (Cold Shutdown). A press release for this event was authorized at 1613 and issued at 1628 (on 9/15/13). The licensee has notified the NRC Resident Inspector. Notified R1DO (Cahill), NRR (Dorman), IRD (Gott), DHS SWO, FEMA, DHS NICC, and Nuclear SSA (email only).

ENS 4934214 September 2013 05:15:00SusquehannaNRC Region 1Manual ScramGE-4At approximately 0330 hours on September 14, 2013, Susquehanna Steam Electric Station Unit 2 reactor was manually scrammed while transitioning the 'A' reactor feed pump from flow control mode to discharge pressure mode. Reactor water level rose to +54 inches causing a trip of reactor feedpumps. Subsequently the mode switch was taken to shutdown to manually scram the Unit 2 reactor. All control rods inserted. Reactor water level lowered to approximately +18 inches. There were no automatic emergency core cooling system initiations. No steam relief valves opened during the event. No containment isolations occurred. All safety systems operated as expected. RCIC system was manually initiated for level control until a reactor feedpump was recovered, then RCIC was manually shutdown. The cause of the feedwater flow transient and trip of the reactor feedwater pumps is under investigation. This report is being made per 10CFR50.72(b)(2)(iv)(B) for a 4 hour report, and 10CFR50.72(b)(3)(iv)(A) for an 8 hour report. Decay heat is being removed via the turbine bypass valve to the condenser. Offsite power remains stable, and there was no impact on Unit 1. The licensee has notified the NRC Resident Inspector. The Pennsylvania Emergency Management Agency will be notified, and the licensee will be making a press release.
ENS 490997 June 2013 13:50:00SusquehannaNRC Region 1Manual ScramGE-4At approximately 1203 (EDT) on June 7, 2013, Susquehanna Steam Electric Station Unit One reactor was manually scrammed during reactor startup. Pressure setpoint was being adjusted to the normal operating setpoint, from 750 psig to 934 psig, when all turbine bypass valves unexpectedly opened. Reactor Feed Pumps, Main Turbine, HPCI and RCIC tripped on the high level setpoint Level 8 (+54 inches) due to the resultant reactor level swell. The reactor operator then inserted a manual scram. All control rods inserted. Reactor water level lowered to approximately -10 inches causing Level 3 (+13 inches) isolations. There were no automatic emergency core cooling system initiations. No steam relief valves opened during the event. All safety systems operated as expected. The cause of the Turbine Bypass valve opening is under investigation. Unit 2 was unaffected. The licensee notified the NRC Resident Inspector and will notify the Pennsylvania Emergency Management Agency.
ENS 4860719 December 2012 20:29:00SusquehannaNRC Region 1Automatic ScramGE-4At approximately 17:31 hours on December 19, 2012, Susquehanna Steam Electric Station Unit Two reactor automatically scrammed on low RPV level (Level 3, +13 inches) while transitioning the 'A' reactor feed pump from discharge pressure mode to flow control mode. All control rods inserted and both reactor recirculation pumps tripped. Reactor water level lowered to approximately -29 inches causing Level 3 (+13 inches) isolations. An automatic trip of the reactor recirculation pumps occurred, but is not expected at this RPV level. There were no automatic emergency core cooling system initiations. No steam relief valves opened during the event. All safety systems operated as expected. The cause of the loss of feed water flow and trip of the reactor recirculation pumps is under investigation. This report is being made per 10CFR50.72(b)(2)(iv)(B) for a 4 hour report, and 10CFR50.72(b)(3)(iv)(A) for an 8 hour report. Decay heat is removed via steam to the main condenser using the bypass valves . On-site electrical power is in the normal configuration. The Unit 2 reactor is currently stable in Mode 3. Unit 1 was not affected and operates at 99% power. The licensee will inform the Commonwealth of Pennsylvania and make a press release. The NRC Resident Inspector was notified.
ENS 484969 November 2012 03:03:00SusquehannaNRC Region 1Manual ScramGE-4At approximately 0118 hours (EST) on November 9, 2012, Susquehanna Steam Electric Station Unit Two reactor was scrammed by plant operators due to a loss of ICS (Integrated Control System; which controls the reactor feed and reactor recirculation systems). The reactor operator placed the mode switch in shutdown when reactor water level reached +25 inches and lowering. All control rods inserted and both reactor recirculation pumps tripped at -38 inches. Reactor water level lowered to -52 inches causing Level 3 (+13 inches) and level 2 (-38 inches) isolations. HPCI and RCIC both automatically initiated. HPCI was overridden prior to injection and RCIC was utilized to restore reactor water level to the normal band. All isolations and initiations at this level occurred as expected. No steam relief valves opened. Pressure was controlled via turbine bypass valve operation. All safety systems operated as expected. The (Unit 2) reactor is currently stable in Mode 3. An investigation into the cause of the loss of ICS is underway. Unit One continued power operation (at 78% power). The NRC Resident Inspectors were notified. A press release will occur. The licensee will inform the State of Pennsylvania. Decay heat removal is being maintained through the main condenser. On-site electrical power is in the normal configuration.
