ENS 49464
ENS Event | |
|---|---|
18:00 Oct 22, 2013 | |
| Title | Postulated Hot Short Fire Event That Could Adversely Impact Safe Shutdown Equipment |
| Event Description | A review of industry operating experience regarding the impact of unfused Direct Current (DC) ammeter circuits in the control room has determined the described condition to be applicable to Nine Mile Point, Units 1 and 2 resulting in an unanalyzed condition with respect to 10 CFR 50 Appendix R analysis requirements. The original plant wiring design and associated analysis for the Class 1E batteries control room ampere indications do not include overcurrent protection features to limit the fault current.
In the postulated event, a fire in the control room could cause one of the ammeter wires to short to the ground plane. Simultaneously, it is postulated that the fire causes another DC wire from the opposite polarity on the same battery to also short to the ground plane. This could cause a ground loop through the unprotected ammeter wiring. This event could result in excessive current flow (i.e., 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 and potentially cause the loss of the ability to conduct a safe shutdown as required by 10 CFR 50 Appendix R. This condition has been entered into the Nine Mile Point corrective action program as Condition Reports CR-2013-008747 (NMP1) and CR-2013-008749 (NMP2). This condition is being reported in accordance with 10 CFR 50.72(b)(3(ii)(B). Interim compensatory measures (i.e., fire watches) have been implemented for affected areas of the plants. The licensee has notified the NRC Resident Inspector. |
| Where | |
|---|---|
Nine Mile Point  New York (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
| LER: | 05000220/LER-2013-002 05000410/LER-2013-003 |
| Time - Person (Reporting Time:+1.47 h0.0613 days <br />0.00875 weeks <br />0.00201 months <br />) | |
| Opened: | Michael Smith 19:28 Oct 22, 2013 |
| NRC Officer: | Donald Norwood |
| Last Updated: | Oct 22, 2013 |
| 49464 - NRC Website
Loading map... {"minzoom":false,"maxzoom":false,"mappingservice":"leaflet","width":"350px","height":"250px","centre":false,"title":"","label":"","icon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"zoom":6,"defzoom":14,"layers":["OpenStreetMap"],"image layers":[],"overlays":[],"resizable":false,"fullscreen":false,"scrollwheelzoom":true,"cluster":false,"clustermaxzoom":20,"clusterzoomonclick":true,"clustermaxradius":80,"clusterspiderfy":true,"geojson":"","clicktarget":"","imageLayers":[],"locations":[{"text":"\u003Cb\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003E\u003Ca class=\"mw-selflink selflink\"\u003EENS 49464\u003C/a\u003E - \u003Ca href=\"/Nine_Mile_Point\" title=\"Nine Mile Point\"\u003ENine Mile Point\u003C/a\u003E\n\u003C/p\u003E\u003C/div\u003E\u003C/b\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003EPostulated Hot Short Fire Event That Could Adversely Impact Safe Shutdown Equipment\n\u003C/p\u003E\u003C/div\u003E","title":"ENS 49464 - Nine Mile Point\n","link":"","lat":43.52021388888889,"lon":-76.40656388888888,"icon":"/w/images/b/be/Constellation_icon.png"}],"imageoverlays":null} | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 500982014-05-08T20:45:0008 May 2014 20:45:00
[Table view]10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Postulated Hot Short Fire Event That Could Adversely Impact Safe Shutdown Equipment ENS 494642013-10-22T18:00:00022 October 2013 18:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Postulated Hot Short Fire Event That Could Adversely Impact Safe Shutdown Equipment ENS 468272011-05-06T17:00:0006 May 2011 17:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Changes in Fuel Vendor Calculation Methodology to Comply with the Eccs Performance Requirements of 10 Cfr 50.46(B) ENS 439902008-02-16T00:02:00016 February 2008 00:02:00 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 Potential Inoperability of Emergency Core Cooling Systems Due to an Unalalyzed Condition ENS 407492004-05-14T13:17:00014 May 2004 13:17:00 Other Unspec Reqmnt, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Change in the Methodology Used by Ge/Gnf to Demonstrate Compliance with Eccs Performance Requirements 2014-05-08T20:45:00 | |