ENS Event | |
|---|---|
01:08 May 7, 2025 | |
| Title | 60-DAY Notification of Invalid Specified System Actuation |
| Event Description | The following is a summary of information that was provided by the licensee via phone and fax:
Millstone Power Station Unit 3 is submitting a 60-day telephonic notification in lieu of a licensee event report (LER) submittal as allowed by 10 CFR 50.73 (a)(1) for an invalid system actuation reportable under 10 CFR 50.73(a)(2)(iv)(A). On May 6, 2025, at approximately 2108 EDT, while Millstone Power Station Unit 3 was in mode 5 during a refueling outage, an invalid safety injection (SI) signal was initiated. The actuation was not the result of intentional manual actuation and not in response to actual plant conditions requiring safety system operation. This resulted in the automatic start of both emergency diesel generators (EDGs), and the complete initiation on both trains of the following: main steam line isolation, containment isolation phase 'A', and safety injection signal. No injection into the reactor coolant system occurred, and the EDGs remained unloaded. All equipment not administratively locked out responded as designed, and the plant remained stable throughout the event. Control room operators responded in accordance with appropriate operating procedures and restored the affected systems. This notification is made pursuant to the reporting requirements specified in 10 CFR 50.73(a)(2)(iv)(A) for an invalid actuation of one of the systems listed in 10 CFR 50.73(a)(2)(iv)(B)- including safety injection signal, containment isolation signal, and start of both emergency diesel generators. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector was notified of the event. |
| Where | |
|---|---|
Millstone  Connecticut (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1354.5 h56.438 days <br />8.062 weeks <br />1.855 months <br />) | |
| Opened: | Scott Mcarthur 11:38 Jul 2, 2025 |
| NRC Officer: | Adam Koziol |
| Last Updated: | Jul 2, 2025 |
| 57793 - NRC Website
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WEEKMONTHYEARENS 577932025-05-07T01:08:0007 May 2025 01:08:00
[Table view]10 CFR 50.73(a)(1), Submit an LER 60-DAY Notification of Invalid Specified System Actuation ENS 550262020-11-07T00:08:0007 November 2020 00:08:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephonic Notification of an Invalid Specified System Actuation 2025-05-07T01:08:00 | |