ENS 40902
ENS Event | |
|---|---|
12:00 Jul 28, 2004 | |
| Title | Plant Shutdown Required by Technical Specifications |
| Event Description | Event: At 08:00 hours Oconee Unit 1 initiated a unit shutdown per Technical Specification (TS) 3.0.3. Unit 2 initiated shutdown at 0900 [ET]. It is expected that Unit 3 will initiate shutdown at 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br />. Target for entry into Mode 3 is 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br /> on all units. At 0129 hours0.00149 days <br />0.0358 hours <br />2.132936e-4 weeks <br />4.90845e-5 months <br /> all three Oconee units received a number of alarms related to power to the 230 KV switchyard (SWYD) battery chargers. At 0200 hours0.00231 days <br />0.0556 hours <br />3.306878e-4 weeks <br />7.61e-5 months <br /> Operations determined that both AC power sources to the SWYD battery chargers required by TS 3.8.3 had tripped and declared entry into TS 3.0.3 because no specific condition of TS 3.8.3 applied. Evaluation for potential applicability of other reporting criteria is still in progress.
Initial Safety Significance: The SWYD batteries currently have normal voltage (being monitored hourly) but are NOT considered operable per TS 3.8.5 at this time, which would also require TS 3.0.3 entry. However, if voltage drops too low the ability to remotely operate SWYD power circuit breakers would be affected, which would impact SWYD isolation capability. Local manual operation would still be possible, and operations personnel are stationed in the SWYD as a contingency. Corrective Action: 1. Maintenance has identified a fault in a power transfer switch. Actions have been completed to isolate the fault and restore power to the battery chargers. 2. Measurements of battery voltages are being taken hourly. A surveillance will be performed to verify TS 3.8.5 compliance after the charger power supply is restored. 3. Shutdown of Oconee units will follow schedule above unless power and battery voltages are restored sooner (as expected). The electrical grid is stable and standby emergency power remains operable. The NRC Resident Inspector has been informed. The licensee does not intend to make any State, local or other Federal notifications or issue any press release at this time.
|
| Where | |
|---|---|
Oconee  South Carolina (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | |
| Time - Person (Reporting Time:+-2.13 h-0.0888 days <br />-0.0127 weeks <br />-0.00292 months <br />) | |
| Opened: | Randy Todd 09:52 Jul 28, 2004 |
| NRC Officer: | Mike Ripley |
| Last Updated: | Jul 28, 2004 |
| 40902 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (92 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (95 %) |
Unit 3 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
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 | |