ML19250C118
| ML19250C118 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 10/29/1979 |
| From: | Wetmore J Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| TASK-02-04, TASK-03-06, TASK-2-4, TASK-3-6, TASK-RR NUDOCS 7911080252 | |
| Download: ML19250C118 (6) | |
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v October 29, 1979 Docket No. 50-409 LICENSEE: Dairyland Power Cooperative FACILITY: La Crosse Boiling Water Reactor (LACBWR)
SUBJECT:
SUMMARY
OF OCTOBER 17, 1979 MEETING REGARDING LIQUEFACTION P0TENTIAL AND SEISMIC ANALYSIS OF SYSTEMS AND STRUCTURES AT LACBWR (SEP TOPICS II-4 AND III-6)
Representatives of Dairyland Power Cooperative (DPC) and their consultants met with members of the NRC staff and their consultants in Bethesda, Maryland, on October 17, 1979. A list of meeting attendees is attached (Attachment 1).
The purpose of the meeting was to discuss (1) the results of the recent soil properties investigation study at the La Crosse site, and (2) the progress being made on the seismic analysis of systems and structures. These subjects are being reviewed as part of the Systematic Evaluation Program (SEP).
A summary of important points follows:
A.
Liquefaction Potential (SEP Topic II-4) 1.
The NRC staff and its consultant, the U. S. Army Engineer Watenfays Experiment Station (WES), have completed a pre-liminary review of a draft Dames and Moore report entitled
" Liquefaction Potential at La Crosse Boiling Water Reactor (LACBWR) Site Near Genoa, Vernon County, Wisconsin," dated August 10, 1979. This draft report was informally transmitted to the staff in late August.
It contains the results of the soil properties investigation program conducted at LACBWR for DPC.
(See meeting summary on this subject dated February 15,1979.) The final report by the same title, and substantially the same in conten*
ed September 28, 1979, was given to the staff on Octo...
7, 1979 and placed in the docket file for LACBWR. The final report concludes that the "... threshold liquefaction resistance level for the LACBWR site corresponds to an SSE producing an acceleration between 0.18 g and 0.20 g at the ground surface".
1274 118 7911080252
- 2.
The staff indicated that the field program and lab testing reflected the latest state-of-art techniques. However, the staff and its consultant, WES, have made a more conservative interpretation, 3f the data than Dames and Moore, and have egncluded that a potential for liquefaction exists at the site below the water table, down to a depth of 35 feet for earthquakes with a ground surface acceleration of as little as 0.12 g.
3.
WES and the staff provided two fundamental reasons for their conclusion. First, they have independently compared the Standard Penetration Testing (SPT) data with the liquefaction and SPT correlations at Niigata, Japan, and obtained factors of' safety less than 1 for soils below the water table down to 35 feet. Second, they believe that the densification of the soil samples during the sampling process, and later in the consolidation of the samples for lab testing, has not been adequately accounted for by Dames and Moore.
In their opinion, correcting for the increased density in the analysis would substantially reduce the factors of safety computed by Dames and Moore.
4.
DPC stated that they could not adequately respond to the staff's concerns at the meeting. They requested that we provide our evaluation and connents on the liquefaction study and any requests for additional information we may have in writing. We agreed to do this.
5.
DPC pointed out that the La Crosse site is located in a seismically stable region, and thus an earthquake of sufficient magnitude to cause liquefaction is very unlikely. The staff agreed that the plant is in a lox seismic area. The staff indicated that the site was being studied to determine an appropriate SSE level.
This study is expected to be largely complete by early next year.
6.
The major plant structures at LACBWR are supported on piles which indicate a measure of inherent design capability to withstand a liquefaction event. The staff asked DPC to determine what damage to the plant might be expected in the unlikely event that liquefaction did occur, and what measures they could employ to safely shutdown. DPC agreed to look into the matter and to contact us within two weeks.
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4
. B.
Seismic Analysis of Systems and Structures (SEP Topic III-6) 1.
The staff provided an anticipated schedule for resolving this topic starting from the time a seismic input spectrum is available for the La Crosse site (see Attachment 2). The staff indicated that DPC should analyze the reactor ct.olant pressure boundary and the reactor building first, then other Category 1 buildings, then systems and equipment.
DPC agreed with this approach.
2.
DPC's consultant, NES, said they have completed the modeling of the containment shell, the reactor vessel and internals, and the pile foundation. They have unverified results that indicate that these structures are adequate for a 0.12 g earthquake. They are somewhat ahead of the schedule provided by the staff an this topic.
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Jack S. Wetmore, SEPM
, Operating Reactors Branch #2
Division of Operating Reactors Attachments:
1.
List of Attendees 2.
Schedule cc w/ attachments:
See next page 1274 120
. cc w/ attachments:
Fritz Schubert, Esquire Staff Attorney Dairyland Power Cooperative 2615 East Avenue South La Crosse, Wisconsin 54601
- 0. S. Heistand, Jr., Esquire Morgan, Lewis & Bockius 1800 M Street, N. W.
Washington, D. C.
20036 Mr. R. E. Shinshak La Crosse Boiling Water Reactor Dairyland Power Cooperative P. O. Box 135 Genoa, Wisconsin 54632 Coulee Region Energy Coalition ATTN: George R. Nygaard P. O. Box 1583 La Crosse, Wisconsin 54601 Charles Bechhoefer, Esq., Chairman Atomic Safety and Licensing Board U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Dr. George C. Anderson Department of Oceanography University of Washington Seattle, Washington 98195 Mr. Ralph S. Decker Route 4, Box 190D Cambridge, Maryland 21613 La Crosse Public Library 800 Main Street La Crosse, Wisconsin 54601 Mr. Frank Linder General Manager Dairyland Power Cooperative 2615 East Avenue South La Crosse, Wisconsin 54601 1274 121
LIST OF ATTENDEES DPC/NRC MEETING SN LIQUEFACTION AND SEISMIC DESIGN OCTOBER 17, 1979 DPC R. Shimshak J. Parkyn E. Tremmel Dames & Moore R. Fox M. Nataraja WES W. Marcuson, III NES I. Husain R. Milos NRC J. Wetmore H. Polk H. Lee C. Hofmayer D. Crutchfield H. Levin J. Greeves L. Reiter R. Jackson P. DiBenedetto L. Heller 127/
122 4
J. Shea
General Group 2 Seismic Milestones WEEK A.
Seismic input available 0
B.
-nalysis and evaluation of reactor building and RCPB complete (Report) 20 C.
Analysis of other Cat. I buildings complete (floor spectra, response profiles) 24 D.
Analysis and evaluation of safe shutdown
\\
systems complete (piping, anchorage of mechanical / electrical equipment) (Report) 40 E.
Structural Evaluations of (C) above complete (Report) 40 F.
Analysis and evaluation of ECCS/ES systems complete (piping, anchorage of nechanical/
electrical equipment) 48 G.
Evaluation of mechanical / electrical equipment 5
complete 64 H.
Licensee submits final reports (with action plan) 72 t
I.
NRC review complete 80 i
j J.
Interim NRC Seismic Report / start of integrated assessment 88 I
I I
l l
1274 123
.