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| Entered date | Site | Region | Scram | Reactor type | Event description | |
|---|---|---|---|---|---|---|
| ENS 55748 | 18 February 2022 08:35:00 | McGuire | NRC Region 2 | Manual Scram | Westinghouse PWR 4-Loop | The following information was provided by the licensee via telephone and email: On 2/18/2022, McGuire Nuclear Station Unit 2 experienced a turbine runback to 55 percent power. Based on concerns with unit stability, the reactor was manually tripped at 0459 (EST). All Auxiliary Feedwater pumps started on low steam generator level as required. The reactor trip was uncomplicated with all systems responding normally post trip. A feedwater isolation occurred as designed. Unit 1 was not affected. Due to the Reactor Protection System actuation while critical, actuation of the Turbine Driven Auxiliary Feedwater Pump and Motor Driven Auxiliary Feedwater pumps along with the Feedwater Isolation, this event is being reported as a four hour, nonemergency notification per 10 CFR 50.72(b)(2)(iv)(B) and an 8 hour nonemergency notification per 10 CFR 50.72(b)(3)(iv)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: All control rods fully inserted. Decay heat is being removed via the condenser and normal feedwater. Unit 2 is in a normal shutdown electrical lineup. |
| ENS 54047 | 3 May 2019 19:00:00 | McGuire | NRC Region 2 | Automatic Scram | At 1554 EDT on 5/3/19, with Unit 1 in Mode 1 at approximately 100 percent power, the reactor automatically tripped on Over Temperature Delta Temperature following a pressure transient in the Reactor Coolant System. The trip was uncomplicated with all systems responding normally post trip. Operations manually started the motor driven auxiliary feedwater pumps and has stabilized the plant. Decay heat is being removed by the condenser. Unit 2 is not affected. Due to Reactor Protection System actuation while critical and actuation of the motor driven auxiliary feedwater pumps, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B) and an 8-hour non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. Unit 1 is in a normal electrical lineup. Prior to the automatic trip, the backup pressurizer heaters were in service as is normal during power ascension. The pressure transient started when the backup heaters were in the process of being removed from service. The licensee notified the NRC Resident Inspector. | |
| ENS 53217 | 16 February 2018 13:58:00 | McGuire | NRC Region 2 | Automatic Scram | Westinghouse PWR 4-Loop | At 1014 (EST) hours on 2/16/18, with Unit 1 in Mode 1 at approximately 100 percent power, the reactor automatically tripped when the Reactor Trip Breakers opened during Train B Solid State Protection System (SSPS) testing. The trip was uncomplicated with all systems responding normally post-trip. Operations manually started the motor driven auxiliary feedwater pumps. The turbine driven auxiliary feedwater pump (TDCAP) auto-started on low steam generator level. A Feedwater Isolation occurred as designed due to the Reactor Trip and Lo Tave condition. Operations stabilized the plant. Decay heat is being removed by the condenser. Unit 2 is not affected. Due to the Reactor Protection System actuation while critical, actuation of the TDCAP and motor driven auxiliary feedwater pumps along with the Feedwater Isolation, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B) and an 8 hour non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 49538 | 14 November 2013 16:03:00 | McGuire | NRC Region 2 | Manual Scram | Westinghouse PWR 4-Loop | On November 14, 2013, at 1313 Eastern Standard Time, Unit 1 was manually tripped from 100% power due to indications of (four) dropped control rods. This manual reactor protection system actuation is reportable per 10 CFR 50.72(b)(2)(iv)(B). The cause of the dropped rods is not confirmed at this time, but may be related to maintenance in a Rod Control Power Cabinet ongoing at the time of the event. The Operations crew entered the reactor trip procedure and stabilized Unit 1 in Mode 3 at normal operating temperature and pressure. All control rods fully inserted into the core following the reactor trip and all plant systems operated as designed. The Auxiliary Feedwater (AFW) system (1A and 1B motor-driven pumps) was manually started for steam generator level control following reactor trip. The start of the AFW system is reportable per 10 CFR 50.72 (b)(3)(iv)(A) for a valid system actuation. Decay heat is being removed via the steam generators (via steam dumps to the main condenser). This event does not impact public health and safety. Unit 2 was not affected by this event. The licensee notified the NRC Resident Inspector.
