ENS 52242
ENS Event | |
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14:08 Sep 15, 2016 | |
Title | Potential Unanalyzed Condition Based on Identified Non-Conforming Conditions |
Event Description | During performance of an extent of condition evaluation of protection for Technical Specification (TS) equipment from the damaging effects of tornadoes, Arkansas Nuclear One, Unit 1, identified non-conforming conditions in the plant design such that specific TS equipment on Unit 1 is considered not [to] be adequately protected from tornado missiles. The reportable condition is postulated by tornado missiles entering vital switchgear rooms 99 and 100 and striking vital switchgears in the rooms. A tornado could generate multiple missiles capable of striking the Unit 1 vital switchgear and rendering both safety related AC electrical trains inoperable.
This condition is reportable per 10 CFR 50.72(b)(3)(ii)(B) for any event or condition that results in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety, and per 10 CFR 50.72(b)(3)(v) for any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to (A) safe shutdown capability, (B) residual heat removal capability, or (D) accident mitigation. This condition was identified as part of an on-going extent of condition review of potential tornado missile related site impacts. Licensee Event Report (LER) 50-313/2016-002-00 was recently submitted addressing previously identified tornado missile vulnerabilities at the Unit 1 plant. Enforcement discretion per Enforcement Guidance Memorandum EGM 15-002 has been implemented and required actions taken. Corrective actions will be documented in a follow-on licensee event report. The licensee has notified the NRC Resident Inspector. |
Where | |
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Arkansas Nuclear Arkansas (NRC Region 4) | |
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)(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 | |
Time - Person (Reporting Time:+-2.83 h-0.118 days <br />-0.0168 weeks <br />-0.00388 months <br />) | |
Opened: | Don Walls 11:18 Sep 15, 2016 |
NRC Officer: | Donald Norwood |
Last Updated: | Sep 15, 2016 |
52242 - NRC Website | |
Unit 1 | |
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Reactor critical | Critical |
Scram | No |
Before | Power Operation (90 %) |
After | Power Operation (90 %) |
Arkansas Nuclear with 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 | |
WEEKMONTHYEARENS 534562023-07-15T10:39:00015 July 2023 10:39:00
[Table view]10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Pressure Boundary Leakage Identified While Shutdown ENS 549542020-10-19T04:13:00019 October 2020 04:13:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Control Room Envelope Inoperable ENS 543392019-10-20T15:30:00020 October 2019 15:30:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Control Room Envelope Breach ENS 522712016-09-30T02:00:00030 September 2016 02:00:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Unisolable Leak on Decay Heat Removal Piping Due to Weld Failure on a 1" Common Pipe ENS 522422016-09-15T14:08:00015 September 2016 14:08:00 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 Unanalyzed Condition Based on Identified Non-Conforming Conditions ENS 522342016-09-11T19:51:00011 September 2016 19:51:00 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)(ii)(B), Unanalyzed Condition Inadequate Design Protection of Safety-Related Equipment Identified During Tornado Missile Impact Evaluation ENS 521952016-08-24T13:41:00024 August 2016 13:41:00 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 Unanalyzed Condition Associated with Damaging Effects of Tornados ENS 518082016-03-19T22:10:00019 March 2016 22:10:00 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 That Could Challenge Rhr Equipment During Flood Conditions ENS 506412014-11-25T18:11:00025 November 2014 18:11:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Deficiency in Methodology Used for Emergency Core Cooling System Performance Requirements ENS 505192014-10-08T15:35:0008 October 2014 15:35:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Fire Induced Cable Failure in Multiple Fire Zones ENS 498732014-03-05T16:20:0005 March 2014 16:20:00 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 Discovery of Individual Pathways That Could Bypass Flood Barriers ENS 486442013-01-02T19:08:0002 January 2013 19:08:00 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 Inadvertent Actuation of Safety Injection, Containment Cooling and Containment Isolation Signals ENS 477772012-03-28T01:20:00028 March 2012 01:20:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Spent Fuel Handling Machine Not Fully Qualified for a Seismic Event ENS 471202011-08-02T18:46:0002 August 2011 18:46:00 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 Vulnerability from a Potential High Energy Line Break ENS 453772009-09-22T18:29:00022 September 2009 18:29:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Resulting from an Unlatched Door Serving as a High Energy Line Break Barrier 2023-07-15T10:39:00 | |