ML20008G180
| ML20008G180 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 06/26/1981 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-81-472-000 10CFR-050.55E, 10CFR-50.55E, PT21-81-472, PT21-81-472-000, NUDOCS 8107020398 | |
| Download: ML20008G180 (2) | |
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3-CC O 400 Chestnut Street Tower II June 26, 1981 e-S 50-328/81-33
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2 JUL 0188W C Mr. James O'Reilly, Director V
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Office of Ins tien and Enforcement s
U.S. Nuclear Re atory Commaission
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Regica II - Suite 00 Q%!
101 Mar 1TAta Street Atlanta, Georgia 3030
Dear Mr. O'Reilly:
SEQUOYAH NUCLEAR PLANT UNIT 2 - REACTOR COOLANT PUMP NO. 3, SEAL NO.1 BYPASS, PIPING ANALYSIS ERROR - SQRD-50-328/81 REVISED FINAL REPORT The subject deficiency was initially reported +.o NRC-0IE Inspector R. Y. Crisajak on May 6,1981 in accordance with 10 CFR 50.55(e) as NCR SQN GB 8111. A final report was submitted on May 26, 1981. Enclosed is our mvised final mport as discussed with R. Y. Celenjak on June 24, 1981. We consider 10 CFR 21 applicable to this deficiency.
If you have any questicas, please get in touch with D. L. Lambert at FTS 857-2581.
Very truly yours, TENNESSEE VALLEf AUTHORITY L. M. Mills, Manager Nuclear Reg.tlation and Safety Enclosure
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oct Mr. Victor Stello, Director (Enclosure)(/
Office of Inspection and Enforceaant U.S. Nuclear Regulatory Commission Washington, DC 20555 1
68 'l 8107020 398 S
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ENCLOSURE SEQUOYAH NUCL5AR PLANT UNIT 2 #
REACTOR COOLANT PUMP NO. 3, SEAL NO. 1 BYPASS PIPING ANALYSIS ERROR SQRDAO-328/81-33 10 CFR 50.55(e)
REVISED FINAL REPORT Description of Condition The 3/4-inch No. 1 seal bypass piping for reactor coolant pump (RCP)
No. 3 had piping movements during hot fbnctional testing which caused certain snubbers to move in a direction opposite to that anticipated by design. The piping analysis for the affected piping is 0600154-08-17 'and is a reanalysis of an EDS Nuclear problem performed by Gilbert Commonwealth. The current analysis was found to have incorrect input movements of the RCP No. 3, which were determined by Gilbert Commonwealth.
Safety Implications Pipe movement in a direction opposite to that for which the snubbers are oriented would cause the snubbers to lock, which would greatly increase the stresses in the pipe. An inordinate increase in pipe stresses could cause the pipe to break, resulting'in a LOCA.
Corrective Action As stated in our last report,' TVA has performed a piping analysis which indicates that resetting one snubber and one spring hanger will resolve this problem. Although our last report stated that modifications would be completed before fuel loading, we have subsequently determined that the corrective actions are not required until initial system heatup following fuel loading. The unacceptable condition does not occur until the thermal mode of operation and the affected piping and components are not in a thermal transient at fuel loading. Thus, these modifications.will be completed before system heatup following fuel loading.
l TVA hNs inst;ructed the contractor to ensure that existing check procedures, which are designed to catch deficiencies of this nature, are more closely adhered to.
In addition, TVA has developed an independent checklist to be completed by TVA which reviews the contractor's analyses. This checklist will be attached to the analysis reports, documenting TVA's review.
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