ML19344B509

Third Revised Final Deficiency Rept Re Spent Fuel Pool Gates.Qa Aspects of Gate Integrity Will Be Verified or Certificates of Compliance Will Be Obtained from Fabricators.Matls & Welds Will Be Inspected & Tested

ML19344B509
Person / Time
Site:	Sequoyah
Issue date:	10/15/1980
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, NCR-SQN-NER-801, NUDOCS 8010210369
Download: ML19344B509 (3)

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17 TENNESSEE VALLEY AUTHORITY t CH ATTANOOGA. TENNESSEE 374cl l 400 Chestnut Street Tower II l

October 15, 1980 l

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Mr. James . O'Reilly, Director Offico of . pection and Enfcrcement l U.S. Xuclear . gulatory Co=1ccion l- Region II - Sul. = 3100 101 Itrietta Stre

• Atlanta, Georgia : "i03

Dear Hr. O'Reilly:

SECUO'lA3 tiUCLEAR PLA ;T UNITS 1 A!iD 2 - SPENT FUEL POOL GATES -

UCR sci hES 8012 - THIRD REVISED FINAL REFORT l The. subject deficiency was initially reported to NRC-CIE Inspector J. D. *diacox cn F.ay 1, 1980, in acccrdance with 10 CFR 50.55(e). Reports swee suocittec en :'.ay 29, June 15, July 2, and Jepcceber 3,1c80. De j fir 21 mport bc 5ccn further roviced :. the reque:: cf C. Parr, Au: ciliary Syctcma 3rinch Chief, to clarif/ t::e cerrsctive r.cticn fcr the spent c.:el pcol cask icading area cate at Scquoych. Enclosed is cur third revised final report.

If you have eny quastions, please set in touch with D. L. Lambert at FTS 357-2561.

Very truly yours, TENNESSCE VALLEY AUTHORITY >

l l L. M. Mills, Manager l Nuclear Regulation and Safety i

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Enclosure y cc: Mr. Victor Stello, Director (Enclosure),y '

Office of Inspection and 2nforcement U.S. tiuclear Regulatory Commission

'Jashinaten, DC 20"35 6

8010249 M T g u tso c=sa,nv cmae v" -

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SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 SPENT FUEL POOL GATES NCR SQN NEB 8012 10CFR50.55(e)

THIRD REVISED FINAL REPORT Descrietion of Deficiency The NCR states that the spent fuel pool gates (one to the transfer canal and one to the cask loading area) are not designed to Seismic Category I requirements in accordance with Regulatory Guide 1.13.

Si=ilar NCR's were written on Watts Bar (WBNNEB8005) and Bellefonte (BLT.:EB8005) Luclear Plants.

safety Italications ,

Structural failure of the gates during a seismic event could result in da: age to stored spent fuel elements. This could result in radiation levels in the spent fuel pool area higher than those assu=ed in the plant safety analysis, and thus could result in doses to plant persennel and the public greater than has been analyzed. This safety-related function results in a Seis=ic Category I(L) classification of the gates. There was a question within TVA as to whether the gates also have a pri=ary safety function of maintaining sufficient water level above the spent fuel. This function, if verified, would have made the gates Seismic Category I and would require QA program coverage of the gates' fabrication. It was found by analyses of pool water level drops due to leaking gates that this is not a required function of the gates; the water level will not drop sufficiently in any case to permit excessive radiation levels in.the pool area.

Corrective Action The spent fuel pool gates for all three plants were designed by TVA, considering seismic loadings. The fabrication was contracted out with the design ensuring the seismic integrity of the gates although the procure =ent documents did not otherwise specify the seismic requirements.

Quality assurance program coverage was not specified because the original designs considered that the gates would normally be stored, and would be installed only when it would be cecessary to dewater the transfer canal of the cask loading area for maintsnance.

Because of ~ increasing QC and QA documentation emphasis within TVA in the

. years since the gate fabri-anion was contracted out, the QA aspects of the gates' integrity is to La verified for all three plants. This will be done through the evaluation of inspection and repair records at the fabricators' facilities and at the sites if possible. Alternatively, certificates of co=pliance will be obtained from the fabricators to verify that the specified materials and construction standards were used in the gates' faorication. Failing both of the above, the verification will be obtained through testing and inspection of.the materials and welds in the gates. Any required corrective actions will be taken. . This work does not affect the reportability to NRC of the three NCR's . dis-1 cussed above.

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The Sequoyah and Watts Bar gate designs were reanalyzed. The only case for potential failure among the four gates at the two plants was for the case of water on bot 1 sides of the installed gates. Only the Sequoyah cask loading area gate was found to be inadequate. This problem at Sequoyah will be corrected by administratively requiring the gate to remain in its storage' location until modifications are made which qualify the gate.

, The transfer canal and the cask loading area gates at Sequoyah and Watts

. Bar were' designed with paired restraints attached to the pool wall at the l top and at the bottom of the gates. Midheight restraints were later added to the Watts Dar gates to correct another problem. The midheight restraints account for the Watts Bar cask loading area gate being qualified. - Midheight restraints were not installed at Sequoyah.

The Bellefente gates were designed after the analysis was made including the case of water on both sides of the gates. The resultant loads were therefore considered in the design, and no midheight restraints were i

needed.

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