ML19290C684

RO-80-01/01T-0:on 800121,excess Letdown Lines Had Several Pipe Stress Points Above Normal or Upset Allowables.Caused by Incorrect Use of Valve Weight for HCV-1201 Pipe Stress Calculations.Snubber Will Be Added to Line

ML19290C684
Person / Time
Site:	North Anna
Issue date:	01/21/1980
From:	VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
References
IEB-79-14, NUDOCS 8002040564
Download: ML19290C684 (1)

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USNRC REGION.:

A LANTA.GFc'r.;3 Virginia Electric and Power Cocpany North Anna Pcwer Station, I! nit il tiRF-4 Cccket No. 50-338 U JAN 2l P3: I6 24 Hour Reportable Event Written ~ Folicw-IJp Event:

Overstressed Piping en Loop Drain Header LER/R0 80-01/017-0 During the review for IE Bulletin 79-14. Stone & 5tebster discovered that excess letdem lines 3/4*-CH-275-1502-Q1 and 3/4'-CH-123-1502-02 both have several points where the pipe stress is above nomal or upset allcwable. The stress en these lines, however, is less than faulted a11cwable.

The pipes are overstressed because incorrect valve weight was used for HCV-1201 in tha calculations for the pipe stress.

A snubber will he designed and added to the line in the area of the isolatica valve for~ the excess letdcm heat exchanger.

There has teen ~no effect on the plant as a result of th$1s nonconfor-mance.

The Ifne ~1eading to the excess letdcwn heat exchanger is isolated during normal cperatica.

The unit is.pr'esently undergoing low power physics testing in Hade 2.

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