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| Entered date | Site | Region | Scram | Reactor type | Event description | |
|---|---|---|---|---|---|---|
| ENS 56790 | 12 October 2023 23:31:00 | Ginna | NRC Region 1 | Manual Scram | Westinghouse PWR 2-Loop | The following information was provided by the licensee via email: On 10/12/23 at 2127 EDT, with the Unit 1 in Mode 1 at 100% Power, operators identified degrading condenser vacuum and manually tripped the reactor. All control rods inserted as expected. The trip was not complex, and all systems responded normally post-trip. The cause of the degraded condenser vacuum was an unexpected closure of the condenser air ejector regulator. The cause of the air ejector regulator going closed is not fully understood and is being investigated. Following the SCRAM, Operators responded and stabilized the plant. Decay heat is being removed by the Main Steam System through the Atmospheric Relief Valves (ARVs) and Auxiliary Feed Water (AFW) systems. Due to the Reactor Protection System (RPS) actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B) and an eight-hour non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A) for a valid specified system actuation. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 56731 | 9 September 2023 15:35:00 | Ginna | NRC Region 1 | Automatic Scram | Westinghouse PWR 2-Loop | The following information was provided by the licensee via email: On 9/9/23 at 1143 EDT, with the Unit 1 in Mode 1 at 100 percent power, all 4 turbine control valves closed resulting in a reactor protection system (RPS) automatic reactor trip on over temperature differential temperature. All control rods inserted as expected. The trip was not complex and all systems responded normally post-trip. The cause of the control valve closure has not been determined. Following the SCRAM, operators responded and stabilized the plant. Decay heat is being removed by the main steam system through the atmospheric relief valves and auxiliary feed water systems. Due to the RPS actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B) and an eight-hour non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A) for a valid specified system actuation. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 49214 | 24 July 2013 17:46:00 | Ginna | NRC Region 1 | Automatic Scram | Westinghouse PWR 2-Loop | At 1419 EDT on 7/24/2013, the reactor tripped due to a reactor protection system (RPS) actuation signal from a turbine trip, which was caused by a generator trip. All control rods inserted on the trip and reactor coolant system (RCS) pressure is currently 2235 psig and stable with RCS temperature stable at 547 degrees F. Decay heat is being removed by steam dumps (to the main condenser) and auxiliary feedwater which auto started as expected. The cause of the generator trip is under investigation. The plant will remain in Mode 3 until the cause of the trip is determined. The plant notified the NRC Resident Inspector. |
| ENS 47338 | 12 October 2011 02:33:00 | Ginna | NRC Region 1 | Automatic Scram | Westinghouse PWR 2-Loop | Automatic Reactor Trip due to Turbine Auto Stop Valve Closure and Actuation of Auxiliary Feedwater System. At 2328 on 10/11/2011, the reactor tripped due to a RPS actuation Signal from a turbine trip, which was caused by a Turbine Auto Stop signal. All control rods inserted on the trip, RCS pressure is currently 2235 psig and stable, and RCS average temperature is 547 degrees and stable. Decay heat removal is being controlled by auxiliary feedwater which auto started as expected and steam generator atmospheric relief valves. The licensee is investigating the cause of the Auto Stop Signal. The plant will be maintained in MODE 3 until the cause of trip is determined. The licensee has notified the NRC Resident Inspector. There is no primary to secondary leakage. Offsite power is normal and all EDG's are available. |
| ENS 43243 | 17 March 2007 02:13:00 | Ginna | NRC Region 1 | Automatic Scram | Westinghouse PWR 2-Loop | At 2209 on 3/16/07, the plant tripped on a Safety Injection (SI) signal initiated because of low main steam line pressure in the 'A' main steam loop. The licensee is currently conducting a post trip review but believes that the low main steam line pressure in 'A' loop was caused by a spurious isolation of the 'B' Main Steam Line Isolation Valve (MSIV). The isolation in the 'B' main steam loop lead to high main steam flow and low main steam line pressure in the 'A' main steam loop. The 'A' MSIV then also auto-closed on the SI signal. The plant is currently stable in Mode 3 at about 2235 psig pressure and 547 degrees average Reactor Coolant System (RCS) temperature. All control rods fully inserted on the trip. Decay heat is currently being removed by auxiliary feedwater feeding the steam generators and steaming out the plant atmospheric steam valves. Since plant pressure did not decrease below 1500 psig, SI did not actually inject into the RCS. The licensee secured SI. No primary PORV's or safety valves lifted. No main steam safeties lifted according to plant closure indicators. There are no primary to secondary steam generator tube leaks. All electrical safeguards buses are powered by offsite power. The Emergency Diesel Generators (EDG) started but did not load and were shut down. The EDGs are operable and available if needed. The licensee notified the NRC Resident Inspector. |
| ENS 43128 | 28 January 2007 00:02:00 | Ginna | NRC Region 1 | Automatic Scram | Westinghouse PWR 2-Loop | On January 27, 2007 at approximately 2040 hours an automatic reactor trip occurred. The cause of the trip was Over Temperature Delta T (2/4). All systems functioned as designed. All control rods inserted on the trip. Decay heat removal is via condenser steam dump and Auxiliary Feedwater. The initial cause of the trip appears to be from a loss of load due to a turbine electro-hydraulic system issue. This is still under investigation. RCS Temperature is 547 Degrees F and stable RCS Pressure is 2235 psig and stable Both pressurizer PORVs momentarily opened and then closed during the transient. For 8Hr Non Emergency 10 CFR 50.72(b)(3) RPS actuation occurred. Auxiliary Feed Water actuation occurred. There was no testing or maintenance in progress at the time of the transient. The licensee informed the NRC Resident Inspector. |
| ENS 40248 | 15 October 2003 13:25:00 | Ginna | NRC Region 1 | Manual Scram | Westinghouse PWR 2-Loop | The plant was in mode 2 (1% power) making preparations to place the unit on-line per procedures. At 0921, the plant had entered ER-SC.1, Adverse Weather Plan, due to sustained winds greater than 55 mph. At 1024, offsite power circuit "751" was lost due to offsite storm damage(tree down on powerline). The loss of circuit "751" led to the loss of the "B" reactor coolant pump on undervotltage. Procedure AP-RCS.2, loss of Reactor Coolant flow was entered. At 1026 a manual Reactor Trip was initiated as directed by procedures. All rods fully inserted, no ECCS injection or safety valves lifted and all ESF systems functioned as designed. Due to the partial loss of offsite power, the "B" emergency diesel auto started and loaded to supply safeguards equipment. The "A" and "B" aux feedwater pumps also auto started. Offsite power was restored to safeguards equipment being supplied power by the "B" emergency diesel within 15 minutes from the second offsite power line. The NRC Resident inspector was notified. |