ML17317B221

Addl Response to IE Bulletin 79-07.Twenty-three Piping Lines Analyzed Using Absolute Summation Technique Proved Capable of Withstanding Seismic Event.Remaining Piping Sys Also Proved Capable

ML17317B221
Person / Time
Site:	Cook
Issue date:	05/04/1979
From:	Bien F INDIANA MICHIGAN POWER CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
AEP:NRC:00186A, AEP:NRC:186A, NUDOCS 7905250371
Download: ML17317B221 (4)

Text

INDIANA R MICHIGAN POWER COMPANY P. 0. BOX 18 BOWLING GRE EN STATION NEW YORK, N. Y. 10004 May 4, 1979 AEP:NRC:00186A Donald C. Cook Nuclear Plant Units 1 5 2 Docket Nos. 50-315 and 50-316 License Nos. DPR-58 and DPR-74 IE Bulletin No. 79-07 Seismic Stress Analysis of Safety-Related Piping Nr. J. G. Keppler, Regional Director U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region III 799 Roosevelt Road Glen Ellyn, Illinois 60137 Ref: (1)'Letter No. AEP:NRC:00186, dated April 24, 1979

Dear >tr. Keppler:

This letter completes our previous response to IE Bulletin No. 79-07, AEP:NRC:00186, dated April 24, 1979. As noted earlier, we were informed by Westinghouse that in the original analysis of 24 individual piping lines performed prior to November 1971, an earlier version of the WESTDYN program which incorporated the algebraic sum of intramodal responses had been used. However, a complete check of our records (not possible within the very short time allowed to prepare transmittal AEP:NRC:00186) has shown that 23 of the 24 piping lines had been subse-quently reanalyzed using the absolute sumation or the SRSS technique.

The support design for all 23 lines was based on the reanalysis done using the correct method of summation of seismic forces. We, thus, conclude that these piping systems and their supports are capable the seismic event. Please note that our original search of'ithstanding to prepare AEP:NRC:00186 had uncovered only 19 individual piping lines that had been reanalyzed.

The remaining piping system that still required reanalysis was the 14" pressurizer surge line (see Table I of Attachment III to Reference (1)).

The reanalysis has been completed by Westinghouse and the results are as shown in Attachment I. As noted in the attachment, all the stresses for the piping and the pipe supports are within the allowable limit (only a 10.31. increase in the seismic stress) and, thus, capable of withstanding the seismic event.

Mr. J. G. Keppler AEP:NRC:00186A May 4, 1979 As a result of all of the above and of Reference (1), we conclude that the capability of the Oonald C. Cook Nuclear Plant to withstand a seismic event is not adversely affected.

Very truly yours, FNB:em . Bien Vice President

Nr. J. G. Keppler AEP:NRC:00186A May 4, 1979 cc: R. C. Callen G. Charnoff R. Walsh P. W. Steketee R. J. Vollen D. V. Shaller-Bridgman R. W. Jurgensen N. C. Moseley-NRC

Mr. J. G. Kepp1er -4 AEP:NRC:00186A" May 4, 1979 ATTACHMENT I STRESS

SUMMARY

FOR PRESSURIZER SURGE LINE - MAXIMUM STRESSES FROM REANALYSIS CALCULATED ALLOldABLE LOCATION STRESS/LOAD STRESS/LOAD MARGIN OBE Piping 8911 PSI 19200 PSI 10289 PSI Interface pipe/pres-surizer nozzle 8278 PSI 19200 PSI 10922 PSI Pipe Support 11.04 KIPS 7 0.0 KIPj 58.96 KIPS..

DBf Piping 11933 PSI 28800 PSII 16867 PSI Interface pipe/pres-surizer nozzle 10665 PSI 28800 PSI 18135 PSI Pipe Support 15.37 KIPS 70.0 KIPS 54.63 KIPS

'(conservative)