ML20237G088
Text
.
' ' ~ * '
f.'
E36",,"
ST.'LEMENTAl.
i UNITED STATES GOVERNMENT FILE COPY Memorandum Roger S. Boyd, Assistant Director DATE: May 25, 1967 l
To for Reactor Projects, DRL THRU:
Robert L. Tedesco, Cnief Reactor Pr anch 2, DRL FROM K. Woodard Reactor Pr ject Branch 2, DRL SUBJEcr: MINUTES OF MEETING WITH PG&E TO DISCUSS SEISMIC DESIGN OF DI'ABLO CANYON l
RE. ACTOR - DOCKET No. 50-275 On May.16, 1967, we and our consultants met with representatives of PG&E to discuss the seismic design of the Diablo Cinyon reactor.
The following persons attended:
AEC ACRS Staff AEC Consultants PG&E
?. A. Morris R. Wilcox N. M. Newmark D. V. Kelley R. L. Tedesco W. J. Hall J. C. Morrissey T. B. Conner L. M. Murphy B. W. Shackelford J. Newell H. W. Coulter J. A. Blume (consultant)
J. Hard l
K. Woodard I. Spicklez F. Schauer l
Dr. Blume reviewed the highlights of his evaluation in terms of seismicity l
and also discussed some new data from the following sources:
(1) Measurements of ground motion from the Nevada test site.
j l
(2) Measurements from recent Chilean earthquakes.
(3) Measurements of relative wave motions in different materials by Russians.
This data, according to Dr. Blume, '.4 ther substantiates his belief that bedrock shaking is less severe (by a factor of 2 or more) than that in alluvium for the same earthquake.
The Diablo Canyon plant will be on bedrock.
Dr. Newmark stated that he could not recommend a factor greater than 1.5 between the shaking in rock vs. elluvium based on his evaluation of the data recorded thus far.
His basic reason is that the data taken has not been for large earthquakes and he believes that the relative difference decreases as the magnitude of the ground motion increases.
1 L
B7oB1303os 0707ay
"-- " C. Savings Bonds Regularly on the Payroll Satings Plan PDR FDIA CONNDRB7-241 pop
{
4 M
e Roger S. Boyd May 25, 1967 Dr. Blume is modeling his proposed erarthquake af ter the Taf t occurrence because site charac teris tics are similar.
Both Mr. Murphy and Dr. Newmark do not believe this should be done because there is no assurance that carth-quakes are similar even if they occur at the same location.
Dr. Coulter pointed out that the Taf t earthquake was not even typical of, most California earthquakes because it was caused by an inverted slip along. the fault.
At this point, Dr. Blume asked Dr. Newmark what.he would consider to be an appropriate spectrum for design purposes.
Dr. Newmark indicated that in the period range of 0.1 to 0.5 seconds, with 5% critical damping, the acceleration should be about 0.9g.
This would correspond to an increase-of about a factor of 1.5 above Dr. Blume's proposed spectrum in this region.
Dr. Blume did not think that the difference was very great depending on the method of design which Dr. Newmark would consider acceptable.
Dr. Newmark presented his views on the two design approaches (time history and modal analysis) being considered and Dr. Blume agreed. that Dr. Newmark's approach was reasonable. A 5% damping factor for the rocking mode will be used.
At the conclusion of the meeting Dr. Blume stated that he would like to make a few sample calculations using the higher spectrum before committing himself to a revised spectrum.
It appeared that PG&E would submit for-our review a revised spectrum, somewhat higher'than the original proposal, toward the end of this month. Ways and means to provide Dr. Newmark with this information were also discussed since he is to be in Japan from May 26 to the end of June.
Distribution:
Suppl. 4 - ~ O DRL Reading RPB 2 Reading P. A. Morris Assistant Directors, DRL Branch Chiefs, DRL T. B. Conner q
J. Hard J. Newell Orig:
KWoodard I. Spickler F. Schauer RP DRL/RP K
dj RLTedesc 7
5/23/67 I
-.--_--L.--