ENS 40433
ENS Event | |
|---|---|
00:02 Jan 9, 2004 | |
| Title | Ts Required Shutdown at Oconee 1 Due to Unidentified Rcs Leakage |
| Event Description | Event Description: Reactor Coolant System, (RCS) Leakage in excess of TS limits. RCS leakage calculations have shown a gradual increase in leakage following Unit l start-up from a refueling outage. On 1/7/2004 @ 1800 hours0.0208 days <br />0.5 hours <br />0.00298 weeks <br />6.849e-4 months <br /> an RCS leakage calculation was performed with the calculated leak rate at 0.300 gpm. On 1/8/2004 @ 1225 hours0.0142 days <br />0.34 hours <br />0.00203 weeks <br />4.661125e-4 months <br />, with Reactor power at approximately 26% Rated Thermal Power (RTP), leakage had increased to 0.778 gpm. Personnel have entered containment and have determined the source to be within the A steam generator cavity. At 1312 hours0.0152 days <br />0.364 hours <br />0.00217 weeks <br />4.99216e-4 months <br /> a power reduction to 17% RTP was initiated to reduce dose sufficiently to allow entry into the cavity in an attempt to identify the exact leak source. On 1/8/2004 @ 1502 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.71511e-4 months <br />, the leak rate was calculated to be one gpm which exceeds the allowed leakage for unidentified leakage. Units 2 and 3 are unaffected and remain at 100% RTP.
Initial Safety Significance: The measured leakage is well within the capacity of the normal RCS make-up system. The increase in leakage rate has been slow, and is not expected to increase significantly prior to completion of the TS required shutdown. The leakage is confined inside containment. At this time, there has been NO RADIOLOGICAL RELEASE associated with this event. NOTE: Entry into the emergency plan is not required unless the leakage is => 10 gpm unidentified or => 25 gpm identified, the current leakage is significantly below those limits. Corrective Action(s)= Unit shutdown per TS is in progress. Isolation or repair of the leak will be evaluated once the location of the leak source is determined. TS 3.4.13 allows 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> to reduce leakage within limits. If the source remains unidentified and leakage remains above limits, the TS requires shutdown to Mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and to Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The NRC resident inspector was notified. |
| Where | |
|---|---|
Oconee  South Carolina (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | |
| LER: | 05000269/LER-2004-001 |
| Time - Person (Reporting Time:+-4.83 h-0.201 days <br />-0.0287 weeks <br />-0.00662 months <br />) | |
| Opened: | Roy Smith 19:12 Jan 8, 2004 |
| NRC Officer: | Rich Laura |
| Last Updated: | Jan 8, 2004 |
| 40433 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (28 %) |
| After | Power Operation (17 %) |
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 | |