ML20147D851
| ML20147D851 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 03/02/1988 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NUDOCS 8803040184 | |
| Download: ML20147D851 (4) | |
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5 TENNESSEE VALLEY AUTHORITY I
CH ATTANOOG A, TENNESSEE 374ot SN 157B Lookout Place MAR 21988 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 centlemen:
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) - RESOLUTION OF OPEN INSPECTION ISSUES During the NRC's inspection in Knoxville, Tennessee, the week of February 15, 1988, a number of miscellaneous open issues were reviewed. Three of these open issues (swing angle allowables, design basis accident (DBA) spectra, and U-bolt allowables) were closed for SQN unit 2 restart in the February 19, 1988 exit meeting pending receipt of a confirmatory letter documenting TVA commitments made during the inspection for follow-up actions.
provides TVA's confirmation of these commitments. provides an abbreviated listing of TVA's commitments presented herein.
Very truly yours, TENNESSEE VALLEY AUTHORITY R. Gridley, Dirac or Nuclear Licensing and.
Regulatory Affairs Enclosures ec: See page 2 f
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An Equal Opportunity Employer
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- U.S. Nuclear Regulatory Connission hAAR 2 1988 Enclosures cc (Enclosures):
Mr. K. P. Barr, Acting Assistant Director for Inspection Programs TVA Projects Division U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. G. G. Zech, Assistant Director for Projects TVA Projects Division U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379
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io ENCLOSURE 1 SEQUOYAH NUCLEAR PLANT OPEN INSPECTION ISSUES Swing Angle Allowables During this inspection, the NRC noted that TVA is using strain gages for monitoring the thermal piping loads on four supports. Although the NRC questioned this approach as an acceptable method to qualify supports, it was agreed that the supports would be acceptable for unit 2 restart if they met allowables provided in SQN interim criteria CEB-CI-21.89.
The affected supports have been reviewed and confirmed as meeting.the allowables in the t
interim criteria.
As the long-term resolution for these four supports. TVA will monitor the thermal loads on the supports, and using that data will qualify them in accordance with long-term design criteria SQN-DC-V-24.2 or i
modify the supports. This work will be completed after SQN unit 2 restart.
DBA Spectra 4
During this inspection, the NRC questioned the basis of the amplified response spectra (ARS) for the DBA.
To resolve this issue. TVA will review the DBA analysis of the steel containment vessel (SCV), and provide the NRC with verification that the use of the double differentiation technique applied to displacement time histories will generate ARS that are consistent with the ARS obtained directly from acceleration time histories. This review will be completed after SQN unit 2 restart.
1 U-Bolt Allovables During the review of calculations for establishing allowables for U-bolt applications, the NRC questioned the acceptability of the allowables presented in SQN design criteria SQN-DC-V-24.2, Revision 2, Figure I-7.
As a result, i
TVA used agreed-upon allowables and reviewed existing SQN unit 2 pipe supports 1
with U-bolts which could be affected by this issue. The supports reviewed were found to be acceptable using the revised allowables. For long-term resolution of this issue. TVA will revise SQN design criteria SQN-DC-V-24.2 to reflect the revised allowables.
The design criteria will be revised after restart of SQN unit 2.
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ENCLOSURE 2 l
SEQUOYAH NUCLEAR PLANT OPEN INSPECTION ISSUES LIST OF COMMITMENTS Swing Angle Allowjble.
1 TVA will monitor the thermal loads on the four supports, and using that data f
will.1ualify them in accordance with long-term design criterla SQN-DC-V-24.2' l
or rodify the supports af ter SQN uait 2 restart.
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DMA Spectra L
After SQN ur restart, TVA will review the DBA analysis of the SCV and provide tb with verification that the use of the double differentiation technique app..ed to displacement time histories will generate amplified l
response spectra (ARS) that are consistent with the ARS obtained directly from acceleration time histories.
U-Bolt Allowables After SQN unit 2 restart, TVA will revise SQN design criteria SQN-DC-V-24.2, Figure I-7, to reflect the new allowables used te qualify SQN unit 2 supports with U-bolts which are subject to the criteria, i
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