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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 52859 | 24 March 2017 19:48:00 | 10 CFR 50.73(a)(1), Submit an LER | Invalid Specified System Actuation During Testing | This telephone notification, as allowed by 10 CFR 50.73(a)(1), is being made pursuant to 10 CFR 50.73(a)(2)(iv)(A) to describe an unplanned, invalid actuation of containment isolation valves in more than one system which occurred during the most recent refueling outage at Fermi 2. On 3/24/2017, at approximately 1548 EDT, when synchronizing an emergency diesel generator (EDG) to the grid during testing, an electrical perturbation occurred. Further investigation found that the EDG was slightly out of phase when it was attempted to be synchronized to the grid. The electrical perturbation resulted in an unexpected half-scram of Reactor Protection System (RPS) A and actuation (closure) of some containment isolation valves. The actuations were invalid as they were not initiated in response to actual plant conditions or parameters satisfying the requirements for initiation. Fermi 2 was shut down for a refueling outage at the time, and therefore, the half-scram of RPS A occurred after the safety function had already been completed. Containment isolation valves actuated (closed) in Division 1 of the Torus Water Management, Drywell Pneumatics, and Drywell Floor and Equipment Drain Sumps systems. All valves operated as expected. Since containment isolation valves in more than one system were actuated by this perturbation, this event constitutes an event or condition that resulted in manual or automatic actuation of the system listed in paragraph 10 CFR 50.73 (a)(2)(iv)(B)(2) and is reportable under 10 CFR 50.73(a)(2)(iv)(A). The NRC Resident Inspector has been informed of this notification. | Reactor Protection System Emergency Diesel Generator | |
| ENS 51128 | 24 May 2015 23:30:00 | 10 CFR 50.73(a)(1), Submit an LER | 60-Day Optional Telephonic Notification for an Invalid Actuation of Containment Isolation Valves | The following was received via phone call and email: This 60-day report, as allowed by 10CFR 50.73(a)(1), is being made pursuant to 10CFR 50.73(a)(2)(iv)(A) to describe an unplanned, invalid actuation of containment isolation valves. At 1930 EDT on May 24, 2015, a loss of power to Reactor Protection System (RPS) Train B occurred. Initial investigation found the RPS Motor Generator (MG) Set B not running, with its Motor Off light illuminated caused by both Normal EPA breakers and MG Set B output breaker being tripped. Visual inspection at the distribution cabinet was inconclusive at the time and revealed no abnormalities and no abnormal odors in the area. Further investigation of the RPS MG Set B verified normal voltages on all fuse clips, and all power and control power fuses were operational. As a result of the loss of RPS B, the following containment isolation valves closures occurred: Reactor Water Cleanup (RWCU) Outboard Isolation valves, Torus Water Management System (TWMS) Outboard Isolation valves, Division 2 Drywell Pneumatics Inboard and Outboard Isolation valves, Primary Containment Radiation Monitoring System Inboard and Outboard Isolation valves, Reactor Recirculation Pump Seal Purge Flow Outboard Isolation valves, and Drywell Floor and Equipment Drain Sump Inboard Isolation Valves. The Resident Inspector has been notified. | Reactor Protection System Primary containment Reactor Recirculation Pump Reactor Water Cleanup | |
| ENS 50112 | 19 March 2014 00:30:00 | 10 CFR 50.73(a)(1), Submit an LER | 60-Day Optional Telephonic Notification for an Invalid Actuation of Containment Isolation Valves | This 60-day report, as allowed by 10 CFR 50.73(a)(1), is being made pursuant to 10 CFR 50.73(a)(2)(iv)(A) to describe an unplanned, invalid actuation of containment isolation valves which occurred during the most recent refueling outage at Fermi 2. On 3/18/2014, at approximately 1930 EST, shortly after transferring Division 2 Reactor Protection System (RPS B) from the alternate to the normal power supply, Operations personnel noted that an unexpected half-scram occurred. Initial investigation found a fuse in an RPS Power Distribution Panel had blown. Further investigation found that a power contactor had failed causing the fuse to blow. The contactor failure resulted in an invalid half scram and actuations (closure) of Torus Water Management System (TWMS) Outboard containment isolation valves, Division 2 Drywell Pneumatics Inboard and Outboard containment isolation valves and the Drywell Floor and Equipment Drain Sumps Inboard containment isolation valves. All valves operated as expected. Since containment isolation valves in more than one system were actuated by this failure, this event constitutes an event or condition that resulted in manual or automatic actuation of the system listed in paragraph 10 CFR 50.73 (a)(2)(iv)(B)(2) and is reportable under 10 CFR 50.73(a)(2)(iv)(A). The NRC Resident Inspector has been informed of this notification. | Reactor Protection System | |
