ML19308A875
| ML19308A875 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 03/23/1978 |
| From: | Volgenau E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | Derrick B HOUSE OF REP. |
| Shared Package | |
| ML19308A876 | List: |
| References | |
| NUDOCS 7912120663 | |
| Download: ML19308A875 (3) | |
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The Honorable Butler Derrick United States House of Representatives Washington, D.C.
20515
Dear Congressman Derrick:
I am pleased to respond to your January 30,,1978 letter addressed to the Director of our Region II office in Atlanta, Georgia.
During(a series of very small earthquakes)y of 1978 a microearthquake late December 1977 and early Januar swarm occurred in the vicinity of the Oconee Nuclear Plant - Lake Jocassee.
It is correct that the largest event of that swarm was of magnitude about 2.2 Richter.-
Duke Power Company, the licensee, informed the NRC by telephone of the increased seismic activity in this area on January 3,1978.
This was in accordan:e with~the procedure which had been agreed to by the licensee by letter dated July 8, 1977 after the microearthquake recorder network was installed on November 1,1976.
The network was installed and is operated by the University of South Carolina as part of a study sponsored by the National Science Foundation.
Duke Power Ccmpany provides a portion of the funding for the system in return for certain data and reports submitted by the University to Duke Power Company.
At the end of two years the need for the network is to be re-evaluated.
At the beginning of this recent activity period, Duke Power Company agreed to communicate to the NRC by telephone on almost a daily basis, significant information on the microearthquake activity.
As a pre-cautionary measure, Duke Power Company was requested to be especially careful to assure that all seismographs continued to be in working order.
Since the events in January of this year the micreeartijouake activity in the area has decreased very significantly, both in magnitude and frequency.
The NRC staff is considering termination of the telephone reports, placing the reporting back on the routine quarterly schedule.
Duke Power Company will be submitting a report on this recent activity early in March 1978. Upon receipt of the report, the NRC staff will begin an evaluation of the data and the report.
A completed evaluation is expected by mid-April 1978.
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The Hencrable Butler Cerrick.
The informtien fren the recent events and any subece,uent data will be considered in final evaluatien of the two-year nicrocarthquake study.
As a result of the inforr.ation we have at the present tico, we are of
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!Jith renard the opinion that there is no irudiate ccncern for sa#cty.
to future carti nua':cs, na cannot eska s::ccific predicticns e.xcept that it is probable that sir.ilar microcarthnuake activity will occur frem tire Such activity has occurred clscwhere in tP.e scutheastern U.S.
to tire.
It is also possible that larmr seisr.:ic events ay occ'tr, but as ycu are
& cassee 23n are d: signed pro!".bly aware, tae eonce *:uclear Flant anr.i r
and built with sinnificant rargins of safety.
As a measure of the significance of thcse recent eve:ts with resn:ct to pleit : fety it is no nible tn u:e a cercaricen 5:021 cn c'rcund. accelera-tien valr.
3<. e of f a s tr. -< ' c'.i;n :d:' ;r:c ~ ': :S. sita :re set to :ctus M at 0.019 The nucinar plam. vas c: ri cd for a.i.13 ts a result of the recent ccthity nce.c of these grcund acceleration, instrwents were activated, thereby indicating the relatively Icw -
ca :nitudS of that activity.
'r'a here that this inf:rutien will servo your.:Mr.
If you d.cire further infor: ation concerninr1 this ratter, plea:e 1: rot hesitata to CCnt3;t rn.
Distribution Sincerely, L. V. Gossick, EDO W. J. Dircks, EDO E. Volgenau, DIE
[Y J. G. Davis, DD:IE N. C. Moseley, RCI:IE Ernst,/olgenau R. E. Shewmaker, RCI:IE Director E. L Jordan, X005:IE Office at Inspection and Enforcement OCA(3)
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r-Executive Director for Operations Signature Mail ROUTING Concurrence: f p,,8,,,
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JeWff reccannended?
ni ecle s Is notification to the GneIV OCd W
Sign % are:
Concurrences received from:
Vol ga m "
( 2/27/78 )
'NPD by pena
( 2/24/78 )
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( 2/23/78 )
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Description:==
Ltr to Rep. Derrick fm Volgenau re microearthquake swarm (a series of very small earthquakes) occurred in the vicinity of the Oconee Nuclear Plant - Lake Jocassee hl.
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