ML16341F740
| ML16341F740 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 06/12/1990 |
| From: | Rood H Office of Nuclear Reactor Regulation |
| To: | Shiffer J PACIFIC GAS & ELECTRIC CO. |
| References | |
| TAC-55305, TAC-68049, NUDOCS 9006210043 | |
| Download: ML16341F740 (22) | |
Text
June 12, 1990 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 77 Beale Street, Room 1451 San Francisco, California 94106
Dear Mr. Shiffer:
DISTRIBUTION c~~
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1 NRC 8
LPDRs GBagchi JLarkins RPichumani DFoster RRothman HRood BGrimes EJordan ACRS (10)
PDV Plant File OGC (for info only)
SUBJECT:
TRANSMITTAL OF DOCUMENT RELATING TO NRC STAFF REVIEW OF DIABLO.
CANYON LONG TERM SEISMIC PROGRAM (LTSP)
(TAC NOS.
55305 AND 68049)
Enclosed for your information and use is a report by an NRC staff consultant, Dr. Kenneth W. Campbell, which relates to the NRC staff review of the Diablo Canyon Seismic Reevaluation Program.
As you know, Dr. Campbell has been performing independent empirical ground motion studies for the staff.
The enclosed repor t describes some reanalysis which has been performed on an augmented data base.
The report is entitled:
"Reanalysis of Strong-Motion Recordings:
Empirical Prediction of Near-Source Ground Motion for the Diablo Canyon Power Plant Site, San Luis Obispo County, California."
If you have any questions regarding this report, please contact me.
Sincerely,
Enclosure:
as stated cc w/encl:
See ne t page
+DRSP/PD5 DRSP/(A)D:PD5 gb HRood JLarkins 06/11/90 06/P/90 OFFICIAL RECORD COPY ORIGINAL SIGNED BY HARRY ROOD Harry Rood, Senior Project Manager Project Directorate V
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Docket Nos. 50-275 and 50-323 t
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 June 12, 1990 Mr. J.
D. Shiffer, 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
Dear Mr. Shiffer:
SUBJECT:
TRANSMITTAL OF DOCUMENT RELATING TO NRC STAFF REVIEW OF DIABLO CANYON LONG TERM SEISMIC PROGRAM (LTSP)
(TAC NOS.
55305 AND 68049)
Enclosed for your information and use is a report by an NRC staff consultant, Dr. Kenneth W. Campbell, which relates to the NRC staff review of the Diablo Canyon Seismic Reevaluation Program.
As you know, Dr. Campbell has been performing independent empirical ground motion studies for the staff.
The enclosed report describes some reanalysis which has been performed on an augmented data base.
The report is entitled:
"Reanalysis of Strong-Motion Recordings:
Empirical Prediction of Near-Source Ground Motion for the Diablo Canyon Power Plant Site, San Luis Obispo County, California."
If you have any questions regarding this report, please contact me.
IP S incere ly,
Enclosure:
as stated cc w/encl:
See next page Harry Ro
, Senior Project Manager Project Directorate V
Division of Reactor Projects - III, IV, V and Special Projects Office of Nuclear Reactor Regulation
Mr. J.
D. Shiffer Pacific Gas and Electric Company Diablo Canyon CC:
Richard F. Locke, Esq.
Pacific Gas
& Electric Company Post Office 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 Count Tele ram Tribune 1321 o nson venue P. 0.
Box 112 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 Mr. John Hickman Senior Health Physicist Environmental Radioactive Hgmt. Unit Environmental Management Branch State Department of Health Services 714 P Street, Room 616 Sacr amento, California 95814 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.
Paci fic Gas and Electr ic 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 San 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 Wilshire Boulevard, Room 800 Los Angeles, California 90010
Mr. J.
D. Shiffer Pacific Gas and Electric Company 2
Diablo Canyon Long Term Seismic Program CC:
Dr. Keiiti Aki 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 Middlefiel d Road Menlo Park, California 94025 Dr. David B. Slemmons 2905 Autumn Haze Lane Las Vegas, Nevada 89117 Dr. Robert Fitzpatrick Building 130 Brookhaven National Laboratory
- Upton, New York 11973 Dr. Steven M. Day Department of Geological Science San Diego State University San Diego, California 92182 Dr. James Johnson EQE 595 Market St., 18th Floor San Francisco, California 94105 Dr. Jean Savy Mail Code L-196 Lawrence Livermore National Laboratory P. 0.