| ENS 43850 | 22 October 2007 23:30:00 | 10 CFR 50.73(a)(1), Submit an LER | Invalid System Actuation | The following information is provided as a 60 day telephone notification under 10 CFR 5O.73(a)(l) in lieu of submitting a written LER to report a condition that resulted in an invalid actuation of a 10 CFR 50.73(a)(2)(iv)(B) system. NUREG 1022, Revision 2, identifies the information that is to be reported as discussed below. On October 22. 2007, at 1830 hours, Division 2 of Residual Heat Removal (RHR) was being placed in Shutdown Cooling (SDC) following completion of a SDC outage. The plant was in Mode 5, Refueling. Reactor Protection System (RPS) A was deenergized for maintenance. RPS B was being supplied by the alternate supply because the B RPS Motor Generator was removed from service for maintenance. Upon start of the RHR D pump motor the RPS B Alternate Supply Electrical Protection Assembly (EPA) breakers tripped due to sensed undervoltage. The loss of the power supply to RPS B resulted in the following: A reactor scram (all rods were already fully inserted), RHR SDC outboard valve isolation, trip of the Reactor Water Cleanup System (RWCU), outboard valve isolation of the Torus Water Management System (TWMS). A secondary containment isolation also occurred resulting in a trip of Reactor Building Heating Ventilation and Air Conditioning (HVAC), auto start of Division 2 of Standby Gas Treatment System (SGTS), and shift of the Control Center HVAC system to recirculation mode. All actuations and isolations were as expected for existing plant conditions. The initiation signal was invalid because it did not result in response to an actual plant parameter, nor did it trip as a result of any other requirement for initiation of a safety function. Due to the actuation of equipment in multiple systems that were not removed from service or otherwise prevented from changing states, this event is reportable under 50.73(a)(2)(iv) as an invalid actuation of one of the specified systems. The reactor scram actuation was complete because a half scram was already present due to RPS A being deenergized for maintenance. The Division 2 SGTS system automatically started, secondary containment fully isolated, Reactor Building HVAC system tripped, and the Control Center HVAC fully shifted into the recirculation mode. The following were partial isolations due to loss of RPS B, Division 2: RHR SDC isolation and TWMS isolation. All systems functioned properly in response to the RPS power loss based on refuel outage system configurations. The licensee believes that the cause of the undervoltage was a result of the start of the RHR pump which caused an in-rush current. The licensee is considering a design change, and captured this event in their corrective action program system as CARD 07-26537. The licensee will notify the NRC Resident Inspector. | Secondary containment Reactor Protection System Shutdown Cooling HVAC Residual Heat Removal Reactor Water Cleanup Standby Gas Treatment System | |
| ENS 43840 | 14 October 2007 07:00:00 | 10 CFR 50.73(a)(1), Submit an LER | Inadvertent Actuation of Emergency Diesel Generator | This 60-day optional telephone notification as allowed by 10 CFR 50.73(a)(1) is being made in lieu of an LER submittal. This notification is made pursuant to the reporting requirements specified in 10 CFR50.73(a)(2)(iv)(A) for an invalid actuation of one of the systems listed in 10 CFR 50.73(a)(2)(iv)(B). On October 14, 2007, at approximately 0200 hours EST with the plant in Mode 5, Refueling, while performing ECCS Start and Load Reject surveillance testing on Emergency Diesel Generator (EDG) 14, the EDG unexpectedly auto-started. Investigation revealed that the auto-start was caused by a faulty test switch. The test switch had been tested multiple times prior to performing the surveillance with no abnormalities noted. EDG 14 is one of two EDG's in Division II of the Onsite Emergency Power system. The EDG responded properly to the auto-start signal. The actuation was complete, in that the EDG started and ran unloaded. The surveillance testing was immediately stopped upon receipt of the inadvertent actuation. In accordance with the EDG operating procedure, the EDG was synchronized, loaded for about an hour, shut down and returned to standby status. Since no actual plant condition existed that required the EDG to auto-start, the actuation was invalid. There were no safety consequences or impact on the health and safety of the public. The event was entered in the corrective action program for evaluation and resolution. The NRC Resident Inspector will be notified of this report. | Emergency Diesel Generator | |
