ML19211C811
| ML19211C811 | |
| 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 | |
| ML19211C810 | List: |
| References | |
| TASK-02-04, TASK-2-4, TASK-RR NUDOCS 8001150020 | |
| Download: ML19211C811 (3) | |
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OCT 2 5 1979 MEMCRANDUM FOR:
D. Crutchfield, Chief, 00R Systematic Evaluation Program Sranch FRGM:
Rcbert E. Jackscn, Chief Geosciences Branch, CSS SUSJECT:
ASST'SSMENT OF LIQUEFACTION FOTENTIAL FOR THE LACROSSE NUCLEAR F0WER STATION
REFERENCES:
(1) Memorandum for Victor Stello, Director, Div.
of Operating Reactors, NRR from R. P. Denise AD for Site Technology, Same Subject dated Jan. 11, 1979 (2) Memorandum for Don Davis, Chief, SEP, COR from J. Carl Stepp, Same Subject dated Dec. 22, 1978 We and our consultant, the U. S. Army Corps of Engineers Waterways Experiment Station (WES) have ccmpleted our review efforts of the applicants' thorcugh investigation of the liquefaction potential at the LACSWR site. The reviewed report is entitled "Liquefacticn Potential at Lacrosse Boiling Water Reactor (LAC 3WR) Site near Genoa, Vernon County, Wisconsin" by Cames and Moore dated August 10, 1979.
Based on review of this report, we can conclude that if sustained strong ground motion with peak accelerations of.12g or higher occurs (normally associated with a magnieJde 5 or greater earthquake) liquefaction can occur down to a depth of 40 feet. Selow.08g, we can conclude that there is little potential for liquefaction. These conclusions are based on our comparison of this site with other sites where liquefaction has occurred and on the use of laboratory strength data as discussed by John Greeves, a staff geotecnnical engineer and Dr. William 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 the basis for this conclusion.
In summary, based en 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 a0 feet is not safe agaiast liquefaction if the licensee designated safe shutdcwn earthquake with a peak acceleration of 0.12g occurs.
Michael C. Farrar, Esq.
Atomic Safety and Licensing 1765 177 Appeal Board U.S. Nuclear Regulatory Commission Washington, DC 20555 go0115002O e
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OCT 2 3 1379
- 0. Crutchfield In our opinion, the more recent investigations, recort dated August 10, 1979, undertaken by the licensee's consultant Cames and Moore, Inc. confirms the previous conclusion that the soils at the Lacrosse site c:uld strain badly for an earthquake producing 2 surface level peak acceleration of 0.12g as noted by WES in "Licuef action Analysis for Lacrosse Nuclear ?cwer Statien," Paper GL-79-il, catea June, 1979.
'We have made an initial estimate of the probacility of excseding a range of peak acceleraticns at the Lacrosse site in order to make an estimate of the hazard associated witn the liquef action potential.
In doing so, we utilized all readily available estimates of earthcuake probability that included the site regicn. These were estimates taken from Milne and Davenport (1969), Algermissen and Perkins (1975), 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 Earthcuake (SSE) free field ground motion designated by the licensee in the Full Term Li ".se application is.12g anchored to a Regulatory Guide 1.50 soectrum.
lased en our review of prcbabilistic studies listed above, the return ceriod for.12g wculd be at least 1,000 years. This peak acceleration (.12g) is equivalent to Intensity VII when utilizing the relaticnship of Trifunac and Bracy (1975). The return period for.08g would be at least 4C0 years. These values are based u:en the minimum return period calculated in the above studies. 'While these values should not be interpreted as absolute minimums, the actual. return period could be an order of magnitude larger. As menticned 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 due to the 1811-1812 New Madrid earthquakes, 800 kileceters from the Lacrosse site. The 1909 Beloit earthquake on the Wisconsin-Illinois border probably produced intensity II to IV at the site. The site is not located near any known localizers of seismicity. Based on a recent staff decision fcr a proposed ccnstruction permit application, the SSE intensity could be VII cr 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 anchor to the Regulatory Guide 1.60 response spectrum.
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1765 178
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- 0. Crutchfield ccr 2 5 1973 We can. conclude based on our evaluations to date that there is a relatively Icw seismic hazard at this site because of the eartnquake history and initial estimates of.the icng return periccs in t. sis regicn for the si::e event that aould have to occur to generate.12g.
We do r.ote hcwever, that our current evaluations indicates that there i; concern in the event that ground motion at the.12g level were to cccur. We conclude that there is a icw seismic hazard fcr this facility during the ?srico recuirec to ccmplete cur evaluation of the SE? seismic methodology and estaolish the seismic design bases for Lacrosse.
It will take ap::roximately three months to establish this value.
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Robert E. Jackstin, Chief Geosciences Eranch Divisicn of p stems Safety
Attachment:
As stated cc: w/ attachment J. Knight D. Ziemann L. Heller L. Reiter
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J. Greeves R. McMullen P. Sobel W. Marcuson, COE H. Levin C. Hofmayer J. Wetmore C. Woodhead 1765 179