ML20214G460

Summary of 720804 & 09 Meetings W/Util & B&R in Bethesda,Md Re Adequacy of 20% of Critical Damping for Horizontal & Vertical Response Used by Applicant for Soil Structure Interaction During Seismic Event.Attendees List Encl

ML20214G460
Person / Time
Site:	Columbia
Issue date:	08/21/1972
From:	Miner S US ATOMIC ENERGY COMMISSION (AEC)
To:	Boyd R US ATOMIC ENERGY COMMISSION (AEC)
References
CON-WNP-0107, CON-WNP-107 NUDOCS 8605220171
Download: ML20214G460 (3)

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AUG 211972 Docket No. 50-397 Roger S. Boyd, Assistant Director for Boiling Water Reactors, Directorate of Licensing THRUt RobertA. Clark, Chief,GasCooledReactorsBranch,Dirggrgtjes gned by of Licensing Rcbert A. Clark MEETINC WITil WASHINGTON PUBLIC POWER SUPPLY SYSTEM (WPPSS) CONCER'iING HANFORD NUMBER IVO MUCLEAR POWER PLANT, DOCKET NO. 50-397 Summary On August 4 and 9 meetings were held with the Washington Public Power Supply System at Bethesda, Maryland. The purpose of the August 4 meeting was to discuss the adequacy of the 20% of critical dampinr:

for horizontal and vertical response used by the applicant for their soil structure interaction during a seismic event. The meeting on August 9 was concerned with allowable containment design stress for penetrations and attachments for pipe whip restraints. The list of attendees at both meetings is attached.

Discussion

1. Damping Factors The applicant, as outlined in the PSAR, utilized the time history technique for his seismic design. In the meeting on August 4 the applicant presented an evaluation utilizing the time history tech-l nique and a 20% of critical soil damping for horizontal and ver-tical response to illustrate the margins he had in his seismic design. The applicant was told that the 10% of critical damping for soil structure interaction was the accepted value by the AEC anL its consultants. If, however, the applicant wished to present his case in a topical, the AEC and their consultants would evaluate I it. However, until such time as the evaluation is complete and the adequacy of the 20% of critical damping factor is established the design should proceed based on a damping factor for e6il structure interaction of 10% of critical. The applicant after reviewing the alternative presented decided to use the 10% of critical damping for horizontal and vertical response. In response to a request by the applicant we agreed that for structure design the response spectra method was satisfactory.

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b We then reviewed the seismic response spectra for various damping rr.tio to be used for the seismic analysis of structures. At this meeting and in a subsequent telephone conversation with the appli-cant it concluded that the amplication factors in the PSAR are satisfactory.

2. Seismic Design Criteria for Systems and Components The applicant was told that his answer to question 12.50 in amend-ment No. 7 on seismic design criteria for systems and components was unsatisfactory. If the applicant wishes to use static factors for the seismic design of systems and components then a satisfactory

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approach would be to use a seultiplication factor of 1.5 on (l'e dominant frequency. The applicant stated he would review his design approach and inform us of his decision in the near future.

3. Allowable Containment Design Stresses The applicant presented his containment design approach for pipe penetrations and pipe support attachments. The proposed design criteria was to utilize faulted conditions for both loads and stresses for the design of containnent attachments taking pipe whip loads and faulted loads and emergency stresses for the pipe penetrations. The pipe rupture forces transmitted to the contain-ment from the pipe whip restraints were calculated usinC the methods outlined in NEDM 10498. The applicant was told that his design criteria for allowable containment stresses was unacceptablev An acceptable approach would be to design both the penetration and the pipe restraint attachment for loads corresponding to faulted conditions and stress limits as outlined ASME B & P code Section III for containments paragraph Ur' 33:2. The applicant agreed to utilize this approach and will confirm this in their next amendment to the PSAR. The applicant was also told that evaluating the effect of jet impingment loads on the containment using allowable stress as 85% of' Appendix F was acceptable. This approach is contained in the Appendix to meeting minutes of the Subcommittaa on Nuclear l Power dated June 22, 1972.

l j Distribution:

N#o'cket FiH BWR Br. Chiefs Origina1 signed by:

RP Reading W. Haass Sydney Miner . . . ..

BCR Reading M. Rosen Sydney Miner, Project Manager l R. S. Boyd R0 (3) Gas Cooled Reactors Branch D. Skovholt S. Miner Directorate of Licensing D. Knuth L. Little R. Maccary J. Richardson R. Tedesco S. N. Hou H. Denton S. B. Burwell R. A. Clark L:GCR omcr > ...S. Miner--

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e ATTENDANCE LIST AEC B&R R. R. Maccary (1) (2) J. J. Byrnes (1) (2)

S. Miner (1) (2) G. A. Marstead (1)

L. E. Little (1) (2) W. J. Ritch (1)

L. Shao (2) E. R. Kununerle (1)

J. E. Richardson (1) (2) B. Bedrosian (1)

S. N. Hou (2) K. Ronis (2)

K. Kapur (1)

WPPSS S. B. Burwell (1) .

R. A. Clark (1)

J. R. Church (1) (2)

E. D'Appolonia Consulting Ennineers D. L. Renberger (1) (2)

L. L. Humphreys (1)

Paul C. Rizzo (1) J. E. Woolsey (1)

O. E. Trapp (2) 1 omer > . . . . . .

summc > . (1).... August. 4. mea ting ..

(2) August %.. meeting

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