ML20134L342

Responds to 850809 Request for Authorization to Use ASME Code Case N-411 for Application in Response Spectrum Seismic Analysis of Piping Sys.Compliance W/Commitments to Revise USAR & Request Acceptable

ML20134L342
Person / Time
Site:	Rancho Seco
Issue date:	08/22/1985
From:	Harold Denton Office of Nuclear Reactor Regulation
To:	Reinaldo Rodriguez SACRAMENTO MUNICIPAL UTILITY DISTRICT
References
TAC-59450, NUDOCS 8509030215
Download: ML20134L342 (3)

Text

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August 22, 1985 )bb Qh Docket No. 50-312 Mr. Ronald J. Rodriguez Assistant General Manager, Nuclear Sacramento Municipal Utility District 6201 S Street P. O. Box 15830 Sacramento, California 95813

SUBJECT:

RANCHO SEC0 NUCLEAR GENERATING STATION - USE OF ASME CODE CASE N-411 We have completed our review of your request for authorization to use ASME Code Case N-411 for application in the response spectrum seismic analysis of piping systems at the Rancho Seco Nuclear Generating Station, as discussed in your August 9,1985 letter.

Code Case N-411, " Alternative Damping Values for Seismic Analysis of Piping,Section III, Division I, Class 1, 2 and 3 Construction" is a conditionally acceptable Code Case and is approved by the staff for specific plant applications pending revision of Regulatory Guide 1.61. Utilities wishing to use this Code Case should submit in their request the following information or comitments:

(a) Comit to use the case for piping systems analyzed by response spectrum methods and not those using time-history analysis methods.

(b) Indicate if the case is to be used for new analyses or for reconciliation work and for support optimization.

(c) Due to the increased flexibility of the system comit to check all systera predicted maximum displacements for adequate clearance with adjacent structures, components and equipment, and that the mounted equipment can withstand the increased motion.

(d) When the alternate damping criteria of this Code Case are used, they will be used in their entirety in a given analysis and shall not be a mixture of Regulatory Guide 1.61 criteria and the alternate criteria of this Code Case.

You have complied with these commitments in your August 9,1985 letter.

Therefore, since the comitments with respect to Code Case N-411 are documented in the referenced letter, we find that your request to use Code Case N-411 to be acceptable for use at the Rancho Seco Nuclear Generating Station Unit in the response spectrum seismic analysis of piping systems.

f 8509030215 850822 PDR ADOCK O 32

Mr. Ronald Rodriguez In addition, we find your commitment to revise the USAR in a subsequent amendment to reflect this change acceptable, i

Sincerely, op sened 4 ILESeen Harold R. Denton, Director Office of Nuclear Reactor Regulation i cc: See next page i

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4 Mr. R. J. Rodriguez Rancho Seco Nuclear Generating 4

Sacramento Punicipal Utility District Station CC*

Mr. David S. Kaplan, Secretary Sacramento County and General Counsel Board of Supervisors i Sacramento Municipal Utility .827 7th Street, Room 424 District Sacramento, California 95014 6201 S Street P. O. Box 15830 Ms. Helen Hubbard Sacramento, California 95813 P. O. Box 63 Sunol, California 94586 Thomas Baxter, Esq.

Shaw, Pittman, Dotts & Trowbridge.

1800 M Street, N.W.

Washington, D.C. 20036 Fr. Robert B. Borsum Babcock & Wilcox

]  ??uclear Power Generation Division Suite 220, 7910 Woodmont Avenue Bethesda, Maryland 20814 i

. Resident Inspector / Rancho Seco c/o U. S. N. R. C.

j 14410 Twin Cities Road Ferald, California 95638 Regional Administrator, Regien V i U.S. Nuclear Pegulatory Commission i 1450 Maria Lane, Suite 710

! Walnut Creek, California 94596 Director j Energy Facilities Siting Division Energy Resources Conservation &

. Developrent Commission i 1516 - 9th Street Cacramento, California 95814 i

Mr. Joseph 0. Ward, Chief ,

i Radiological Health Branch  !

i State Department of Health Services l 714 P Street, Office Building #8

Sacramento, California 95814 i

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