ML20073P435

Forwards Revised Spectra Plots,Incorporating Theoretical 84th Percentile Ground Spectrum for upper-bound Soil Properties Per 830411 Request.Spectra Should Be Included at 830428 Meeting to Resolve SER Outstanding Issue 3

ML20073P435
Person / Time
Site:	Clinton
Issue date:	04/18/1983
From:	Wuller G ILLINOIS POWER CO.
To:	Schwencer A Office of Nuclear Reactor Regulation
References
0982-L, 982-L, U-0633, U-633, NUDOCS 8304250201
Download: ML20073P435 (3)

Text

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0982-L ILLINDIS POWER COMPANY f30_0hzng_3gy_g y)y g 500 SOUTH 27TH STREET, DECATUR, ILLINolS 62525 Docket No. 50-461 April 18, 1983 Director of Nuclear Reactor Regulation Attention: Mr. A. Schwencer, Chief Licensing Branch No. 2 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

Clinton Power Station Unit 1 SER Outstanding Issue #3 (NUREG-0853)

Reference:

IP letter U-0628, dated April 5, 1983, G. E. Wuller to A. Schwencer, NRC As requested by NRC in the telephone conversation with Illinois Power Company and Sargent & Lundy on April 11, attached is a copy of the revised spectra plots, incorporating the theoretical 84th percentile ground spectrum for upper-bound soil properties. The methodology to obtain this ground spectrum is the same as described in steps 2 through 5 of the referenced letter, except that the mean plus sigma values listed in Table 6 of the referenced letter for upper-bound soil properties have been used as requested by the NRC Staff.

As can be seen from the attached figure, the new ground surface spectrum is enveloped by the design basis time-history spectrum for all frequencies, except in the narrow range of 1.1 to 1.6 hertz. Since there 800I C304250201 830418 PDR ADOCK 05000461 E PDR

0982-L U-0633 L30-83(04-18)-L April 18, 1983 Page 2

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are no structural frequencies in this range, our judgment is that the Clinton plant design is not impacted by this narrow exceedance. We propose that discussion of the revised saectra be included in the upcoming meeting at Bet'aesda on April 28 for

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resolution of SER outstanding issue #3.

Sincerely, G. E. Wuller Supervisor-Licensing Nuclear Station Engineering GEW/lt attach, cc: Dr. H. Abelson, NRC Clinton Project Manager Mr. G. V. Giese-Koch, NRC GB Mr. B. N. Jagannath, NRC HGEB Mr . N. C. Chokshi, NRC SEB Mr. A. J. H. Lee, NRC EQB Mr. D. Terao, NRC MEB Mr. H. H. Livermore, NRC Resident Inspector Illinois Department of Nuclear Safety i

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Theoretical Spectra Considering Soil Ampli- _

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Figure 1: Comparison of Design Basis Design Time History Spectrum to Theoretical Spectra Considering Soil Amplification

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