ML20092A476
| ML20092A476 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 06/12/1984 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NCR-1885, NUDOCS 8406190234 | |
| Download: ML20092A476 (2) | |
Text
TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNES 01 gilipeh 400 Chestn wer II June 12, 1984 BLRD-50-438/84-37 BLRD-50-439/84-34 U.S. Nuclear Regulatory Commission Region II Attn:
Mr. James P. O'Reilly, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323
Dear Mr. O'Reilly:
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - FAILURE OF SSD ANCHORS IN CONCRETE WALLS - BLRD-50-438/84-37, BLRD-50-439/84 FINAL REPORT The subject deficiency was initially reported to NRC-0IE Inspector P. E. Fredrickson on May 15, 1984 in accordance with 10 CFR 50.55(e) as NCR 1885. Enclosed is our final report.
If you have any questions concerning this matter, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, Manager Nuclear Licensing Enclosure cc:
Mr. Richard C. DeYoung, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Records Center (Enclosure)
Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339 8406190234 940612 PDR ADOCK 05000439 8
b 1983-TVA SOTH ANNIVERSARY
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I An Equal Opportunity Employer k
IJ ENCLOSURE d
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 FAILURE OF SSD ANCHORS IN CONCRETE WALLS NCR 1885 BLRD-50-438/84-37, BLRD-50-439/84-34 10 CFR 50.55(e)
FINAL REPORT
' Description of Deficiency TVA~ previously repceted a deficiency involving numerous expansion shell anchor (SSD) failures, which was documented on nonconformance report (NCR) 1381 (BLRD-50-438/81-23, BLRD-50-439/81-25).
~ Subsequently, numerous SSD failures, in addition to those identified in NCR 1381, have occurred in the Control Building concrete pour C7-3A. The proof load failures in the entire C7-3A pour area appear to be excessive when compared to other areas -tested. NCR 1885 expands the suspect area to incorporate the entire C7-3A pour area due to the additional high percentage failure rats of SSD anchors tested.
NCR 1381 documented SSD failures in the M and P line walls from column C8 to C10 and between elevation 680.36 to 687.0'which is a portion. of the concrete pour designated C7-3A.
As noted in TVA's final report on NCR 1381, anchors failed due to low surface strength in.the concrete in pour C7-3A.
Safety Implications Since -the surface strength of the poured concrete is less than that required to. safely secure the shell anchors, it is possible that the SSD anchors would have failed: which subsequently could have adversely affected the safety of the plant.
Corrective Action TVA is in the process of replacing the-SSD anchors with wedge bolts or grouted anchors that are more deeply embedded in the concrete to ensure acceptable strength capacity. To prevent recurrence, Bellefonte Quality, Control Procedure BNP-QCP 2.8, " Bolt Anchors Set in Hardened Concrete," has
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been revised to prohibit any future installation of SSD anchors in the entire l
C7-3A pour area. All TVA action will be complete by October 15, 1984.
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