ENS 52083
ENS Event | |
|---|---|
20:00 Jul 12, 2016 | |
| Title | Degraded Fire Barrier |
| Event Description | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73.
During the performance of a fire seal and barrier surveillance test, a degraded fire seal barrier that provides 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> separation between two fire zones containing redundant safe shutdown trains was identified in the 100 foot elevation of the PVNGS Unit 1 Auxiliary Building. This condition is reportable in accordance with 10CFR50.72(b)(3)(ii)(B) as an unanalyzed condition. Fire protection detection and mitigation systems in both fire zones are operable and compensatory measures (fire watches) have been implemented for affected areas. The NRC Resident Inspector has been notified. The degraded fire barrier consists of two holes in the through wall fire barrier surrounding two two-inch conduits. The two holes are approximately one to one and a half inches across.
Subsequent Engineering evaluation concluded the degraded fire seal in PVNGS Unit 1 reported on July 12, 2016, did not place PVNGS in an unanalyzed condition that significantly degraded plant safety. The degraded fire seal would have continued to provide the required degree of separation for redundant safe shutdown trains. The evaluation found a fire initiated in a fire zone on either side of the barrier would not propagate within one hour into the adjacent zone with redundant safe shutdown equipment. These conclusions were based on an existing fire analysis which was used to demonstrate that the required degree of separation between safe shutdown equipment remained intact. Based on the above information, PVNGS is retracting event notification#52083, as the degraded fire seal did not place PVNGS Unit 1 an unanalyzed condition that significantly degraded plant safety. The NRC Resident Inspectors have been informed. Notified R4DO (Proulx). |
| Where | |
|---|---|
Palo Verde  Arizona (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
| Time - Person (Reporting Time:+1.88 h0.0783 days <br />0.0112 weeks <br />0.00258 months <br />) | |
| Opened: | Ivory Byers 21:53 Jul 12, 2016 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | Aug 18, 2016 |
| 52083 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 539682019-04-01T03:06:0001 April 2019 03:06:00
[Table view]10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Unanalyzed Condition Due to Eccs Leakage ENS 520832016-07-12T20:00:00012 July 2016 20:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Degraded Fire Barrier ENS 494112013-10-04T16:46:0004 October 2013 16:46:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Postulated Fire Event Could Result in a Hot Short That Could Adversely Impact Safe Shutdown Equipment ENS 488142013-03-09T02:21:0009 March 2013 02:21:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Spent Fuel Pool Criticality Analysis of Record Not Revised Following Power Uprate ENS 474592011-11-19T15:28:00019 November 2011 15:28:00 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 the Low Pressure Safety Injection System Was Subjected to High Pressure Resulting in Both Trains Being Declared Inoperable ENS 448462009-02-11T20:18:00011 February 2009 20:18:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Possibly Inadequate Backup Nitrogen Supply for Atmospheric Dump Operation ENS 431402007-02-03T19:32:0003 February 2007 19:32:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Technical Specification 3.0.3 Entered During Routine Surveillance Testing of Control Element Assemblies (Cea'S) ENS 428472006-09-19T08:05:00019 September 2006 08:05:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Pressurizer Heater Capacity Less than Tech Spec Limit ENS 427322006-07-27T02:00:00027 July 2006 02:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Limiting Condition for Operation 3.7.4 Deemed to Be Nonconservative ENS 420502005-10-11T23:02:00011 October 2005 23:02:00 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, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Tech Spec Required Shutdown of Both Unit 2 and 3 ENS 417892005-06-23T15:23:00023 June 2005 15:23:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unit 2 Aux Feedwater Train Separation Not Maintained During Operation 2019-04-01T03:06:00 | |