ENS 4656925 January 2011 08:12:00SusquehannaNRC Region 1Manual ScramGE-4At 0610 EST hours on January 25, 2011, Susquehanna Steam Electric Station Unit 1 reactor was manually scrammed due to an unisolable extraction steam system leak in the 1C Feed Water Heater Bay area. At 0517 EST reactor operators commenced lowering reactor power from 98.4% to 65%. Attempts to isolate the source of the leakage were unsuccessful. Based on continued indications of unisolated steam leakage, operations decided to shut down the plant. The reactor operator placed the mode switch in shutdown. All control rods inserted. Reactor water level lowered to -31 inches causing Level 3 (+ 13 inches) isolation and RCIC initiation. The operations crew subsequently maintained reactor water level at the normal operating band using FW (feedwater). No steam relief valves opened. All safety systems operated as expected. RCIC automatically initiated on a -30 inch level signal and was manually secured. The reactor is currently stable in Mode 3. Investigation into the cause of the extraction steam system leakage is underway. The NRC Resident Inspector was notified. A voluntary notification to PEMA and press release will occur. The steam leak was isolated after the turbine was tripped. The plant is stable at normal temperature and pressure. Decay heat is being removed via the condenser steam dumps to the main condenser. The electrical lineup is in a normal configuration. Estimated time to restart is not known.
ENS 4610316 July 2010 20:03:00SusquehannaNRC Region 1Manual ScramGE-4At approximately 1641 EDT on July 16, 2010, Susquehanna Steam Electric Station Unit 1 reactor was manually scrammed due to a large unisolable circulating water system leak in the main condenser area. Attempts to isolate the source of the leakage were unsuccessful. During these attempts, reactor operators lowered reactor power from approximately 90% to about 39%. Based on rising water level in the condenser area and unsuccessful isolation of the source of the leakage, Operations decided to shut down the plant. The reactor operator placed the mode switch in shutdown. All control rods (fully) inserted. Reactor water level lowered to -28 inches causing Level 3 (+13 inches) isolations. The Operations crew subsequently maintained reactor water level at the normal operating band using RCIC. No steam relief valves opened. The main steam isolation valves were manually closed and the circulating water system was shut down. Pressure control was initiated using HPCI in the pressure control mode. All safety systems operated as expected. The reactor is currently stable in Mode 3. Actions to isolate and investigate the cause of the circulating water system leakage are underway. Unit 2 continued power operation. The licensee has notified the NRC Resident Inspector, and will be issuing a press release.
ENS 4593015 May 2010 01:17:00SusquehannaNRC Region 1Manual ScramGE-4At approximately 2301 hours EDT on May 14, 2010, Susquehanna Steam Electric Station Unit One reactor scrammed while performing a condensate pump trip test. The reactor operator placed the mode switch in shutdown when reactor water level reached +51 inches and rising. The main turbine tripped due to high reactor water level. All control rods inserted and both reactor recirculation pumps tripped. Reactor water level lowered to -30 inches causing Level 3 (+13 inches) isolations. The Operations crew restored reactor water level to the normal operating band using RCIC (Reactor Core Isolation Cooling) and subsequently the feedwater system. All isolations at this level occurred as expected. No steam relief valves opened. Pressure was controlled via turbine bypass valve operation. All safety systems operated as expected. The reactor is currently stable in Mode 3. An investigation into the cause of the shutdown is underway. Unit Two continued power operation. The NRC Resident Inspectors were notified. A press release will occur. The licensee was performing testing on the digital feedwater control system which was installed during their recent refueling outage when the loss of level control occurred. It appears that the control system did not respond fast enough to control water level. This resulted in the reactor operator inserting a manual scram at +51 inches prior to reaching the reactor automatic scram setpoint of +54 inches for water level. Currently, the plant is removing decay heat via main steam line drains to the condenser. The plant is in its normal shutdown electrical lineup with all safety equipment available. The licensee has notified the Pennsylvania Emergency Management Agency.
ENS 4586622 April 2010 13:20:00SusquehannaNRC Region 1Automatic ScramGE-4At 10:51 on 4/22/10, Susquehanna Unit 1 experienced an automatic reactor SCRAM on reactor low level, +13", during the initial testing of the Feedwater Integrated Control System. Following the SCRAM, reactor water level dropped to approx. -30", and the Reactor Core Isolation Cooling system initiated and injected into the vessel. Level was recovered by the Feedwater System and the RCIC system. Division 2 Alternate Rod Insertion unexpectedly initiated during the level transient. Due to scheduled maintenance activities, the 11B Aux Bus did not transfer to the off site power supply post SCRAM. The 11B Aux bus was restored at 12:17. There were no ECCS initiations and no challenges to containment. This event is a Reactor Protection System (RPS) actuation when the reactor is critical, and is reportable as a four hour ENS Notification under 10 CFR 50.72(b)(2)(iv)(B). This event is also an unplanned actuation of a system used to mitigate the consequences of a significant event and is reportable as an eight hour ENS notification under 10CFR50.72(b)(3)(iv)(A). The scram was described as uncomplicated. All rods fully inserted and all systems functioned as required. The initiation of the alternative rod insertion should not occur unless level drops below -38" but the initiation did not result in any complications. The offsite supply breaker to Aux bus 11B was under maintenance when the scram occurred and so the loss of power was expected. This bus supplies some balance of plant loads which were lost (recirculation pump, condensate pump, and circulating water pump) but the loss of these components had no impact on the transient. The NRC Resident Inspector has been notified. The licensee will notify State authorities and also plans a press release.
