ENS 51917
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ENS Event | |
|---|---|
16:38 May 10, 2016 | |
| Title | Containment Cooling Water System Inoperable Due to Unanalyzed Condition |
| Event Description | During scheduled maintenance, at 1138 CDT, the Fort Calhoun Station Shift Manager was notified via phone call and condition report of an unanalyzed condition which was the result of the maintenance on Shutdown Cooling Heat Exchanger valves. This condition could have led to the inability of the Component Cooling Water (CCW) system to perform its design function of providing a cooling medium for the Containment atmosphere under Loss of Coolant Accident (LOCA) conditions. This was identified by OPPD [Omaha Public Power District] staff engaged in Design Basis Reconstitution.
As part of the maintenance, HCV-484, Shutdown Cooling Heat Exchanger AC-4A CCW Outlet Valve, and HCV-481, Shutdown Cooling Heat Exchanger AC-4B CCW Inlet Valve, were opened. Under these conditions, with the assumed single failure loss of DC control power and accident conditions of a LOCA, CCW would be allowed to flow through both shutdown cooling heat exchangers, effectively bypassing flow to the Containment Cooling Units. These conditions are not assumed under plant design basis calculations, and therefore placed the plant in an unanalyzed condition. Following clearance removal at 1535 CDT, both HCV-484 and HCV-481 were returned to service and the condition described above no longer exists. The licensee notified the NRC Resident Inspector.
Discovered 6/15/2016 at 1330 CDT: During the extent of condition review for the above ENS notification, it was discovered that the unanalyzed condition that occurred on 5/10/2016 also occurred five other times during the past 3 years. Details for these additional occurrences will be included in the 60-day Licensee Event Report associated with the original 5/10/2016 ENS notification. The licensee has notified the NRC Resident Inspector. Notified R4DO (Taylor). |
| Where | |
|---|---|
Fort Calhoun  Nebraska (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+3 h0.125 days <br />0.0179 weeks <br />0.00411 months <br />) | |
| Opened: | Justin Wiemer 19:38 May 10, 2016 |
| NRC Officer: | Donald Norwood |
| Last Updated: | Jun 15, 2016 |
| 51917 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (85 %) |
| After | Power Operation (85 %) |
Fort Calhoun with 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 522012016-08-25T20:23:00025 August 2016 20:23:00
[Table view]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 Unanalyzed Condition Involving Potential Tornado Missile Damage ENS 519172016-05-10T16:38:00010 May 2016 16:38:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Containment Cooling Water System Inoperable Due to Unanalyzed Condition ENS 514872015-10-21T18:50:00021 October 2015 18:50:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Pressurizer Heater Bank Potential Circuit Failure Vulnerability ENS 508002015-02-09T23:30:0009 February 2015 23:30:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Safety Injection Tank Level Results in an Unanalyzed Condition ENS 494782013-10-28T17:30:00028 October 2013 17:30:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Postulated Event Could Result in a Hot Short That Could Adversely Impact Safe Shutdown Equipment ENS 493782013-09-23T18:40:00023 September 2013 18:40:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition - Epoxy Floor Coatings Do Not Meet Design Basis Requirements in Two Rooms ENS 493242013-09-05T13:31:0005 September 2013 13:31:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Low Pressure Safety Injection Pump Run Out Condition ENS 491192013-06-14T16:00:00014 June 2013 16:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Invalid Conditions Discovered Due to Exclusion of Small Bore Piping from Analysis ENS 491122013-06-13T13:05:00013 June 2013 13:05:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition ENS 490502013-05-17T05:00:00017 May 2013 05:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Embedment Depth for Seismic Anchors Inadequate ENS 488062013-03-04T20:00:0004 March 2013 20:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Mechanical Seal Material Design ENS 487872013-02-27T02:12:00027 February 2013 02:12:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Relay Backing Plate Fasteners Discovered to Be at Less than Specified Torque ENS 487812013-02-24T23:00:00024 February 2013 23:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Inverters Potentially Inoperable During Emergency Diesel Generator Operation ENS 487302013-02-07T20:30:0007 February 2013 20:30:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Possible Run-Out of High Pressure Safety Injection Pump ENS 480942012-07-11T21:03:00011 July 2012 21:03:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Analysis