ML20234C027

Requests Clarification of Procedures & Criteria Proposed in Design of Structures & Components to Withstand Oscillations & Vibrations from Major Earthquakes

ML20234C027
Person / Time
Site:	05000000, Bodega Bay
Issue date:	07/08/1964
From:	Price H US ATOMIC ENERGY COMMISSION (AEC)
To:	Whelchel C PACIFIC GAS & ELECTRIC CO.
Shared Package
ML20234A767	List: IA-85-665, Discusses Seismic Design of Nuclear Power Plants,Including Const of Nuclear Plants in Seismically Active Zones ML20234A761 ML20234A769 ML20234A792 ML20234A798 ML20234A803 ML20234A812 ML20234A816 ML20234A827 ML20234A830 ML20234A838 ML20234A841 ML20234A844 ML20234A847 ML20234A851 ML20234A855 ML20234A858 ML20234A861 ML20234A864 ML20234A868 ML20234A871 ML20234A874 ML20234A893 ML20234A896 ML20234A900 ML20234A911 ML20234A922 ML20234A929 ML20234A932 ML20234A937 ML20234A944 ML20234A956 ML20234A965 ML20234A968 ML20234A976 ML20234A984 ML20234A993 ML20234A996 ML20234A999 ML20234B005 ML20234B008 ML20234B023 ML20234B032 ML20234B035 ML20234B040 ML20234B062 ML20234B066 ML20234B076 ML20234B084 ML20234B098 ... further results
References
FOIA-85-665 NUDOCS 8709210148
Download: ML20234C027 (2)

Text

-_

,~

"' 4*, UNITED STATES

$ t ATOMIC ENERGY COMMISSION I'l L*, I* WASHINGTON 25, D.C.

% 8 C0PY July 8, 196h Mr. C. C. Whelchel Vice-President Pacific Gas and Electric Company 2h5 Market Street San Francisco, California

Dear Mr. Whelchel:

Question #h of our letter of May 19,196h referred to the need for clarification of the procedures and criteria Pacific Gas and Electric Company proposes to use in the design of the structures and components to withstand oscillations ard vibrations from major earthquakes. At the meeting on June 17,196h between representatives of the ccmpany, of the ACRS and of our staff, we attempted to amplify this question and its relation to Question #1 of our previous letter.

As we pointed out at the meeting, the opinion is held.by some that the spectrum of ground motions in case of another major earthquake on the San Andreas fault may be more severe than that which occurred in the El Centro Earthquake. Further, such an earthquake migh be accom-panied by shear displacement up to a pessible 3 feet, and would likely be followed by aftershocks which might be as large as the El Centro earthquake of 19h0.

Against the possibility of earthquakes of these dimensions, we would l like to explore the design arrangements and their feasibility in pro-tecting the plant against damage which would result in hazards to the health and safety of the public. At the meeting, we requested Pacific l Gas and Electric Company to consider these questions:

1. Assume an earthquake having a vibration spectrum similar to that of El Centro but with maximum acceleration of 2/3 g*; velocities up to 21/2 ft./sec.; ground displacements up to 3 ft.; shear displace-ment (faulting) of 2 ft. in the foundations of the plant, and with the occurrence of an aftershock equal to El Centro before remedial action could be taken. What plant arrangements, design criteria and procedures I

could be developed to prevent impairment of functions of structures, equipment and systems important to safety? This should include method of analysis indicating the margins to allowable stress or deformation limits.

l l

8709210140 851217 hES -665 PDR, k

, . . _ . . - - . . . . - . . . . . _ _ . . - - - . , , - . - - - . . - ~ ~ ~ ~

1

o :- .

i , .'

i

, i ,

Mr. C. C. Whelchel July 8,19% ]

2 Assume an earthquake having a vibration spectrum similar to that of El Centro but with accelerations generally up to 2/3_ g plus intermitt

/sec.; gr.ent oundpulses of acceleration displacements up shear up to 3 ft.; to 1 g*;' velocities (faulting) displacement up to 21/2 ft.

in the plant foundations of 3 ft.; and with the occurrence of an after-shock equal to El Centro before remedial action could be taken. .What plant arrangements,' design criteria and procedures could be developed ~

which would assure shutdown and maintenance of the plant in safe shut-down condition?

Sincerely yours,

/s/

Harold L. Price Director of Regulation i

Dhe mmv4== of acceleration, velocity and displacement would not occur for the same periods of vibrations.

s 1

1

'l

- It A

rr _ r:rarc== r==~r_ x- ~ ~~ -- ---

-m-+-- A