ML19290C640

Submits Analyses of Unit 2 Excavation Seal Involving Assessment of Mass Fill Strength of Lean Concrete as Foundation Matl.Fulfills Util 791019 Commitment.Requests Prompt Review & Authorization to Proceed Under LWA

ML19290C640
Person / Time
Site:	Black Fox
Issue date:	12/12/1979
From:	Ewing T PUBLIC SERVICE CO. OF OKLAHOMA
To:	Varga S Office of Nuclear Reactor Regulation
Shared Package
ML19262B963	List: ML19262B962 ML19290C640 ML19290C645
References
6212-123-3500, NUDOCS 8001220303
Download: ML19290C640 (3)

Text

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• 6212 DIN 8-019-767 PUBLIC SERVICE COMPANY OF OKLAHOMA ~~ ,

A CENTRAL AND SOUTH WEST COMPANY PO. BOX 201/ TULSA. OKLAHCMA 74102 / (918) 583-36'1 Public Service Company of Oklahoma Decembe.' 12,1979 Black Fox Station Units 1 and 2 File 6212.125.3500.21L Excavation Seal Unit 2 U.S. NRC Docket No. STN50-556, 50-557 Mr. Steven A. Varga, Assistant Director Division of Project Management Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 2G302

Dear Mr. Varga:

As promised in our letter of October 19, 1979, we are transmitting herewith, for staff review, analyses we have done regarding the excavation seal on Unit 2 of the Black Fox Station. These analyses involve an assessment of the strength of a mass fill of lean concrete as a foundation material as compared with the natural rock structure and the effect of this relatively thick con-crete fill on the dynamic responses of the safety related structures. The attached material is in the format of the BFS PSAR, Subsection 3.0 5. We intend to submit this material as a PSAR Amendment in conjunction with a TMI related amendment which will be filed prior to the comencement of the safety hearings.

The purpose of the concrete fill is, of course, to replace the excavated silt-stone with concrete which meets the design basis established for-the under-lying competent siltstone during the NRC's Site Suitability Evaluation. The attached analysis demonstrates that the design basis is met and that there will be no soil structure interaction as a result of seismic events and that the impact on the dynamic response of the safety related structures is insigni-ficant.

Since a concrete fill represents a relatively large concrete pour, PS0 will utilize full quality procedures and quality control concrete in this activity even though this work cannot be construed as safety related. This has been done with all of the concrete poured as a part of the excavation seals for Unit 1 and Unit 2. In addition, the computed value of the shear wave velocity for the lean concrete backfill will be verified by actual tests in the field to insure that it is not lower than 3500 fps, ensuring the design basis is met.

This transmittal fulfills our commitment to provide analysis and placement descriptions prior to commencing the mass fill. PS0 believes that the accom-panying aralysis demonstrates acceptability of proceeding with completion of 1785 001

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g001220 f} CENTRAL AND SOUTH WEST SYSTEM xi n m 3OS s.n..n ci rtr, Pwr West Texas Utet<es

Steven A. Varga Page 2 the excavation seal for Unit 2 under the Limited Work Authorization now in effect. We request your prompt review and authorization so we may proceed with this activity.

Very truly yours, k*

T.N. Ewing, M er BlackFoxSpt'on Nuclear Pro t TNE/VLC/dah attachments cc. BFS Service List e

a 4

1785 002

BLACK FOX STATION SERVICE LIST Mr. Lawrence Burrell MHB Technical Associates, Inc.

Route 1, Box 197 1723 Hamilton Avenue, Suite X Fairview, OK 73737 San Jose, CA 95125 Andrew T. Dalton Michael I. Miller 1437 So. Main St., Suite 302 Isham, Lincoln & Beale Tulsa, OK 74119 One First National Plaza, Suite 4200 Chicago, IL 60603 L. Dow Davis, William D. Paton, and Colleen Woodhead Mr. Jan A. Norris Counsel for NRC Staff USNRC, Environmental Projects Branch 3 USNRC Phillips Building Washington, D.C. 20555 7920 Norfolk Avenue Bethesda, MD 20014 Mrs. Carrie Dickerson Citizens Action for Safe Energy, Inc. Charles S. Rogers, Asst. Attorney General P. O. Box 924 112 State Capitol Building Claremore, OK 74017 Oklahoma City, OK 73105 Mr. Cecil Thomas Mr. Gerald F. Diddle, Gen. Mgr. USNRC Associated Electric Cooperative, Inc. Phillips Building P. O. Box 754 7920 Norfolk Avenue Springfield, M0 65801 Bethesda, MD 20014 Joseph R. Farris, John R. Woodard III Mrs. Ilene Younghein Feldman, Hall, Franden, Reed and 3900 Cashion Place Woodard Oklahoma City, OK 73112 816 Enterprise Building Tulsa, OK 74103 Mr. Joseph Gallo Isham, Lincoln & Beale 1050 17th Street, N.W.

Washington, D.C.

Mr. William G. Hubacek USNRC, Region IV Office of Inspection and Enforcement 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76012 Mr. Maynard Human, Gen. Mgr.

Western Farmers Electric Cooperative P. O. Box 429 Anadarko, OK 73005 d85003 .