ML19224D563

Interim Deficiency Rept Re Concrete Void Discovered on 790604 in Auxiliary Bldg Slab.New Repair Procedures Have Been Approved But Not Yet Performed.Final Rept Will Follow

ML19224D563
Person / Time
Site:	Marble Hill
Issue date:	07/05/1979
From:	Coughlin J PSI ENERGY, INC. A/K/A PUBLIC SERVICE CO. OF INDIANA
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
NUDOCS 7907120618
Download: ML19224D563 (2)

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0705790121 S

PUBUC SEFWICE .

INDUWA July 5, 1979 Mr. Jam 6s G. Keppler, Director U.S. Nuclear Regulatory Cons:tission Docket Nos.: STN 50-546 Region III STN 50-547 799 Roosevelt Road Construction Permit Nos. : CPPR-170 Glen Ellyn, Illinoin 60137 CPPR-171 Marbla Hill Nuclear Generating Station Units 1 & 2

Dear Mr. Keppler:

On June 4,1979, Mr. C. E. Chmielewski of Public Service Company of Indiana, Inc. (PSI) telephoned year office to notify you of the following reportable incident as required by 10CTR50.55(e). A concrete void was discovered on March 29, 1979 in the auxiliary building slab, elevation 373'6".

PSI, Sargent & Lundy, and Newberg Construction Company personnel visually surveyed the void in the 36-inch thich concrete slab on April 6,1979. As a result of this inspection, the void was believed to extend vertically fron the bottou layer of tl+ einforcing bars to the mud nat below, a dis-tance of approximately 12". The void was also believed to extend approxi-mately 20' in the north-south direction and approximately 4'6" in the east-west direction.

The concrete void was ultrasonically tested on May 7 & 8, 1979. The results of this test revealed that the void was apprnximately 25' in the north-south direction and up to 9' in the east-west direction. However, the void still extended approximately 12" vertically. PSI felt that the concrete void could potentially degrade the structural integrity of the auxiliary building and therefore not enable it to meet its seismic requirements. PSI decided that this incident was reportable as a significant construction deficiency under 10CPR50.55(e) .

A new procedure, WPN 33, was prepared by the Newberg Construction Company which established methods to repair concrete voids of this size. This pro-cedure was reviewed and approved by Sargent & Lundy and PSI. On June 9 & 10, repair work was initiated with the application of a coating of shoterete per WPN 33. NRC inspectors were preeent to witness this work.

Six-day and eleven-day Cylinder Compressive Strength Tests of the shoterete have already been perfornad Lt.iG vcrify that t.he aquired structural strength G 4!4 089 p 7907120&i2 S is

Mr. James C. Keppler, Director July 5, 1979 SEmACE INDIANA of the concrete slab can be maintained. An ultrasonic examination of the void aran was performed on June 29, 1979 and confir: sed the adequacy of the above repair work.

Currently, final repair work has not been performed and also all the per-tinent doctucentation has not been finalized. Therefore, the above con-stitutes an interim report as defined by 10CF250.55(e)(3). Upon c #-

pletion of the final repair work and receipt of the final docu=antation, PSI will submit th&lr final report.

Sincerely,

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James Coughlin Vice President-Nuclear PAB:jb cc: Director of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D. c. 20555 E. R. Schweibinz, P.E.

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