ML20003B782
| ML20003B782 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 01/20/1981 |
| 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-CEB-803, NUDOCS 8102250508 | |
| Download: ML20003B782 (2) | |
Text
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TENNESSEE VALLEY AUTHORITY
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CHATTANCOGA. TENNESSEE '374o1 400 Chestnut Street Tower II January 20, 1981
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.j..3 0 Mr. James P. O'Reilly, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Regica II - Suite 3100 101 Marietta Street Atlanta, Georgia 30303
Dear Mr. O'Reilly:
SEQUOYAH NUCLEAR PLANT UNIT 2 - NONREINFORCED CONCRETE BLCCK WALLS -
NCR SQN CEB 8031 - FINAL REPORT The subject deficiency was initially reported to NRC-0IE Inspector R. W. Wright on October 16, 1980, in accordance with 10 CFR 50.55(e). An interim report was submitted en November 14, 1980. Inclosed is our final report.
If ye-have any questions, please get in touch with D. L. Lambert at FTS 857-2581.
Very truly yours, TENNESSEE VALLET AUTHORITY k
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L. M. Mills, Manager -
Nuclear Regulation and Safety l
94 Enclosure
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Mr. Victor Stello, Director (Enclosure)
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SEQUOYAH NUCLEAR PLANT UNIT 2 NCNREINFORCED CCNCRETE MASCNRY BLOC'< WALLS NCR SCNCE38031
FINAL REPORT Descriptien of Deficiency In the process of respending to " Nuclear Regulatory Cc= mission Information Request on Category I Mason Walls," it was discovered that the nonreinforced concrete =asonry block walls were not designed for a site seisric event. These walls were constructed to serve as either radiaticr. shield walls, partition walls, or as access openings for enclosed equipment, and no structural functions were intended. An investigation and structural evaluation of all nonreinforced =asenry block walls located in Category I structures concluded that ten (10) walls could possibly fail,and endanger safety-related systems if subjected to the conditions of a site seismic event.
Safety !=plications The occurrence of a seismic event could lead to the collapse of the
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masonry walls, which in turn could damage safety-related equipment in j
the fall area. The damage of this equipment =ay adversely affect the j
safety of the plant.
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Corrective Action A field survey to identify and locate all nonreinforced concrete masonry walls in the Category I structures at SQN has been completed.
TVA has designed restraints for the ten (10) questionable walls, and construction drawings have been revised. The restraints for the ten (10) walls will be completed thirty (30) days before fuel loading.
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All future nonreinforced concrete masonry block walls which are planned to be constructed in an area where safety-related systems may be jeopardized by failure of a particular wall shall be designed and constructed in accordance with the new T7A design criteria " Evaluation of Unreinforced Masenry Walls Constructed from Solid Concrete Blocks" which accounts for restraints necessary to prevent wall failure.
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