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| Discovered date | Reporting criterion | Title | Event description | |
|---|---|---|---|---|
| ENS 52042 | 24 June 2016 16:15:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Manual Reactor Scram Due to Reactor Recirculation Pumps Degradation | At 1215 (EDT) on 6/24/2016, James A. FitzPatrick (JAF) was at 100% power when Breaker 710340 tripped and power was lost to L-gears L13, L23, L33, and L43. These provide non-vital power to Reactor Building Ventilation (RBV), portions of Reactor Building Closed Loop Cooling (RBCLC), and 'A' Recirculation pump lube oil systems. Off-site AC power remains available to vital systems and Emergency Diesel Generators (EDG) are available. Due to the loss of RBV, Secondary Containment differential pressure increased. At 1215 (EDT), Secondary Containment differential pressure exceeded the Technical Specifications (TS) Surveillance Requirement SR-3.6.4.1.1 of greater than or equal to 0.25 inches of vacuum water gauge. The Standby Gas Treatment (SBGT) system was manually initiated and Secondary Containment differential pressure was restored by 1219 (EDT). The 'A' Recirculation pump tripped at 1215 (EDT) and reactor power decreased to approximately 50%. 'B' Recirculation pump temperature began to rise due to the degraded RBCLC system. At 1236 (EDT), a manual scram was initiated. Reactor Pressure Vessel (RPV) water level shrink during the scram resulted in a successful Group 2 isolation. All control rods have been inserted. The RPV water level is being maintained with the Feedwater System and pressure is being maintained by main steam line bypass valves. A cooldown is in progress and JAF will proceed to cold shutdown (Mode 4). Due to complete loss of RBCLC system, the Spent Fuel Pool (SFP) cooling capability is degraded but the Decay Heat Removal system remains available. SFP temperature is slowly rising and it is being monitored. The time (duration) to 200 degrees is approximately 117 hours. The initiation of reactor protection systems (RPS) due to the manual scram at critical power is reportable per 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A). The general containment Group 2 isolations are reportable per 10 CFR 50.72(b)(3)(iv)(A). In addition, the temporary differential pressure change in Secondary Containment is reportable per 10 CFR 50.72(b)(3)(v)(C), as an event that could have prevented fulfillment of a safety function. The licensee notified the NRC Resident Inspector and the State of New York. |
| ENS 48113 | 24 May 2012 14:20:00 | 10 CFR 50.73(a)(1), Submit an LER | 60 - Day Optional Telephone Notification of an Invalid Division 2 Containment Isolation Signal | This 60-day telephone notification is being made per the reporting requirements specified in 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(3)(1) to describe an invalid actuation signal affecting containment isolation valves in more than one system. On May 24, 2012, Nine Mile Point Unit 2 (NMP2) received a Division 2 primary containment isolation signal which resulted in closure of Group 3, 8, and 9 primary containment isolation valves (PCIVs) in the following systems: Group 3 PCIVs: Traversing Incore Probe (TIP) ball valves (the TIPS were already withdrawn and the ball valves were already closed); nitrogen purge to TIP indexing mechanism. Group 8 PCIVs: Reactor building closed loop cooling system; drywell equipment drain system; drywell floor drain system; instrument air system; hydrogen recombiner system; containment monitoring system; reactor recirculation system flow control valve hydraulic system; containment leakage monitoring system. Group 9 PCIVs: Containment purge system (the containment purge valves were already closed). All affected PCIVs responded as designed. In addition, the Division 2 containment isolation signal resulted in isolation of the Reactor Building normal ventilation system, starting of the Division 1 and Division 2 standby gas treatment subsystems, starting of the Division 1 and Division 2 Reactor Building safety-related unit coolers, and starting of the Division 2 Control Room envelope filtration subsystem. The Division 2 isolation signal was generated during a maintenance activity involving the replacement of a relay in a main control room panel. During the activity, an installed jumper became dislodged from its point of origin, leading to a blown control power fuse and generation of the Division 2 isolation signal. Since the isolation signal was not initiated in response to actual plant conditions or parameters satisfying the requirements for initiation, the isolation signal was determined to be invalid. This event was entered into the corrective action program as Condition Report (CR) 2012-005128. There were no safety consequences or impact on the health and safety of the public as a result of this event. The Licensee has notified the NRC Resident Inspector. |