ML16342B571

Forwards Request for Addl Info & Transmittal of Documents Re NRC Review of Plant long-term Seismic Program.Comments by NRC Consultants Also Encl

ML16342B571
Person / Time
Site:	Diablo Canyon
Issue date:	06/01/1989
From:	Rood H Office of Nuclear Reactor Regulation
To:	Shiffer J PACIFIC GAS & ELECTRIC CO.
Shared Package
ML16342B573	List: ML16342B571 ML20247M685
References
TAC-55305, TAC-68049, NUDOCS 8906120289
Download: ML16342B571 (14)

Text

Junw 1, 1989 Docket Nos.

50-275 and 50-323 Mr. J.

D. Shiffer, Vice President Nuclear Power Generation c/o Nuclear Power Generation, Licensing Pacific Gas and Electric Company

/7 Beale Street, Room 1451 San Francisco, Ca 1 ifor ni a 94106

Dear Mr. Shiffer:

DISTRIBUTION

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. NChokshi JLee RRothman BGrimes LReiter EJordan 'Rood ACRS (10)

PDV Plant File OGC (for info'only)

SUBJECT:

kE(VEST FOR ADDITIONAL INFORMATION AND TRANSMITTAL OF DOCUMENTS RELATING TO NRC STAFF REVIEW OF DIABLO CANYON LONG TERM SEISMIC PROGRAM (LTSP)

(TAC NOS.

55305 AND 68049)

Enclosure 1 is a request for additional information which the NRC staff has developed as a result of its review of seismic ground motion at Diablo Canyon.

We request that you provide a response to the enclosed questions as soon as possible, so that our review of ground motion may continue.

The first twelve questions in Enclosure 1 were previously transmitted to you in the meeting summary (dated March lI, 1989) of the March 1-3, 1989 meeting.

Also enclosed for your information and use are comments by NRC consultants reviewing the LTSP.

Comments by Doctors Aki, Archuleta, Day, Campbell, and Veletsos address the ground motion issues raised at the March 1-3, 1989 meeting.

Comments by Doctors Brown and Slemmons address the areas of geology, geophysics, and tectonics.

Sincer ely,

/s/

Harry Rood, Senior Project Manager Project Directorate V

Division of Reactor Projects

- III, IV, V and Special Projects Office of Nuclear Reactor Regulation

Enclosures:

1.

Request for additional information 2.

Comments by NRC consultants cc w/encl:

See next page DRSP/PD5 D SP/D:Pob HRood GKnighton 06/ ) /89 06/ i/89 OFFICIAL RECORD COPY ot I

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Docket Nos.

50-275 and 50-323 UNITEDSTATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 June 1,

1989 Mr. J.

D. Shifter, Vice President Nuclear Power Generation c/o Nuclear Power Generation, Licensing Pacific Gas and Electric Company 77 Beale Street, Room 1451 San Francisco, California 94106

SUBJECT:

RE(VEST FOR ADDITIONAL INFORMATION.AND TRANSMITTAL OF DOCUMENTS RELATINC TO NRC STAFF REVIEW OF DIABLO CANYON LONG TERM SEISMIC PROGRAM (LTSP)

(TAC NOS.

55305 AND 68049)

Enclosure 1 is a request for additional information which the NRC staff has developed as,a result of its review of seismic ground motion at Diablo Canyon.

We request that you provide a response to the enclosed questions as soon as possible, so that our review of ground motion may continue.

The first twelve questions in Enc1osure 1 were previously transmitted to you in the meeting summary (dated March 17, 1989) of the March 1-3, 1989 meeting.

Also enclosed for your information and use are comments by NRC consultants reviewing the LTSP.

Comments by Doctors Aki, Archuleta, Day, Campbell, and Veletsos address the ground motion issues raised at the March 1-3, 1989 meeting.

Comments by Doctors Brown and Slemmons address the areas of

geology, geophysics, and tectonics.

Sincerely, Harry Rood, Senior Project Manager Project Directorate V

Division of Reactor Projects - III, IV, V and Special Projects Office of Nuclear Reactor Regulation

Enclosures:

1. Request for additional information 2.

Comments by'NRC consultants cc w/encl:

See next page

C

Mr. J.

D. Shiffer Paci fic Gas and E 1ectri c Company Diablo Canyon CC:

Richard F. Locke, Esq.

Pacif ic.Gas 5

E 1ectri c Company Post Ofiice Box 7442 San Francisco, California 94120 Ms. Sandra A. Silver 660 Granite Creek Road Santa Cruz, California 95065 Mr. Peter H. Kaufman Deputy Attorney'General State of California 110 West A Street, Suite 700 San Diego, California 92101 Managing Editor The County Tele ram Tribune P.

ox 11 San Luis Obispo, California 93406 Ms. Nancy Culver 192 Luneta Street San Luis Obispo, California 93401 Regional Administrator, Region V

U.S. Nuclear Regulatory Commission 1450 Maria Lane Suite 210 Walnut Creek, California 94596 NRC Resident inspector Diablo Canyon Nuclear Power Plant c/o U.S. Nuclear Regulatory Commission P. 0.

Box 369 Avila Beach, California 93424 Bruce Norton, Esq.

c/o Richard F. Locke, Esq.

Pacific Gas and Electric Company Post Office Box 7442 San Francisco, California.

94120, Dr.

R.

B. Ferguson Sierra Club - Santa Lucia Chapter Rocky Canyon Star Route Creston, California 93432 Chairman

'an Luis Obispo County Board of Supervisors Room 270 County Government Center San Luis Obispo, California 93408 Michael M. Strumwasser, Esq.

