ML20084H464

Final Deficiency Rept Re Defective Seismic Supports in Braces for Reactor Level Instrument Piping.Initially Reported on 740806.Deficiency Caused by QC Breakdown at Vendor Plant.Supports Replaced,Documented & Tested

ML20084H464
Person / Time
Site:	Browns Ferry
Issue date:	09/04/1974
From:	Gilleland J TENNESSEE VALLEY AUTHORITY
To:	Knuth D US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084H462	List: ML20084H464 ML20084H470 ML20084H472 ML20084H474
References
NUDOCS 8305040292
Download: ML20084H464 (3)

Text

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ENNESSEE VALLEY A HOPtlTY E F"d CHATTANOOGA, TENNESSEE J eik.g'I'

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ANNIVEASARY .q,'

OF PEOPLE IN  ; _* " .

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, .y Mr. Donald F. Knuth, Director . r i g..

Directorate of Regulatory Operations U.S. Atomic Energy Commission [. t.}, f-  :'[f4 Washington, DC 20545 p:

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Dear Mr. Knuth:

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p/ M BROWNS FERRY NUCLEAR PLANT UNIT 3 - DEFECTIVE SEISMIC SUPPORTS IN .j;

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BRACES FOR REACTOR LEVEL INSTRUMENT PIPING J-if ,;

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Initial report of the subject potential deficiency was made on - 'Y .2.

August 6, 1974. In compliance with paragraph 50.55(e) of 10 -c UY. .' i.. /

CFR Part 50, we submit the enclosed final report of the deficiency. K.] ..

1 Very truly yours, 2. e 5 y.. .

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J. E. Gilleland 9ku;I A Assistant to the Manager of Power f .p.: .;.,

f,l Y Enclosure W-CC (Enclosure): ') v, .

Mr. Norman C. Moseley, Director M '6 ..

Directorate of Regulatory Operations ,

P .M U.S. Atomic Energy Comission Region II - Suite 816 230 Peachtree Street, NW.

Atlanta, Georgia 30303 0292 74093p h5gOCK05000296 S

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ENCLOSURE O

• O BROWNS FERRY NUCLEAR PLANT UNIT 3 DEFECTIVE SEISMIC SUPPORT '

FINAL REPORT ,

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On August 6,1974, an initial report was made regerding the subject deficiency on Unit 3 to Richard Lewis, AEC-DRO Inspector, Re ton II. This report was .

made during a telephone conversation between Rober,t Bradley, Dan DeFord, Dan Bolinger, J. J. Wilder, and Richard Lewis, in compliance with ,

Paragraph 50.55(e) of 10CFR50. This is the final report for this occurrence.

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Description of Occurrence . -

Dur'ing the startup testing program on Unit 2, an obstruction to one of the subject supports on a Yarway water column was discovered. While in the '

process of removing the obstruction it became necessary to unpin one of the supports. It was then discovered that the unpinned support, winich was now '

i extended, could not be retracted into its proper position. As reported in Abnormal Occurrence Report BFAO-50-260/741W the rest of the supports were then tested and a total of 11 out of 14 were found to be defective. The supports for Unit 3 were then tested and 5 of 14 were found inoperative.

Cause of Deficiency .

The cause of this deficiency was a breakdown of QA at the vendor's plant.

Inspection of the Unit 3 supports in storage revealed that they were'not lubricated during assembly at the factory. -

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Safety Implications '

I The mechanical seismic supports for the Yarway water columns perform two  !;

functions. First, they secure the piping, preventing its collapse during b the unlikely occurrence cf an carthquake. Second, they allow the piping f the freedom to expand or contract under the cyclic. thermal loads for which .,

l they wer'el designed.

l In the latter case, had the defective supports been installed and subsequently -

locked up, sufficient thermal stress cycles could have developed over the life af the plant to cause the failure of the Yarway water columns. Vibration I j

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@ e water columns.

slone, however, would not adversely affect the supports or .

' Only the combination of thermal cycling preceded by vibrations could have detrimental results.

Description of corrective Action ,

First, all the scismic Three steps were taken to correct this deficiency.

Second, QA supports were replaced with new ones obtained from the factory.

documentation was received on each of the new supports certifying that thdy were inspected at each step of their assembly.' Third., each new support was

• functionally tested upon receipt.

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Means Taken to Prevent a Recurrence ad been checked to hheequipmentwasreplacedwithallnewsupportsthat '

guarantee they were fully functional. TVA is presently investigating new ,

Auditionally, .

equipment and/or. a better means for performing the same function.

on all future contract awards for this type seismic support, selected vendors shall be required to provide evidence of a' Quality Assurance Program which shall assur.e .

adequate. inspection prior to shipment. ,

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