ENS 49423
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ENS Event | |
|---|---|
22:30 Oct 9, 2013 | |
| Title | Postulated Hot Short Fire Event That Could Adversely Impact Safe Shutdown Equipment |
| Event Description | A review of industry operating experience with respect to fire induced damage to unfused Direct Current (DC) ammeter circuits in the control room has determined that the condition described below is applicable to Wolf Creek Nuclear Generating Station. This condition results in an unanalyzed condition with respect to 10CFR50 Appendix R analysis requirements. The original plant wiring design did not include overcurrent protection features to limit the fault current in these circuits. The wiring design for the ammeters contains a shunt in the current flow from each NK direct current (DC) battery or charger. Two leads run from the shunt to a current meter in the main control room (MCR). These leads are tied to the positive polarity of the NK battery system. The ammeter wiring attached to the shunt is not overcurrent protected. It is postulated that a fire could cause one of these ammeter wires to short to ground at the same time the fire causes another DC wire from the opposite polarity on the same battery to also short to ground. This would cause a ground loop through the unfused ammeter cable. This event could result in excessive current flow (heating) in the ammeter wiring to the point of causing a secondary fire in the raceway system. The secondary fire could adversely affect safe shutdown equipment. Reference Palo Verde plant event #49411. A Breech Authorization with compensatory Control Room hourly fire watch for this issue is in place and will remain in effect until this deficiency is resolved.
This condition has been discussed with the Resident Inspector. Similar Events #49422 and #49419 |
| Where | |
|---|---|
Wolf Creek  Kansas (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
| Time - Person (Reporting Time:+0.28 h0.0117 days <br />0.00167 weeks <br />3.83544e-4 months <br />) | |
| Opened: | Johnney Camp 22:47 Oct 9, 2013 |
| NRC Officer: | Charles Teal |
| Last Updated: | Oct 9, 2013 |
| 49423 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 526662017-04-05T19:00:0005 April 2017 19:00:00
[Table view]10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition for Both Edg Transfer Line Connections ENS 506282014-11-19T21:37:00019 November 2014 21:37:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Postulated Hot Short Fire Event That Could Adversely Impact Safe Shutdown Equipment ENS 504682014-09-18T16:55:00018 September 2014 16:55:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Postulated Hot Short Fire Event That Could Adversely Impact Safe Shutdown Equipment ENS 494232013-10-09T22:30:0009 October 2013 22:30:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Postulated Hot Short Fire Event That Could Adversely Impact Safe Shutdown Equipment ENS 481342012-07-25T21:02:00025 July 2012 21:02:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Identification of a Degraded or Unanalyzed Condition ENS 474122011-11-03T21:00:0003 November 2011 21:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition for a Postulated Control Room Fire ENS 470762011-07-20T18:15:00020 July 2011 18:15:00 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 Fire Protection Program Concern ENS 469092011-06-01T18:15:0001 June 2011 18:15:00 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)(ii)(B), Unanalyzed Condition Both Trains of Component Cooling Water Declared Inoperable Due to Voiding ENS 464882010-12-17T21:35:00017 December 2010 21:35:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition - Potential Equipment Actuations Due to Electrical Short Circuits ENS 464282010-11-18T22:26:00018 November 2010 22:26:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Post Fire Safe Shutdown Unanalyzed Condition ENS 461962010-08-21T22:00:00021 August 2010 22:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition One Train Eccs Declared Inoperable Due to Void in "a" Rhr Heat Exchanger ENS 461362010-07-28T19:22:00028 July 2010 19:22:00 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)(ii)(B), Unanalyzed Condition Three Auxiliary Feedwater (Afw) Trains Declared Inoperable ENS 458592010-04-20T18:07:00020 April 2010 18:07:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Five Potential Issues Discovered During Post-Fire Safe Shutdown Review ENS 456922010-02-10T00:00:00010 February 2010 00:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Post Fire Safe Shutdown Unanalyzed Condition ENS 452772009-08-19T20:00:00019 August 2009 20:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Time to Establish Charging Flow Exceeded Thermal Hydraulic Analysis ENS 445862008-10-21T05:00:00021 October 2008 05:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition During Design Basis Fire in Area A-27 of Auxiliary Building ENS 441722008-04-26T18:18:00026 April 2008 18:18:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Discovered Due to Improperly Installed Fuse Wiring in Class 1E Air Conditioning Unit ENS 441312008-04-10T15:15:00010 April 2008 15:15:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition "Analysis Indicates Containment Coolers May Not Have Automatically Started in Slow Speed Following Postulated Main Steam Line Break ENS 426032006-05-24T15:38:00024 May 2006 15:38:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Discovered During Post-Fire Safe Shutdown Area Review ENS 423272006-02-10T17:00:00010 February 2006 17:00:00 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 Potential for Loss of Safe Shutdown Capability ENS 421822005-12-02T00:30:0002 December 2005 00:30:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition - Emergency Diesel Capability ENS 421462005-11-16T21:30:00016 November 2005 21:30:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Failure to Meet Required Response Times for Shutdown Outside Control Room ENS 420292005-09-30T14:45:00030 September 2005 14:45:00 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)(ii)(B), Unanalyzed Condition Potential Vulnerabilities Discovered During Design Basis Fire Review ENS 417862005-05-10T21:55:00010 May 2005 21:55:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Emergency Safety System Actuation Dampers Inoperable ENS 413272005-01-13T01:45:00013 January 2005 01:45:00 Other Unspec Reqmnt, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 24 Hour Condition of License Report Regarding Halon System- Actuator Connection Error ENS 413172005-01-07T23:00:0007 January 2005 23:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Loss of a Fire Safe Shutdown Success Path 2017-04-05T19:00:00 | |
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