A subsequent licensee evaluation determined that there were ten dropped control rods. Notified the R1DO (Desai). |
| ENS 48775 | 21 February 2013 12:49:00 | McGuire | NRC Region 2 | Automatic Scram | Westinghouse PWR 4-Loop | At 0957 EST on 02/21/13, Unit 1 Reactor automatically tripped from 100% power, due to a turbine trip. The turbine trip was caused by a loss of both main feedwater (MFW) pumps. The 1A motor driven auxiliary feedwater (AFW) pump auto started to feed the "A" and "B" Steam Generators (S/G). The 1B motor driven AFW pump was unavailable due to planned maintenance, so the turbine driven AFW pump was manually started to feed the "C" and "D" S/Gs. The reactor trip was uncomplicated. All control rods fully inserted. Decay heat removal is to the main condenser via the turbine bypass valves. There was no primary to secondary leakage. Electrical buses are being supplied via offsite power. Steam generator levels are being returned to normal and MFW has been reset and is available. All other plant systems functioned as designed during and after the reactor trip. There is no impact on Unit 2. There is no impact on the health and safety of the public. The loss of the MFW pumps is still under investigation. The licensee has informed the NRC Resident Inspector. |
| ENS 46559 | 20 January 2011 16:12:00 | McGuire | NRC Region 2 | Manual Scram | Westinghouse PWR 4-Loop | Unit 1 performed a manual reactor trip (from 28% power) due to the trip of the 1B main feedwater pump trip concurrent with the 1A main feedwater pump having been previously tripped per the shutdown procedure. Reactor power was below the setpoint for an automatic reactor trip from a turbine trip. All rods fully inserted, heat removal is from auxiliary feedwater and condenser steam dumps, and the electrical system is in a normal alignment. The plant has stabilized at normal RCS pressure and temperature. Both Units 1 and 2 are being shutdown as per Tech Spec 3.0.3 associated with an inoperable Nuclear Service Water System. Unit 2 is at 40% and decreasing power due to the Tech Spec action and was not effected by the Unit 1 reactor trip. Both units will be placed in Mode 5. The licensee has notified the NRC Resident Inspector. |
| ENS 46003 | 12 June 2010 09:14:00 | McGuire | NRC Region 2 | Manual Scram | Westinghouse PWR 4-Loop | McGuire Unit 1 was operating at 44% power due to a previously dropped control rod. Indication was received of a second control rod drop and the reactor was manually tripped in accordance with abnormal operating procedure guidance. All control rods fully inserted. The auxiliary feedwater system was manually started due to an approaching autostart setpoint. The unit is stable in Mode 3 at normal operating temperature and pressure. Normal containment air release remains in progress. The steam generators are being fed through the auxiliary feedwater system and will transition to the normal feedwater system. Decay heat removal is to the condenser through the steam dumps. There was no impact on Unit 2. The licensee is investigating the cause of the control rod drop indication. The licensee notified the NRC Resident Inspector. |
| ENS 44624 | 3 November 2008 04:35:00 | McGuire | NRC Region 2 | Manual Scram | Westinghouse PWR 4-Loop | Manually opened reactor trip breakers in Mode 5 to insert control bank 'B' due to blown fuse in rod control cabinet. Licensee was moving control rod bank "B" following I & C work, and the control rod bank failed to move as expected. All other control rod banks were inserted into the core at the time of the event. EDG's and offsite power sources are OPERABLE, and there is no increase in plant risk. The licensee will inform the NRC Resident Inspector. * * * RETRACTION ON 12/31/08 AT 1326 FROM RICK ABBOTT TO PETE SNYDER * * * Regarding the NRC Event Number 44624 conveyed November 3, 2008, McGuire Nuclear Station has determined that manually opening the reactor trip breakers was not reportable and hereby retracts this