ML20147D888
| ML20147D888 | |
| 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 8803040195 | |
| Download: ML20147D888 (3) | |
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TENNESSEE VALLEY AUTHORITY CH ATTANOOG A, TENNESSEE 37401 SN 157B Lookout place MAR 21988 U.S. Nuclear Regulatory Cottunission ATTN:
Document control Desk Washington, D.C.
20555 Gentlement 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 a
During the NRC inspection in Knoxville, Tennessee, the week of February 15, 1988, a number of miscellaneous issues were reviewed. One of the issues identified was the effect of zero period acceleration (ZPA) on SQN unit 2 piping during the design basis accident (DBA). This issue is open pending TVA providing additional information for review by the NRC.
The enclosure describes a study performed by TVA that demonstrates that the phenomenon does not significantly affect the design of piping, pipe supports, or penetrations, If you have any questions, please telephens D. L. Williams at (615) 632-7170.
i Very truly yours.
TENNESSEE VALLEY AUTHORITY
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Nuclear Licensing and Regulatory Affairs Enclosure cc:
See page 2 j
8803040195 880302
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DCD lj An Equal Opportunity Employer
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~ 4> U.S. Nuclear Regulatory Commission MAR 2 1988 Enclosure cc (Enclosure):
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 Division of TVA Projects Office of Special Projects 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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ENCLOSURE SEQUOYAH NUCLEAR PLANT UNIT 2 EVALUATION OF DBA/ZPA' EFFECTS The effects of zero period acceleration (ZPA) for the design basis accident (DBA) event have been assessed for the Sequoyah unit 2 piping. The effects were evaluated for_five sample piping systems that were selected based: #pon their sensitivity to the issue. Selection criteria were as follows:
1.
Piping attached to the steel containment vessel (SCV) at locations with the highest ZPA levels.
2.
Rigid piping spans which are (1) attached to the SCV, (2) located close to the SCV, and (3) potentially influenced by the ZPA.
3.
Piping with high faulted stress level combinations (low faulted stress margin).
4 Piping with a low number of modes considered in the code-of-record stress analysis.
The five analyses selected for review contain 85 supports.
The evaluation of these five an'alyses demonstrated that:
1.
Resulting piping stresses are within design code allowable limits.
2.
For 59 of the 85 supports, resulting pipe support reactions increased by less than 10 percent.
Reactions for the remaining 26 supports increased by more than 10 percent but were demonstrated to be within design allowable limits.
3.
Resulting penetration loadings meet code allowable limits.
Based on the selection criteria, the samples evaluated envelop the remaining piping systems attached to the SCV.
Therefore, the effects of DBA/ZPA are not considered to have impact on SQN design or unit 2 restart.
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