ML20095J315
| ML20095J315 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 08/24/1984 |
| From: | Woolever E DUQUESNE LIGHT CO. |
| To: | Knighton G Office of Nuclear Reactor Regulation |
| References | |
| 2NRC-4-133, NUDOCS 8408290222 | |
| Download: ML20095J315 (2) | |
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2NRC-4-133 (412) 787 - 5141 Telecopy Nuclear Construction Division Au3ust 24, 1984 Robinson Plaza, Building 2, Suite 210 Pittsburgh, PA 15205 United States Nuclear Regulatory Commission
-Washington, DC 20555 ATTENTION:
Mr. George W. Knighton,' Chief Licensing Branch 3 Of fice of Nuclear Reactor Regulation
SUBJECT:
Beaver Valley Power Station - Unit No. 2 Docket No. 50-412 Response to Draf t SER Open Item No.179 Gentlemen:
This letter forwards the attached response to the NRC Geotechnical Engineering Section's Draft SER Open Item No. 179.
DUQUESNE LIGHT COMPANY By e
E. JL Woolever JD0/wjs Vice President Attachment cc:
Ms. M. Ley, Project Manager (w/a)
Mr. E. A. Licitra, Project Manager (w/a)
Mr. G. Walton, NRC Resident Inspector (w/a)
COMMONWEALTH OF PENNSYLVANIA )
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COUNTY OF ALLEGHENY
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On this g d day of (Lad
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, be fo re me, a Notary Public in and for said Commdwealth and County, [>ersonally appeared E.J. Woolever, who being duly sworn, deposed and said that (1) he is Vice President of Duquesne Light, (2) he is duly authorized to execute and file the foregoing Submittal on behalf of said Company, and (3) the statements set forth in the Submitt al are true and correct to the best of his knowledge.
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g ANITA ELAINE REITER, NOTARY PUBLIC
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ROBINSON TOWNSHIF, ALLEGHENY COUNTT i
MY COMMISSION EXPlRES OCTOBER 20,158
Draft SER Open Item No. 179 (Section 2.5.4.3.5) - Soil Damping Values As stated in Section 2.5.4.1.2, the engineering properties of the in situ sands and gravels were not determined by laboratory tests because of the inability to obtain undisturbed samples of these granular materials.
In the soil structure interaction analysis of the Reactor Containment, the applicant varied the soil shear undulus value by 130 percent, but has not so varied the damping value.
The applicant has
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been asked to justify not varying the soil damping value by 130 percent because of the uncertainty involved in the soil properties and the presence of thick clay lenses.
Response
Variations of soil properties and dampings are accounted for in the soil-structure interaction analysis of structures at BVPS-2 by peak-broadening the resulting floor response spectra by +25 and -20 percent of the corresponding period (FSAR Section 3.7B.2.9).
Peak-broadening is recognized by SRP 3.7.2,Section II.9, as being an acceptable method for considering variations of structural properties, dampings, soil proper-ties, and soil-structure interactions. This SRP section states that the peak width should be increased by a minimum of 115 percent to be acceptable if no special study is performed for this purpose.
Since the BVPS-2 criteria used fo r peak-broadening floor response spectra are cons ide rably more conservative than those specified in SRP 3.7.2, further variations in the soil prope rties used in the soil-structure interaction analyses were not considered.
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