ENS 41402
ENS Event | |
|---|---|
04:00 Feb 11, 2005 | |
| Title | Technical Specification Required Shutdown Due to Loss of Electrical Power Sources |
| Event Description | Event: At 23:00 [EST] on 2-10-05, Oconee Unit 1 initiated a plant shutdown as required by its Technical Specifications. Technical Specification 3.8.1 Condition M, Required Action M.1 requires Oconee Unit 1 to enter Mode 3 by 03:06 on 2-11-05 due to Keowee Hydro Unit 2 and CT-1 inoperable. Keowee Hydro Unit 2 is inoperable due to a planned outage, with restoration in progress. CT-1 is inoperable due to experiencing a lockout at 12:12 on 2-10-05 during testing to restore Keowee.
Initial Safety Significance: Oconee Unit 1 is being shut down in accordance with Technical Specifications. Unit auxiliaries will be powered from the Standby busses and a Lee Combustion Turbine. When the turbine is tripped, the Unit will enter into the natural circulation mode of cooling due to loss of Reactor Coolant Pumps. Corrective Action(s): 1) Restoration of Keowee Hydro Unit 2 is in progress. 2) A Unit Threat Team has been assembled and is investigating the cause of the lockout on CT-1. CT-2 cross connect is in progress to allow the unit, if tripped, to avoid loss of Reactor Coolant Pumps. The licensee notified the NRC Resident Inspector.
At the time of the initial notification, Oconee reported that, at 2346 EST on 02/10/05, the CT-2 cross connect has been completed, allowing the unit, if tripped, to avoid a loss of Reactor Coolant Pumps. The power reduction to enter Mode 3 by 03:06 continues. Restoration of Keowee Hydro Unit 2 and investigation into the cause of the lockout on CT-1 remain in progress. The licensee notified the NRC Resident Inspector. Notified R2 DO (M. Widman), IRD (Crlenjak), and NRR EO (W. Beckner).
At 0033 EST 02/11/05, restoration of Keowee Hydro Unit 2 to operable status was completed and Technical Specification 3.8.1 Condition M, Required Action M.1 requiring Oconee Unit 1 to enter Mode 3 by 03:06 on 2-11-05 was exited. The power reduction was stopped with power at 85% at 0034 EST. Technical Specification 3.8.1, Condition A, which was entered on 1106 EST on 02/10/05, requires restoration of CT-1 by 2306 on 02/11/06. The licensee notified the NRC Resident Inspector. Notified R2 DO (M. Widman), IRD (Crlenjak), and NRR EO (W. Beckner). |
| Where | |
|---|---|
Oconee  South Carolina (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | |
| Time - Person (Reporting Time:+-3.73 h-0.155 days <br />-0.0222 weeks <br />-0.00511 months <br />) | |
| Opened: | David Nix 00:16 Feb 11, 2005 |
| NRC Officer: | Mike Ripley |
| Last Updated: | Feb 11, 2005 |
| 41402 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (90 %) |
WEEKMONTHYEARENS 495272013-11-11T10:20:00011 November 2013 10:20:00
[Table view]10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown, 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Unit 1 Commenced a Technical Specification Required Shutdown Due to Rcs Leakage ENS 465262011-01-08T19:00:0008 January 2011 19:00:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown Due to Partial Closure of Letdown Line Isolation Valve 1Hp-5 ENS 419662005-08-31T18:28:00031 August 2005 18:28:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Unit 3 Experienced an Automatic Reactor Trip During Routine Testing ENS 414022005-02-11T04:00:00011 February 2005 04:00:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown Due to Loss of Electrical Power Sources ENS 409022004-07-28T12:00:00028 July 2004 12:00:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Plant Shutdown Required by Technical Specifications ENS 404332004-01-09T00:02:0009 January 2004 00:02:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Ts Required Shutdown at Oconee 1 Due to Unidentified Rcs Leakage 2013-11-11T10:20:00 | |