ENS 45855
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ENS Event | |
|---|---|
03:25 Apr 19, 2010 | |
| Title | Lco 3.0.3 Entry and Loss of Safety Function Due to Loss of Turbine Building High Energy Line Break Compensatory Measure |
| Event Description | At 2225 CDT on 4/18/2010, Operations discovered that the Unit 1 Turbine Building Truck Aisle Rollup Door Security Fence was closed. This fence was to be maintained open as the truck aisle is a required drainage path from the Unit 1 Turbine Building to outside in the event of flooding resulting from a High Energy Line Break (HELB). With the expanded metal mesh door [fence] closed, turbine building debris could clog the drainage path and result in a higher than calculated water level being reached for this event. As the final water level cannot be predicted, this represented an unanalyzed condition. The higher water levels would be reached at least one hour after the postulated turbine building HELB event. High water levels could result in a Loss of Safety Function for Unit 1 Emergency Diesel Generators. Auxiliary Feedwater (both units) and DC Electrical Power (both units) if water levels exceed critical heights in the associated rooms.
The doors [fence] were reopened at 2227 CDT. Unit 1 entered LCO 3.0.3 for this two minute period. With the doors [fence] opened, Unit 1 and 2 LCO conditions were again satisfied. The Unit 2 truck aisle was in the assumed condition, and Unit 2 is in Mode 5 so loss of AFW or DC power would not result in an LCO 3.0.3 entry. Unit 2 Emergency Diesel Generators are not affected as the Unit 2 truck aisle drain path would prevent water levels from reaching critical heights. The initial investigation determined that a Security Officer had closed the gate at approximately 1855 CDT on 4/18/2010. The NRC Resident Inspector has been notified. A press release is not planned.
In reference to the 4/18/2010 discovery of the security fences (screen door) closed on the Unit One Turbine Building truck aisle door and the Tech Spec LCO 3.0.3 entry on Unit One, further analysis of HELB flooding scenarios in the plant configuration known to be in effect at that time has shown that the LCO 3.0.3 entry was not warranted. Engineering analysis demonstrates that water levels in the Unit One Turbine Building from a postulated worst case HELB flooding event would only have rendered the 12 Motor Driven Auxiliary Feedwater Pump inoperable. Thus TS LCO 3.7.5 Condition B would have been the only LCO action statement required to be entered. No loss of safety function existed." The licensee will notify the NRC Resident Inspector. Notified the R3DO (Skokowski). |
| Where | |
|---|---|
Prairie Island  Minnesota (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+-0.22 h-0.00917 days <br />-0.00131 weeks <br />-3.01356e-4 months <br />) | |
| Opened: | John Kempkes 03:12 Apr 19, 2010 |
| NRC Officer: | Donald Norwood |
| Last Updated: | Apr 22, 2010 |
| 45855 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Prairie Island with 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
WEEKMONTHYEARENS 555292021-10-18T00:30:00018 October 2021 00:30:00
[Table view]10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Emergency Diesel Generators Simultaneously Inoperable ENS 538532019-01-31T13:43:00031 January 2019 13:43:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident En Revision Imported Date 3/25/2019 ENS 535462018-08-10T05:00:00010 August 2018 05:00:00 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 Emergency Diesel Generator Cooling Water Pumps Declared Inoperable ENS 530672017-11-12T09:03:00012 November 2017 09:03:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Containment Spray Pump Control Switches Out of Service ENS 526382017-03-20T21:39:00020 March 2017 21:39:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Historical Event Related to Past Operability ENS 518772016-04-21T20:50:00021 April 2016 20:50:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Missing Fire Barriers ENS 516422016-01-08T01:00:0008 January 2016 01:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition - Appendix R Credited Procedures Not in Place ENS 516162015-12-21T22:25:00021 December 2015 22:25:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Non-Compliant Fire Protection Manual Operator Actions ENS 514982015-10-26T12:03:00026 October 2015 12:03:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Associated with a High Energy Line Break ENS 514292015-09-28T18:27:00028 September 2015 18:27:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Both Unit 1 Emergency Diesel Generators Inoperable at the Same Time ENS 509942015-04-19T22:45:00019 April 2015 22:45:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Non Compliance with 10 Cfr 50 App R ENS 508262015-02-16T22:44:00016 February 2015 22:44:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Control Room Special Vent Boundary Inoperable ENS 508012015-02-10T08:50:00010 February 2015 08:50:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Voids Identified That Result in an Unanalyzed Condition ENS 505312014-10-13T19:25:00013 October 2014 19:25:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to a Missing Fire Barrier ENS 505232014-10-10T22:17:00010 