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| Entered date | Event description | |
|---|---|---|
| ENS 54364 | 1 November 2019 10:03:00 | On November 1, 2019 at 0316 EDT, Nine Mile Point Unit 2 (NMP2) received Control Room annunciation for HPCS SYSTEM INOPERABLE and inoperable status light indication for TRIP UNITS OUT OF FILE/POWER FAIL. Initial investigation has identified a potential failed 24 vdc power supply which supplies power to the HPCS trip units for system initiation and control. The HPCS system has been declared inoperable per TS 3.5.1 resulting in an unplanned 14 day LCO. All other plant systems functioned as required. NMP2 is currently at 100 percent power in Mode 1. This condition is reportable under 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 licensee notified the NRC Resident Inspector. |
| ENS 51856 | 7 April 2016 22:32:00 | Nine Mile Point Unit 2 (NMP2) experienced a momentary loss of Secondary Containment due to both Reactor Building (RB) airlock doors being opened at the same time. At 1730 (EDT) on 04/07/16, both RB airlock doors were opened simultaneously for less than 5 seconds. This resulted in Secondary Containment being declared Inoperable (TS 3.6.4.1). Secondary Containment was restored to Operable when the doors were closed. The event is reportable in accordance with 10 CFR 50.72(b)(3)(v)(C), '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 control the release of radioactive material.' The condition has been entered into the station's corrective action program and the NRC Resident Inspector has been notified. There is no interlock on these doors, just lights to verify the opposite door is open or shut. An Operator was entering secondary containment as another Operator was leaving. |
| ENS 50732 | 12 January 2015 23:17:00 | At 1939 (EST) on January 12, 2015, Nine Mile Point Unit 2 entered Tech Spec 3.6.4.1 when secondary containment was declared inoperable due to secondary containment differential pressure being above the Tech Spec Surveillance Requirement of -0.25 inches vacuum water gauge. This condition is related to sustained high winds. At 1956 on January 12, 2015 the differential pressure was restored, the secondary containment was declared operable and the Tech Spec 3.6.4.1 exited. Secondary containment being inoperable is a 8-hour report for 10 CFR 50.72(b)(3)(v)(c), '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 mitigate the consequences of an accident'. The NRC Resident Inspector has been notified. The licensee notified the New York Public Service Commission. |
| ENS 50296 | 22 July 2014 21:36:00 | This report is being made pursuant to 10CFR50.72(b)(3)(v)(D), Event or Condition that could have prevented fulfillment of a Safety Function needed to Mitigate the Consequences of an Accident. During the conduct of the Unit 2 Division 3 High Pressure Core Spray (HPCS) Diesel Generator (DG) surveillance test, one of 2 Cooling Water Outlet Valves failed to automatically open. The Division 3 Diesel is supplied by two redundant trains of cooling water one from each Service Water Divisional Header. Although the redundant cooling water supply was fully available and supplied adequate cooling to the diesel generator, the DG was at reduced margin to have adequate cooling water supply, if required during a loss of offsite power. Due to this loss of margin and inoperable condition, it has been determined that this failure could potentially affect the safety function of this system, and is being reported as an 8 hour ENS notification. The licensee has attributed the failure to high resistance in a relay which is currently being replaced. This places Unit 2 in the Technical Specification Action Statement 3.8.1, which requires restoration of Diesel Generator within 72 hours or commence a Reactor Shutdown. All other ECCS Systems have been verified operable. The licensee informed the NRC Resident Inspector and will inform the State of New York.
This update retracts Event Notification #50296, which reported an event or condition that could have potentially prevented fulfillment of a Safety Function needed to mitigate the consequences of an accident. Upon further review, it was determined that the ability of the HPCS system (single supported train) remained operable and capable of performing its safety function as evaluated by the NMP Unit 2 Safety Function Determination Process (TS 5.5.11). The NRC Resident Inspector has been notified. Notified the R1DO (Ferdas). |
| ENS 49948 | 24 March 2014 05:14:00 | At 0031 (EDT) on March 24, 2014, Nine Mile Point Unit 2 was lowering power for the planned refueling outage. The loss of reactor building heating resulted in the isolation of the reactor building to maintain building temperature. Isolation of the reactor building resulted in the isolation of the reactor building vent radiation monitor (Vent WRGMS) which is a loss of emergency assessment capability. The isolation of the reactor building also resulted in declaring secondary containment inoperable due to secondary containment differential pressure being positive. Secondary containment was declared operable at 0034 (EDT) when differential pressure was restored to greater than negative 0.25 inches water gauge. Secondary containment being inoperable is a 8-hour report for 10 CFR 50.72(b)(3)(v)(c), 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 mitigate the consequences of an accident. The unplanned isolation of Vent WRGMS is a 8-hour report for 10 CFR 50.72(b)(3)(xiii), any event that results in a major loss of emergency assessment capability. The NRC Resident Inspector has been notified. The licensee will notify the New York Public Service Commission. |
| ENS 49832 | 16 February 2014 18:21:00 | An automatic initiation of Emergency Diesel Generators was received due to a loss of one of two off-site power sources. On February 16, 2014 at 1216 (EST), Nine Mile Point Unit 2 experienced an automatic initiation of the Division 1 and 3 Emergency Diesel Generators (EDGs) due to a loss of Line 5. Line 5 is one of the two 115KV offsite power sources. Line 5 was lost due to an offsite event that is currently being evaluated by the grid operator. During the electrical transient, Nine Mile Point Unit 2 also experienced a feedwater level control lockup, requiring manual control. No Emergency Core Cooling Systems actuated, and feedwater level control was returned to automatic. Nine Mile Point Unit 2 remained at 100% power during the loss of Line 5, one of the offsite power sources. The NRC resident has been notified. The licensee also notified the State of New York. Unit 2 is currently in a 24-hour Technical Specification Limiting Condition of Operation (TS LCO) Action Statement 3.8.1.A3. Once Division III is realigned to the "B" side Line 6 offsite power, Unit 2 will be in a 72-hour LCO. Both EDGs are currently running. There was no effect on Unit 1.
