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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| ENS 56980 | Peach Bottom | 19 February 2024 15:45:00 | Loss of Reactor Building Ventilation | The following information was provided by the licensee via email:
At 1045 EST, on 2/19/2024, during a maintenance activity, a loss of all reactor building ventilation occurred on Unit 2. With no flow past the ventilation radiation monitors, the radiation monitors were inoperable to support their ability to perform primary and secondary containment isolation functions or start the standby gas treatment system. Reactor building ventilation was restored within 15 minutes. Due to this inoperability, the radiation monitor system was in a condition that could have prevented 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).
There was no impact on the health and safety of the public or plant personnel.
The NRC Resident Inspector will be notified.
- * * RETRACTION ON 3/15/24 AT 1315 EDT FROM BILL LINNELL TO ADAM KOZIOL * * *
Upon further investigation, it was verified that the reactor building and the refueling floor radiation monitors are not needed to control the release of radiation for events described in chapter 14 of the updated Final Safety Analysis Report. For the analyzed loss of coolant accident (LOCA), the primary and secondary signals for this purpose were available and unaffected by this event. The radiation monitors provide a tertiary redundant method that is not credited within the station analysis. For all other analyzed accidents, the signal provided by the radiation monitors is not needed, as the secondary containment isolation function and start of the standby gas treatment system are not credited. Additionally, the fuel handling accident was not credible during the time of the event because no activities were in progress on the refueling floor. Therefore, the threshold for reporting the issue as an event or condition that could have prevented the fulfillment of a safety function was not met.
The NRC Resident Inspector has been notified.
Notified R1DO (Jackson) | | IR 05000333/2023004 | FitzPatrick | 7 February 2024 | Integrated Inspection Report 05000333/2023004 and Independent Spent Fuel Storage Installation Inspection Report 07200012/2023001 | | | IR 05000352/2023004 | Limerick | 31 January 2024 | Integrated Inspection Report 05000352/2023004 and 05000353/2023004 | | | IR 05000397/2023004 | Columbia | 29 January 2024 | Integrated Inspection and Independent Spent Fuel Storage Installation Report 05000397/2023004 and 07200035/2023001 | | | ML24003A770 | | 18 January 2024 | Monthly (28-day) Federal Register Notice - Applications and Amendments to Facility Operating Licenses and Combined Licenses Involving No Significant Hazards Considerations - Publication Date: January 23, 2024 | | | NRC-23-0077, Submittal of Revision 50 to the Fermi 2 Radiological Emergency Response Preparedness Plan | Fermi | 4 December 2023 | Submittal of Revision 50 to the Fermi 2 Radiological Emergency Response Preparedness Plan | | | RS-23-121, Sixth Ten-Year Interval Inservice Testing Program | Dresden | 30 November 2023 | Sixth Ten-Year Interval Inservice Testing Program | | | ML23345A084 | Susquehanna | 28 November 2023 | Technical Requirements Manual | | | ML23345A088 | Susquehanna | 28 November 2023 | Technical Requirements Manual | | | IR 05000321/2023011 | Hatch | 17 November 2023 | Biennial Problem Identification and Resolution Inspection Report 050003212023011 and 050003662023011 | |
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