ML20010J679
| ML20010J679 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 09/30/1981 |
| From: | Parris H TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-81-497-000 PT21-81-497, PT21-81-497-000, NUDOCS 8110060341 | |
| Download: ML20010J679 (3) | |
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TENNESSEE VALLEY AUTHORITY 4H ATTANOOG A. * 'NESSEE 374ot 500A Ch2stnut Street Tower II
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- September 30, 1981 b
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F OCT 6 198 4 rg Mr. James P. O'Reilly, Director
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U.S. Nuclear Regulatory Commission
\\i Office of Inspection and Enforcement y?A.
Region II
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6 101 Marietta Street, Suite 3100 Ii' Atlanta, Georgia 30303
Dear Mr. O'Reilly:
TENNESSEE VALLEY AUTHORITY - SEQUOYAH NUCLEAR PLANT UNIT 1 -
DOCKET No. 50-327 - FACILITY OPERATING LICENSE DPR 10 CFR 21 REPORT It has been discovered that t.welve first-row tubes in each steam generator on Sequoyah Nuclear Plant unit I have surface damage. This damage was caused by a flow-induced vibration frw the tube lane blocking devices.
This problem, which is reportable under 10 CFR 21, was reported to me on September 30, 1981.
The enclosed Part 21 report contains additional information about this matter.
-Very truly yours, TENNESSEE VALLEY AUTHORITY H. G. Parris Manager of Power Enclosure l
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An Eaual Opporturuty Employer 8110060341 81093om
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gDRADOCK 05000327' PDR.
PART 21 REPORT Plant: Sequoyah Nuclear Plant Component or System Identification: Tube lane blocking devices insta ued in the steam generators.
Supplier of Component: Westinghouse Model 51 - Steam Generator, vertical shell and U-tube evaporator with integral moisture separator.
Nature of Defect: Twelve (12) first-row tubes in each steam generator on unit 1 were discovered with surface damage caused by flow-induced vibration from the tube lane blocking devices. No damage occurred on unit 2 since there has been no appreciable flow to date.
(Unit 2 has been licensed but has not been critical.)
Extent of Safety Hazard: This condition, if uncorrected, could have led to a possible steam generator tube rupture.
Date Which Defect or Noncompliance Was Discovered: During steam generator sludge lancing on September 20, 1981.
Number of ' Identical Components in Use: There are two (2) tube lane blockir.g devices per steam generator and fous-(4), steam generators per unit.
Location of Components: The tube lane blocking devices are attached to the steam generators at the handhole approximately 14 inches above the tube sheet.
Corrective Action Taken or To Be Taken: On unit 1 a total of 97 tubes near the tube lane blocking devices in all four (4) steam generators have been eddy current tested. Of these 97 tubes, twenty (20) tubes were discovered with measurable wall damage. Seven (7) of these twenty (20) tubes had damage of greater than 20 percent but less than 40 percent of the wall thickness. No more than two (2) of these seven (7) were on any one steam generator. The tube lane blocking dev'.ces on both units 1 and 2 steam generators were modified to prevent vibration and future damage to the tubes.
Has defect or noncompliance been reported previously? Yes No X
JMM:MRH dBK CET 9/29/81
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r QA PROGilAM RELATED Ref. N 0QAM Part lli, Sec 1
Page 7 Attachm..; 2 4
t/ ART 21 EVALUATION SilEET 6/25/81 A
Does the problem involve:
1.
Failure of goods and services to comply with applicable NRC requirements (regardless of whether these requirements are included in the procurement document).
Yes O No [
If yes, go to C 2.
Condition or circumstance that could contribute to exceeding a safety limit as defined by plant technical specifications.
Yes O No 8 If yes, go to B 3.
Departure of a delivered component or service from the technical requirements of a procurement document. Delivery occurs upon acceptance by NUC PR (e.g., a't receipt inspection).
Yes O No O If yes, go to B 4.
Deviation in a portion af the plant which has been transferred (final transfer) to NUC PR.
Yes O No O If yes, go to C Answer all 4 questions above.
If aLL "No's", STOP IIERE. If any "Yes's",
continue as indicated by the applicable "GO T0" statement.
B.
Is component necessary to ensure:
1.
The integrity of the reactor coolant pressure Yes O No O 2.
The capability to shut down the reactor and maintain it in a safe shutdown condition Yes O No O 3.
The capability to prevent or mitigate the consequences of accidents Yes L/ No L/
Is security system deficiency involved?
Yes O No O If all "No's", STOP HERE - If any "Yes's" - GO TO C C.
Could the defect have caused a substantial safety hazard? (By definition, iteta A2 constitutes a substantial safety hazard.)
Yes $ [ No O If "No",
this item is not reportable - If yes, this item is reportable under Part 21.
D.
Is this item reportable by NUC PR under Part 21?
Yes h No O Evaluated By
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d Date 09-29-81 Approved By M M Date 0_9-29-81 m
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