ML19341D703
| ML19341D703 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 04/01/1981 |
| 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, SQRD-50-328-81, NUDOCS 8104080459 | |
| Download: ML19341D703 (2) | |
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400 Chestnut Street Tcwer II April 1, 1981 N
SCRD-50-328/81-08
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[~3 p> $k4 si Mr. James O'Reilly, Director b
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Office of In'apection and Enforcement N
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U.S. Nuclear Aegulatory Commission
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% 7 6-101 Marietta Str et Atlanta, Georgia 0303
Dear Mr. O'Reilly:
SEQUO'lAH NUCLEAR PLANT UNIT 2 - UNCONSERVATIVE LOADS ON PIFE SUPPORT DESIGN MODIFICATIONS - SQRD-50-328/81 FINAL REPORT The sub, ject deficiency wa initially reported to NRC-CIE Inspector
- R. W. Wright en Decenter 17, 1980, in accordance with 10 CFR 50.55(e) as NCR SQN GB 8039. This was followed b'I our interim reports dated January 19 and March 2, 1981. Enclosed is our final report. This nonconformance as also reported for Watts Bar Nuclear Plant as NCR
'/SN GB 8013.
If you have any questions, please get in touch with D. L. Lambert at FTS 857-?581.
Yery truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, Manager Nuclear Regulation and Safety Enclosure f'
cc:
Mr. Victor Stello, Director (Enclosure) V Office of Inspection and Enforcement-U.S. Nuclear Regulatory Coussission ON Washington, DC 20555 5
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ENCLOSURE SEQUOYAH NUCLEAR PLANT UNIT 2 UNCONSERVATIVE LOADS ON PIPE SUPPORT DESIGN MCDIFICATIONS SQRD-50-328/81-08 10 CFR 50.55(e)
FINAL REPORT Description of Deficiency Piping system analyses and support design for class 1, 2, and 3 systems inside containment were contracted out to EDS Nuclear, Incorporated. EDS tabulated design loads for the pipe supports on support drawings. FDS had design and revision responsibility for all piping reanalysis results which could have an i= pact on existing support designs. Load increases that resulted from piping reanalyses but did not require design codifications were not revised on the support drawings. Design control responsibility for all support drawings was subsequently turned over to TVA, and subsequent design
=odifications by TVA were based on the design leads tabulated on the
- drawings. Therefore, sc=e design modifications by TVA nay be based on unconservative.lcads. At the time of EDS's contract, TVA did not recognize that these load increases could have an adverse impact on subsequent support designs and therefore did not require that EDS tabulate these loads en the affected support drawings.
Safety Implications Piping supports being based on unconservative design loads could fail during a seismic event. Failure of the supports could lead to pipe break and subsequent reduced coolant to the core which could adversely affect the safety of the plant.
f Corrective Action TVA is comparing the load values shown on the indivMual pipe rupport drawings to the corresponding loading on the revised EDS load tables.
Drawings which have load discrepancies are being evaluated on a case by case basis bo determine if. supports are ' adequate as designed or if redesign -
is necessary. The complete evaluation and rework of supports, if requireu, will be completed for. Sequoyah before fuel loading.
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