ML20237C069

Lists Two Options & Factors Recommended for Use by Licensee for Future Seismic Qualification Work at Facility,Per 871117 & 18 Audit of New Seismic Floor Response Spectra Methodology.General Methodology Deemed Appropriate

ML20237C069
Person / Time
Site:	Oyster Creek
Issue date:	12/16/1987
From:	Dromerick A Office of Nuclear Reactor Regulation
To:	Fiedler P GENERAL PUBLIC UTILITIES CORP.
References
NUDOCS 8712210003
Download: ML20237C069 (3)

Text

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w :.9 DEC 161987 fdr. P. B. Fiedler Distributi_on j

Vice President and Director Docket File,

ADromerick Oyster Creek ?!uclear Generating Station NRC & Local PDRs OGC-Beth Post Office Box 308 PDI-4 Reading File EJordan Forked River, New Jersey 08731 SYarga JPartlow DBoger ACRS(10)

Dear Mr. Fiedler:

SNorris

SUBJECT:

METHODOLOGY TO DEVELOP NEW SEISf41C FLOOR RESPONSE SPEC 1RA FCR OYSTER CREEK NUCLEAR GEhERATING STATICH On November 17 and 18, 1987 the staff conducted an audit at URS/Blume in San Francisco, California, concerning the soil structure interaction (SSI) analysis. GPU Nuclear Corporation plans to use the analysis for developing the ficor response spectra for future work at the Oyster Creek Nuclear Generating Station. As a result of the audit, the staff concluded that in general the methodology used was appropriate.

However, the staff has ctriain concerns regarding the site specific spectra and its usage.

As discussed c'uring the trieconference on this subiect on Decerrber 10, 1987, i

the staff is recontending two options for use by the licensee for future seismic qualification work at the Oyster Creek Nuclear Generating Station. For i

the option selected, the licensee is requested to provide the study results which account for the following factors prior to ir.;plementation.

1.

Variations in soil properties 2.

Modelling uncertainties 3.

Computational parameters and their limitations 4.

Verification and validation of computer code with the measured results 5.

Power Spectral density for the time history being used 6.

Effect of saturated soil 7.

Torsional effects on structures Op, tion 1 (a) Use the 0.75 SEP design spectra (Rcgulatory Guide 1.60 shaped spectra) in the free-field at foundation level.

(b) Use the design spectra compatible ground motion applied at the botton of the first soft soil layer (i.e. El.6'-0").

The design spcctra compatibility nay be established via use of a properly verified cornputer code such as SUPER FLASH (c) Perform the appropriate SSI analysis.

(d)

Limit the mtximum reduction in th( basenat spectral crdinates frem those of design spectra to EST kk kb

[

P 1

m

];

Oition2-l (a)I Use the proposed revision to SRP Sections 2.5.2, 3.7.1, 3.7.2 (alternate 2)

E and 3.7.3 consistently to perform response analysis.

In this context, the

. licensee is' advised to develop a free-field site-specific ground motion-for the Oyster Creek site.

The suit'e of records chosen should be those from magnitude-(m 5

(0.5

or_less)earthquakesatdistanceslessthan25kmatsiteswhoN9)oca.3 1

l site conditions are similar to the Oyster Creek site.

If such records are not available, a suite of site specific rock records should be assembled where point of input is at hypothetical rock outcrop.

If possible both approaches l

should be used, and postulated ground motion should be compared (after appropriate deconvolution) at common reference-points (e.g. soil surface, bottom of foundation). As in past licensing applications of site specific spectra, there should be coordination with the staff to avoid misunderstandings and delays.

(b) This input should be used for a detailed SSI analysis If Option 2 is selected, the results of the analysis will be evaluated by the staff to (1) assure consistency of various elements'(e.g. irput motion, SSI) with each other, (2) assure consistency with physically reasonable phenomena and (3) determine limitations if necessary, that need to be applied to its application.

The reporting end/or recordkeeping requirements contained in this letter affect fewer than 10 respondents; therefore, Ot1B clearance is not required under P.L.96-511.

Sincerely, WOW gs Alexander W. Dromerick, Project lianager Project Directorate I-4 Division of Reactor Projects I/II cc: See next pace PDI-4

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Mr. P. B. Ff edler Oyster Creek Nuclear Oyster Creek Nuclear Generating Station Generating Station l

l cc:

Ernest L. Blake, Jr.

Resident Inspector Shaw, Pittman, Potts and Trowbridge e/o U.S. NRC 2300 N Street, NW Post Office Box 445 Washington, D.C.

20037 Forked River, New Jersey 08731 J.B. Libeman, Esquire Commissioner Bishop, Liberman, Cook, et al.

New Jersey Department of Energy 1155 Avenue of. the Americas 101 Comerce Street New York, New York 10036 Newark, New Jersey 07102 Mr. David M. Scott, Acting Chief l

Regional Administrator, Region 1 Bureau of Nuclear Engineering l

U.S. Nuclear Regulatory Comission Department of Environmental Protection CN 411 p

631 Park Avenue Trenton, New Jersey 08625 l

King of Prussia, Pennsylvania 19406 BWR Licensing Manager GPU Nuclear Corporation k.

I Upper Pond Road l~.

Parsippar,y, New Jersey 07054 Deputy Attorney General State of New Jersey Department of Law and Public Safety 36 West State Street - CN 112 5

Trenton, New Jersey 08625 Mayor Lacey Township 818 West Lacey Road l

Forked River, New Jersey 08731 Licensing Manager

- Oyster Creek Nuclear Generating Station Mail Stop: Site Emergency B1dg.

P. O. Box 388 Forked River, New Jersey 08731 l

I

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