ML20126D526
| ML20126D526 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 11/19/1979 |
| From: | Stampelos J Advisory Committee on Reactor Safeguards |
| To: | Bender M Advisory Committee on Reactor Safeguards |
| Shared Package | |
| ML20126D531 | List: |
| References | |
| ACRS-SM-0176, ACRS-SM-176, NUDOCS 8005020174 | |
| Download: ML20126D526 (2) | |
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i November 19, 1979 s
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p Myer Bender-SAN ONOFRE (f2 and #3) SEISMOLOGY MEETING (Wshington, D. C.; November
/ 16, 1979)
The NRC Staff met with the applicants, the applicant's consultant (Woodward-Clyde), the United States Geological Survey, and NRC consultants to discuss the determination of the magnitude and site ground motion parameters for the postulated controlling earthquake source.
In 1972 the Atomic Energy Commission s
and its consultants agreed to a 2/3 g design basis earthquake for the Safety i
Evaluation Report (SER). A conservatively large earthquake was postulated for a fault S miles offshore from the site.
No earthquake magnitude, however, p.
was estimated for the controlling earthquake source.
As of August 1979, Units 2 and 3 were respectively 7?% and 60% complete and scheduled for. commercial
' operation in 10/80 and 1/82.
Y The NRC Staff is preparing) questions on a report prepared by the applicant's i
consultant (Woodward-Clyde " Report on the Evaluation of Maximum Earthquake and Site Ground Motion Parameters Associated with the Offshore Zone of-Defomation, San Onofre Nuclear Generating Station," June 1979; a summary is included in the attachments, a full copy has been requested).
Previous questions and concerns were expressed at the Menlo Park Meeting (September 1979 ).
This meeting stressed the following points to be addressed in the applicant's report:
l 1.
Slip rate is based on gathering historical data. Why can we rely on this data? " bat is the sensitivity of slip rate to earthquake magnitude?
t How would the discovery of new data points effect Woodward-Clyde's tectonic model? Sensitivity analysis should be employed.
t 2.
The probability of seeing various g values at the plant should be evaluated.. The recurrence of different magnitudes of earthquake and their effect or challenge to the plant should be evaluated.
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3.
The NRC does not have an approved tectonic model for the site area.
4.
Woodward-Clyde's seismic analysis should include all data bases even though the quality of foreign information may require further evaluation.
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How does the maximum magnitude earthquake mentioned in the Woodward-Clyde report relate to the requirements.of 10 CFR 100 (Appendix A)?
The next meeting on this subject is scheduled for the week ending December 21, 1979.
t John Stampelos ACRS Fellow cc: ACRS Members ACRS Technical Staff Consultants to the San _Onofre Subcommittee
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Attachments:
- 1. Summary of the Woodward-CDde Report E. Program Development Plans
- n. Development of naximum magnitude for the OZD
- b. Development of site ground motion parameters
- 3. Approximate relationships between intensity, acceleration and magnitude for earthquakes
- 4. Faulting Offshore of Southern California (2 page map) 4 1
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ACRS FILE:
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