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ENS 57663
Show incoming properties 
Category
ENS Notification  and Power Reactor
CFR
10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown +, 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded +, 10 CFR 50.72#b2i +  and 10 CFR 50.72#b3iiA +
Current power
0  +
Description
The following information was provided by … The following information was provided by the licensee via phone and email:</br>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 hours and mode 4 in 36 hours. Columbia Generating Station was in mode 3 at time of determination for (entering TS) 3.4.5. Therefore, the event is reportable within 4 hours per 10 CFR 50.72(b)(2)(i) due to the initiation of a plant shutdown required by the plant's TS. </br>The event is also reportable within 8 hours 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.</br>The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:</br>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 hours.enter mode 4 within the required 36 hours.  +
Discovered date
09:23:00, 12 April 2025  +
Emergency class
Non Emergency +
Entered date
08:17:00, 12 April 2025  +
Event date
09:23:00, 12 April 2025  +
Event description
The following information was provided by … The following information was provided by the licensee via phone and email:</br>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 hours and mode 4 in 36 hours. Columbia Generating Station was in mode 3 at time of determination for (entering TS) 3.4.5. Therefore, the event is reportable within 4 hours per 10 CFR 50.72(b)(2)(i) due to the initiation of a plant shutdown required by the plant's TS. </br>The event is also reportable within 8 hours 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.</br>The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:</br>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 hours.enter mode 4 within the required 36 hours.  +
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ENS 57663 +, ENS 57663 +, ENS 57663 +, ENS 57663 +, ENS 57663 +, ENS 57663 +, ENS 57663 +, ENS 57663 +, ENS 57663 +, ENS 57663 +, ENS 57663 +, ENS 57663 +, ENS 57663 +, ENS 57663 +, ENS 57663 +  and ENS 57663 +
Hours
1.388889e-4 d (0.00333 hours, 1.984127e-5 weeks, 4.566e-6 months)  +, 4.166667e-4 d (0.01 hours, 5.952381e-5 weeks, 1.3698e-5 months)  +, 4.62963e-5 d (0.00111 hours, 6.613757e-6 weeks, 1.522e-6 months)  +  and 9.259259e-5 d (0.00222 hours, 1.322751e-5 weeks, 3.044e-6 months)  +
Initial power
0  +
Last update date
00:00:00, 12 April 2025  +
Modification date"Modification date" is a predefined property that corresponds to the date of the last modification of a subject and is provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a>.
11:20:10, 14 April 2025  +
NRC officer
Ernest West +
Notification date
08:17:00, 12 April 2025  +
Originated by
Robert Rood +
Reactor critical
false  +
Reactor scram
false  +
Reactor type
GE-5 +
Region
NRC Region 4 +
Reporting criterion
10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown +  and 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded +
Reporting time
-0.0458 d (-1.1 hours, -0.00655 weeks, -0.00151 months)  +
Site
Columbia +
Start date
09:23:00, 12 April 2025  +
State
Washington +
TS
TS-3.4.5 +
Title
Shutdown Required by Technical Specifications  +
Topic
Pressure Boundary Leakage +  and Operational leakage +
URL"URL" is a <a href="/Special:Types/URL" title="Special:Types/URL">type</a> and predefined property provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a> to represent URI/URL values.
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2025/20250414en.html#en57663  +
Unit
2  +
 
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