ENS 40847
ENS Event | |
|---|---|
09:29 May 22, 2004 | |
| Title | Invalid Actuation of Division 1 Primary Containment Isolation Due to Loss of a Rps Bus |
| Event Description | The following information was received from the licensee via facsimile:
On May 22, 2004, at approximately 4:29 am EDT, while the plant was operating at 100% power, the normal power supply to the Division 1 Reactor Protection System (RPS) bus was lost. This caused the actuation of the Division 1 primary containment isolation logic circuit. This was an event that resulted in the actuation of a general containment isolation signal affecting more than one system. However, as this event meets the definition of an invalid actuation (i.e., not a response to an actual plant parameter exceeding a trip setpoint), this notification is being made in accordance with 10CFR50.73(a)(1) in lieu of a Licensee Event Report. Operators implemented the applicable response procedures, and shifted Division 1 RPS to its alternate power supply. The containment isolation signal was reset, and systems were restored to normal alignment. Reactor power was not affected by this event. All safety related equipment controlled by the affected circuits responded to the loss of Division 1 RPS as required, with one exception. The Division 1 control building emergency filtration train should have automatically initiated, but did not. Subsequent troubleshooting discovered a failed relay in its control circuitry. This defect would not have prevented the Division 2 control building emergency filtration train from performing its safety function. It was determined that a relay coil in the control circuitry for the Division 1 RPS motor-generator set failed. This caused the main output contactor on the MG set to open, interrupting power to the bus. Repairs were completed on June 3, 2004, and the Division 1 RPS bus was then shifted back to its normal power supply. The licensee has notified the NRC Resident Inspector of this notification. |
| Where | |
|---|---|
River Bend  Louisiana (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+937.52 h39.063 days <br />5.58 weeks <br />1.284 months <br />) | |
| Opened: | Danny Williamson 11:00 Jun 30, 2004 |
| NRC Officer: | Arlon Costa |
| Last Updated: | Jun 30, 2004 |
| 40847 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 572062024-05-14T00:28:00014 May 2024 00:28:00
[Table view]10 CFR 50.73(a)(1), Submit an LER Invalid Partial Containment Isolation ENS 541212019-04-30T11:50:00030 April 2019 11:50:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephonic Notification Due to Invalid Actuation of a General Containment Isolation Signal ENS 517842016-01-10T08:43:00010 January 2016 08:43:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of the Primary Containment Isolation Logic ENS 510032015-02-24T22:02:00024 February 2015 22:02:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephone Notification of Invalid System Actuation Due to Motor Generator Output Breaker Trip ENS 507742014-12-06T16:12:0006 December 2014 16:12:00 10 CFR 50.73(a)(1), Submit an LER 60 Day Optional Report - Half Scram and a Division 2 Primary Containment Isolation Signal ENS 468442011-03-20T12:24:00020 March 2011 12:24:00 10 CFR 50.73(a)(1), Submit an LER "a" Train Reactor Protection System Unexpectedly De-Energized Resulting in a Half Scram Signal ENS 445172008-08-01T00:30:0001 August 2008 00:30:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Containment Isolation Valves Due to a Power Failure ENS 443472008-06-02T11:24:0002 June 2008 11:24:00 10 CFR 50.73(a)(1), Submit an LER Invalid System Actuation of Division 1 Containment Isolation Valves ENS 442782008-04-23T20:56:00023 April 2008 20:56:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Notification of Invalid Specified System Actuation ENS 430122006-09-29T18:33:00029 September 2006 18:33:00 10 CFR 50.73(a)(1), Submit an LER Invalid Specific System Actuation ENS 408472004-05-22T09:29:00022 May 2004 09:29:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Division 1 Primary Containment Isolation Due to Loss of a Rps Bus 2024-05-14T00:28:00 | |