ML19211D381
| ML19211D381 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 01/14/1980 |
| From: | Linder F DAIRYLAND POWER COOPERATIVE |
| To: | Ziemann D Office of Nuclear Reactor Regulation |
| References | |
| TASK-02-04, TASK-03-06, TASK-2-4, TASK-3-6, TASK-RR LAC-6733, NUDOCS 8001180350 | |
| Download: ML19211D381 (2) | |
Text
-
n.1IIt wt ND I*0 Weft COUI* Eft.t TI VE Ea Groue, O LornO, 54601 January 14, 1980 In reply, please refer to LAC-6733 DOCKET NO. 50-409 Director of Nuclear Reactor Regulation ATTN:
Mr. Dennis L.
Ziemann, Chief Operating Reactors Branch No. 2 Division of Operating Reactors U. S. Nuclear Regulatory Commission Washington, D.
C.
20555
SUBJECT:
DAIRYLAND POWER COOPERATIVE LA CROSSE BOILING WATER REACTOR (LACBWR)
PROVISIONAL OPERATING LICENSE NO. DPR-45 LIQUEFACTION POTENTIAL AND SEISMIC ANALYSIS OF SYSTEMS AND STRUCTURES AT LACBWR -
(SEP TOPICS II-4 AND III-6)
Reference:
(1)
DPC Letter, Linder to Director of NRR, LAC-6664, dated November 29, 1979.
Gentlemen:
Our letter (Reference 1) proposed measures to mitigate the NRC-that the LACBWR postulated potential for liquefaction in the event plant site experiences soil liquefaction in the top forty (40) feet due to a Safe Shutdown Earthquake (SSE) resulting in a ground surface acceleration of 0.12g.
Since our submittal of Reference 1 and subsequent to the meetings with the Nuclear Regulatory Commission (NRC) staff last year, our consultants, Dames & Moore, have obtained independent review of the report titled " Liquefaction Potential at La Crosse Boiling Water Reactor (LACBWR) Site, near Genoa, Vernon County, Wisconsin", dated September 28, 1979.
The reviews were done by Professor H. Bolton Seed and Dr. Sukhmander Singh.
Professor Seed, a professor in the Civil Engineering Depart-ment at the University of California in Berkely, is an internationally renowned expert on liquefaction.
His work was used in the Dames &
Moore report as well as in the analyses done by the NRC.
Dr. Singh is His Ph.D a specialist on soil properties pertaining to liquefaction.
thesis pertaine to soil properties and liquefaction and was done under the supervision of Professor Seed.
_ 1_
O 1765 322 soon so.
Mr. Dennis L.
Ziemann, Chief LAC-6733 Operating Reactors Branch No. 2 January 14, 1980 Professor Seed concluded that, for the design earthquake at the La Crosse site, (maximum horizontal ground acceleration of 12 per-cent gravity at the ground surface due to the occurrence of a local MM Intensity VI earthquake) his analyses indicate a safe condition against liquefaction at the La Crosse site.
His ccnclusion was based on three separate approaches, namely empirical approachen based on past performances, the Japanese empirical approach and the analysis-testing approach.
Another significant conclusion pertains to the apparent uncertainty en the effects of possible sample disturbance on the results of cyclic load tests.
Both Professor Seed and Dr. Singh concluded that, for the La Crosse rite, it may be estimated that the effects of sampling dis-turbance has miner influence on the results of these tests due to counteracting influences.
Professor Seed and Dr. Singh will be willing to meet with NRC staff at an appropriate time and place in the near future to present their findings in more detail.
Dames & Moore has indicated at previous neetings with the NRC that tney believe that the La Crosse site is safe against liquefaction fcr the earthquake design parame*ers that were assumed.
Their findings have been substar.tiated by those of Professor seed and Dr. Singb.
We strongly recommend that this new developnent be given serious con-sideration by you and your staff prior to any decision by the NRC to issue an order to show cause which requires substantial mitigative measures for an alleged potentially hazardous condition at the site.
Further information regarding the above conclusions and proposed schedules for a meeting will follow on January 15, 1980.
Very truly yours, DAIRYLAND POWER COOPERATIVE gn bJ
)
Frank Linder, General Manager FL: RES : a f cc:
J.
Keppler, Reg. Dir., NRC-DRO III 1765 323