ML20136G390

Approves Use of ASME Code Case N-411 in Seismic Analyses of Addl Piping Sys & Reanalysis of Existing Piping Sys,Per .Use of Code Case N-411 & 850531 Commitments Should Be Included in Future Amend to Updated FSAR

ML20136G390
Person / Time
Site:	Calvert Cliffs
Issue date:	08/07/1985
From:	Harold Denton Office of Nuclear Reactor Regulation
To:	Lundvall A BALTIMORE GAS & ELECTRIC CO.
References
NUDOCS 8508190385
Download: ML20136G390 (2)

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- 4 August 7, 1985 DISTRIBUTION:

1XGETTRT ACRS+10 Docket Nos. 50-317 NRC PDR Gray File and 50-318 L PDR HDenton ORB #3 Rdg HThompson OELD Mr. A. E. Lundvall, Jr. EJordan Vice President - Supply BGrimes Baltimore Gas & Electric Company JPartlow P. O. Box 1475 DHJaffe Baltimore, Maryland 21203 PMKreutzer

Dear Mr. Lundvall:

By your letter dated April 19, 1985, you requested NRC approval for use of ASME Code Case N-411 in connection with the seismic analyses of additional piping systems and the reanalysis of existing piping systems at the Calvert Cliffs Nuclear Power Plant Units 1 and 2. Code Case N-411 has not, as yet, been incorporated in NRC Regulatory Guide 1.85, " Code Case Acceptability-ASME Section III Materials."

Code Case N-411, " Alternative Damping Values for Seismic Analysis of Piping Section III, Division 1, Class 1, 2 and 3 Construction" is a conditionally acceptable Code Case and is approved by the NRC pending revision of Regulatory Guide 1.61, " Damping Values for Seismic Design of Nuclear Power Plants."

Based upon your letter of May 31, 1985, we understand that:

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

(2) Code Case N-411 is to be used for new analyses or for reconciliation work for new or existing systems.

(3) Due to the increased flexibility of the system, BG&E commits to check all system predicted maximum displacements for adequate clearance with adjacent structures, components and equipment, and that the mounted equipment can withstand the increased motion.

(4) When the alternate damping criteria of Code Case N-411 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.

We find the above commitments to be acceptable.

8508190385 850007 PDR ADOCK 05000317 P PDR

Mr. A. E. Lundvall, Jr. Accordingly, based upon irformation contained in BGAE's letters of April 19, 1985 and May 31, 1985, we conclude that, with regard to use of ASME Code Case N-411, this case provides an acceptable level of quality and safety. We, therefore, in accordance with 10 CFR 50.55a(a)(3),

authorize the use of ASME Code Case N-411 at Calvert Cliffs Nuclear Power Plant Units 1 and 2. Use of Code Case N-411, together with the commitments contained in your letter dated May 31, 1985, should be included in a future amendment to the Calvert Cliffs FSAR.

Sincerely,

@ @?.!?$ N Harold R. Denton, Director Office of Nuclear Reactor Regulation cc: See next page 4

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