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The following information was provided by … The following information was provided by the licensee via phone and email:</br>This 60-day telephone notification is being made per the reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe an invalid actuation of a general containment isolation signal affecting more than one system (for Browns Ferry Unit 2).</br>On March 28, 2025, operations personnel were performing post-maintenance testing of 2-HS-64-33 (hand switch), which operates 2-FSV-64-33, the suppression chamber exhaust outboard isolation valve. When the hand switch was taken to 'open' multiple annunciators were received, including 9-5B window 34, 'Fuse Failure'. Light indications above the hand switch were not lit. This condition resulted in a 'B'-side partial group 6 isolation. All systems responded as expected.</br>Plant conditions which initiate primary containment isolation system (PCIS) group 6 actuations are reactor vessel low water level (level 3), high drywell pressure, or reactor building ventilation exhaust high radiation (reactor zone or refuel zone). </br>At the time of the event, these conditions did not exist; therefore, the actuation of the PCIS was invalid and there were no safety consequences or impact to the health and safety of the public as a result of this event.</br>Upon investigation a fuse was found to be cleared, which was the cause of the isolation. The fuse was replaced, the condition was cleared, and all systems were realigned as necessary.</br>This event was entered into the corrective action program as condition report 2002404.</br>The NRC Resident Inspector has been notified of this event.</br>The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:</br>Units 1 and 3 were not affected.Guidance:
Units 1 and 3 were not affected. +
21:04:00, 28 March 2025 +
57,733 +
11:17:00, 27 May 2025 +
21:04:00, 28 March 2025 +
The following information was provided by … The following information was provided by the licensee via phone and email:</br>This 60-day telephone notification is being made per the reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe an invalid actuation of a general containment isolation signal affecting more than one system (for Browns Ferry Unit 2).</br>On March 28, 2025, operations personnel were performing post-maintenance testing of 2-HS-64-33 (hand switch), which operates 2-FSV-64-33, the suppression chamber exhaust outboard isolation valve. When the hand switch was taken to 'open' multiple annunciators were received, including 9-5B window 34, 'Fuse Failure'. Light indications above the hand switch were not lit. This condition resulted in a 'B'-side partial group 6 isolation. All systems responded as expected.</br>Plant conditions which initiate primary containment isolation system (PCIS) group 6 actuations are reactor vessel low water level (level 3), high drywell pressure, or reactor building ventilation exhaust high radiation (reactor zone or refuel zone). </br>At the time of the event, these conditions did not exist; therefore, the actuation of the PCIS was invalid and there were no safety consequences or impact to the health and safety of the public as a result of this event.</br>Upon investigation a fuse was found to be cleared, which was the cause of the isolation. The fuse was replaced, the condition was cleared, and all systems were realigned as necessary.</br>This event was entered into the corrective action program as condition report 2002404.</br>The NRC Resident Inspector has been notified of this event.</br>The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:</br>Units 1 and 3 were not affected.Guidance:
Units 1 and 3 were not affected. +
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00:00:00, 27 May 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>.
11:20:03, 29 May 2025 +
11:17:00, 27 May 2025 +
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59.593 d (1,430.22 hours, 8.513 weeks, 1.959 months) +
21:04:00, 28 March 2025 +
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