Box 808 Livermore, California 94550 Dr. Anestis S. Veletsos 5211 Paisley Avenue
- Houston, Texas 77096 Dr. Kenneth Campbell Dames and Moore 27728 Whirlaway Trail Evergreen, Colorado 80439 Dr. C. J. Costantino Building 129 Brookhaven National Laboratory
- Upton, New York 11973 Dr.
M. K. Ravindra EQE 3150 Bristol Street, Suite 350 Costa Mesa, California 92626 Dr. Michael Bohn Organization 6412 Sandia National Laboratory Post Office Box 5800 Albuquerque, New Mexico 87185 Dr. James Davis Division of Mines and Geology 660 Bercut Drive Sacramento California 95814 Dr. Morris Reich Building 129 Brookhaven National Laboratory
- Upton, New York 11973
I l
REANALYSIS OF STRONG-MOTION RECORDINGS EMPIRICAL PREDICTION OF NEAR-SOURCE GROUND MOTION FOR THE DIABLO CANYON POWER PLANT SITEg SAN LUIS OBISPO COUNTY'ALIFORNIA INTRODUCTION In a previous report (Campbell, 1989), attenuation relationships for peak ground-motion parameters and PSRV response spectra were developed for Soil sites.
An analysis of residuals indicated that there was no statistically significant difference in the mean residuals between Soil and Soft-Rock recordings.
As a result, the report concluded that the attenuation relationships could be used to predict ground-motions at Diablo Canyon, a Soft-Rock site as defined by the geologic criteria used to classify sites in the previous report.
A subsequent analysis of these same data by PG&E indicated that, although the differences in the residuals between the two site types were not significantly different, the style-of-faulting factor was substantially reduced when Soft-Rock recordings were added to the data base.
Since the primary objective of this study is to estimate free-field ground motions for a Soft-Rock site, Soil and Soft-Rock recordings have been combined and the previous analysis repeated to provide revised attenuation relationships more appropriate for the Diablo Canyon site.
Only changes to the previous analysis are discussed here.
The reader is referred to the report by Campbell (1989) for a complete description of the ground-motion model and the analysis techniques used to develop the previous and revised attenuation relationships.
GROUND-MOTION MODEL The ground-motion model is the same as that described by Campbell (1989).
A possible change to the model was considered when it appeared that that Soft-Rock recordings might attenuate differently than Soil recordings.
- However, an anlysis of residuals indicated that this difference in attenuation was controlled by only two earthquakes, the 1978 Tabas,
- Iran, and the 1985 Michoacan, Mexico, events.
As a result, no adjustment for attenuation was made in the model.
STRONG-MOTION DATA BASE The data base used in the reanalysis is the combined Soil and Soft-Rock data bases presented by Campbell (1989), with a few exceptions.
The fault mechanism for the 1957 Daly City earthquake was changed from strike slip to reverse, consistent with a reanalysis of this earthquake by seismologists at the University of California, Berkeley.
Furthermore, depth to basement rock was revised for several sites that recorded the 1978 Tabas and 1985 Michocan earthquakes.
Finally, all
recordings from the 1985 Michoacan earthquake were excluded from the analysis because of their extremely low ground-motion amplitudes and the large uncertainty associated with determining the magnitude and the appropriate distance to seismogenic rupture for this event.
A brief justification for this is presented below.
Studies of strong-motion, regional, and teleseismic recordings of the great Michocan earthquake indicated that the ground motions recorded during this event were dominated by two large asperities.
These asperities, rupturing about 30 sec
- apart, are believed to have been located approximately 90 km from one another.
In fact, the accelerograph at Caleta de Campos, near the first asperity, had shut off for several seconds before it was retriggered by ground motions from the second asperity.
Therefore, in the near-source region, the event appeared as if it were two smaller events rather than a single great event as the long-period surface-wave magnitude and seismic moment had indicated.
REGRESSION ANALYSES The regression analyses were similar to those described in Campbell (1989), except for two modifications.
The analyses were restricted to peak horizontal acceleration (PHA), peak vertical acceleration (PVA), peak horizontal velocity (PHV), and peak vertical velocity (PVV) due to budgetary constraints..'In addition, hypothesis tests on the residuals were performed using the actual weights, not the square-root of the weights as before.
This modification was suggested by Norm Abrahamson (personal communication, 1990) after discussing the issue with David Brillinger at the University of California, Berkeley.
Revised regression coefficients are listed in Table 1 and revised attenuation relationships are plotted in Figures 1 and 2.
Hypothesis tests were used to determine whether the weighted residuals for the Soft-Rock recordings were significantly different from those for the Soil recordings.
As before, the tests indicated that the hypothesis that the means of the two sets of residuals are the same could be accepted at a 10 percent significance level (representing 90 percent confidence).
