RC-95-0058, Application for Amend to License NPF-12,requesting Discontinuation of Seismic Monitoring Network

Application for Amend to License NPF-12,requesting Discontinuation of Seismic Monitoring Network

ML20080R770
Person / Time
Site:	Summer
Issue date:	03/06/1995
From:	Gabe Taylor SOUTH CAROLINA ELECTRIC & GAS CO.
To:	Stephen Dembek NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RC-95-0058, RC-95-58, NUDOCS 9503100070
Download: ML20080R770 (5)

Text

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th Carolina Electric & Ga3 Comp ny J.T ylor

,j.

, JenkinsvWie, SC 29065 Nuclear Operations :

(803) 345-4344 _;

SCF.&G ASCAA510wnpsy March 6,1995 Referto: RC-95-0058 Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555.

L Attention: Mr. Stephen Dembek Gentlemen:

Subject:

VIRGIL C. SUMMER NUCLEAR STATION (VCSNS)

DOCKET NO. 50/395 OPERATING LICENSE NO. NPF-12 SEISMIC NETWORK DISCONTINUATION in accordance with 10 CFR 50.90, South Carolina Electric & Gas Compan (SCE&G),

acting for itself and as agent for South Carolina Public Service Authorit , hereby requests an amendment to the Virgil C Summer Nuclear Station (VCSN Operatin License (OL). The purpose of this change is to request the discontinuation of the g seismic monitoring network around the Virgil C. Summer Nuclear Station, on the basis that the minimum requirements of Operating License Condition 2.C (24) have been satisfied. This License Condition required SCE&G to maintain responsibility for a seismic monitoring program as discussed in Section 2.5.3 of the NRC Safety Evaluation Report [NUREG-0717] until a request is made by the Licensee and approved by t he NRC Staff for reduction or elimination of the program.

The SCE&G seismic monitoring network was originall installed in 1977 (prior to the impoundment of Monticello Reservoir)as required the NRCin a Safety Evaluation performed in 1974. Referring to attached Figure 1, t seismic network is currently composed of five (5) seismometers identified as Sites MR-01,02,05,07,10. The .

seismic network has been re-configured several times during its operation with a varying number of instruments deployed. Station JSC was installed by the United States Geological Survey in 1973 as part of the South Carolina Seismic Network (SCSN). Station JSC was used from 1974-77 to identify the background natural i seismic activity of the area, which was determined to be on the order of one event i every six days prior to the impoundment of Monticello Reservoir.

Since 1977, SCE&G has used the seismic network to record earthquake activity resulting from Reservoir induced Seismicity (RIS) and other natural events. SCE&G currently funds the University of South Carolina to maintain, operate and analyze data from the network in order to provide reports to the NRC on a quarterly basis.

As fromshown by these the network reports has shown a steady and Figure decline 2, after the of overall peak RIS seismicity activity including the (of 1978-80, da l

- number of events of magnitude 2.0 and larger),with the exception of a slight increase during 1985.  ;

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'.CCO30 o 9503100070 950306 PDR P ADDCK 0500o395 i PDR o . ___ .

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' Docum:nt Centrcl Desk

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- Page 2 of 2 The seismic activity for the past two years has now been less than the pre-impoundment background levels of 1974-77. On this basis,5CE&G proposes to t continue the seismic network until the end of the first quarter,1995, after which time, monitoring and reporting on a quarterly basis will be discontinued.

It is requested that the NRC 5taff review this proposal and advise of its acceptability by May 24,1995, in order to allow SCE&G time to make arrangements for discontinuation with the involved parties. Due to the small magnitudes (< 3.0) of the earthquakes recorded over the past 17, years and the. lack of safety significance of these small events, SCE&G no longer beheves that the burden and costs of this seismic monitoring and reporting are justified.

This proposed OL change has been reviewed and approved by both the Plant Safety Review Committee and the Nuclear Safety Review Committee.

This request replaces the previous request for seismic network discontinuation dated February 21,1995 (Refer to: RC-95-0046), due to the omission of an oath or affirmation statement as required by 10 CFR 50.30(b).

I declare that these statements set forth herein are true and correct to the best of my knowledge,information, and belief.

Should you have any questions, please contact Mr. Bob Whorton at (803) 345-4725 or Mr. Michael J. Zaccone at (803) 345-4328.

Very truly yours, Gar for )

MJZ/GJT/nkk Attachments (3)  :

1 c: O. W. Dixon R. R. Mahan (w/o figures)

R. J. White

5. D. Ebneter

5. Dembek

5. F. Fipps NRC Resident inspector -

J. B. Knotts Jr.

J. W. Flitter NSRC  ;

Central File System RTS (TSP 940005)

File (813.20) l I

NUCLEAR EXCELLENCE- A SUMMER TRADITIONI

Attrchmint I  :

TSP 940005

[ Pcgo 1 cf 1 l Virail C. Summer Nuclear Station I Docket No. 50/395 Operatina Licensina Condition 2.C(24) 10 CFR 50.92 Evaluation No Sianificant Hazards Determination ,

South Carolina Electric & Gas Company (SCE&G) has reviewed this request and  ;

determined that:  ;

1. The proposed amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated since the seismic monitoring network provides no direct input for operator action to control the alant. This network only functions to provide an estimate of the magnitude and  !

ocation of an earthquake. '

2. The proposed amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated since the seismic i monitoring network serves to record an earthquake with no direct in put for  !

operator action. Removal of the network will have no affect on the o esign or i operation of the plant. j

3. The proposed amendment does not involve a significant reduction in the margin )

of safety since the microseismic network does not control any safety functions of 1 the plant nor provide any annunciation for operator action to control the plant. l Based on the above reasoning, SCE&G has determined that the proposed amendment does not involve a significant hazards consideration.

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Figure 1 TSP 940005 Page'I of 1 Monticello Reservoir Seismic Network i

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