ML20004E278
| ML20004E278 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 05/26/1981 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-81-435-000, REF-PT21-81-435-070 10CFR-050.55E, 10CFR-50.55E, PT21-81-435, PT21-81-435-000, SQRD-50-328-81, NUDOCS 8106110461 | |
| Download: ML20004E278 (3) | |
Text
TENNESSEE VALLEY AUTHORITY CH ATTANOOG A. TENNESSEE 37401 400 Chestnut Street Tower II pgg May 26, 1981 SQRD-50-328/81-34
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Mr. James O'Reilly, Director Office of Inspytion and Enforcement U.S. Nuclear Re latory Commission Region II - Suite 100 101 Marietta Street Atlanta, Georgia 30 3
Dear Mr. O'Reilly:
SEQUOYAH NUCLEAR PLANT UNIT 2 - STEAM GENERATOR BLOWDOWN LINE - LOOP NO. 2 PIPING ANALYSIS ERROR - SQRD-50-328/81 FINAL REPORT The subject deficiency was initially reported to NRC-0IE Inspector R. V. Crlenjak on May 6, 1981 in accordance with 10 CFR 50.55(e) as NCR SQN CEB 8112. Enclosed is our final mport. We consider 10 CFR 21 applirable to this deficiency.
If you have any questions, please get in touch with D. L. Lambert at FTS 857-2581.
Very truly yours, TENNESSEE VALLEY AUTHORITY l
L. M. Mills, Manager Nuclear Regulation and Safety Enclosure
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cc:
Mr. Victor Stello, Director (Enclosure) V Office of Inspection and Enforcenent U.S. Nuclear Regulatory Comission Washington, DC 20555
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An Equal 0;::ortunity Er;:loyer
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ENCLOSURE SEQUOYAH NUCLEAR PLANT UNIT 2 STEAM GENERATOR BLOWDOWN LINE - LOOP NO. 2 PIPING ANALYSIS ERROR SQRD-50-328/81-34 10 CFR 50.55(e)
FINAL REPORT Descriptio'n of Deficiency Piping movements of the steam generator blowdown line, loop No. 2, were greater during hot functional testing than anticipated in the design; consequently, certain snubbers would have bottomed out. TVA discovered that a lateral support that had been installed before hot functional testing had been inadvertently omitted from the thermal load case analysis.
Omitting the lateral support from the analysis resulted in smaller movements of the piping in the analysis than actually occurred.
Safety Implications Snubbers bottoming out due to pipe movements greater than anticipated in the design would greatly increase the stresses in the pipe.
Inordinate increases in these stresses could cause the pipe to break, resulting in a LOCA.
Corrective Action TVA performed a reanalysis of the steam generator blowdown line and found that by omitting the support the analysis would result in acceptable design stress levels for all postulated load cases.
Therefore, the lateral support will be removed before fuel loading.
1 TVA has instructed the contractor to ensure that existing check procedures, which are presently designed to catch deficiencies of this l
nature, are more closely adhered to.
In addition, TVA has developed an independent checklist to be completed by TVA which reviews the ccAtractor's analyses. This checklist will be attached to the analysis reports, documenting TVA's review.
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