ML20072D638
| ML20072D638 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 03/03/1983 |
| From: | Dixon O SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-SSINS-6820 IEB-79-14, NUDOCS 8303210400 | |
| Download: ML20072D638 (2) | |
Text
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SOUTH CAROLINA ELECTRIC & GAS COMPAy p{,]QN '
post o,,ica 7e4
' Q,s, c_
-T; COLUMBIA. SOUTH CAROUNA 29218 O. W. DixoN, JR.
vies enese or March 3, 1983 l
NuCLsan OMmations Mr. J.
P. O'Reilly, Director U. S. Nuclear Regulatory Commission Region.Il, Suite 3100 101 Marietta Street, N.W.
Atlanta, GA 30303
Subject:
Virgil C. Summer Nuclear Station Docket No. 50/395 Operating License NPF-12 IEB 79-14, " Analyses for As-Built Safety-Related Piping Systems"
Dear Mr. O'Reilly:
In our letter dated November 4, 1982, South Carolina Electric and Gas Company (SCE&G) committed to performing a study of our overlap techniques for pipe analyses.
This commitment was made in order to finally resolve and close IEB 79-14.
This study is now complete except for the final report.
The overlap study as discussed in the referenced letter selected a " typical piping problem," and made comparisons of loads and stresses of the overlapped and anchor-to-anchor analyses.
There are fifty (50) analytical problems for Virgil C. Summer Nuclear Station which utilized this technique.
The salection of the study problem was in fact a " worse case" problem because of a small population from which to choose, since only five (5) problems had non-enveloping response spectra.
This selection was based on the number of supports in the overlap region, the lowest significant frequency in the overlap region, and the spectral differences (maximum peak) between the problems.
Reviews of the overlapped problems based on these criteria resulted in the selection of CC02/06A to CC02/06B as the study problem.
Piping analysis of CC02/06A to CC02/06B modeled anchor-to-anchor indicated that the peak stresses occurred in the same pipe regions as in the individual analysis problems.
In addition, stresses are all within code allowable.
Comparison of previous support loads to those of the anchor-to-anchor analysis indicates that of a total of 192 supports, six (6) have load increases in excess of the acceptance criteria.
The criterion has been that if a load increase is less than 10% and 250 pounds, the increase is acceptable.
The six (6) supports are as follows:
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- Mr. < J.
P. O ' Reilly
'IEB 79-14 March 3, 1983-Page.#2 Support Percent Increase CCH-008 13 CCH-009 11 CCH-012 13 CCH-128 13 CCH-263 50 CCH-333-20 It is SCE&G's position that with the study ' results, the overlap technique used for Virgil C.
Summer Nuclear Station has been shown to provide acceptable support loads and pipe stresses.
The final report is being completed at this time.
It is expected that this final-report will be submitted to the NRC by March 16, 1983 If.you require additional information, please advise.
Ver trul you s, s
W. D on N
RBC:0WD/fje G.
D. Moffatt cc:
V.
C.
Summer Site QA T.
C. Nichols J. C. Miller l
E.
C. Roberts C. L. Ligon (NSRC)
O. W. Dixon, Jr.
G. J. Braddick H. N..Cyrus J. L.
Skolds H.
T.
Babb J.
B. Knotts, Jr.
D.
A. Nauman B.
A.
Bursey M.
B. Whitake r, J r.
V.
E.
Brownlee W. A. _ Williams, Jr.
I&E (Washington)
O.
S. Bradham Document Management Branch R.
B. Clary
- (55e, 21, LER)
C.. A. Price NPCF A.
R.
Koon File
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