ML20032B377

Forwards Engineering Evaluation of Curing Compound on Const Joints in Response to Unresolved Items Noted in IE Insp Repts 50-413/80-20 & 50-414/80-20

ML20032B377
Person / Time
Site:	Catawba
Issue date:	08/24/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
NUDOCS 8111050485
Download: ML20032B377 (2)

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0 Powsu Dun.mwo 422 SocTu Cnuncu STazzT, CRARI.OTTE, N. C. 2824a

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')Q Mr. James P. O'Reilly, Director

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U. S. Nuclear Regulatory Commission i

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Atlanta, Georgia 30303 j p,,,,

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Re: RII:JRH 50-413/80-20 4

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Dear Mr. O'Reilly:

l Please find attached. an engineering evaluation concerning " Curing Compounds on Construction Joints." This was identified as Unresolved Item 50-413/80-20-02 and 50-4_14/80-20-02 in'the above' referenced Inspection Report.

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'Very'truly yours, O Non l.h.

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cw William O. Parker, Jr RWO/php Attachment cc:

Mr. K..Jabbour Mr. P. K. VanDoorn Office of Nuclear Reactor Regulation NRC-Resident Inspector U. S. Nuclear Regulatory Cammission Catawba Nuclear Station Washington, D. C. 20555 hIgK05000413 85 810824 G

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4 Duke Power Company Catawba Units 1 and'2 The design methods used to transfer shear at construction joints dofnot take

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L credit for bond as a measure of. shear or' tensile resistance. Where' direct-shear transfer is required in the Reactor Building, the shear: friction method has 'been employed. in accordance with Section 11.15 of ACI 318-71, ',' Building :

Code Requirements for Reinforced Concrete."

-This method requires.only a specified roughness and ar2a 'of reinforcing steel to be provided at' the joint

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for ~ fresh _ concrete placed against hardened concrete. In the' Auxiliary

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4 Building and safety related yard structures = the' typical method employed to

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transfer direct shear is the shear key method which also does not depend on i,

bond for either tensile or shear resistance. The particular requirements for shear transfer by the shear friction or shear 1 key methods are specified on the Duke construction' drawings for all safety related structures as appropriate.

-i' for design conditions.

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Duke Specification CNS-1109.00-1, " Specification for concrete for Category I

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Struc[tures,"adoptedtheprovisionsofChapter12_ofACI301-72,"Specifica-tionLfor. Structural Concrete for Buildings," for the curing of. concrete.

In doing so the specification failed to. clarify our position on the require-ments of paragraph 12.2.1.7 concerning the use of curing compounds on surfaces to which concrete or other materials are to be bonded. Section-5.4 of Duke's_

specification requires that joints not be bonded in accordance with Section 8.5 of-ACI 301-12 except as specified on the drawings..Our intent is to specify

' on the drawings 'the joints which require bond.and the method which~ should. be used to achieve bond. Since bond has not been a design factor for shear e

transfer in joints to dat'e, the reference to bond requirements in ACI.301

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paragraph 12.2.1.7 is not applicable.

The use of curing components on joint surfaces has been discontinued..Construc-tion" joints are currently cured by absorptive fabrics kept continuously wet.

Also, Specification CNS-1109.00-1 has been revised to clarify and address provisions which will be required when bond is required in construction

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joints..This clarification was incorporated into Revision 18, dated October 17,

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1980. We have also completed a review of all safety related design calcula-tions to ensure that shear transfer at construction joints complies' with design requirements.

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