ML19210C155
| ML19210C155 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 10/25/1979 |
| From: | Rolonda Jackson Office of Nuclear Reactor Regulation |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19210C154 | List: |
| References | |
| TASK-02-04, TASK-2-4, TASK-RR NUDOCS 7911130366 | |
| Download: ML19210C155 (3) | |
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UNITED STATES
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a oci s mg MEMORANDUM FOR:
D. Crutchfield, Chief, D0R 7
Systematic Evaluation Pro, gram Branch
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Robert E.. Jackson, Chief' Geosciences Branch, DSS SUBJENT:
ASSESSMENT OF. LIQUEFACTION-POTENTIAL FOR THE LACROSSE NUCLEAR POWER STATION
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REFERENCES:
(1) Memorandum for Victor Stello, Director, Diy.
of Operat'ng Reactors, NRR from R. P. Denise AD for Site Technology, Same Subject dated'
, Jan. 11, U.'
(2) Memorandt.m for Don Davis, Chief, SEP, DDR from J. Carl Stepp, Same Subject dated Dec. 22, 1978 We and our consultant, the U. S. Amy Corps of. Engineers Wateivays Experiment Station (WES) have completed our review efforts of tSe applicants' thorough investigation of the liquefaction potenLN at the LACBWR site.' The reviewed report is. entitled " Liq.:efaction Potential at Lacrosse Boiling Water Reactor (LACBWR) She near Genoa, Vernon County, Wisconsin" by Dames and. Moore dated August 10, 1979.
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Based on review of this report, we can conclude that if sustained strong
.jround motion with peak accelerations of.12g or higher occurs (nomally associated with a magnitude 5 or greater earthouake) liquefsetion can occur d an to a depth of 40 feet. Below.083, we can conc 19 that there is little potential for liquefaction. These conclusions are. based on our comparison of this site with other sites where liquefaction has occurred a staff geotechnical engineer and Dr. Willi,as discussed by John Greev and on the use of laboratory streng. h data t
am Marcuson, a WES geotechnical engineer, at a meeting with the licensee on October 16, 1979. WES has provided a letter (attached) dated October 19, 1979 which further defines
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the basis for this conclusion.
In sumary, based on judgement concerning
.'the density and strength data and on empirical correlations.WES concludes that the foundation material below the water table down to a depth of 40 feet is not safe against liquefaction if the licensee designated safe shutdown
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earthquake with a peak acceleration of 0.12g occurs..
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In our. opinion..the more recent investigations, report dated. August 10, 1979,
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undertaken by the licensee's consultant Dames and Moore, Inc. confims the previous conclusion that the soils at the Lacrosse site could strain badly for an earthquake producing a surface level peak acceleration of 0.12g as noted by WES in " Liquefaction Analysis for Lacrosse Nuclear Power Station," Paper GL-79-ll, dated June, 1979.
'We have made.an initial estimate of the probability of exceeding a range of peak accelerations at the Lacrosse site in order to make an estimate of the hazard ascociated with the liquefaction potential. In.doing so, we utilized all.aadily available estimates of earthouake probability that included the site region. These were estimates.taken from Milne and Davenport (1969), Algermissen and Perkins (1976), the Applied Technology
~ Council (1978), the. Haven Site Preliminary Safety Analysis Report (1978),
and preliminary results from the Systematic Evaluation Program (SEP) probabilistic study of the Lacrosse site.
The Safe Shutdown Earthquake (SSE) free field ground motion designated by the licensee in the Full Term License application is.12g anchored to a Regulatory Guide 1.60 spectrum. Based on our review of probabilistic.
studies listdd above, the. return period for.12g would be at least 1,000 years. This. peak acceleration (.12g) is equivalent to Intensity VII when utilizing the relationship of Trifunac and Brady (1975). The return period for.08g would be at least 400 years.
These values are based upon the minimum return period calculated in the above studies. Kaile these values should not be interpreted as absolute minimums, the actual return t
period could be an order of magnitude larger. As mencioned above, these
-estimates are preliminary and only serve to indicate the general level of seismic hazard at the site..._
.As part of'the SEP program, we are currently reevaluating the SSE seismic design at Lacrosse. Based upon limited consideration of current Standard
' Review Plan' procedures, the Lacrosse site. lies in an area of low seismicity in the Central Stable Region Tectonic Province. The highest intensity near the site historically was estimated to be Intensity V dua to the 1811-1812 New Madrid earthquakes, 800 kilometers from the Lacrosse. site. The 1909 Beloit earthquake on the Wisconsin-Illin'ois border probably produced intensity II to IV at the site. The site is not located near any known localizers of seismicity.
Basec' cn a recer.t staff decision for a proposed construction permit applicatior. Ge SSE intensity could be VII or VII-VIII for the general region including the Lacrosse site.
Using the Trifunac and Brady (1975) relationship, the free field ground motion corresponding to intensity VII would be.13g and intensity VII-VIII would be.20g, which would be used as the high frequency shor to the Regulatory Guide 1.60 response spe'ctrum.
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D. Crutchfield r
We can. conclude based on our evaluations to da.
that there is a relatively low seismic hazard at this site because of the earthquake history and initial estimates of.the long return periods in this region for the size event that would have'to occur to generate.12g. We do note however, that our current evaluations indicates that there is concern in.the event that ground motion at the.12g level were to occur. We conclude that there is a low seismic hazard for this facility during the period required to complete our evaluation of the SEP seismic methodology and establish the seismic design. bases for Lacrosse. It will take approximately three months to establish this value.
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Robert E. Jack
',n, Chief Geosciences afich Division of stems Safety
Attachment:
As stated cc: w/ attachment J. Knight D. Ziemann L. Heller L. Reiter J. Greeves R. McMullen P. Sobel
. W. Marcuson, COE H. Levin C. Hofmayer J. Wetmore C. Woodhead 9
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