ML19254F007

LER 79-026/03L:on 790926,during Safety Class Shock Suppressor Insp,Snubbber RR-13 on Loop a Recirculation Pump Had No Visible Fluid Level in Sight Glass.Caused by Leakage of Lenz Fitting.Snubber Completely Rebuilt & Tested

ML19254F007
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	10/30/1979
From:	Conway W VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19254F004	List: ML19254F003 ML19254F007
References
LER-79-026-03L, LER-79-26-3L, NUDOCS 7911050336
Download: ML19254F007 (2)

Text

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VTVYS1 05000271 LER 79/26-3L EVENT DESCRIPTION AND PROBABLE CONSEOUENCES Visual inspection of Vermont Yankee's safety class shock sup-pressors was performed as required by Technical Specifications 4.6.I. 4 during the 1979 refuel outage. Snubber RR-13 on the A loop recirculation pump was found with no visable fluid level in its sight glass. The snubber was removed and funct:'onally tested in the as-found condition. The snut5er did not lockup in tension within the required tolerances and was declared a visual inspection failure. The snubber was repaired and returned to service prior to reactor startup as required by Tech. Spec. section 3.6.I.4.

Based on the above, and the lack of any seismic event which would require the snabber to be functional, there were no adverse consequences of this occurrence to the health and safety of the public. Similar previous occurrences were reported to the Commission in RO 76-26/3L and RO 79-9/3L.

CAUSE DESCRIPTION AND CORRECTIVE ACTION Functional testing on the VY test machine revealed leakage at the Lenz fitting on the snubber rod end tube connection. No obvious seal degredation was observed; however, the fitting 0-rings were ssmewhat brittle. Snubber RR-13 was completely rebuilt and was functionally tested prior to reinstallation. As a result of the failure of snubber RR-13 to pass the visual examination, the next required inspection interval is 12 months

• 25%. RR-13 is a 4" Grinnel Figure 201 shock suppressor.

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