Special Assistant Attorney General state of California Department of Justice 3580 Wi lshire Boulevard, Room 800 Los Angeles, California 90010 Mr. Paul Sza 1 ins ki, Chief Radiological Health Branch State Department of Health Services 714 P Street, Office Building ¹8 Sacramento, California 95814

hg c l'

Mr. J.

D. Shifier Pacific Gas and Electric Company Diablo Canyon Long Term Seismic Program CC:

Dr. Keiiti ski Department of Geological Sciences University Park University of Southern California Los Angeles, California 90089-0741 Dr. Ralph J. Archuleta Department of Geological Sciences University of California Santa Barbara Santa

barbara, California 93106 Dr. Robert D. Brown, Jr.

U.S. Geological Survey Mail Stop 977 345 Middlefield Road Menlo Park, California 94025 Dr.. David B. Slemmons Center for Neotectonic Studies MacKay School of Mines University of Nevada-Reno

Reno, Nevada 89557-0047 Dr. Robert Fitzpatrick Building 130 Brookhaven National Laboratory

upton, New York 11973 Dr. C. J. Costantino Uuilding 129 Brookhaven National Laboratory

Upton, New York 11973 Dr. Michael Bohn Sandia Lab. - Organization 6412 Post Office Box 5800 Albuquerque, New Mexico 87185 Dr. J.

Johnson EQE s95 Market Street - 18th Floor San Francisco, California 94105 Dr. Steven M. Day Department of Geological Science San Diego State University San Diego, California 92182 Dr. George Gazetas Dept.

oi Civil Engineering 212 Ketter Hall SUNY-Buffalo Buffalo, New York 14260 Dr. Jean Savy Mail Code L-196 Lawrence Livermore National Laboratory P. 0.

Box 808 Livermore, California 94550 Dr. Anestis S.

Ve letsos 5211 Paisley Avenue

Houston, Texas 77096 Dr.

Ken Campbell U.S. Geological Survey P.O.

Box 25046, Mail Stop 966 Denver Federal Center

Denver, Colorado 80225 Dr. M. K. Ravindra EQE 3150 Bristol Street, Suite 350 Costa Mesa, California 92626

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ENCLOSURE I Request for Additional Ground Motion Information What are the potential effects on the ground motion regression analysis results of including the very hard rock sites in the empirical data set.

Provide a justification of the methods used for the selection and adjustment of the data used in the near-source ground motion and empirical ground motion estimates.

The justsfication should demonstrate that the methods usea do not bias the ground motion to the low side.

Identify the records which were used in each of the subsets of the empirical data set used for each of the various analyses.

The median and 84% spectra resulting from the numerical modeling studies have a dip in amplitude between 5 and 10 Hertz.

PGSE stated that this is an artifact of the random number set used in the calculations.

Substantiate this by prov'iding spectra generated with a different sets of random numbers where this dip does not occur.

How much woula the empirical ground motion estimates change if the type ot faulting was assumed to be all oblique slip rather than 65% strike slip, 30% oblique slip, and 5% reverse slip?

Is the apparent magnitude dependence of the dispersion in the empirical ground motion anaIysis real or is it an artifact'of the data set?

For lower magnitudes the uncertainty may be due to inter-event dispersion while at larger magnitudes it may be due to intra-event dispersion.

Provide a step-by-step discussion of the uncertainty in the numerical modeling study.

Show the effect of different assumptions of fault type (strske slip, oblique slip, and reverse slip) in the numerical modeling study.

Provide a comparison between the numerical modeling study and the frequency-wave number method of the 1.5 km and 3

km source depth contributions.

'rovide the eleven three-component time series for bilateral rupture for both the Imperial Valley and Coalinga aftershock sources from the numerical modeling study.

The amplitudes of low frequency portion of the spectra generated in the

.numerical modeling study appear to be deficient.

At what frequencies are these spectra dependable?

To aid in accessing the proposed lack of topographic effect at the Diablo Canyon site, provide a numerical study using vertically polarized shear waves with ground motion amplitude referenced to sea level.

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ENCLOSURE I (continued)

Request for Additional Ground Motion Information Limits on parameters used to establish the empirical data base appear to be constrained to the point where some earthquakes which may be important are not included.

To determine the significance of the choice of magnitude and distance ranges to the LTSP site specific spectra, expand the data base to include earthquakes down to magnitude 6, particularly the Parkfield and Morgan Hill events, and distances to about 30 kilometers and provide the resulting spectra.

Since the Imperial Valley earthquake data were recorded on deep soi 1 sites, their use in developing the site specific response spectra for Diablo Canyon has been questioned.

Provide site specific response spectra obtained without the use of the Imperial Valley earthquakes.

The derivation of the various adjustment factors used to modify. the empirical ground motion an'd their individual effects have not been described in sufficient aetail to permit an evaluation of their appropriateness.

Please provide this information.

Recent Work on the Nahanni earthquake Site 2 data (Weichert, 1989) and in the San Fernando earthquake Pacoima Dam recording (Anooshehpoor, 1988) indicate that the high ground motions recorded may not be due to site effects.

In view of this, modification of these records to account for topographic amplification is questionable.

Hnat would the ground motion estimates be without these modifications?

Describe the analyses including the data bases used to determine the style of faulting factors derived from both the empirical and numerical studies.

It has been suggested that stress drops are higher for oblique and thrust faults than for strike-slip faults.

What is the justification for using a constant stress drop of 50 bars for all fault types in the numerical modeling studies?

To what extent would the use of higher stress drops impact the results?

Directivity effects have been observed from earthquake ruptures propagating toward and away from seismic stations.

There do not appear be any directivity effects observed in the ground motions from the numerical modeling studies;

although, from the geometry of the station array they might be expected.

Is this an artifact of the way the simulations are performed?

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ENCLOSURE 2

Comments by NRC Consultants

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