ML20065G222

Final Deficiency Rept Re Control Bldg Termination Cabinet Support Sills.Initially Reported on 820615.Welded Studs to Be Replaced by drilled-through Anchor Bolts Tied Directly to Base Concrete.Work Will Be Completed by 820930

ML20065G222
Person / Time
Site:	Nine Mile Point
Issue date:	09/23/1982
From:	Manno S NIAGARA MOHAWK POWER CORP.
To:	Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8210040071
Download: ML20065G222 (2)

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Y NIAGARA NuMOHAWK NIAGARA MONAWK POWER CORPORAT10N/300 ERIE BOULEVARD WEST, SYRACUSE, N Y.13202/ TELEPHONE (315) 4741511 SAMUE L F. MANNO VICE PRESIDENT NUCLE AR CONSTRUCTION September 23, 1982 Office of Inspection and Enforcement Region I Attention: Mr. R. W. Starostecki, Director Division of Project and Resident Prograns U. S. Nuclear Regulatory Connission 631 Park Avenue King of Prussia, PA 19406 Re: Nine Mile Point - Unit 2 Docket He. 50-410

Dear fir. Starostecki:

Enclosed is a final report in accordance with 10CFR50.55(e) for the deficiency regarding the control building termination cabinet support sills.

This condition was reported by telephone to Mr. H. Kister of your staff on June 15,1982, as a potentially reportable deficiency.

Very truly yours, HIAGARA M0 HAWK POWER CORPORATION N

Samuei F. Manno Vice President -

Nuclear Construction l

SFM/NLR: san Enclosure xc: Director of Inspection and Enforcement l U.S. !!uclear regulatory Connission Washington, DC 20555 l Mr. R. D. Schulz, Resident Inspector 8210040071 820923 PDR ADOCK 05000410 PDR g(d S

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A NIAGARA M0 HAWK POWER CORPORATION Nine Mile Point - Unit 2 Docket No. 50-410 Final Report for a Deficiency Under 10CFR50.55(e) Regarding the Control Building Termination Cabinet Support Sills Description of Deficiency The deficiency pertains to channels in the control building designed for use as embedded sills to support termination cabinets. These channels are located at elevation 288 ft 6 in between column lines AC and AK.

The problem was discovered when a stud failed during torque testing of the studs we?ded on top of the channels. These studs are provided to anchor the termination cabinets to the channels. An investigation revealed that a C6X8.2 channel was installed instead of a C6X13 channel as specified in the design.

Analysis of Safety Implications An evaluation indicates that the stress in the C6X8.2 channel would exceed the allowable yield stress, but not the ultimate stress, when subjected to maximum design loads. Since this channel was installed and because it could exceed yield stress, we have decided to report the deficiency within the requirements -

of 10CFRSC.55(e).

Corrective Action Sone of the studs welded on top of the C6X8.2 channel will be replaced by drilled-through anchor bolts tied directly to the base concrete, thereby transferring part of the design load directly to the base concrete and reducing maximum stresses in the channel to within normal design allowable limits. This work will be completed by September 30, 1982.

To prevent reoccurrence of this problem in the future, the following corrective actions have been taken:

1. The Contractor has instructed Craft Supervisor Personnel responsible for welding of the requirements for verification of all base materials used to fabricate electrical equipment embedded sills. These verifications must include as e minimum correct size and type as specified on controlling documents (such as the latest issue of the drawing or Engineering and Design Coordination Report). The method to accomplish this is by cross checking the heat numbers on the material received /used against mill certs, and/or other documents traceable to the material.

2. Additionally, a new Construction Completion Control Program Checklist is being implemented for use prior to attaching studs to the sills.

This checklist will have additional attributes requiring the verification of identification, marking, and type of material used.

The referenced Construction Completion Control Program Checklist was placed in effect September 13, 1982.

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