ENS 40899
ENS Event | |
|---|---|
14:40 May 30, 2004 | |
| Title | Invalid Actuation of Containment Isolation Valves Due to Partial Loss of 120 Vac Modular Power Unit 2 Loads |
| Event Description | This 60-day optional verbal report, as allowed by 10 CFR 50.73(a)(1), is being made to describe an unplanned, invalid actuation of specified systems, specifically the Primary Containment Isolation System. Since this event meets the definition of an invalid actuation, this notification is being made in accordance with 10CFR50.73(a)(2)(iv)(A) in lieu of a Licensee Event Report.
On May 30, 2004, at approximately 10:40 am EDT, while the plant was operating at 100% power, a voltage regulator failed on Division 2 120 VAC Modular Power Unit No. 2 (MPU-2) which resulted in blown fuses and the loss of a number of loads from one of the three MPU-2 distribution cabinets. Since only one of the three distribution cabinets was lost, the isolations that occurred were only a portion of the isolations that would have occurred if all of the MPU-2 loads had been lost. This caused containment isolations by Division 2 Drywell Pneumatic supply valves (Primary Containment Isolation Group 18) and by Torus Water Management system outboard isolation valves (Primary Containment Isolation Group 12). Division 2 Secondary Containment Isolation Logic was also actuated, and the reactor building ventilation isolated. The Division 2 Standby Gas Treatment System automatically started. All equipment controlled by the affected circuits was determined to have responded to the loss of MPU-2 Cabinet 2 power as expected. Operators implemented applicable response procedures. The MPU was returned to service, and isolation signals were reset. Reactor power was not affected by this event. The NRC Resident Inspector was notified of this event by the licensee. |
| Where | |
|---|---|
Fermi  Michigan (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1391.95 h57.998 days <br />8.285 weeks <br />1.907 months <br />) | |
| Opened: | Jeff Yeager 14:37 Jul 27, 2004 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Jul 27, 2004 |
| 40899 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 528592017-03-24T19:48:00024 March 2017 19:48:00
[Table view]10 CFR 50.73(a)(1), Submit an LER Invalid Specified System Actuation During Testing ENS 511282015-05-24T23:30:00024 May 2015 23:30:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephonic Notification for an Invalid Actuation of Containment Isolation Valves ENS 501122014-03-19T00:30:00019 March 2014 00:30:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephonic Notification for an Invalid Actuation of Containment Isolation Valves ENS 438502007-10-22T23:30:00022 October 2007 23:30:00 10 CFR 50.73(a)(1), Submit an LER Invalid System Actuation ENS 438402007-10-14T07:00:00014 October 2007 07:00:00 10 CFR 50.73(a)(1), Submit an LER Inadvertent Actuation of Emergency Diesel Generator ENS 424282006-02-10T16:20:00010 February 2006 16:20:00 10 CFR 50.73(a)(1), Submit an LER Invalid Specified System Actuations ENS 408992004-05-30T14:40:00030 May 2004 14:40:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Containment Isolation Valves Due to Partial Loss of 120 Vac Modular Power Unit 2 Loads 2017-03-24T19:48:00 | |