ML19323J025

LER 80-011/03L-1:on 800508,following Shutdown,Broken Saddle Clamp Bolt Found on Hydraulic Snubber Hanger 490002.Caused by Fatigue & High Impact Loading.Bolts Replaced W/High Strength Bolts for High Temp Svc

ML19323J025
Person / Time
Site:	Millstone
Issue date:	06/06/1980
From:	Clement C NORTHEAST NUCLEAR ENERGY CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19323J024	List: ML19323J023 ML19323J025
References
LER-80-011-03L, LER-80-11-3L, NUDOCS 8006170661
Download: ML19323J025 (1)

Text

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LICENSEE EVENT REPORT -

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S 60 61 DOCKET NUM8ER EVENT DESCRIPiloN AND PROB ABLE CONSEQUENCES h al21i Following a plant shutdown, a broken saddle clamp bolt was found on hydraulic snubber J

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hanger 4'90002. Hanger 490002 restrains one of four 28" steam leads downstream of I the main turbine stop and control valves. The unit complied with Tech'nical I g,,, ,

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Specification 3.7.8.1. The bolt was a 13/4" UNC carbon steel machine bolt. I I

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TAKEN A TO ON PL NT M T HOURS 22 5 e e FOR B, $ PPLlE MANUFACTURER l33A jgl34z l@ l z lg [z,j@ l 010 l 0 l 0 l 37 lN l@ l42N l@ l43A l@ lBl1l3101 47 35 36 40 el . 44 CAUSE oESCRIPTION AND CORRECTIVE ACTIONS

,jOj l This failure and previously reported failures were'due to fatioue. The final failure  !

, i, j i was cause by the hign impact loading caused by turbine valve trios. The failed bolts I

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grade 87). The improved fatigue characteristics of this low alloy steel material I

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