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| Entered date | Event description | |
|---|---|---|
| ENS 41094 | 5 October 2004 18:48:00 | At approximately 1334, during realignment from monthly surveillance testing of the normal and alternate power supply breakers to the 10 A404 vital 4 Kv bus, an inadvertent undervoltage condition appears to have occurred. This condition resulted in initiation of the diesel load sequencer and tripping of the normal loads supplied by this bus. The undervoltage condition was momentary in nature, the load sequencer stopped upon restoration of voltage prior to starting the emergency diesel generator and operators successfully restarted the equipment that had tripped and restored the load sequencer. The D Emergency Diesel Generator is considered to be operable at this time. The cause of the occurrence is under investigation. The plant is stable in Operational Condition 1 at 100% power. This event is being reported in accordance with 10CFR50.72(b)(3)(iv)(A) 'Any event or condition that results in valid actuation of any of the systems listed in paragraph (b)(3)(iv)(B) subsection 8', specifically in this case, Emergency ac electrical power systems." LAC Township notified by licensee. The NRC Resident Inspector was notified of this event by the licensee.
Upon further review this event was determined to not meet the reportability requirements of 10CFR50.72. The event that caused the momentary interruption to the 10A404 vital bus (i.e., less then a second) did not result in an actuation of a listed system (Emergency ac electrical power systems, including: Emergency diesel generators (EDGs)). Because the event did not meet the NUREG 1022 reporting requirement specified in 10CFR50.72 (b)(3)(iv)(A) it has been determine to not be reportable." The NRC Resident Inspector was notified of this event by the licensee. LAC Township notified by licensee. Notified R1DO (Dimitriadis) |
| ENS 40876 | 16 July 2004 14:10:00 | A Unit shutdown was initiated at 1100 (ET 07/16/04) to comply with Technical Specifications. The High Pressure Coolant Injection (HPCI) System was declared inoperable at 1000 on 7/16/04 due to an inability to demonstrate that it is capable of meeting its design flow and pressure requirements identified during an extent of condition review being conducted in conjunction with an ongoing Safety System Design Inspection. Concurrently, the `D' Emergency Diesel Generator (EDG) was inoperable due to an in-progress surveillance. This rendered the `D' Low Pressure Coolant Injection (LPCI) subsystem and `B' Core Spray subsystem inoperable resulting in entry into Technical Specification 3.0.3 requiring within 1 hour initiating action to place the unit in at least startup within the next 6 hours, hot shutdown within the following 6 hours and cold shutdown within the subsequent 24 hours. Power ascension was in progress with reactor power at 95%. Power ascension was suspended. Preparations for power reduction were initiated. Actions were taken to restore the `D' EDG to an operable, standby alignment, which was complete at 1145 rendering `D' LPCI subsystem and `B' Core Spray subsystem operable. Technical Specification 3.0.3 was exited. No power reduction was conducted. The HPCI system remains inoperable constituting a condition that could have prevented the fulfillment of a safety function. The investigation is ongoing including a determination of the need for any physical modifications that may be required. Prior to the event, the `C' Station Service Water pump, `D' Filtration Recirculation, Ventilation System recirculation fan, and `B' Primary Containment Instrument gas compressor were out of service for scheduled maintenance. There were no personnel injuries as a result of this event. The NRC Resident inspector was notified of this event. |