Therefore, no adjustment to the ground-motion model was needed as a result of adding Soft-Rock recordings to the data base.
As anticipated, the addition of Soft-Rock recordings has significantly reduced the style-of-faulting factors for each of the peak parameters.
The multiplicative factors for PHA and PVA are now 1.24 and 1.12, as compared to their previous values of 1.47 and 1.27.
The reason for this reduction is not known at this time.
GROUND-MOTION ESTIMATES'FOR DIABLO CANYON Revised estimates of peak ground-motion parameters for PG&E's proposed Long Term Seismic Program (LTSP) analysis earthquake a moment magnitude (Mw) 7.2 earthquake located on the Hosgri fault approximately 4.5 km from the site (PG&E, 1988) are given in Table 2.
Note that the effect of adding Soft-Rock recordings has been to decrease Oblique/Reverse/Thrust, estimates for PHA by 11-13 percent and those for PVA by 23 percent.
On the other hand, strike-slip estimates of PHA have been increased by 2-5 percent, while those for PVA have been decreased by about 13 percent.
If ground-motion estimates for each fault type are combined according to the weighting scheme proposed by PG&E (1988) a weight of 0.65 for strike-slip faulting and a weight of 0.35 for oblique, reverse and thrust faultingthe weighted median and median-plus-one-standard-deviation (median+1a) estimates of PHA and PHV are 0.56g, 0.88g, 60 c'm/sec, and 95 cm/sec, respectively; and similar estimates for PVA and PVV are 0.56g, 1.00g, 25 cm/sec, and 42 cm/sec.
This represents a
1 percent decrease in the weighted median+la estimate of PHA and a 16 percent decrease in the weighted median+1cr estimate PVA from those given in the previous report.
Since a reanalysis of PSRV response spectra data were not included in this study, it is not possible to determine the potential effect of including Soft-Rock recordings on'stimates of PSRV at this time.
One should not simply rescale the response spectra developed by Campbell (1989) with the revised estimates of peak parameters given here, since it is likely that the PSRV shapes themselves will change when Soil and Soft-Rock recordings are combined.
REFERENCES
- Campbell, K.W. (1989). "Empirical Prediction of Near-Source Ground Motion for the Diablo Canyon Power Plant Site, San Luis Obispo County, California," U.S. Geological Survey Open-File Report 89-484.
PG&E (1988). "Final Report of the Diablo Canyon Long Term Seismic Program for the Diablo Canyon Power Plant," Pacific Gas and Electric Company report to the U.S. Nuclear Regulatory Commission, Docket Nos. 50-275 and 50-323, July 31,
- 1988, San Francisco, Calif.
, TABLE 1 Results of Regression Analyses:
PHA PVA PHV and PVV Parameter, Y
a b
c1 c2 d
e g1 g2 h1 h2 h3 no. of no. of c
records events PHA, g
-2.245 1.09 0.361 0.577
-1.89 0.218
-0.137
-0.403 243 26 0.449 PVA, g
-3.829 0.991 0.0790 0.661
-1.50 0.111
-0.337 240 25 0.573 PHV, cm/sec
-1.765 1.38 0.0203 0.958
-1.44 0.101 0.529 0.471 0.0926 0.219 174 21 0.453 PVV, cm/sec
-3.914 1.45 0.00394 1.17
-1.24 0.205 0.462 2.68 0.276
-0.108 0.405 173 21 0.541
TABLE 2 Site-Specific Estimates of PHA, PVA, PHV and PVV:
Diablo Canyon Site, California (Ms = 7.2g R = 4.5 km; D = 4 km)
Parameter, Y
Peak Ground Motion Strike Slip Oblique/Reverse/Thrust Median Median+la Median Median+la PHA, g PVA, g PHV, cm/sec PVV, cm/sec
- 0. 516 0.538 58.2 22.9
- 0. 809 0.955
- 91. 6 39.3 0.642 0'02 64.4 28.1
- 1. 01 1.07 101.3 48.2
4
PEAK ACCELERATION Strike-Slip; M ~ 6, 6, 7, 8 Peak Horizontai Acceleration {g) 0.1 0.0 t Horizontal Vertical 10 Distance to Seismogenic Rupture (km)
Flg.
1Acceleration Relatlonshlps 100
n
~
V iS
~
PEAK VELOCITY Strike-Slip; M - 5, 6, 7, 8; D - 0 Peak Horizontal Velocity (cm/sec) 100 0.1 Horizontal Vertical 10 Distance to Seismogenic Rupture (km)
Flg. 2Velocity Relationships 100
~ 4
~ k