Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 52889 | 6 August 2017 00:26:00 | At 2235 (EDT) Nine Mile Point Unit 2 experienced an automatic scram on high reactor pressure. Turbine stop valve testing was in progress at the time of the scram. All control rods inserted. Pressure control is via the turbine bypass valves. The cause of the scram is being investigated. This is a 4-Hour report for 10CFR50.72(b)(2)(iv)(B) RPS (Reactor Protection System) Actuation. The NRC Resident Inspector has been notified. Reactor water level is being maintained with normal feedwater flow. No safety or relief valves lifted. The plant is in its normal shutdown electrical lineup. |
| ENS 49859 | 27 February 2014 03:37:00 | On February 24th at 0400 (EST), the Division 3 diesel (HPCS diesel) was declared inoperable for planned maintenance. Technical Specification (TS) 3.8.1 condition B was entered with a required action to restore the diesel to operable status within 72 hours. Shortly after starting the diesel for post maintenance testing, operations observed erratic voltage regulator operation. The diesel was secured at 1621 on 2/24/14 before completing the required post maintenance operability test and troubleshooting is ongoing. At 0330 on 2/27/14, the High Pressure Core Spray System (HPCS) was declared inoperable and TS 3.5.1 condition B was entered. With the HPCS system declared inoperable, TS 3.8.1 condition B was exited in accordance with the following note modifying TS 3.8.1: 'Division 3 AC electrical power sources are not required to be OPERABLE when High Pressure Core Spray (HPCS) System is inoperable.' The HPCS system is a single train system that is discussed in Chapters 6 and 15 of the Final Safety Analysis Report. The unplanned inoperability of the HPCS system is reportable in accordance with 10 CFR 50.72(b)(3)(v)(D) as, 'Any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to: (D) Mitigate the consequences of an accident.' The condition has been entered into the NMP corrective action program as CR-2014-001623. The NRC Resident Inspector has been notified.
The NMP Unit 2 Division 3 diesel testing was completed satisfactorily. The licensee declared the Division 3 diesel and HPCS systems operable at 1013 EST on 2/27/14 and exited TS 3.8.1 and 3.5.1. The licensee has notified the NRC Resident Inspector. Notified the R1DO (DeFrancisco). |
| ENS 48794 | 28 February 2013 17:01:00 | On February 28, 2013, at 1319 EST, Nine Mile Point Unit 2 (NMP2) experienced a failure of 2CSH*P2, High Pressure Core Spray System Pressure Pump. The HPCS system was currently inoperable for planned maintenance for planned pump room unit cooler maintenance with a 14 day completion time per Technical Specification 3.5.1. Shortly after the starting of the HPCS pump as part of routine surveillance testing, the system pressure pump failed. Initial troubleshooting has found the pump motor windings to be shorted. Initial investigation identified smoke in the HPCS pump room, no indications of fire were identified. No breaker failures were identified. All other plant systems functioned as required. The licensee notified the NRC Resident Inspector. |
| ENS 48110 | 17 July 2012 13:23:00 | On July 17 2012, at 1118 (EDT), Nine Mile Point Unit 1 experienced an automatic reactor scram due to high neutron flux as measured by the Average Power Range Monitoring system. The cause is currently under investigation. All control rods fully inserted and all plant systems responded per design following the scram. The High Pressure Coolant Injection (HPCI) system, which is an operating mode of the feedwater system, initiated as expected. There were no planned activities in progress at the time which could have contributed to the event. Nine Mile Point Unit 1 is currently in Hot Shutdown, with reactor water level and pressure maintained within normal bands. Decay heat is being removed via steam to the main condenser using the bypass valves. The offsite grid is stable with no grid restrictions or warnings in effect. All emergency power sources are available in standby. The unit is currently implementing post scram recovery procedures. This was an uncomplicated Reactor Scram and the plant is stable with normal levels, temperature, and pressure. Offsite power is in a normal alignment. HPCI has been secured and returned to normal alignment. The cause to the high neutron flux is still under investigation. This event had no impact on Unit 2. The licensee has informed the NRC Resident Inspector and State Authorities. |
| ENS 48113 | 17 July 2012 16:07:00 | 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. |