ENS 49638: Difference between revisions

v t e ENS Event
22:27 Dec 16, 2013
Title	Unanalyzed Condition Due to Unfused Direct Current Ammeter Circuits
Event Description	At 1627 CST on December 16, 2013 Farley Nuclear Plant determined that the following was an unanalyzed condition: As a result of recent industry operating experience (OE 305419, EN 49411, EN 49419) regarding the impact of un-fused Direct Current (DC) ammeter circuits in the Control Room, Farley performed a review of ammeter circuitry for similar issues. The review determined the described condition to be applicable to Farley resulting in an unanalyzed condition with respect to 10 CFR 50 Appendix R analysis requirements. The wiring design for the ammeters contains a shunt in the current flow from each DC battery and battery charger, but the ammeter wiring attached to the shunt does not contain fuses. It is postulated that a fire could cause one of the ammeter wires to short to ground. Concurrently, 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 un-fused ammeter cable. The potential exists that the cable could heat up, causing a secondary fire in the ammeter raceway. The secondary fire could adversely affect safe shutdown equipment and potentially cause the loss of the ability to safely shutdown per 10 CFR 50 Appendix R. This condition is reportable in accordance with 10 CFR 50.72(b)(3)(ii)(B) as an unanalyzed condition. Compensatory measures have been implemented for affected areas of the plant. The NRC Resident Inspector has been notified.

ENS 49638 +/-
Where
Farley Alabama (NRC Region 2)
Reporting

10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition
Time - Person (Reporting Time:+-0.83 h-0.0346 days <br />-0.00494 weeks <br />-0.00114 months <br />)
Opened:	Darrin Gard 21:37 Dec 16, 2013
NRC Officer:	Daniel Mills
Last Updated:	Dec 16, 2013
49638 - 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 49638\u003C/a\u003E - \u003Ca href=\"/Farley\" title=\"Farley\"\u003EFarley\u003C/a\u003E\n\u003C/p\u003E\u003C/div\u003E\u003C/b\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003EUnanalyzed Condition Due to Unfused Direct Current Ammeter Circuits\n\u003C/p\u003E\u003C/div\u003E","title":"ENS 49638 - Farley\n","link":"","lat":31.223047222222224,"lon":-85.11253055555555,"icon":"/w/images/1/14/Southern_Nuclear_icon.png"}],"imageoverlays":null}
v • d • e

v t e Emergency Notification System
Farley with 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition
WEEKMONTHYEAR2018-05-08T04:00:00 [Table view]
[ENS list for Farley]

@@ Line 16: / Line 16: @@
 | event date = 12/16/2013 16:27 CST
 | last update date = 12/16/2013
-| title = Unanalyzed Condition Due To Unfused Direct Current Ammeter Circuits
+| title = Unanalyzed Condition Due to Unfused Direct Current Ammeter Circuits
 | event text = At 1627 CST on December 16, 2013 Farley Nuclear Plant determined that the following was an unanalyzed condition:
 As a result of recent industry operating experience (OE 305419, EN 49411, EN 49419) regarding the impact of un-fused Direct Current (DC) ammeter circuits in the Control Room, Farley performed a review of ammeter circuitry for similar issues. The review determined the described condition to be applicable to Farley resulting in an unanalyzed condition with respect to 10 CFR 50 Appendix R analysis requirements. The wiring design for the ammeters contains a shunt in the current flow from each DC battery and battery charger, but the ammeter wiring attached to the shunt does not contain fuses.

v t e Unit 1
W-3-LP
Reactor critical	Critical
Scram	No
Before	Power Operation (100 %)
After	Power Operation (100 %)

v t e Unit 2
W-3-LP
Reactor critical	Critical
Scram	No
Before	Power Operation (100 %)
After	Power Operation (100 %)

ENS 49638: Difference between revisions

Latest revision as of 21:52, 1 March 2018

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ENS 49638: Difference between revisions

Latest revision as of 21:52, 1 March 2018

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