ENS 52646: Difference between revisions

v t e ENS Event
00:57 Mar 29, 2017
Title	Unanalyzed Condition for a Postulated Moderate Energy Line Break
Event Description	On March 28, 2017 at approximately 1957 CDT, a condition was discovered whereby a postulated moderate-energy line break (MELB) involving three fire protection (FP) pipe segments in the Safeguards Building did not contain MELB shielding. It was subsequently determined a postulated crack in one of the affected FP piping sections could adversely affect circuitry associated with the cooling support system for the train A RHR [Residual Heat Removal] pump room, potentially causing the ventilation system to be unavailable to support operation of the train A RHR pump. This condition is not consistent with the CPNPP licensing basis for the protection of essential safe shutdown RHR equipment. At approximately 1957 CDT train A RHR was declared inoperable but available and the unit entered a seventy-two hour LCO [Limiting Condition for Operation] Action Statement per Technical Specification 3.5.2 B pending completion of mitigative actions. Since Unit 1 train B RHR system components and related supporting equipment have been periodically declared inoperable at various times in the last three years for surveillance testing or maintenance, given the MELB condition, both trains of RHR and or support equipment could have been inoperable and this represents an unanalyzed condition per 10 CFR 50.72(b)(3)(ii)(B). At the time of discovery, train B RHR and support equipment were operable. Therefore, the identified condition is not reportable as a loss of safety function per 10 CFR 50.72(b)(3)(v). The Senior NRC Resident Inspector has been notified. Compensatory actions will include installing a spray shield on the affected cable trays. * * RETRACTION FROM JOHN ALEXANDER TO VINCE KLCO ON 5/23/17 AT 1720 EDT * * * On 03/29/2017 Comanche Peak reported an ENS Report (no. 52646) related to the identification of potential moderate-energy line break (MELB) considerations in the Safeguards Building and the potential for adverse interaction with specified Unit 1 electrical equipment. The specific interactions of concern were related to ventilation equipment which would support operation of the Unit 1 A RHR train and several segments of fire protection piping. Subsequent investigations by Engineering have determined: (1) all but one of the suspected potential interactions were determined to not be credible, i.e., the potential MELB would not result in an adverse interaction with the 'target' equipment, and (2) for the remaining potential interaction, an assessment of piping stresses determined there was not a credible MELB source in the affected piping segment and therefore there was not a potential for adverse interaction with the ventilation support equipment. Based on the above, the condition described in ENS 52646 is not considered to be an un-analyzed condition as described in 10 CFR 50.72(b)(3)(ii)(B). The licensee informed the NRC Resident Inspector. Notified the R4DO (Groom).

ENS 52646 +/- *RETRACTED*
Where
Comanche Peak Texas (NRC Region 4)
Reporting

10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition
Time - Person (Reporting Time:+2.52 h0.105 days <br />0.015 weeks <br />0.00345 months <br />)
Opened:	Raul Martinez 03:28 Mar 29, 2017
NRC Officer:	Mark Abramovitz
Last Updated:	May 23, 2017
52646 - 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 52646\u003C/a\u003E - \u003Ca href=\"/Comanche_Peak\" title=\"Comanche Peak\"\u003EComanche Peak\u003C/a\u003E\n\u003C/p\u003E\u003C/div\u003E\u003C/b\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003EUnanalyzed Condition for a Postulated Moderate Energy Line Break\n\u003C/p\u003E\u003C/div\u003E","title":"ENS 52646 - Comanche Peak\n","link":"","lat":32.29839166666667,"lon":-97.78532222222222,"icon":"/w/images/d/d7/Luminant_icon.png"}],"imageoverlays":null}
v • d • e

v t e Emergency Notification System
Comanche Peak with 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition
WEEKMONTHYEAR2017-06-21T15:00:00 [Table view]
[ENS list for Comanche Peak]

@@ Line 17: / Line 17: @@
 | event date = 03/28/2017 19:57 CDT
 | last update date = 05/23/2017
-| title = Unanalyzed Condition For A Postulated Moderate Energy Line Break
+| title = Unanalyzed Condition for a Postulated Moderate Energy Line Break
 | event text = On March 28, 2017 at approximately 1957 CDT, a condition was discovered whereby a postulated moderate-energy line break (MELB) involving three fire protection (FP) pipe segments in the Safeguards Building did not contain MELB shielding. It was subsequently determined a postulated crack in one of the affected FP piping sections could adversely affect circuitry associated with the cooling support system for the train A RHR [Residual Heat Removal] pump room, potentially causing the ventilation system to be unavailable to support operation of the train A RHR pump. This condition is not consistent with the CPNPP licensing basis for the protection of essential safe shutdown RHR equipment.
 At approximately 1957 CDT train A RHR was declared inoperable but available and the unit entered a seventy-two hour LCO [Limiting Condition for Operation] Action Statement per Technical Specification 3.5.2 B pending completion of mitigative actions.

v t e Unit 1
W-4-LP
Reactor critical	Critical
Scram	No
Before	Power Operation (100 %)
After	Power Operation (100 %)

ENS 52646: Difference between revisions

Latest revision as of 20:42, 1 March 2018

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ENS 52646: Difference between revisions

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