ML19259B171

Forwards Addl Info Re Design of Certain Piping Sys Support Base Plates.Potential Design Deficiency Identified.Design Did Not Consider Plate Flexibility in Determination of Max Load

ML19259B171
Person / Time
Site:	Sequoyah
Issue date:	01/05/1979
From:	Varga S Office of Nuclear Reactor Regulation
To:	Niav Hughes TENNESSEE VALLEY AUTHORITY
References
NUDOCS 7901170007
Download: ML19259B171 (4)

Text

e f* ** Gs%

UNITED STATES f

I's

't NUCLEAR REGULATORY COMMISSION W ASdlNGTON, D. C. 20555 JAN 5 1979 Docket Nos:

50-327 50-T28 Mr. N. B. Ilughes Manager of Power Tennessee Valley Authority 830 Power Building Chattanooga, Tennessee 37401

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION - SEQUOYAll A potential design deficiency has recently been identified concerning the design of some piping system support base plates in which the support design did not properly take into account the suppcrt plate ficxibility in the determination of the maximum load that would be applied to the support bolts under seismic loading.

This can result in under-estimation of the load and subsequent use of support bolts with inadequate load carrying capability.

To resolve this issue for Scquoyah, please respond to the attached request for ndditional information, which has previously been made availabic to members of your staff.

Your earliast possibic respon';c to this request for additional information is required to preclude further delays in completion of our eview.

(

i hcere E

StevenA.\\akg hief Light Water Rea to s Branch No. 4 Division of Project Management

Enclosure:

Request for Additional Information cc:

See next page f

7901170007

Tennessee Valley Authority JAN 5 1979 CCs:

Herbert S. Sanger, Jr. E sq.

General Counsel Tennessee Valley Authority 400 Connerce Avenue E 118 33 Knoxville, Tennessee 37902 Mr. E. G. Beasley Tennessee Valley Authority 400 Commerce Avenue Knoxville, Tennessee 37902 Mr. Michael Harding Westinghouse Electric Corporation P. O. Box 355 Pittsburgh, Pennsylvania 15230 Mr. David Lambert Tennessee Valley Authority 303 Power Building Chattanooga, Tennessee 37401

ATTACHMEriT JAN 5 1979 MECHANICAL Ef1GIffEERING BRANCH DIVISION OF SYSTEMS SAFETY REQUEST FOR ADDITIONAL INFORMATION 110.

MECHANICAL ENGIllEERING BRANCH 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.

Tor connections of supports which are anchored to a concrete structures provide in addition:

a.

The type of anchoc bolt.

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, ai.d 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 AS"E Code.

- 2_

JAN 5 1979 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 analytical or experimental justification for this assumption.

=

6 e

%