In addition to the initiation of Division 1 and 3 Emergency Diesel Generators, Service Water Radiation Monitor 2SWP*RE146A and Radwaste/Reactor Building Vent Gaseous Effluent Monitoring Systems were also lost. Compensatory actions were established as required by station procedures and the Offsite Dose Calculation Manual. The loss of these instruments is reportable as a major loss of Emergency Assessment Capability per 10CFR50.72(b)(3)(xiii). The Service Water Radiation Monitor 2SWP*RE146A was restored to service on February 16, 2014 at 1450 EST. The Radwaste/Reactor Building Vent Gaseous Effluent Monitoring Systems were restored to service on February 17, 2014 at 0240. It is recognized that this notification is not within eight hours of the event. Line 5 is restored to OPERABLE February 17, 2014 at 1628. The NRC Resident Inspector has been informed of this additional reportable condition (and the update on the lost off-site power source). The condition has been entered into the corrective action program. The licensee also notified the State of New York Public Service Commission. The licensee exited the 72-hour LCO for the lost off-site power at 1628 on February 17, 2014. Notified R1DO(Krohn), NRREO (Monninger) and ILTAB (Whitney). |
| ENS 49391 | 28 September 2013 19:25:00 | At 1213 EDT on September 28, 2013 Nine Mile Point Unit 2 received (Digital Radiation Monitor System) DRMS low sample flow alarm and monitor status of sample pump off for 2SWP*RE146A. The chemistry department was notified to collect and analyze grab samples per (Offsite Dose Calculation Manual) ODCM 3.3.1 as a compensatory measure with the service water radiation monitor 2SWP*CAB146A out of service. 2SWP*RE146A was restarted at 1517 EDT and declared functional. At 1548 EDT on September 28, 2013 Nine Mile Point Unit 2 received DRMS low sample flow alarm and monitor status of sample pump off for 2SWP*RE146B. Chemistry was again notified to collect and analyze grab samples per ODCM 3.3.1 as a compensatory measure with the service water radiation monitor 2SWP*CAB146B out of service. The service water radiation monitors are necessary for accident assessment and are credited for Emergency Action Level (EAL) classification. The inability to classify an EAL due to an out of service monitor is considered a loss of assessment capability per CFR 50.72(b)(3)(xiii). This condition does not affect the health or safety of the public or the operation of the facility. Compensatory actions remain in place to sample per the requirements of the ODCM. The NRC Resident Inspector has been notified.
The Service Water radiation monitors have been restored to service and declared functional. 2SWP*CAB146B restored after maintenance Saturday, 09/28/13 at 2243 EDT. 2SWP*CAB146A was removed from service for maintenance at 2243 EDT on 09/28/13, restored to service and declared functional Saturday, 09/28/13 at 2337 EDT. The NRC Resident Inspector will be notified. Notified R1DO (Welling).
Update to notification: Received subsequent DRMS low sample flow alarm and sample pump trip at 0619 on 9/29/13 for Service Water Radiation monitor 2SWP*CAB146B. The sample pump was returned to service and subsequently tripped again. The monitor has been declared non-functional and Compensatory Actions are being taken per ODCM. Maintenance is engaged for resolution. Investigation includes potential impact from Service Water Mollusk Biocide Treatment which concluded 9/26/13. The licensee informed the NRC Resident Inspector. Notified R1DO (Welling).
The Service Water Radiation monitor 2SWP*CAB146B was removed from service for inspection. The cause of the radiation monitor tripping is attributed to the scale that is forming on the flow switch sensing element. Flow switch element on 2SWP*CAB146B has been cleaned and radiation monitor has been placed back in service. The monitor was placed in service on 9/29/13 at 1200 and has been functioning properly since then. As of 2100, 2SWP*CAB146B has been declared functional and ODCM 3.3.1 actions have been exited. The licensee will notify the NRC Resident Inspector. Notified R1DO (Joustra). |