ML20062F802
| ML20062F802 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 08/05/1982 |
| 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-1390, NRC-1390, NUDOCS 8208120153 | |
| Download: ML20062F802 (3) | |
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vf TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNESSEE 37401 400 Chestnut Street Tower II August 5, 1982 BLRD-50-438/82-16 s
BLRD-50-439/81-23 U.S. Nuclear Regulatory Commission
,1 Region II 7,'
Attn:
Mr. James P. O'Reilly, Regional Administrator p
101 Marietta Street, Suite 3100 co Atlanta, Georgia 30303
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Dear Mr. O'Reilly:
u BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - LACK OF REBAR AT MAIN STEAM AND c
FEEDWATER FLUED HEADS - BLRD-50-438/82-16, BLRD-50-439/81 FINAL REPORT The subject deficiency was initially reported to NRC-0IE Inspector R. V. Crlenjak on February 27, 1981 in accordance with 10 CFR 50.55(e) as NCR 1390. This was followed by our interim reports dated March 31, June 3, August 31, and November 20, 1981 and March 11, April 22, and June 4, 1982.
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.
I Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, Manager Nuclear Licensing i
Enclosure cc:
Mr. Richard C. DeYoung, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 l
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I $h ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 LACK OF REBAR AT MAIN STEAM AND FEEDWATER FLUED HEADS NCR 1390 BLRD-50 438/82-16,' BLRD-50-439/81-23 10 CFR 50.55(e)
FINAL REPORT Description of Deficiency The lack of reinforcing bars (rebars) documented by this NCR was discovered while chipping concrete, in accordance with the disposition of NCR 1308, to determine the locations of steel rebars at main steam and feedwater flued head support anchor plates.
Chipping revealed that robars were not present octween the supports and that rebars which should lace between the anchor plate support bars were cut off below the supports at several anchor plate locations. However, each anchor plate location was unique in number and type of discrepancies. Several factors may have contributed to the root cause of this deficiency.
1.
Original design of the rebar and embedment steel was complex and required proper scheduling in order to install rebar through penetrations in embedments.
2.
Field Change Requests (FCRs) that were incorporated apparently caused confusion for personnel installing and inspecting rebar and embedded parts.
3 Unauthorized modifications may have been made to rebar which was installed, inspected, and accepted in previous concrete pours.
4.
The overall complexity of the modifications prevented the QC inspectors from identifying and correcting the omissions and incorrect cutting of the rebar.
Two different inspectors checked the rebar on unita 1 and 2.
This situation prevented consistent installgtion of the rebar between units.
Cafety Implications The extensive omission of rebar described here could result in a failure of the main steam and feedwater piping in addition to the coincident accident and single failure considered in the plant safety analysis. Such multiple failures, if they occurred, woulo degrade the safety of operations of the plant.
Corrective Action Concrete stiffening walls have been designed taking into account the missing rebars and drawings released to increase the capacity of the R-line wall in the vicinity of the units 1 and 2 center main steam pipe anchors.
These stiffening walls, in conjunction with the existing R-line wall and remaining reinforcing, provide sufficient capacity to resist the applied anchor loads. The walls at the corner main steam and feedwater anchors
i dk.
Page 2 were determined to be acceptable as is.
The adjacent walls and slabs, acting together with the existing R-line wall and remaining reinforcing, provide adequate capacity to resist the applied anchor loads at the corners. The modifications will be completed by September 1, 1983, for unit 1 and Septetber 1, 1984, for unit 2.
The design and installation of the anchor plates and supporting rebar i 2 both unique and complex. Based on the correct installation of rebar in adjacent areas as verified when rebar is tied into previous lower pours, TVA believes that this installation and inspection deficiency is an isolated ca se.
Inspectors have been reinstructed to report installation conflicts between embedments and rebars to the construction engineering organizaticn for coordinated modifications with the design project organiza tion.
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