ENS 417466 June 2005 15:44:00SusquehannaNRC Region 1Automatic ScramGE-4At approximately 1233 hours, the Susquehanna Unit Two reactor automatically scrammed due to an apparent generator load reject. All rods inserted, and both reactor recirculation pumps tripped. Reactor water level lowered to -6" causing level 3 (setpoint +13") isolations, and was restored to normal level (+35") by the feedwater system. All isolations at this level occurred as expected. Two steam relief valves opened, then reclosed. Pressure was subsequently controlled via turbine bypass valve operation. All safety systems operated as expected. Some balance of plant loads shutdown apparently due to a voltage perturbation. A reactor recirculation pump was restarted to re-establish forced core circulation. The reactor is currently stable in condition 3. An investigation into the cause of the shutdown is underway. Unit One continued power operation. The NRC resident inspectors were notified. A press release will occur. The licensee will be notifying the State of Pennsylvania.
ENS 4164628 April 2005 09:18:00SusquehannaNRC Region 1Manual ScramGE-4At approximately 0700 U2 B Main Transformer cooling was lost. Unit 2 reactor power was reduced from 100% to 75%. Attempts to restore the 2B Main Transformer cooling were unsuccessful, and Unit 2 was manually scrammed from 75% reactor power. RPV water level decreased to -30" due to the SCRAM and was restored by normal Feedwater and RCIC injection. The Main Condenser remained available as a heat sink and there were no SRV lifts. The low water level did result in receiving the Level 2 Division 2 containment isolation signal (-38"), and all expected isolations and initiations did occur. This event requires a 4 hour ENS notification in accordance with 10CFR50.72(b)(2)(iv)(B) for an RPS actuation when critical, and an 8 hour ENS notification per 10CFR50.72(b)(3)(iv)(A) for the injection from RCIC and receipt of the level 2 Containment Isolation signal. Additionally, a press release to the public will be issued, and requires a 4 hour ENS notification in accordance with 10CFR50.72(b)(2)(xi). All rods fully inserted during the manual scram. The electrical system is in a normal shutdown lineup. Secondary containment ventilation was momentarily disrupted in unit-1 and successfully restored. The licensee notified the NRC Resident Inspector and will be notifying the state and media concerning this event.
ENS 4069521 April 2004 18:06:00SusquehannaNRC Region 1Manual ScramGE-4At 1635 on 04/21/2004, Susquehanna Unit 1 was returning to service from its 13th Refueling and Inspection Outage which included main turbine replacement. During start-up turbine testing with the generator off line, several main turbine bearings experienced high vibration. In response to these high vibrations, the reactor was manually scrammed from approximately 17% power. The main steam line isolation valves were manually closed and main condenser vacuum was broken in order to more rapidly slow the main turbine speed. All control rods fully inserted on the SCRAM, a level 3 containment isolation signal was received as expected. RCIC was manually initiated to control reactor water level. Lowest reactor water level reached was approximately 3" narrow range. There were no radioactive releases. This RPS actuation is reportable under 10CFR50.72(b)(2)(iv)(B) as an 'Unplanned RPS Actuation with the Reactor Critical.' The RPS Actuation and the RCIC injection are reportable per 10CFR50.72(b)(3)(iv)(A) 'Unplanned Actuations of Systems that Mitigate the Consequences of Significant Events.' Investigation into the high main turbine bearing vibrations is ongoing. The main turbine was tripped prior to the manual scram and no SRVs have lifted due to low decay heat level. The electric plant is in a normal lineup. The licensee notified the NRC Resident Inspector and the PEMA representative.
ENS 4019624 September 2003 03:20:00SusquehannaNRC Region 1Automatic ScramGE-4At 0053 hours on September 24, 2003 with Susquehanna Unit 1 operating at 100% power an automatic reactor scram occurred due to low water level. At the time of the scram, reactor feed pump testing was in progress and the 'C' reactor feed pump tripped. The reactor recirc pumps runback initiated as expected when water level reached 30" with the feed pump tripped. Level continued to drop and reached the Level 3 auto scram setpoint. Level continued to drop and reached a low level of approximately -48" wide range. Reactor Core Isolation Cooling and High Pressure Coolant Injection auto started at their initiation setpoints and injected to the vessel to recover level. All level 2 and 3 containment isolations occurred as expected. The reactor recirc pumps tripped as expected when level 2 was reached. Reactor Pressure was controlled with bypass valves, there were no Safety Relief Valve lifts. There are no challenges to containment. Unit 1 is currently stable in Mode 3 with both reactor recirc pumps restarted. A human performance error was the cause of the reactor feed pump trip. Investigation is continuing into the plant response to the reactor feed pump trip. The NRC Resident Inspector was notified of this event.