October 2014 22:17:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Missing Fire Barrier ENS 504922014-09-24T20:33:00024 September 2014 20:33:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Unit 1 Train B Rvlis and Iccm Inoperable Due to Data Errors ENS 504752014-09-19T18:53:00019 September 2014 18:53:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Missing Fire Barriers ENS 503622014-08-08T15:26:0008 August 2014 15:26:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Lack of Appropriate Fuse Protection ENS 501702014-06-04T00:02:0004 June 2014 00:02:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Diesel Generators Declared Inoperable Due to Not Meeting High Energy Line Break Requirements ENS 496852013-12-31T15:33:00031 December 2013 15:33:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Removal of Multiple Steam Generator Lateral Support Shims and Bumpers ENS 493612013-09-19T17:20:00019 September 2013 17:20:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition No Documented Plan in Place to Receive Additional Fuel Oil During Maximum Probable Flood Condition ENS 491282013-06-17T21:15:00017 June 2013 21:15:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Unanalyzed Condition - Carbon Dioxide Fire Suppression System Does Not Meet Design Requirements ENS 486192012-12-21T15:00:00021 December 2012 15:00:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Both Unit Two Auxiliary Feedwater Pumps Declared Inoperable ENS 481862012-08-14T08:12:00014 August 2012 08:12:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown Based on Both Emergency Diesels Being Declared Inoperable ENS 481222012-07-20T19:00:00020 July 2012 19:00:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor Unit 2 Emergency Diesel Generators Inoperable Due to Missing Flood Control Barrier Seal ENS 480632012-07-02T20:51:0002 July 2012 20:51:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor Both Diesel Generators Declared Inoperable ENS 479492012-05-22T21:30:00022 May 2012 21:30:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Identified During a Fire Protection Review ENS 475222011-12-09T17:59:0009 December 2011 17:59:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition- Degraded Fire Barrier Between Fire Areas ENS 470102011-06-27T18:44:00027 June 2011 18:44:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Offsite Power Sources Declared Inoperable ENS 469342011-06-07T18:49:0007 June 2011 18:49:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Both Emergency Diesel Generators Declared Inoperable Due to Excess Outside Ambient Air Temperature ENS 466992011-03-25T15:53:00025 March 2011 15:53:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Unanalyzed Condition Due to Power Level Greater than Limit ENS 465082010-10-23T00:49:00023 October 2010 00:49:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition - Battery Chargers May Lockup During a Design Basis Event ENS 463182010-10-07T18:52:0007 October 2010 18:52:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Degraded Fire Barrier ENS 462612010-09-16T18:43:00016 September 2010 18:43:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition - Degraded Fire Barrier Identified ENS 459972010-06-09T16:35:0009 June 2010 16:35:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor Battery Rooms Declared Inoperable Due to Potential Flooding ENS 459372010-05-19T21:40:00019 May 2010 21:40:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Both Trains of Residual Heat Removal (Rhr) Inoperable ENS 458552010-04-19T03:25:00019 April 2010 03:25:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Lco 3.0.3 Entry and Loss of Safety Function Due to Loss of Turbine Building High Energy Line Break Compensatory Measure ENS 455672009-12-14T18:00:00014 December 2009 18:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Related to Certain Fire Conditions ENS 449312009-03-23T22:00:00023 March 2009 22:00:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition for Postulated Missile Hazard That Could Disable Both Trains of Component Cooling ENS 448592009-02-17T17:00:00017 February 2009 17:00:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Both Emergency Diesel Generators Declared Inoperable After Review of Work Boundary Isolation ENS 447732009-01-14T17:30:00014 January 2009 17:30:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Manual Actions for Fire Not in Compliance ENS 443792008-07-31T18:45:00031 July 2008 18:45:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Postulated High-Energy Line Break That Could Disable Both Trains of Component Cooling ENS 435922007-08-24T16:30:00024 August 2007 16:30:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Fire Barrier Separation Criteria Not Met for Afwp Rooms ENS 434042007-06-04T21:00:0004 June 2007 21:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Identified Non Compliant Fire Protection Manual Operator Actions ENS 430102006-11-25T01:45:00025 November 2006 01:45:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition ENS 413772005-02-06T02:46:0006 February 2005 02:46:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 4160 Volt Relaying and Metering Single Failure Vulnerability 2021-10-18T00:30:00 | |
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