ENS 52552
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ENS Event | |
|---|---|
18:37 Feb 15, 2017 | |
| Title | Loss of Secondary Containment Differential Pressure |
| Event Description | 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.
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. 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 The licensee has notified the NRC Resident Inspector.
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. NUREG-1022, Section 3.2.7, includes the following guidance: '...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).' 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. The licensee notified the NRC Resident Inspector. Notified R1DO (Jackson). |
| Where | |
|---|---|
Susquehanna  Pennsylvania (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | |
| Time - Person (Reporting Time:+-0.45 h-0.0188 days <br />-0.00268 weeks <br />-6.1641e-4 months <br />) | |
| Opened: | Lonnie Crawford 18:10 Feb 15, 2017 |
| NRC Officer: | Bethany Cecere |
| Last Updated: | Apr 12, 2017 |
| 52552 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (94 %) |
| After | Power Operation (94 %) |
Susquehanna with 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | |
WEEKMONTHYEARENS 540782019-05-22T06:56:00022 May 2019 06:56:00
[Table view]10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Technical Specification Required Shutdown ENS 533102018-04-03T04:19:0003 April 2018 04:19:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment Following Surveillance Testing ENS 532022018-02-12T03:03:00012 February 2018 03:03:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Differential Pressure Out of Specification ENS 530982017-11-30T15:26:00030 November 2017 15:26:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Differential Pressure Briefly Indicated Outside of Tech Spec Limit ENS 529732017-09-16T17:30:00016 September 2017 17:30:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment Differential Pressure ENS 528922017-08-09T00:44:0009 August 2017 00:44:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment Differential Pressure ENS 528442017-07-10T06:50:00010 July 2017 06:50:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment Due to Failure of Non-Safety Related Discharge Damper ENS 528262017-06-24T14:28:00024 June 2017 14:28:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment ENS 527972017-06-09T09:09:0009 June 2017 09:09:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Exhaust Fan Breaker Failure Causing Low Secondary Containment Differential Pressure ENS 525992017-03-08T07:39:0008 March 2017 07:39:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment Due to Containment Fan Trip ENS 525522017-02-15T18:37:00015 February 2017 18:37:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment Differential Pressure ENS 523692016-11-16T15:45:00016 November 2016 15:45:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Failure of Unit 2 B Engineered Safeguards System Bus Sync Selector Switch ENS 522662016-09-27T20:44:00027 September 2016 20:44:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Leakage Exceeding Requirements ENS 522552016-09-22T07:20:00022 September 2016 07:20:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment Differential Pressure ENS 519252016-05-13T05:10:00013 May 2016 05:10:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Manual Reactor Scram Due After Loss of an Essential Motor Control Center ENS 518722016-04-20T01:59:00020 April 2016 01:59:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Inoperable Secondary Containment ENS 518512016-04-06T17:37:0006 April 2016 17:37:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Reactor Building Airlock Doors Opened Simultaneously ENS 518302016-03-30T02:56:00030 March 2016 02:56:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment Differential Pressure ENS 517772016-03-08T07:32:0008 March 2016 07:32:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Differential Pressure Outside Specification ENS 517642016-03-02T18:30:0002 March 2016 18:30:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Inoperable ENS 517502016-02-22T18:45:00022 February 2016 18:45:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Unit 1 Secondary Containment Inoperable When Personnel Opened Both Access Doors Simultaneously ENS 515882015-12-06T10:46:0006 December 2015 10:46:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment Differential Pressure Due to Exhaust Fan Trip ENS 515872015-12-06T08:50:0006 December 2015 08:50:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment Differential Pressure Due to Icing of Intake Supply Plenum Screens ENS 515762015-12-01T17:45:0001 December 2015 17:45:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Inoperable Due to Reactor Building Airlock Doors Being Opened Simultaneously ENS 515332015-11-12T16:32:00012 November 2015 