ML19351F127
| ML19351F127 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 12/05/1980 |
| From: | Bechhoefer C Atomic Safety and Licensing Board Panel |
| To: | |
| References | |
| ISSUANCES-SC, NUDOCS 8012290555 | |
| Download: ML19351F127 (3) | |
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UNITED STATES OF AMERICA 1.y
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sj ATOMIC SAFETY AND LICENSING BOARD 9,
4i,g-e Charles Bechhoefer, Chairman Dr. George C. Anderson dl #'
Ralph S. Decker In the Matter of DAIRYLAND POWER COOPERATIVE
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Docket No. 50-409-SC
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Prov. Op. Lic. DPR-45 (La Crosse Boiling Water Reactor)
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MEMORANDUM (December 5, 1980)
Following are certain questions which we expect to have answered prior to any final determination in this proceeding (see our Memorandum and Order dated November 12, 1980):
1.
(a)
What is the effect of Mississippi River water level on the below grade water table and on soil properties and liquefaction potential at LACBWR?
Describe any differences in the effect of Mississippi River water level on soil properties and liquefaction potential for the LACBWR containment building, curbine building and stack.
(b)
Please provide in tabular or graphic form a historical record of the fraction of time the river water level exceeds various specific Y
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0 801 22eo
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- 4 levels including flood levels.
Does this correlate with water table level?
(c)
Is there currently a technical specification requiring reactor shutdown should river water level exceed or be expected to exceed some specific level?
2.
Assuming that the driving and presence of piling does indeed increase soil density, is there a density gradient radially outward from each piling?
If so, was such gradient taken into account in assessing the liquefaction potential of soils under the containment building, turbine building, and stack?
Where were soil samples taken radially outward from the nearest pile?
3.
What is the estimated cost of designing, installing and making operational a dewatering system?
Would the same dewatering system designed to preclude liquefac-tion in the event of an earthquake producing 0.12g ground acceleration at the site also be effective in precluding liquefaction in the event of an earthquake producing 0.20g ground acceleration?
If not, what differences exist (in terms of both technical systems and cost)?
Please explain.
o
- 4 To what extent does liquefaction depend on the num-ber of cycles of ground shaking?
Wh'at is the appro-priate number of cycles associated with a 0.12g earth-quake and how was that number deter =ined?
Does peak acceleration alone suffice to determine liquefaction?
How about a=plitude and/or period?
Please explain.
5.
(a) (For Licensee).
What is the "nor= ally accepted minimum factor of safety" against the occurrence of liquefaction in the event of an earthquake with a peak ground accaleration of 0.12g (see Nataraj a affidavit, par. 9, 10)?
By who= is this factor accepted?
How was it derived or ascertained?.
(b) What safety factor should be used to evaluate the safety against the occurrence of liquefaction?
At the prehearing conference which is to follow the evidentiary hearing commencing on December 16, 1980, the parties should be prepared to address how the foregoing questions should be answered in the context of this proceeding.
FOR THE ATOMIC SAFF.TY Ali.
LICINSING 30ARD l
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a~A v 0.e.$$.cshv Charles 3echhoefer,Cpairman Dated at Bethesda, Maryland this 5th day of December 1980.
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