ENS 57663
ENS Event | |
|---|---|
09:23 Apr 12, 2025 | |
| Title | Shutdown Required by Technical Specifications |
| Event Description | The following information was provided by the licensee via phone and email:
During a planned shutdown at Columbia Generating Station for a refueling outage, pressure boundary leakage was identified from the bonnet vent line of loop `B' discharge motor operated isolation valve during a drywell inspection. Leakage was initially identified during a drywell entry at 15 percent [reactor] power and identified as pressure boundary leakage during a subsequent entry in mode 3. The leak exceeds technical specification (TS) 3.4.5 'RCS Operational Leakage' of no pressure boundary leakage. TS action `C' was entered, requiring [the plant to be in] mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and mode 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. Columbia Generating Station was in mode 3 at time of determination for [entering TS] 3.4.5. Therefore, the event is reportable within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> per 10 CFR 50.72(b)(2)(i) due to the initiation of a plant shutdown required by the plant's TS. The event is also reportable within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> per 10 CFR 50.72(b)(3)(ii)(A) due to an event that resulted in the condition of the nuclear power plant, including principal safety barriers, being seriously degraded. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The NRC Resident Inspector has been informed. Columbia Generating Station estimates the leak rate to be less than 0.2 gallons per minute. Columbia Generating Station expects to enter mode 4 within the required 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. |
| Where | |
|---|---|
Columbia  Washington (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | |
| Time - Person (Reporting Time:+-1.1 h-0.0458 days <br />-0.00655 weeks <br />-0.00151 months <br />) | |
| Opened: | Robert Rood 08:17 Apr 12, 2025 |
| NRC Officer: | Ernest West |
| Last Updated: | Apr 12, 2025 |
| 57663 - NRC Website
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Columbia with 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown, 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | |
WEEKMONTHYEARENS 576632025-04-12T09:23:00012 April 2025 09:23:00
[Table view]10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown, 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Shutdown Required by Technical Specifications ENS 555602021-11-03T19:31:0003 November 2021 19:31:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Incorrect Local Leak Rate ENS 524432016-12-19T07:20:00019 December 2016 07:20:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Unisolable Leak on High Pressure Core Spray ENS 451312009-06-13T18:30:00013 June 2009 18:30:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition Due to Reactor Coolant Pressure Boundary Leak ENS 432912007-04-09T05:32:0009 April 2007 05:32:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown 2025-04-12T09:23:00 | |