ENS 41742: Difference between revisions

From kanterella

Latest revision as of 21:20, 1 March 2018

v t e ENS Event
23:49 Jun 2, 2005
Title	Appendix R Assessment on Remote Shutdown Panel
Event Description	The licensee provided the following information via facsimile: On 6/2/05, while performing an Appendix 'R' assessment, it was determined that the capability to achieve and maintain safe shutdown conditions, as required by Appendix 'R', has not been adequately demonstrated. Specifically, a postulated fire requiring the evacuation of the Control Room could also cause a spurious hot short in the protective relaying circuitry for the credited division of essential electrical power and subsequent loss of that division. It was recently determined that the hot short could occur at anytime during the transient, whereas previous evaluations had assumed any such hot short would be associated with the initiating event. Consequently, existing compensatory measures would only be implemented if the adverse consequences were apparent, and therefore might not be implemented within the timeframe required to assure satisfactory results. The result is that Appendix 'R' requirements are not met, and an unanalyzed condition that significantly degrades plant safety may exist. A 30 day LCO was entered at 1749 per Tech Spec LCO 3.3.3.2 Function 4.e for the Remote Shutdown Panel 'B' Essential 4160 Instrumentation transfer and control. The licensee notified the NRC Resident Inspector.

ENS 41742 +/-
Where
Duane Arnold Iowa (NRC Region 3)
Reporting

10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition
LER:	05000331/LER-2005-001
Time - Person (Reporting Time:+-1.97 h-0.0821 days <br />-0.0117 weeks <br />-0.0027 months <br />)
Opened:	Hans Olson 21:51 Jun 2, 2005
NRC Officer:	Mark Abramovitz
Last Updated:	Jun 2, 2005
41742 - 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 41742\u003C/a\u003E - \u003Ca href=\"/Duane_Arnold\" title=\"Duane Arnold\"\u003EDuane Arnold\u003C/a\u003E\n\u003C/p\u003E\u003C/div\u003E\u003C/b\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003EAppendix R Assessment on Remote Shutdown Panel\n\u003C/p\u003E\u003C/div\u003E","title":"ENS 41742 - Duane Arnold\n","link":"","lat":42.10089166666667,"lon":-91.77759444444445,"icon":"/w/images/9/9b/NextEra_Energy_icon.png"}],"imageoverlays":null}
v • d • e

v t e Emergency Notification System
Duane Arnold with 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition
WEEKMONTHYEAR2015-03-31T20:09:00 [Table view]
[ENS list for Duane Arnold]

@@ Line 16: / Line 16: @@
 | event date = 06/02/2005 17:49 CST
 | last update date = 06/02/2005
-| title = Appendix R Assessment On Remote Shutdown Panel
+| title = Appendix R Assessment on Remote Shutdown Panel
 | event text = The licensee provided the following information via facsimile:
 On 6/2/05, while performing an Appendix 'R' assessment, it was determined that the capability to achieve and maintain safe shutdown conditions, as required by Appendix 'R', has not been adequately demonstrated.  Specifically, a postulated fire requiring the evacuation of the Control Room could also cause a spurious hot short in the protective relaying circuitry for the credited division of essential electrical power and subsequent loss of that division.  It was recently determined that the hot short could occur at anytime during the transient, whereas previous evaluations had assumed any such hot short would be associated with the initiating event.  Consequently, existing compensatory measures would only be implemented if the adverse consequences were apparent, and therefore might not be implemented within the timeframe required to assure satisfactory results.  The result is that Appendix 'R' requirements are not met, and an unanalyzed condition that significantly degrades plant safety may exist.