notification. Upon further consideration it was determined that manually opening the reactor trip breakers was a conservative decision to fully insert control rods based on the failure mechanism causing a single rod to drop to the fully inserted position. Manual actuation of the reactor trip breakers was not required by abnormal procedures and was performed only after consultation between operations, engineering and senior station management agreed that this was the preferred option. Therefore, the decision to manually open the reactor trip breakers is considered to be a preplanned actuation of the reactor protection system and is not reportable. The licensee informed the NRC Resident Inspector. Notified R2DO (M. Lesser). |
| ENS 44618 | 31 October 2008 13:45:00 | McGuire | NRC Region 2 | Manual Scram | Westinghouse PWR 4-Loop | Initial conditions: Low Power Physics Testing after outage. Performing Dynamic Rod Worth measurements. Single dropped rod (K-2) on Control Bank B occurred after movement disagreement between rod groups. Entered AP-14, 'Rod Control Malfunction'. Performed a manual reactor trip and manual start of Auxiliary Feedwater as directed by Normal Operating Procedures for unit shutdown. Feedwater isolation occurred due to Low T-Ave concurrent with reactor trip. All control rods were fully inserted. Licensee has notified NRC Resident Inspector. |
| ENS 42211 | 17 December 2005 03:45:00 | McGuire | NRC Region 2 | Automatic Scram | Westinghouse PWR 4-Loop | 'A' Steam Generator hi/hi level caused a turbine trip which in turn caused a Unit 1 reactor trip. The hi/hi steam generator level also caused both feedwater pumps to trip which caused the auxiliary feedwater pumps to auto-start. The hi/hi level also caused a feedwater isolation. Appropriate emergency procedures have been implemented and the plant is currently stable. All control rods fully inserted on the trip. Offsite power is available and powering safety related buses. The emergency diesel generators are available if required. There are no known primary to secondary leaks in the steam generators. The licensee will notify the NRC Resident Inspector. |
| ENS 41453 | 1 March 2005 16:19:00 | McGuire | NRC Region 2 | Manual Scram | Westinghouse PWR 4-Loop | The following information was provided by the licensee via facsimile (licensee text in quotes): (The licensee) reduced power on Unit 2 due to a steam leak on a moisture separator reheater vent line. The reactor was manually tripped at 20% reactor power per normal shutdown sequence. All systems and components operated correctly. Unit restart will commence following completion of a planned refueling outage. All rods fully inserted. One steam line secondary PORV lifted and reseated. Decay heat removal is via AFW and steam bypass valves to the main condenser. The steam leak was reported to be on a 2-inch MSR vent line elbow. The licensee has notified the NRC Resident Inspector.
The following information was obtained from the licensee via facsimile (licensee text in quotes): On March 1, 2005, McGuire Unit 2 experienced a steam leak on a two-inch pipe in the heater bleed steam system. In consideration of that leak, Unit 2 was shutdown by manually tripping the reactor. This was reported as an unplanned valid actuation of the reactor protection system (10CFR 50.72 (b) (2)(iv)(B)). Reference Event Report 41453. The manual reactor trip of Unit 2 was not required to mitigate the steam leak. However, in consideration of the steam leak, a decision was made to perform a shutdown of Unit 2 using the normal reactor shutdown procedure. This procedure requires that the control rods be inserted by manually tripping the reactor. As per guidance provided in NUREG-1022, the above actions do not satisfy the criteria for reporting under the requirements of 10CFR 50.72 (b) (2)(iv)(B) or any other reporting criteria. Therefore, McGuire is retracting Event Report 41453. The licensee has notified the NRC Resident Inspector. Notified R2DO (Cahill). |