05000443/LER-2024-002, Manual Reactor Trip Due to B MFP Trip
| ML25013A036 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 01/10/2025 |
| From: | Mack K Point Beach |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-2025-013 LER 2024-002-00 | |
| Download: ML25013A036 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 4432024002R00 - NRC Website | |
text
NEXTera~
EN~~~~
U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001 Re:
Seabrook Station Docket No. 50-443 Reportable Event: 2024-02-00 Date of Event: November 19, 2024 Unplanned Reactor Scram January 10, 2025 L-2025-013 10 CFR 50.73 The attached Licensee Event Report 2024-02 is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event.
Should you have any questions regarding this submission, please contact Maribel Valdez, Fleet Licensing Manager, at 561-904-5164.
Sincerely, Ke~/~
Director, Licensing and Regulatory Compliance Attachment cc:
Seabrook Station NRC Senior Resident Inspector Seabrook Station NRC Project Manager NextEra Energy Seabrook, LLC PO Box 300, Seabrook, NH 03874
Abstract
On November 19, 2024, at 13:50 EST, during maintenance on the 'B' Main Feedwater Pump (MFP)(IEE JK), the reactor was manually tripped due to lowering Steam Generator (SG)(IEE JB) water levels. The lowering levels were due to a trip of the 'B' MFP. The reactor trip was uncomplicated with all systems responding as expected, including the actuation of the Emergency Feedwater (EFW)(IEE BA) System, upon low steam generator level. This event is being reported pursuant of 50.73(a)(2)(iv)(A) System Actuation.
Description
I
- 2. DOCKET NUMBER
- 3. LER NUMBER IB SEQUENTIAL REV NUMBER NO.
00443
- - I I -0 02 On November 19, 2024, at 13:50 EST, during maintenance on the 'B' MFP, the reactor was manually tripped due to lowering SG water levels. The lowering levels were due to a trip of the 'B' MFP. This occurred during maintenance activities to resolve recently received 'B' MFP diagnostic alarms. The alarms were related to the 'B' MFP Electrical Trip Devices. The maintenance activities directed technicians to replace both the Turbine Specific Primary Trip Pack (PTUR) and the Emergency Turbine Protection Pack (PPRO). After replacing the PTUR pack, a software download and system reboot was required. Contrary to previous downloads where only the replaced pack was rebooted, more than one pack had been selected for rebooting. Once rebooting was initiated, the 'B' MFP tripped.
Cause of the Event
The cause of the event was a lack of adequate detail related to software download interface in the maintenance instructions.
Safety Significance
This event resulted in a unit shutdown and an NRC reportable event. All systems responded normally post trip.
This Licensee Event Report is being reported pursuant of 10 CFR 50.73(a)(2)(iv)(A), System Actuation.
This event did not result in a Safety System Functional Failure.
Corrective Actions
To address the cause of the event, the maintenance work instructions for the Turbine Specific Primary Trip Pack replacements will be revised to include the required detail to prevent inadvertent MFP trips.
Similar Events
A review of events over the past 5 years did not identify any similar events with the same cause as this event. Page 2
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