The standby gas treatment system (SBGT) or (SGT) is a filtration system for secondary containment. Normally inactive, it is meant activate in the event of an Design Basis Accident.
Reporting Notes
Loss of Safety Function: SBGT is a safety system (responds to a DBA). It typically contains two redundant trains so you would need to loss both at the same time to be considered reportable as a loss of safety function.
System actuation reporting: The SBGT system is not list of systems required to reported if it were to actuate unexpectedly under 10 CFR 50.72(b)(3)(iv)(A), System Actuation.
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| | Site | Start date | Title | Description |
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| IR 05000237/2025003 | Dresden | 31 December 2025 | Integrated Inspection Report 05000237/2025003 and 05000249/2025003 and Exercise of Enforcement Discretion | | | IR 05000461/2025003 | Clinton | 29 December 2025 | Integrated Inspection Report 05000461/2025003 and 07201046/2025001 | | | IR 05000341/2025003 | Fermi | 22 December 2025 | Integrated Inspection Report 05000341/2025003 | | | IR 05000333/2025003 | FitzPatrick | 22 December 2025 | Integrated Inspection Report 05000333/2025003 and Independent Spent Fuel Storage Installation Report 07200012/2025001 and Exercise of Enforcement Discretion | | | IR 05000416/2025003 | Grand Gulf | 22 December 2025 | And Independent Spent Fuel Storage Installation Integrated Inspection Report 05000416/2025003 and 07200050/2025001 | | | NL-25-0421, Subsequent License Renewal Application Response to Request for Additional Information and Request for Confirmation of Information, Set 1 | Hatch | 22 December 2025 | Subsequent License Renewal Application Response to Request for Additional Information and Request for Confirmation of Information, Set 1 | | | ML25343A364 | Technical Specifications Task Force | 11 December 2025 | Final SE of TSTF-602, Revise the Ventilation Filter Testing Program to Permit Alternate Challenge Agents | | | ENS 58049 | Limerick | 19 November 2025 08:28:00 | Loss of Reactor Enclosure Recirculation | The following is a summary of information provided by the licensee via phone and email:
On November 18, 2025, at 0328 CST, as the licensee was initiating the standby gas treatment system in support of planned maintenance on normal reactor building ventilation, the '2A' reactor enclosure recirculation system (RERS) fan failed to establish flow upon the system initiation signal. The '2B' RERS fan was previously inoperable due to a planned maintenance window. Technical specification action statement 3.6.5.4.B was entered with both Unit 2 RERS fans inoperable. The '2B' RERS fan was restored to operable at 0523 EST. The licensee returned normal reactor building ventilation to service to restore secondary containment differential pressure.
Due to inoperability of both RERS trains, the system was in a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72.(b)(3)(v)(C).
The licensee reported there was no impact to the health and safety of the public or plant personnel. The NRC Resident Inspector was notified.
- * * RETRACTION ON 01/08/2026 AT 0838 EST FROM BRAD SMITH TO ROBERT THOMPSON * * *
The following information was provided by the licensee via phone and email:
Limerick completed a review and confirmed that '2B' RERS fan operability was established following routine maintenance, prior to the '2A' RERS fan being declared inoperable.
Consequently, the '2B' RERS fan remained capable of performing its safety-related function during the period when the '2A' RERS fan was unavailable, thereby ensuring the overall RERS safety function was maintained. As such, no condition existed that would have prevented the fulfillment of a safety function. Based on this assessment, event notification 58049 is being retracted.
The NRC Senior Resident Inspector has been notified.
Notified R1DO (Seeley). | | ML25304A099 | Crane | 31 October 2025 | Crane Clean Energy Center - Radiological Emergency Plan | | | ML25304A102 | Crane | 31 October 2025 | Crane Clean Energy Center - Radiological Emergency Plan | |
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