ML19241A712

Final Deficiency Rept:Pipe Support 1-RCH-93 Failed to Slide During Hot Functional Testing.Caused by Failure to Lubricate Sliding Surfaces,Resulting in Plastic Deformation of Piping. Pipe Support Redesigned

ML19241A712
Person / Time
Site:	Sequoyah
Issue date:	06/22/1979
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML19241A710	List: ML19241A709 ML19241A712
References
NUDOCS 7907090318
Download: ML19241A712 (1)

Text

I ESCLUSURE SEQUCYAH tiL'CLL\R PLAST LSIT 1 PRES 5URI;ER REL;CF PlPING SUPPuRT SCR SWP-79-5-8 10 CFR 50.55(e)

FINAL REPCRT De.-cription of Deficiency Pipe support 1-RCH-93 for the pressurizer relief piping was designec te slide in the vertical direction as the cressurizer expanded during heatup of the reactor coolant system. During hot functional testing of unit 1, the hanger failed to slide because the required lubricant (Mollkote 321) had not been applied to the sliding surfaces and causcc the e-inch pressurizer relief piping to undergo plastic defor:at;or-The lubricant was not applied to the support because a note spec;;< r.s les use for this support was inadverteatly crittec from the suppert fabrication crawing by EDS Suclear, Inc., the contractor whc atsignt: t ..c support.

Safet 1 ,12 cation Statement 1:.c ceformed 6-inch pressurizer relief piping is part of tne reacter coolant pressure boundary. A failure of this piping would have lec ::

an uncontrolled blowdown of the reactor coolant system. Tnis event ;s wita;n the spectrum of reactor coolant system breaks evaluated :n .

cha;tur 15 of the firal safety analysis report.

Lorrect;ve Action P;;e support 1-RCH-93 has been redesigned so that lubrication :s net rega; red and will be modified to prevent recurrence.

lne cefarica 6-inch pressurizer re:ief piping will be returne: tc the re; aired snape by selective depos; tion of welding mater:al or otner aggro,r:ste means.

Inese corrective actions will be completed before fuel loadin;.

309 108 1' d1 "?p31/

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