16:32:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Inoperable ENS 514322015-09-29T14:30:00029 September 2015 14:30:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Both Trains of the Standby Gas Treatment System Declared Inoperable ENS 513552015-08-27T17:47:00027 August 2015 17:47:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Brief Loss of Secondary Containment Due to Both Airlock Doors Open Simultaneously ENS 512692015-07-27T15:18:00027 July 2015 15:18:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment Due to Opening Single Door Without Proper Authorization ENS 510402015-05-04T18:39:0004 May 2015 18:39:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Low Differential Pressure Resulting in Loss of Secondary Containment ENS 510172015-04-27T12:50:00027 April 2015 12:50:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Boundary Door Found Ajar ENS 510012015-04-22T02:58:00022 April 2015 02:58:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Inoperable Secondary Containment ENS 509742015-04-11T04:51:00011 April 2015 04:51:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Inoperable Due to Failure of Running Fans ENS 508852015-03-13T13:19:00013 March 2015 13:19:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment Due to Ventilation Plenum Door Open ENS 505952014-11-05T16:15:0005 November 2014 16:15:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Zones 2 and 3 Unintentionally Crosstied ENS 500552014-04-24T06:30:00024 April 2014 06:30:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment During Routine Swap of a Power Supplies ENS 500402014-04-17T07:35:00017 April 2014 07:35:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment During Preparation for Loca/Loop Testing ENS 498842014-03-08T08:25:0008 March 2014 08:25:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Unit 2 Loss of Secondary Containment Due to Discharge Damper Failure ENS 498672014-03-04T05:25:0004 March 2014 05:25:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Declared Inoperable During Surveillance Testing ENS 498212014-02-12T12:11:00012 February 2014 12:11:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Boundry Door Found Ajar ENS 496142013-12-07T14:50:0007 December 2013 14:50:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Fails Retest of Drawdown Surveillance Test ENS 495882013-11-27T15:01:00027 November 2013 15:01:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Unit 1 Reactor Building Secondary Containment Differential Pressure Out of Specification ENS 495652013-11-21T03:40:00021 November 2013 03:40:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Fails Drawdown Surveillance Testing ENS 495312013-11-13T07:26:00013 November 2013 07:26:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Zone II Differential Pressure Lost During Recovery from Ventilation Drawdown Test ENS 494922013-11-01T07:09:0001 November 2013 07:09:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Differential Pressure Not within Limits Following Trip of Exhaust Fan ENS 494892013-10-31T06:51:00031 October 2013 06:51:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Differential Pressure Not within Limits Following Trip of Exhaust Fan ENS 494652013-10-23T10:20:00023 October 2013 10:20:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Reactor Building Differential Pressure Less than Required by Technical Specifications ENS 494322013-10-13T08:20:00013 October 2013 08:20:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Differential Pressure at Zero Inches Water Gauge ENS 485252012-11-20T11:45:00020 November 2012 11:45:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Condition That Could Have Prevented Automatic Isolation of Reactor Water Cleanup System ENS 478442012-04-17T19:40:00017 April 2012 19:40:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Unit 2 Secondary Containment Affected by Violation of Unit 1 Secondary Containment Integrity During Outage ENS 439632008-02-05T23:45:0005 February 2008 23:45:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Irradiated Fuel Movement Performed with a Required Accident Mitigation/Radiation Release System Bypassed ENS 435632007-08-13T18:20:00013 August 2007 18:20:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Inoperable Radiation Monitors Due to Setpoint Calculation Errors ENS 412152004-11-22T20:10:00022 November 2004 20:10:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Portion of Primary Instrument Lines Not Aligned to Secondary Containment ENS 409702004-08-20T16:15:00020 August 2004 16:15:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Railroad Access Process Radiation Monitors Actuation Capability Was Inadvertently Defeated ENS 406462004-04-05T15:40:0005 April 2004 15:40:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Safety Function for Emergency Diesel Generators During Surveillance Testing 2019-05-22T06:56:00 | |
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