ML20212L232
| ML20212L232 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Diablo Canyon |
| Issue date: | 09/17/1976 |
| From: | Allison D Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20150F500 | List:
|
| References | |
| FOIA-86-391 NUDOCS 8608250257 | |
| Download: ML20212L232 (7) | |
Text
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-I-SEP 171976 e
Docket ilos. 50-275 and 50-323 Applicant: Pacific Gas and Electric Company (PG&E)
Facility: Diablo Canyon tiuclear Power Station, Units 1 and 2 (Diablo Canyon)
SIM1ARY OF MEETING HELD ON SEPTE!1BER 7,1976 TO DISCUSS SEISMIC DESIGft REEVALUATI0ft We met with the applicant and the applicant's consultants on September 7,1976, to discuss the reevaluation of the plant's seismic design capabilities. A list of attendees is provided in Enclosure No.1.
Background
gg:e PGSE was reevaluating the plant's seismic design capabilities in tems of a magnitude 7.5 earthquake on the Host;ri fault. An effective horizontal ground acceleration of 0.759 at the plant site was being used for the development of design response spectra (which determine the input to the engineering calculations). This represented more severe ground shaking than had been considered in the plant's original design.
In Amendment 45 to the Final Safety Analysis Report (FSAR) dated July 29, 1976, PG&E had described the design response spectra proposed for use in the reevaluation. These spectra were based on the recormlendation of PG&E's consultant Dr. John A. Blume.
In response to our request, PG&E had provided additional information concerning the proposed spectra at a meeting on August 11, 1976.
In addition, our consultant, Dr. itathan !. Uewmark, had independently developed design response spectra for use in the reevaluation. These spectra were documented in Dr. Neunark's report to the f;RC dated June 15,197G and Septenber 3,1976.
He had reviewed the applicant!s proposals and our own consultant's recomendations which differed sonewhat from the applicant's proposals.
He had also discussed our thinking with PGT4E by telephone, but some differences of opinion between PG'.E and the staff had renained.
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4 Pacific Gas and Electric Company 2-gfP 1 i B76 Discussion PGSE's proposed spectra were based on eight earthquake records taken on rock close to the earthquake epicenters. Dr. Blume described a comparison he had made between; (1) the calculated building responses associated with the proposed design response spectra and;-(2) the calculated building responses from each of the eight earthquake records. This had been done for several specific elements in the containment and auxiliary buildings.
In general, for the sample elements considered, he had found that the individual earthquakes seldom produced calculated loads that were greater than the loads associated with the proposed design response spectra.
When the individual earthquake loads were greater, they were seldom significantly greater.
A general discussion of design response spectra ensued. PG&E and Dr. Blume summarized their positions concerning the design response spectra. The staff and Dr. flewmark outlined their current thinking. We noted that a staff caucus would be needed before we could give PG8E the staff's position.
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A number of variables which could affect the final result entered into
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the discussions. These included: credit for non-linear effects (ductility), amount of reduction due to building size and combination of earthquake loads with loads from a postulated loss-of-coolant accident.
fir. Pusche noted for the staff that we should ensure that we were considering all such factors in judging the various proposals so that we would be focusing on the rwaningful results rather than some intemodiate step.
Staff Position At a, staff caucus, Dr. tiewmark and the staff members present discussed these natters Following the caucus we infomed the applicant that we would acce.t design response spectra based on the following criteria:
(1) The respona spectra recommended by our consultant, Dr. ?!cunark, would be acceptable for use in reevaluating the plant's seismic design capabilities. As discussed in Dr. !!ewmark's reports, the spectra would be modified to account for building size effects.
In doitg so, the response spectrum for each structure would be detemined according to the following values for transit time parameter (Tau):
(a) Containment or Intake Structure: Tau = 0.04
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.(b) Auxiliary Building: Tau = 0.052 (c) Turbine Building: Tau = 0.00 (d) Smaller Structures: Tau = 0 Further reduction of these spectra to ' account for non-linear effects would not be made. However, if the applicant proposes to take credit for this in certain specific areas, then we would consider it on an individual case basis.
(2) Alternately, the response spectra proposed by the applicant would be generally acceptable for use in reevaluating the plant's seismic design capabilities. They would be used in the following manner:
(a) As a starting point, for small structures where Tau = 0, the applicant's proposed response spectrum would be used. However, this spectrum would be raised as necessary in certain frequency ranges so that it does not fall below the spectrum for small r^
structures recomended by our consultant, Dr. Plewmark.
