ENS Event | |
|---|---|
22:37 Aug 31, 2010 | |
| Title | Invalid Primary Containment Isolation System Actuation Due to a Voltage Transient |
| Event Description | This telephone report is being made in accordance with 10 CFR 50.73(a)(2)(iv)(A) as an event or condition caused by an invalid signal that resulted in an automatic Group 6 isolation. On August 31, 2010 at 1737 CDT, Group 6 of Primary Containment Isolation System (PCIS) actuated. This resulted in completion of Secondary Containment isolation, initiation of the Standby Gas Treatment System and Control Room Emergency Filtration System. An invalid signal occurred apparently as a result of a voltage transient on the Nebraska City 345kV line. This was from a 3-phase fault to ground due to a structural failure during a severe thunder storm with high winds.
The equipment associated with the Group 6 isolation functioned successfully and the isolation was complete. The Group 6 PCIS was reset. Cooper Nuclear Station operators reviewed the parameters that would cause a Group 6 trip signal (i.e. reactor water level, drywell pressure, reactor building radiation) and determined there were no valid conditions that would have caused the isolation. This event was most likely due an act of nature, thus no corrective actions were required. The NRC Resident Inspector will be notified. |
| Where | |
|---|---|
Cooper  Nebraska (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1362.03 h56.751 days <br />8.107 weeks <br />1.866 months <br />) | |
| Opened: | David Nelson Madsen 16:39 Oct 27, 2010 |
| NRC Officer: | Dong Park |
| Last Updated: | Oct 27, 2010 |
| 46367 - NRC Website
Loading map... | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 580682025-10-06T15:13:0006 October 2025 15:13:00
[Table view]10 CFR 50.73(a)(1), Submit an LER 60-DAY Optional Telephonic Notification of Invalid Specified System Actuation ENS 537762018-10-13T05:00:00013 October 2018 05:00:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephonic Notification of Invalid Specified System Actuation ENS 524362016-10-28T07:39:00028 October 2016 07:39:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Containment Isolation Valves ENS 463672010-08-31T22:37:00031 August 2010 22:37:00 10 CFR 50.73(a)(1), Submit an LER Invalid Primary Containment Isolation System Actuation Due to a Voltage Transient ENS 430972006-11-20T02:28:00020 November 2006 02:28:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Primary Containment Isolation System ENS 406972004-03-09T18:42:0009 March 2004 18:42:00 10 CFR 50.73(a)(1), Submit an LER Invalid System Actuation Due to Momentary Power Interruption 2025-10-06T15:13:00 | |