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On February 15, 2017 at 1337 (EST), Second … On February 15, 2017 at 1337 (EST), Secondary Containment Zone 1 (Unit 1 Reactor Building) differential pressure lowered to 0 inches WG (Water Gauge) due to a trip of the running Unit 1 B Filtered Exhaust Fan. Required differential pressure per SR (Surveillance Requirement) 3.6.4.1.1 could not be maintained. Zone 1 differential pressure recovered to greater than 0.25 inches WG less than one minute later after start of the standby Zone 1 Filtered Exhaust Fan. Zone 2 (Unit 2 Reactor Building) and Zone 3 (Common Areas of Unit 1&2 Reactor Buildings) ventilation remained in service and stable. </br>This event is being reported under 10 CFR 50.72(b)(3)(v)(C) and per the guidance of NUREG-1022, Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment System.</br>Post-maintenance testing was underway when the fan tripped. While the investigation is on-going to determine the cause, the licensee does not believe the maintenance or testing caused the fan to trip </br>The licensee has notified the NRC Resident Inspector.</br>* * * RETRACTION FROM RONALD FRY TO DONALD NORWOOD AT 0833 EDT ON 4/12/2017 * * *</br>The Unit 1 B Filtered Exhaust Fan trip that resulted in loss of secondary containment differential pressure occurred during post maintenance testing (PMT). The PMT was being performed following replacement of a flow controller associated with the Unit 1 B Filtered Exhaust Fan. In support of the PMT, Technical Specification (TS) 3.6.4.1 Condition A had been entered and was in effect at the time of the fan trip. The maintenance and the associated PMT were performed in accordance with approved work instructions/procedure. Subsequent to the initial report, Susquehanna troubleshooting determined that the fan trip was the result of an internal leak in the newly installed controller that prevented the new controller from functioning properly. The condition was therefore determined to have been the result of the completed maintenance.</br>NUREG-1022, Section 3.2.7, includes the following guidance:</br>'...reports are not required when systems are declared inoperable as part of a planned evolution for maintenance or surveillance testing when done in accordance with an approved procedure and the plant's TS (unless a condition is discovered that would have resulted in the system being declared inoperable).'</br>Following completion of the troubleshooting, Susquehanna determined that, per NUREG-1022, Section 3.2.7, the event was not reportable. Secondary Containment was declared inoperable as a part of a planned evolution for maintenance which was done in accordance with an approved procedure and the Susquehanna TS. The discovered condition was not a pre-existing condition that would have resulted in the system being declared inoperable prior to the planned maintenance activity.</br>The licensee notified the NRC Resident Inspector.</br>Notified R1DO (Jackson).C Resident Inspector.
Notified R1DO (Jackson).
18:37:00, 15 February 2017 +
52,552 +
18:10:00, 15 February 2017 +
18:37:00, 15 February 2017 +
On February 15, 2017 at 1337 (EST), Second … On February 15, 2017 at 1337 (EST), Secondary Containment Zone 1 (Unit 1 Reactor Building) differential pressure lowered to 0 inches WG (Water Gauge) due to a trip of the running Unit 1 B Filtered Exhaust Fan. Required differential pressure per SR (Surveillance Requirement) 3.6.4.1.1 could not be maintained. Zone 1 differential pressure recovered to greater than 0.25 inches WG less than one minute later after start of the standby Zone 1 Filtered Exhaust Fan. Zone 2 (Unit 2 Reactor Building) and Zone 3 (Common Areas of Unit 1&2 Reactor Buildings) ventilation remained in service and stable. </br>This event is being reported under 10 CFR 50.72(b)(3)(v)(C) and per the guidance of NUREG-1022, Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment System.</br>Post-maintenance testing was underway when the fan tripped. While the investigation is on-going to determine the cause, the licensee does not believe the maintenance or testing caused the fan to trip </br>The licensee has notified the NRC Resident Inspector.</br>* * * RETRACTION FROM RONALD FRY TO DONALD NORWOOD AT 0833 EDT ON 4/12/2017 * * *</br>The Unit 1 B Filtered Exhaust Fan trip that resulted in loss of secondary containment differential pressure occurred during post maintenance testing (PMT). The PMT was being performed following replacement of a flow controller associated with the Unit 1 B Filtered Exhaust Fan. In support of the PMT, Technical Specification (TS) 3.6.4.1 Condition A had been entered and was in effect at the time of the fan trip. The maintenance and the associated PMT were performed in accordance with approved work instructions/procedure. Subsequent to the initial report, Susquehanna troubleshooting determined that the fan trip was the result of an internal leak in the newly installed controller that prevented the new controller from functioning properly. The condition was therefore determined to have been the result of the completed maintenance.</br>NUREG-1022, Section 3.2.7, includes the following guidance:</br>'...reports are not required when systems are declared inoperable as part of a planned evolution for maintenance or surveillance testing when done in accordance with an approved procedure and the plant's TS (unless a condition is discovered that would have resulted in the system being declared inoperable).'</br>Following completion of the troubleshooting, Susquehanna determined that, per NUREG-1022, Section 3.2.7, the event was not reportable. Secondary Containment was declared inoperable as a part of a planned evolution for maintenance which was done in accordance with an approved procedure and the Susquehanna TS. The discovered condition was not a pre-existing condition that would have resulted in the system being declared inoperable prior to the planned maintenance activity.</br>The licensee notified the NRC Resident Inspector.</br>Notified R1DO (Jackson).C Resident Inspector.
Notified R1DO (Jackson).
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