ML20024D894

Final Rept on Significant Deficiency SD-29 Re Cracks in Concrete in Containment Crane Wall Near Embedments.Initially Reported on 821207.Plate Capacity Adequate to Resist Forces from Pipe Rack Trusses.Deficiency Satisfactorily Resolved

ML20024D894
Person / Time
Site:	Millstone
Issue date:	07/27/1983
From:	Counsil W, Sears C NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
10CFR-050.55E, 10CFR-50.55E, B10839, SD-29, NUDOCS 8308080377
Download: ML20024D894 (3)

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me esopMa8' esWCL5aA EadaGT Coww (203) 666-6911 July 27,1983 Docket No.30-423 B10839 Dr. Thomas E. Murley, Regional Administrator Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406

References:

(1) W. G. Counsil letter to R. C. Haynes, Millstone Nuclear Power Station, Unit No. 3, Reporting of Potential Significant Deficiencies in Design and Construction: Cracks Related to Embedments in the Containment Crane Wall (SD-29), dated December 7,1982.

(2) W. G. Counsil letter to T. E. Murley, Millstone Nuclear Power Statien, Unit No. 3, Reporting of Potential Significant Deficiencies in Design and Construction: Cracks Related to Embedments in the Containment Crane Wall (SD-29), dated June 16,1983.

Dear Dr. Murley:

Millstone Nuclear Power Station, Unit No. 3, Reporting of Potential Significant Deficiencies in Design and Construction:

Cracks Related to Embedments in the Containment Crane Wall (SD-29)

In Reference (1), Northeast Nuclear Energy Company (NNECO) reported a potential significant deficiency as required by 10CFR50.55(e) concerning cracks in the concrete in the containment crane wall near embedments. Reference (2) provided you with an update of our progress in resolving this potential deficiency. As outlined below, this investigation has been completed and it was found that the plate capacity is adequate to resist the forces from the pipe rack trusses.

The cracks occurred adjacent to embedment plates which act as supports for the annulus pipe racks carrying Category I piping. This condition was originally reported on M&D 0646 for one location. While performing an investigation leading to the N&D disposition, cracks at other similar plates were discovered.

A clear indication of the direction of the cracks was established by chipping the concrete. The cracks extend from the face of the concrete to the heads of the j first row of studs and then over at an angle of approximately 45 degrees towards the center of the plate (see Attachment A). i p 8308080377 830727 I PDR ADOCK 05000423 l k S PDR

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The capacity of the plates was calculated based on the cracked section shown on Attachment A, and using the appropriate safety factors. Analysis of critical sections of the pipe rack trusses was performed using current support load information. The resulting reactions at the plates are less than the calculated plate capacity. Structural repairs were f ound not to be necessary.

NNECO considers this deficiency to lie resolved. Therefore, this letter constitutes our final report closing out SD-29. We trust the above information satisf actorily responds to your concerns, however, if you should have any further questions, feel free to contact us.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY l

\x . t, .tmmO W. G. Counsil Senior Vice President By: C. F. Sears Vice President Nuclear and Environmental Engineering i

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