ML20077N335
| ML20077N335 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 09/02/1983 |
| From: | Dixon O SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8309130027 | |
| Download: ML20077N335 (3) | |
Text
=
a SOUTH CAROLINA ELECTRIC & GAS COMPANY POST OPPICE 764 COLUMelA. SOUTH CAROLINA 29218 O. W. DixON. JR.
.Vice PasslotNT September 2, 1983 nuCoa*= o.. rio.
Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear. Regulatory Commission Washington, D.C.
20555
Subject:
Virgil C. Summer Nuclear Station Docket No. 50/395 Operating License No. NPF-12 Seismic Confirmatory Program
Dear Mr. Denton:
On June 22, 1983, South Carolina Electric and Gas Company (SCE&G) submi2ted responses to Staff questions on our Seismic Confirmatory Program which were previously transmitted to SCE&G by letters dated May 4 and June 10, 1983.
Based on all previous submittals and detailed technical discussions with the NRC Staff during the evaluation of our Seismic Confirmatory Program, SCE&G is proceeding with the following program for submittal to the NRC by November 16, 1983.
This program will satisfy ASLB License Condition C(25).
Additionally, the ACRS recommendation to evaluate seismic design margin for systems and components whose function is important to the assurance of the continuing removal of L
shutdown heat will be evaluated concurrently in this program.
The ACRS criteria for evaluating the maximum near-field 1.
Reservoir Induced Seismic (RIS) event will be used to compare with design of equipment and components at the Summer Nuclear Station.
In this case, a RIS Virgil C.
event of magnitude Mn=4.5 with a peak acceleration anchor point of 0.22 g (as defined in SER Supplement 4) shall be used in the analysis.
99 8309130027 830902
) ($
i PDR ADOCK 05000395 I
P PDR
+;
.e Mr. Harold R.
Denton
> ' Seismic Confirmatory Program September 2, 1983 7
Page'#2
- 2..'For the ASLB License Condition,7 the Staff has agreed that a reduced envelope spectrum may be used tx) represent.the
- foundation motion.of the nuclear plant structures.
Composite spectra will-be developed in accordance with the Staff recommendations for.each_of.the three types of soil, c'issons and, rock.
. structure foundations:
a 3.
The original design SSE floor response-spectra at founda-
' tion will.be compared-to the ASLB reduced envelope spectra
'for each foundation type to determine in which structures (and at.what elevation)' exceedances occur, and-where additional analyses are required.
Additionally, the SSE i
' ground'apectra will be compared with the ACRS RIS-spectra, and additional analyses will be performed. for structures
-with dominant frequencies in the region where the ACRS RIS
- spectra exceeds the SSE ground spectra.
l 4.
For. structures where additional analyses are required, equipment and components (including Class lE) will be Inelastic.
classified as either active.or passive.
response spectra will be used to compare the~ relative
~
~
severity of different dynamic loadings, and thus,-
demonstrate'the_ relative dynamic' margins of passive
_ equipment available for the ACRS RIS spectra, ASLB reduced envelope spectra, and SSE spectra.
5.
For active equipment.and components in those structures requiring additional. analyses, evaluations will be performed to determine actual design margin for both the ACRS RIS spectra and the ASLB reduced envelope spectra.
I This program-is in full progress and will be completed for i
L
--submittal to the NRC by November 16, 1983.. Should changes to L
the program described above be required, completion will slip beyond' November 16,-1983.
i I
e.
a
-Mr. Harold R. Denton Seismic Confirmatory Program September 2, 1983 Page #3 If you have any questions, please contact us at your convenience.
Very truly yours,
/
O. W.
ixo Jr.
RBW:OWD/fjc cc:
V. C.
Summer T.
C. Nichols, Jr./O. W. Dixon, Jr.
E. H. Crews, Jr.
E.
C. Roberts H.
N.
Cyrus J. P. O'Reilly Group / General Managers O. S. Bradham R. B..Clary C. A. Price A.
R. Koon C.
L. Ligon (NSRC)
G. J. Braddick J. C. Miller J. L.
Skolds J. B.
Knotts, Jr.
NPCF File (Lic./Eng.)