(b) For larger structures, the spectrum described in (a) above would be reduced to account for building size in accordance with the methods proposed by the applicant using the following values for Taur (i) Containment or Intake Structure: Tau = 0.04 (ii) Auxiliary Building: Tau = 0.052 (iii) Turbine Building: Tau = 0.08 (c) The spectra discussed above would be reduced to account for non-linear behaviour using a ductility ratio up to 1.3.
(d) The calculated value for zero period acceleration would not be rounded to a lower value, but used as calculated.
(c) For each structure, the spectrura obtained by these means would be adjusted in certain frequency ranges as necessary so that it does not fall below the spectrun recomended by our consultant Dr. fiewmark.
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Pacific Gas and Electric Company SEP 17 B76 PG&E indicated that the reanalysis would proceed u:ing response spectra which satisfied these criteria.
Orininal S!qned by D. P. Allison, Project Manager Light Water P.cactors Branch flo. 1 Division of Project Management
Enclosure:
Attendance List lT4 TEN LWR g L
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Pacific Gas and Electric Company cc: Pacific Gas and Electric Company Mr. John Forster
- ATTN: Mr. John C. Ibrrissey 985 Palm Street Vice President & General Counsel San Luis Obispo California 93401 77 Beale Street San Francisco, California 94106 Mr. William P. Cornwell P. O. Box 453 Philip A. Crane, Jr., Esq.
Morro Bay, California 93442 Pacific Gas and Electric Company 77 Beale Street Mr. W. J. Lindblad, Project Manager San Francisco, California 94106 Pacific Gas and Electric Company 77 Beale Street Andrew J. Skaff, Esq.
San Francisco, California 94106 California Public Utilities Comission 350 McAllister Street Mrs. Thelma Hirdler San Francisco, California 94102 811 Fair Oaks Avenue Arroyo Grande, California 93420 Mr. Frederick Eissler, President Scenic Shoreline Preservation Mr. W. C. Gangloff Conference. Inc.
Westinghouse Electric Corporation NN 4623 More Mesa Drive P. O. Box 355 Santa Barbara, California 93105 P1ttsburgh, Pennsylvania 15230 Ms. Elizabeth E. Apfelberg Mr. Paul Morton 1415 Cazadero California Division of flines and San Luis Obispo, California 93401 Geology 28 Civic Center Plaza
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Ms. Sandra A. Silver Room 642 5055 Radford Avenue Santa Ana, California 92701 fiarth Hoilywood, California 91607 Dr. N. M. Net. mark Mr. Gordon A. Silver Consulting Engineering Services 5055 Radford Avenue 1211 Civil Engineering Building florth Hollywood, California 91607 University of Illinois Urbana, Illinois 61801 Paul C. Valentine 400 Channing Avenue Mr. James F. Devine Palto Alto, California 94301 Department of the Interior U. S. Geological Survey Yale I. Jones, Csq.
f'ational Center, !! ail Stop 9G9 100 Van Ness Avenue South Lake Drive 19th Floor Reston, Virginia 22092 San f rancisco, California 94102
!!s. Raye Fleming 1746 Charro Street San Luis Obispo, California 93401 c.
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ENCLOSilRE NO. 1 ATTENDEES PGAE Westinghouse W. Lindblad T. Esselman V. Ghio J. Dorycott G. Blume PG&E Consultants J. Blume R. Gallagher NRC Consul tant N. Newmark g
NRC Staff K. Kapur J. Knight I. Sihweil
- 4. C. Stepp R. DeYoung D. Allison J. O'Brien D. Vassallo W. Gamill H. Denton F. Schroeder R. Hofman J. Tourte110tte B. Rusche
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I MEETING SUMf1ARY DISTRIBUTION Docket File J. Knight NRC PDR D. Ross Local PDR R. Tedesco TIC S. Pawlicki NRR Reading I. Sihweil LWR 1 File P. Check B. C. Rusche T. Hovak E. G. Case Z. Rosztoczy R. S. Boyd G. Lainas R. C. DeYoung V. Renaroya D. Skovholt T. Ippolito J. Stolz V. Moore K. Kniel R. Vollmer
- 0. Parr M. Ernst W. Butler W. Gammill D. Vassallo G. Knighton L. Crocker B. Youngblood R. Clark W. Regan T. Spets D. Bunch CC#
P. Collins J. Collins C. Heltmes W. Kreger R. Houston R. Ballard S. Varga M. Spangler J. Miller J. Stepp F. J. Williams L. Hulman R. Heinman H. Smith H. Denton V. Stello D. Muller S. Levine Project Manager T. Hirons Attorney, ELD J. Wetmore IE E. Hylton NRC participants ACRS (16)
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