ML19319A910
| ML19319A910 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 02/09/1977 |
| From: | Rolonda Jackson, Kellener J Office of Nuclear Reactor Regulation |
| To: | Gammill W Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19308B393 | List: |
| References | |
| NUDOCS 7912300168 | |
| Download: ML19319A910 (4) | |
Text
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FEB 9 1977
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i HEHORANDLM FORs Willima P. Camm111, Assistant Director for Site Technology, DSR i
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FROMs Robert E. Jackson, Coologist, Ceology/Seimnology tr===% DSE John Kelleber, Seismologist, Geology /Saismology
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Branch, DSE I
i THEUs J. Carl St*Ppe Chief, Coology/Satanology Branch, DSE i
- 1. 5. Bof====, leader, Geology Section, CSR, DSE j
SUMECT:
000 NEE /JOCASSEE DAN SEISMICITT i
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We have been following the situation at Oconee/Jocassee dans since i
July,1976, and this memo will update what has happened since that time. At the July 27,197o site visit the staff requested that,Ds = l Power company provide a report discusstag the earthquake activity" i"
at Jocassee Dars. On July 21, 1976, the Assistant Director for i
Operating Beactors was informed that another meeting with the utility would probably be mecded (July 21, 1976 mens Gemmill to Coller, Attached). This mano also itesised a===har of eamearns relating to the seismicity near Jocassee dem. h staff also recommended that operation of a seimmic monitoring network be reinst.ituted. As a result, a meettag with the utility was held on September 21, 1976 j
to discuss responses to these questions. At that time the applicant
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supplied several reports relating to the observed seimnicity and site geology (see attached meeting sunnery by G. Zech). On October 25, I
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1976 we were infocued that a seimmic monitoring progree would be reinstalled and operational on November 1,1976 (letter, Parker t.o Rusche, October 25, 1976). On Jamnary 7, 1977 we met with 1
Drs. Dave Simpsea and Klaus Jacob of Lamont-Doberty Geological 4
Observatory to seek advi:s on methods of resolving this situation.
Our consideracian of this issue to date has indicated a need to nest with the appliemme as soon as possible to discuss specifice of dass design, the earthquake activity since July, the seismic monitoring pr..r a ~ s o.
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- It is anticipated that our continued involvement will be required in' order to review data gathered by the utility.
In addition, fur-ther requests for additional information relating.to seiomie : a f, I
adequacy of the dam, local geologic conditions, and other seismologic j
questions will be forthcoming.
Dr. Dave Simpson of Lanont-Doherty Geological Observatory, an expert in reservoir-induced seicnic activity
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'has indicated a villingness to act as consultant to us on this rc.rictr.
Because of the existence of reservoir-induced seismicity in the I
vicinity of this large dam upstream from the Oconca nuclear plants i.
we do have a high level of concern. !!oderately large da. aging earth-quakes have occurred in other parts of the world near similar large e
i dams. The presence of this seismicity requires that the sciemicity, site geology and their possible impact on the dma be examined j
vigorously and as soon as possible by both the staff and the utility.
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c, t. Robert E. Jackson, Geologist v:
Ceology/ Seismology Branch, DSB
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j John Kc11eher, Seisnoloaist Geology /Scismology Branch, DSE i
Attachments: As stated.
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R. Jackson J. Kelleher'
-J. Stepp l
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' TENTATIVE DISCUSS 10ll ITEMS FOR MEETING WITH DUKE POWER COMPANY 000 NEE /JOCASSEE DAM
. 1.
. Geology and Seismology Staff Objectives
- 2.
Specifics of Seismic Network Operation-a.-
Station locations
.b.. Network capability - magnitude and threshold, distance
'and depth capability Discussion of hypocentral activity since July 1976, c.
including focal plane solutions d.
Reporting procedures to NRC staff 3.
Specific Information on Geologic Reconnaissance of Site Area h.
Location of discovered faulting b.
Basis of fault age dating
- c. - Available photos of dam abutments and foundation
- d. - Subsurface ~ geology -~models 4.-
Reservoir-Induced-Seismicity-a.
Similarities - difference Jocassee to known damaging carthquakes y
5.
Seismic Adequacy of Dam
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- a.
' Construction progress photos /airphotos b.
Groundwater elevation before/after dam-filling (time-head plots)
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c '. Embankment const'ruction_ specifications (engineering properties for design and basis, density, gradation for all zones,
" settlement and alignment-of crests and slope as a function
.tof time)
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g-9 d.
Su page rates (relief wells, weiss, drains Simple strain computations to assess approach to e.
threshold of cracking core f.
History of inspections and repairs to date c.
Sensitivity of dam to surface fault movement (thickness and location of filters, strain distribution - rough calculations) h.
Time - acceleration plot of expected carthquake (reference
.12 g for 5.6 M carthquake - considerations, basis justification) y' We request personnel that can discuss the above items and other related peripheral items be present at the meeting.
This should include the scismological consultants and dam engineers.
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