ML20062F240

Requests Addl Info Re Bolted Connections in Linear Component Supports,Inasmuch as Design May Have Underestimated Load Capacity Under Seismic Loading

ML20062F240
Person / Time
Site:	Summer
Issue date:	12/07/1978
From:	Baer R Office of Nuclear Reactor Regulation
To:	Crews E SOUTH CAROLINA ELECTRIC & GAS CO.
References
NUDOCS 7812150208
Download: ML20062F240 (5)

Text

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[.. ..,S o UNITED STATES

.POR tr'; NUCLEAR REGULATORY COMMiss!ON

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i  ;.Wy-/,j f WASHINGTON, D. C. 20555 s w:hj/'/ DEC 0 7 iT/3 Docket No. 50-395 .

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Mr. E. H. Crews, Jr. , Vice President ';

i and Group Executive - Engineering .

and Construction _

South Carolina Electric and Gas Company P. O. Box 764 Columbia, South Carolina 29218 i

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SUBJECT:

SAFETY OF BOLTED CONNECTIONS IN LINEAR COMPONENT SUPPORTS

(. Virgil C. Sumer Nuclear Station)'

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! We have beccme aware of the potential for the design of some piping system l support base plates not properly taking into account support plate flexi-i bility when determining the maximum load that would be applied to the i support bolts under seismic loading. This could result in underestimation

of the load and subsequent use of support bolts with inadequate load carrying capability.

In order for us to detennine if the design for similar components in the Virgil C. Summer Nuclear Station is acceptable, we request that you pro-vide the information requested in the Enclosure. Please provide us with your schedule for submittal of your response. If you have any questians cn this matter, please feel free to contact us.

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Sincerely, 7

Robert L. Baer, Chief Light Water Reactors Branch No. 2 Division of Project Mcnagement

Enclosure:

Request for Additional Infonnation ecs w/ enclosure:

See page 2 781215 # 8 s

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.p Mr. E. H. Crews, Jr., Vice President and Group Executive - Engineering and Construction South Carolina Electric & Gas Company P. O. Box 764 Columbia, South Carolina 29218 I

cc: Mr. H. T. Babb, General Manager South Carolina Electric & Gas Company P. O. Box 764 Columbia, South Carolina 29218 G. H. Fischer, Esq.

Vice President & General Counsel

,,.' South Carolina Electric & Gas Company

(' P. O. Box 764 Columbia, South Carolina 29218 j

Mr. William C. Mescher President & Chief Executive South Carolina Public Service Authority 223 North Live Oak Drive Moncks Corner, South Carolina 29461 Mr. William A. Williams, Jr.

Executive Assistant to the General Manager South Carolina Public Service Authority 223 North Live Oak Drive Moncks Corner, South Carolina 29461 Wallace S. Murphy, Esq.

General Counsel j ( South Carolina Public Service Authority 223 North Live Oak Drive Moncks Corner, South Carolina 29461 Troy B. Conner, Jr. , Esq.

Ccnner, Moore & Corcer 1747 Pennsylvania Avenue, N. W.

Washington, D. C. 20006 Mr. Mark B. Whitaker, Jr.

Licensing and Staff Engineer South Carolina Electric & Gas Company P. O. Box 764 Columbia, South Carolina 29218 Mr. O. W. Dixon Group Manager, Production Engineering South Carolina Ilectric & Gas Company P. O. Box 764 Columota, South Carolina 29218 s

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Mr. E. H. Crews , J r. - -

cc: Mr. Brett Allen Bursey Route 1 Box 93C Little Mountain, South Carolina 29076 I

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ENCLOSURE f

REQUEST FOR ADDITIONAL INFORMATION 110.

MECHANICAL ENGINEERING BRANCH 110.39 Appendix XVII-2461.1 of the ASME Code Section III requires that

' bolt loads in bolted connections for linear component supports include prying effects due to the flexibility of the connection.*

1.

(' Provide confirmation that the loads in bolted connections for linear component supports were determined by considering the deformation of the connection and tension-shear interaction for the bolts.

For connections of supports which are Lachored to a concrete structures provide in addition:

a. The type of anchor bolt.

t b.

The factors of safety (and their bases) against pullout

(_ under static, repeated and transient loading.

This information should include representative diagrams of the , connections, material properties, and interaction diagrams, the analytical techniques and models used, and the maximum

• Similar requirements for structural joints are also stated in the AISC Manual of Steel Construction,1970 Edition for plants in which support design predates Subsection NF of Section III of the ASME Code.

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.. dEC 0 7 M stresses in the bolts and the connections under both static, repeated, and transient type loading.

2. If any connection was assumed to be rigid, provide complete I

! analytical or experimental justification for this assumptien. i l

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