05000348/LER-2009-001
| Joseph M Farley Nuclear Plant - Unit 1 | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| Initial Reporting | |
| ENS 44855 | 10 CFR 50.72(b)(3)(iv)(A), System Actuation |
| 3482009001R00 - NRC Website | |
Westinghouse -- Pressurized Water Reactor Energy Industry Identification Codes are identified in the text as [XX]
Description of Event
On February 16, 2009 at 16:55, Emergency Diesel Generator (EDG) 1C received an auto start signal due to de-energization of 4160 volt emergency Bus 1H [E13]. The bus was de-energized when a material handling cart inadvertently struck a relay cabinet containing the bus protective relays. The impact on the cabinet resulted in the phase two differential relay actuating which opened the supply breaker and actuated a lockout relay. With the undervoltage signal present on Bus 1H, EDG 1C received a start signal. EDG 1C started and all equipment functioned as designed. Per design, since indication of a fault on Bus 1H was present, EDG 1C output breaker did not close and the bus remained de-energized. Unit 1 remained at 100 % power during the event. Recovery actions were initiated and no damage was found on Bus 1H or in the relay cabinet. Normal equipment alignment was reestablished at 20:53 hours. In accordance with 10 CFR 50.72(b)(3)(iv)(A) for a valid actuation of the emergency AC electrical power system, an eight hour non-emergency report was issued at 21:09 hours, Event Notification 44855.
Cause of Event
The material handling cart that struck the relay cabinet was being used during a maintenance outage on EDG 1-2A. The cart was stored next to the relay cabinet which is located adjacent to the walk way into the EDG 1-2A room. As another material handling cart was being moved through the walk way, it struck the stored cart which impacted the relay cabinet. The wheels on the stored cart were not chocked to prevent movement as required by plant procedures.
Safety Assessment This event had no adverse effect on the safety and health of the public.
The Farley onsite standby power source is provided from four EDGs (1-2A, 1B, 2B, and 1C). The continuous service rating of 1C EDG is 2,850 kW and 4,075 kW for EDGs 1-2A, 1B, and 2B. EDG 1-2A and 1C are A-Train and EDGs 1B and 2B are B-Train. Farley also has a fifth diesel generator (2C) that serves as a station blackout diesel which can be manually aligned to supply B-Train power to either unit and power Loss of Site Power (LOSP) loads.
On February 16, 2009, EDG 1-2A was out of service for a planned maintenance outage. As required by plant technical specifications, with A-Train EDG inoperable, the B-Train EDG was operable on both Units. The unavailability of Bus 1H and the starting of EDG 1C had no adverse impact on B-Train power for either Unit. The requirements of Technical Specifications for one EDG Set being inoperable were met with at least one train (B-Train) of the onsite AC sources and the offsite AC sources remaining operable at all times. Therefore, the safety and health of the public was not adversely affected.
Corrective Action Work was suspended on EDG 1-2A. The area was walked down to ensure no other carts or materials were improperly stored in the area. A walkdown of other safety related areas of the plant was conducted to verify all stored carts were properly secured. No additional problems were identified. The relay cabinet and electrical Bus in the Diesel Generator Building that are located close to the walkways and access doors to the EDG rooms, were labeled as sensitive equipment and marked with boundary tape. Prior to work resuming on EDG 1-2A, personnel involved in the EDG 1-2A outage activities and task managers for upcoming EDG outages were briefed on the procedural requirements to secure carts when not in use.
EDG 1C was shutdown, verified to have functioned per design, and returned to emergency standby service.
The actuated relays were inspected and found to be functioning correctly. Recovery actions were initiated and no damage was found on Bus 1H or in the relay cabinet. Normal equipment alignment was reestablished and Bus 1H was reenergized.
Operating Experience (OE) on the event has been issued.
Additional Information
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