| ENS 42428 | 10 February 2006 16:20:00 | 10 CFR 50.73(a)(1), Submit an LER | Invalid Specified System Actuations | The following information is provided as a 60 day telephone notification to NRC under 10 CFR 50.73(a)(1) in lieu of submitting a written LER to report a condition that resulted in an invalid actuation of a 10 CFR 50.73(a)(2)(iv)(B) system. NUREG1022 Revision 2 identifies the information that needs to be reported as discussed below. (a) The specific train(s) and system(s) that were actuated: On February 10, 2006, at 1120 EST, a surveillance was in progress to calibrate the Division 2 Fuel Pool Ventilation Exhaust Radiation Monitor D11-K611D. During jumper removal an adjacent terminal was contacted by the jumper while still connected to a 24 VDC power source resulting in a blown power supply fuse. The loss of the power supply resulted in the following automatic actions: Primary Containment Isolation Valve Group 14; Drywell and Suppression Chamber Ventilation System; and Group 16, Nitrogen Inerting System received an isolation signal. All primary containment isolation valves in both groups were previously in their safety function position (closed). Secondary containment isolated resulting in a trip of the Reactor Building Heating and Ventilation System and Division 2 Standby Gas Treatment System automatically started. The Control Center Heating, Ventilating and Air Conditioning System automatically shifted into the Recirculation mode. The initiation signal was invalid because it did not result in response to an actual high radiation condition, nor did it trip as a result of any other requirement for initiation of the safety function, such as a downscale or inoperable trip, for example. (b) Whether each train actuation was complete or partial. The Division 2 Standby Gas Treatment System automatically started, secondary containment fully isolated, Reactor Building Heating and Ventilation System tripped, and the Control Center Heating, Ventilating and Air Conditioning System automatically shifted into the Recirculation mode. These were complete actuations. The primary containment isolation valves Group 14 and 16 remained in their safety function (closed) position. This was a complete actuation. (c) Whether or not the system started and functioned successfully. The above systems functioned successfully. The licensee will notify the NRC Resident Inspector. | Secondary containment Primary containment Standby Gas Treatment System | |
| ENS 40899 | 30 May 2004 14:40:00 | 10 CFR 50.73(a)(1), Submit an LER | Invalid Actuation of Containment Isolation Valves Due to Partial Loss of 120 Vac Modular Power Unit 2 Loads | This 60-day optional verbal report, as allowed by 10 CFR 50.73(a)(1), is being made to describe an unplanned, invalid actuation of specified systems, specifically the Primary Containment Isolation System. Since this event meets the definition of an invalid actuation, this notification is being made in accordance with 10CFR50.73(a)(2)(iv)(A) in lieu of a Licensee Event Report. On May 30, 2004, at approximately 10:40 am EDT, while the plant was operating at 100% power, a voltage regulator failed on Division 2 120 VAC Modular Power Unit No. 2 (MPU-2) which resulted in blown fuses and the loss of a number of loads from one of the three MPU-2 distribution cabinets. Since only one of the three distribution cabinets was lost, the isolations that occurred were only a portion of the isolations that would have occurred if all of the MPU-2 loads had been lost. This caused containment isolations by Division 2 Drywell Pneumatic supply valves (Primary Containment Isolation Group 18) and by Torus Water Management system outboard isolation valves (Primary Containment Isolation Group 12). Division 2 Secondary Containment Isolation Logic was also actuated, and the reactor building ventilation isolated. The Division 2 Standby Gas Treatment System automatically started. All equipment controlled by the affected circuits was determined to have responded to the loss of MPU-2 Cabinet 2 power as expected. Operators implemented applicable response procedures. The MPU was returned to service, and isolation signals were reset. Reactor power was not affected by this event. The NRC Resident Inspector was notified of this event by the licensee. | Secondary containment Primary Containment Isolation System Primary containment Reactor Building Ventilation Standby Gas Treatment System |