of Internal Containment Support Beam Exceeds Load Combination Limit ENS 479922012-06-04T20:14:0004 June 2012 20:14:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Reactor Coolant System in a Degraded Condition Due to an Instrument Rack Seismic Design Issue ENS 479002012-05-04T15:00:0004 May 2012 15:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Containment Equipment Not Analyzed for Environmental Conditions of Record ENS 478922012-05-02T16:55:0002 May 2012 16:55:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Unanalyzed Condition with Containment Pressure Instruments ENS 478622012-04-25T14:00:00025 April 2012 14:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Conditions Resulting from a Non-Conservative Error in Calculations ENS 478842012-03-02T13:41:0002 March 2012 13:41:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Degradation of Reactor Containment Electrical Penetration Seals ENS 476582012-02-10T06:00:00010 February 2012 06:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition - Guidance Not Adequate to Mitigate a Design Basis Flood ENS 473592011-10-20T15:50:00020 October 2011 15:50:00 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 Flood Barrier Penetrations Not Water Tight ENS 478482011-10-06T18:44:0006 October 2011 18:44:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Waste Disposal System Class One Seismic Support Inoperable ENS 470882011-07-22T13:30:00022 July 2011 13:30:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Fire Supression Pumps Inoperable ENS 469652011-06-16T17:30:00016 June 2011 17:30:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Additional Penetration Identified for Mitigation During Walkdown ENS 468932011-05-26T05:15:00026 May 2011 05:15:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Potential Flooding Path Discovered ENS 467472011-04-12T14:15:00012 April 2011 14:15:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Unsealed Flood Barrier Penetration ENS 467412011-04-08T15:24:0008 April 2011 15:24:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Unsealed Flood Barrier Penetration ENS 467232011-04-04T20:00:0004 April 2011 20:00:00 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 Scaffolding Affecting Safety Related Equipment ENS 467162011-04-01T02:26:0001 April 2011 02:26:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Identified Unsealed Flood Barrier Penetrations ENS 466902011-03-22T18:08:00022 March 2011 18:08:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Potential Flooding of Raw Water Pump ENS 466892011-03-22T15:58:00022 March 2011 15:58:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Containment Coolers Declared Inoperable ENS 466742011-03-15T20:56:00015 March 2011 20:56:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Flood Barrier Penetration Not Sealed ENS 465902011-01-27T22:23:00027 January 2011 22:23:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Unsealed Penetrations Discovered in the Intake Structure ENS 463682010-10-27T17:22:00027 October 2010 17:22:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Unit Commenced Shutdown After Declaring Containment Spray Inoperable ENS 462972010-09-30T21:16:00030 September 2010 21:16:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Potential Flooding Via Condensate Drain Lines ENS 458282010-04-08T21:22:0008 April 2010 21:22:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown Due to Inoperable Steam Generator Inlet Isolation Valve ENS 454672009-10-26T15:50:00026 October 2009 15:50:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Pressurizer and Feedwater Storage Tank Level Indications Do Not Meet Appendix R Requirements ENS 465942009-09-09T14:02:0009 September 2009 14:02:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Unsealed Penetrations Discovered in the Intake Structure ENS 441382008-04-14T17:45:00014 April 2008 17:45:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Energy Line Break Analysis Revealed Potential Accident Mitigation Deficiency ENS 429432006-10-28T22:09:00028 October 2006 22:09:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition ENS 429022006-10-12T22:30:00012 October 2006 22:30:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Steam Generator Instrumentation Nonconformance ENS 428962006-10-10T20:00:00010 October 2006 20:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Containment Spray Valve Mispositioned ENS 425122006-04-19T14:45:00019 April 2006 14:45:00 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 Postulated Scenario Where Containment Spray System May Be Unable to Fulfill Design Safety Function ENS 413862005-02-08T15:20:0008 February 2005 15:20:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Steam-Driven Auxiliary Feedwater (Afw) Pump Declared Inoperable Due to Design Issue 2016-08-25T20:23:00 | |
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