ML20205R156

Forwards Request for Addl Info Re Seismic Design of Bldg 10, for Nrc/Bnl Review.Site Visit to Review Response to Encl Questions,To Insp Bldg 10 & to Audit Supporting Structural Matl Recommended within 60 Days of Ltr Receipt

ML20205R156
Person / Time
Site:	Fort Saint Vrain
Issue date:	03/31/1987
From:	Heitner K Office of Nuclear Reactor Regulation
To:	Robert Williams PUBLIC SERVICE CO. OF COLORADO
References
TAC-55287, NUDOCS 8704060242
Download: ML20205R156 (4)

Text

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March 31, 1987 Docket No. 50-267 Mr. R. O. Williams, Jr.

Vice President, Nuclear Operations Public Service Company of Colorado Post Office Box 840 Denver, Colorado 80201-0840

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION ON FORT ST. VRAIN - BUILDING 10 The staff and it's consultant, Brookhaven National Laboratory, are continuing their review of your submittals concerning the seismic design of Building 10 at Fort St. Vrain. We request that you provide certain additional information as indicated in the enclosure. This information is requested to aid in the completion of this review.

To facilitate a timely resolution of this issue, we recommend that you prepare the responses to these questions, and make the supporting material for all Building 10 structural analyses available for audit. The staff and its consultants would then meet with you at the site to review the responses, inspect Building 10 and audit the supporting material. This site visit should be conducted no later than 60 days from the date of this letter.

The information requested in this letter affects fewer than 10 respondents; therefore, OMB clearance is not required under P.L.96-511.

Sincerely, original signed by Kenneth L. Heitner, Project Manager Standardization and Special Projects Directorate Division of PWR Licensing-B-Office of Nuclear Reactor Regulation

Enclosure:

As stated cc w/ enclosure:

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March 31, 1987 Docket No. 50-267 Mr. R. O. Williams, Jr.

Vice President, Nuclear Operations Public Service Company of Colorado Post Office Box 840 Denver, Colorado 80201-0840

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION ON FORT ST. VRAIN - BUILDING 10 The staff and it's consultant, Brookhaven National Laboratory, are continuing their review of your submittals concerning the seismic design of Building 10 at Fort St. Vrain. We request that you provide certain additional infonnation as indicated in the enclosure. This information is requested to aid in the completion of this review.

l To facilitate a timely resolution of this issue, we recommend that you prepare the responses to these questions, and make the supporting material for all Building 10 structural analyses available for audit. The staff and its consultants would then meet with you at the site to review the responses, inspect Building 10 and audit the supporting material. This site visit should be conducted no later than 60 days from the date of this letter.

The information requested in this letter affects fewer than 10 respondents; therefore, OMB clearance is not required under P.L.96-511.

Sincerely, Kenneth L. Heitner, Project Manager Standardization and Special Projects Directorate Division of PWR Licensing-B Office of Nuclear Reactor Regulation

Enclosure:

1 As stated

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1 cc w/ enclosure:

See next page

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'l Mr. R. O. Williams Public Service Company of Colorado Fort St. Vrain cc:

Mr. D. W. Warembcurg, Manager Albert J. Hazle, Director Nuclear Engineering Division Radiation Control Division Public Service Company Department of Health of Colorado 4210 East lith Avenue P. O. Box 840 Denver, Colorado 80220 Denver, Colorado 802C1 Mr. David Alberstein, 14/159A Mr. R. O. Williams, Acting Manager GA Technologies, Inc.

Nuclear Production Division Post Office Box 85608 Public Service Company of Colorado San Diego, California 92138 16805 Weld County Road 19-1/2 Platteville, Colorado 80651 Mr. H. L. Brey, Manager Nuclear Licensing and Fuel Division Mr. P. F. Tomlinson, Manager Public Service Company of Colorado Quality Assurance Division P. O. Box 840 Public Service Company of Colorado Denver, Colorado 80201 16805 Weld County Road 19-1/2 Platteville, Colorado 80651 Senior Resident Inspector U.S. Nuclear Regulatory Commission Mr. R. F. Walker P. 0. Box 840 Public Service Company of Colorado Platteville, Colorado 80651 Post Office Box 840 Denver, Colorado 80201-0840 Kelley, Stansfield & 0'Donnell Public Service Company Building Commitment Control Program Room 900 Coordinator 550 15th Street Public Service Company of Colorado Denver, Colorado 80202 2420 W. 26th Ave. Suite 100-D Denver, Colorado 80211 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 l

Arlington, Texas 76011 Chaiman, Board of County Commissioners of Weld County, Colorado Greeley, Colorado 80631 Regional Representative Radiation Programs Environmental Protection Agency 1 Denver Place 999 18th Street, Suite 1300 Denver, Colorado 80202-2413

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Enclosure Request For Additional Information Fort St. Vrain Building 10 1.

In the analysis of the Building 10 caissons, two foundation moduli valaes were considered.

It should be demonstrated that these two cases bound the actual condition, where a stiff layer is sandwiched between two soft layers. Consideration should be given to both the equivalent interaction springs and dampers.

2.

The rocking interaction parameters were developed based on the assumption that the foundation is rigid in flexure relative to the axial stiffness of the caisson. Provide information so that the validity of this assumption may be reviewed.

3.

The seismic input ground motion used for Building 10 and the turbine building are different.

Information describing and justifying the use of two different inputs should be provided.

4.

The license's submittal includes spectra labeled " Isolated" and

" Coupled." It is not clear whether the " coupled" spectra are the spectra of the turbine building basemat motion, or spectra of the response of Building 10 to an input motion due to the turbine building basemat motion.

If the first is the case, then information should be provided demonstrating that this solution bounds the structure / soil / structure interaction situation.

If the latter is true, information describing the model used and the input motion should be provided.

5.

The basis for the displacements of the turbine building and Building 10 used to determine the relative building displacements should be provided.

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