ML20236Q089
| ML20236Q089 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 11/17/1987 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| RTR-REGGD-01.061, RTR-REGGD-1.061 NUDOCS 8711190174 | |
| Download: ML20236Q089 (3) | |
Text
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l' TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 374o1 SN 157B Lookout Place Pi()V 171987 U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter of
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Docket Nos. 50-327 Tennessee Valley Authority
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50-328 SEQUOYAH NUCLEAR PLANT (SQN) - UNIT 2 SUPPORT MODIFICATION RESTART CRITERIA SUPPLEMENTAL REVISION
Reference:
TVA letter to NRC dated August 31, 1987, "Sequoyah Nuclear Plant (SQN) - Unit C Support Modification Restart Criteria for Rigorous Analysis Piping" The SQN unit 2 restart criteria for support modifications on rigorous analysis piping were initially submitted for NRC review by the referenced letter.
These criteria are bein5 utilized at SQN for the prioritization of required pipe support modifications, in accordance with an NRC staff approval granted to TVA at our meeting of September 1, 1987.
Further discussions have subsequently been held with Bob Herman and John Fair, of your staff, on October 29 and 30, 1987, on this subject.
This letter summarizes the a5reements reached durin5 these discussions and documents the revisions that will be made to the presented restart criteria, CEB-CI-21.89.
1.
An anchor bolt factor of safety of 2.0 can be utilized on an interim basis.
2.
Snubber swing an51e tolerances are not a design constraint if visual monitoring during plant heatup shows no thermal binding.
3.
Latest code of record rules can be utilized for support evaluations.
4.
Code Case N-411 (variable dampi
) can be utilized if:
The 84th percentile earthquake is utilized, a.
b.
Three dimensional earthquake motion is considered.
Independent support motion cannot be assumed.
c.
5.
Re5ulatory Guide 1.61 dampin5 values may be used if:
84th percentile earthquake is utilized.
a.
b.
Three-dimensional earthquake motion is considered.
Independent support motion can be utilized.
c.
6.
Support flexibility may be used to reduce piping thermal load effects on pipe supports.
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An Equal Opportunity Employer
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NOV 171987 U.S. Nuclear Regulatory Commission These criteria and implementation rules apply to the planned SQN unit 2 restart.
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Additionally, it is TVA's understanding that margin discussions for NF versus non-NF snubbers and structural components are still required but are not considered a restart item.
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If any questions exist on this matter, please telephone H. R. Harding at (615) 870-6422.
Very truly yours, TENNESSEE VALLEY AUTHORITY R.
- ridley, ector Nuclear Licensing and Regulatory Affairs Enclosure cc (Enclosure):
Mr. G. G. Zech, Assistant Director for Inspection Programs Office of Special Projects U.S. Nuclear Regulatory Commission 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. J. A. Zwolinski, Assistant Director for Projects Division of TVA Projects office of Special Projects U.S. Nuclear Regulatory Commission j
4350 East-West Highway i
EW 322 Bethesda, Maryland 20814 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379 E- -- -
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'ENCLOSNRE.
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TVA Conunitment Restart. Pipe Support Criteria CEB-CI-21.89
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. Issue' revision 1 to Restart Pipe Support Criteria CEB-CI-21.89
- incorporating agreements made between TVA and NRC in discussions j
October'29 and 30. 1987. Scheduled congletion date' before restart of j
.SQN unit 2.
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