ML19309G740

Final Deficiency Rept Re Concrete Void in Auxiliary Bldg Slab at Elevation 373 Ft 6 Inches.Repair of Void Completed. Intended Configuration of Bottom Slab Restored W/Shotconcrete

ML19309G740
Person / Time
Site:	Marble Hill
Issue date:	04/28/1980
From:	Shields S PSI ENERGY, INC. A/K/A PUBLIC SERVICE CO. OF INDIANA
To:
Shared Package
ML19309G741	List: ML19309G740 ML19309G750
References
NUDOCS 8005070484
Download: ML19309G740 (2)

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PUBLIC SERVICE INDIANA S. W. Shields Vice Presicant E'ectric Syrem April 28, 1980 Mr. James G. Keppler, Director Docket Nos.: STN 50-546 U. S. Nuclear Regulatory Co= mission STN 50-547 Region III Construction Permit Nos.: _

799 Roosevelt Road CPPR - 170 Glen Ellyn, Illinois 60137 CPPR - 171 Marble Hill Nuclear Generating Station Units 1 and 2

Dear Mr. Keppler:

On June 4, 1979, Mr. C. E. Chmielewski of Public Service Company of Indiana, Inc. (PSI) telephoned your office to notify you of a potentially reportable item as required by 10CFR 50.55(e). The following repcrt resolves that item and constitutes a final report under the Regulation.

On March 29, 1979, a concrete void was discovered in the Auxiliary Lu11 ding slab at elevation 373'-6". The void was visually inspected on April 6, 1979, and ultrasonically tested on May 7 and 8, 1979. The results of these inspections revealed that the void extended 25' in the north-south direction, up to 9' in the east-west direction and vertically from the bottem layer of reinforcing bars to the mud mat 12" below. A void of this size could degrade the structural integrity of the Auxiliary Building and therefore make it unable to meet its seismic requirements.

A repair of the void was, implemented by first excavating enough material under the slab to allow access for workmen and tools. All unsound concrete was removed. The intended configuration of the bottom of the slab was then restored with shotcrete. The shotcrete repair was tested ultrasonically and found to be acceptable. The ultrasonic examination of this void before and after repair is also discussed in the Sargent

& Lundy report, SL-3753, Evaluation of In-Place Concrete, Marble Hill Nuclear Generating Station, Units 1 and 2. An approved procedure written by the Newberg Construction Company will be utilized for filling in the remainder of the void and for backfilling the excavated material under the slab. This procedure is enclosed with this letter.

30/7 s6

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1000 East Main Street. Plainfield, Indiana 46168 317. 839 .9611

A PUBUC SERVICY

. INDIANA Letter: Mr. James G. Keppler April 28, 1980 4

Corrective actions taken to prevent the reoccurrence of this problen are discussed in the " Description of License Activities Addressing Order Confirming Suspension of Construction" sabmitted to the Nuclear Regulatory Cc=sission on February 2S, 1980. If you have any questions

! on this report, please feel free to contact'=e.

i Sincerely, s' _

S. W. Shields j TDG/brs cc: Jirector of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D. C. 20555 E. R. Schweibinz, P. E. <

J. J. Harrison i

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