ENS Event | |
|---|---|
19:43 Jan 26, 2026 | |
| Title | Invalid System Actuation |
| Event Description | The following information was provided by the licensee via phone and email:
This 60-day telephone notification is being made in lieu of a licensee event report (LER) in accordance with 10 CFR 50.73(a)(1) for an invalid actuation of the emergency service water (ESW) system reportable under 10 CFR 50.73(a)(2)(iv)(A) at the Prairie Island Nuclear Generating Plant Units 1 and 2. At 1343 CST on January 26, 2026, during post maintenance testing associated with the time delay relay replacement work for the 22 diesel driven cooling water pump (DDCLP), an ESW pump on `B' train, a jumper was installed to test an annunciator. The jumper bypassed part of the normal start circuitry and allowed a spurious start signal. As a result, the 22 DDCLP automatically started without operator command. At the time of the start, the pump was inoperable and return-to-service testing had not been completed; certain isolations, including DC control power, had been restored, which made the unintended actuation possible. This event is considered an invalid system actuation of the ESW system. The actuation was not initiated in response to actual plant conditions or parameters. The 22 DDCLP started and functioned as expected in response to the start signal. The NRC Resident Inspector has been notified. |
| Where | |
|---|---|
Prairie Island  Minnesota (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1240.28 h51.678 days <br />7.383 weeks <br />1.699 months <br />) | |
| Opened: | Matt Newman 11:00 Mar 19, 2026 |
| NRC Officer: | Ernest West |
| Last Updated: | Mar 19, 2026 |
| 58210 - NRC Website
Loading map... | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 582102026-01-26T19:43:00026 January 2026 19:43:00
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