ML19257B929

Responds to IE Bulletin 79-02,Revision 2, Pipe Support Base Plate Designs Using Concrete Expansion Anchor Bolts. Concrete Expansion Anchor Baseplate Assemblies Will Be Designed Per Aci 349,App B

ML19257B929
Person / Time
Site:	Bailly
Issue date:	01/03/1980
From:	Shorb E NORTHERN INDIANA PUBLIC SERVICE CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
IEB-79-02, IEB-79-2, NUDOCS 8001210262
Download: ML19257B929 (5)

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,',U,'v$55;.*,%", January 3,1980 Mr. James G. Keppler U. S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, Illinois 60137 RE: NRC IE Bulletin 79-02 Rev. 2 (November 8,1979)

Pipe Support Base Plate Designs Using Concrete Expansion Anchor Bolts Docket No. 50-367

Dear Mr. Keppler:

Northern Indiana Public Service Company's (NIPSCO) Bailly Generating Station Nuclear-1 has yet to resume construction activities and as such no work of the nature involved in the Bulletin has been performed. NIPSCO's response to revision 2 of IE Bulletin 79-02 is as follows:

1.) In response to the clarification of item #2, concrete expansion anchor baseplate assemblies for Bailly Generating Station Nuclear-1 will be designed in accordance with ACI 349 Appendix B. This criteria will result in a factor of safety equal to 4. O applied to the manufacturer's recommended ulti-mate loads for emergency and faulted piping load combinations re spectively.

2.) With regard to the new item #5, the following four (4) responses are submitted in the same order as presented in the bulletin.

a. The present design criteria for Bailly N-1 do not permit safety related piping systems to be attached to concrete masonry walls. -

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Northern 8ndiene Putallo Service Cornpe ng M r. James G. Keppler Hammond, Indiana

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U. S. Nuclear Regulatory Commission January 3,1980 Page Two

b. The use of concrete expansion anchors in concrete masonry walls at Bailly Generating Station Nuclear-1 will be restricted to solid concrete masonry walls, and to the attachment of small loads, typically less than 500 pounds. Items falling under this category, for example, are electrical junction boxes and conduit. Heavier loads will not be permitted to be attached to concrete masonry walls, nor will concrete expansion anchors be used in hollow concrete masonry walls.

All concrete masonry walls will be designed for a con-centrated live load of 180 pounds applied on one-foot wide horizontal beam strips, spanning the length of the wall over its entire height. The 180 pound concentrated live load will be placed on the beam strips to envelope the maximum resultant moment and shear. Items actually attached to concrete masonry walls will be verified by field survey, and a final load check conducted to assure the adequacy of the walls to carry the applied loads.

c. The allowable design loads for expansion anchors in concrete masonry walls have been determined by static tests conducted at various units currently under con-struction. The anchors in these tests were installed in solid concrete masonry units and in the masonry mortar joints. The ultimate loads for concrete expansion anchors installed in concrete masonry walls have, thereby, been established as approximately one-half of the corresponding allowables in plain concrete. The following concrete masonry units will be used at Bailly Generating Station Nuclear-1:

i. ) Masonry units - ASTM C145, Type N-I blocks, having a minimum net compressive strength equal to 1800 psi.

ii. ) Mortar - ASTM C270, Type M, having a minimum compressive strength equal to 2500 psi at 28 days.

The concrete masonry walls at Bailly N-1 will be designed using elastic techniques. The allowable stresses in concrete masonry walls are.in '

accordance with the National Concrete. Masonry

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• Mr. James G. Keppler Hammond, Indiana U. S. Nuclear Regulatory Commission January 3,1980 Page Three Association Specifications for Non-Reinforced Concrete Masonry. These stresses are:

Type M Allowable Stress M ortar Shear 34 psi Tension in flexure normal to bed joints 39 psi Tension in flexure parallel to bed joints 78 psi These allowable stresses are upon a factor of safety equel to approximately 3. 0 against ultimate stresses.

No overstress has been permitted for OBE load c ombinations. For SSE loading combinations, the resultant factor of safety is equal to approximately

2. 0 against ultimate stresses.

Concrete expansion anchor baseplate assemblies in concrete masonry walls will be analyzed using rigid plate theory. N1PSCO, in earlier responses to IE Bulletin 79-02, has previously demonstrated that the rigid plate analysis procedure provides results compati-ble with a flexible plate analysis at the ultimate loading conditions when the effects of expansion anchor flexibility and baseplate flexibility are properly accounted for.

Northern Indiana Public Service Company has reviewed the deficiencies identified in IE Bulletin 79-28 con-cerning the adequacy of concrete masonry walls to support attached items at the Trojan plant, and will assure that a similar situation will not exist at Bailly N-1.

d. Tests have been performed on the capacity of concrete expan-sion anchors in concrete masonry walls on several plants

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Northern Ineslana PsatzIlo Servloe Compangd

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Mr. James G. Keppler Hammond, Indiana

• U. S. Nuclear Regulatory Commission January 3,1980 Page Four currently under construction. These static tests have indicated that the ultimate capacity of expansion anchors in solid and grouted concrete masonry walls to be more than 50% of their corresponding capacity in plain con-crete. NIPSCO has tentatively committed to participate in a comprehensive static and dynamic test program to substantitate the behavior of expansion anchors in con-crete masonry walls. The final commitment for partici-pation will be made as soon as construction activities re sume. These tests will include:

i. ) Static load tests on individual anchors.

ii. ) Load relaxation te sts on individual anchors.

iii. ) Dynamic tests on individual anchors under the following conditions:

a) Pipe transient cyclic loads.

b) OBE and SSE seismic loads.

The test program will encompass the following combination of variables:

i. ) Expansion anchor types - Wedge type anchors.

ii. ) Anchor diameters a) 3/8" b) 1/2" c) 5/8" d) 3/4" iii. ) Embedment Depth - 8 anchor diameters iv.) Embedment material a) Masonry units - ASTM C145, Type N-I blocks

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orteseres Indemna Putallo Servloe Compang

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Mr. James G. Keppler Hammond, Indiana

• U. S. Nuclear Regulatory Commission January 3,1980 Page Five b) Masonry mortar - ASTM C270, Type M The results of the static and dynamic test program for con-crete expansion anchors in concrete masonry will be available and reported to the Nuclear Regulatory Commission upon completion.

3.) With regards to new item #6, the following three (3) responses are submitted in the same order as presented in the bulletin.

a. Not applicable, inasmuch as no work of this nature has been performed as of this date.

b. Concrete expansion anchors will be used to attach structural steel shapes to concrete walls to support safety related piping systems. Structural angles will be the predominant steel shape used. These structural shapes will be used to support relatively light loads, less than 1,000 pounds.

c. Previous discussions within this response indicate that the concerns of this bulletin have been adequately addressed so that all systems will meet operability requirements in the event of an SSE.

Very truly yours,

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-a EMS: cgs cc: United States Nuclear Regulatory Commission Office of Inspection and Enforcement Division of Reactor Construction Inspection Washington, D. C. 20555

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