ML19207C372

Forwards Table Re Analysis of Earthquake Intensity at Site. Two of Three Equations Used for Attenuation Contained Errors Resulting in Overestimation of Average OBE Recurrence Intervals

ML19207C372
Person / Time
Site:	05000502
Issue date:	08/31/1979
From:	Burstein S WISCONSIN ELECTRIC POWER CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
NUDOCS 7909110484
Download: ML19207C372 (4)

Text

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O Wisconsin Electnc POWER COMPANY 231 W. MICHIGAN, P.O. BOX 2046. MILWAUKEE, WI 53201 August 31, 1979 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. NUCLEAR REGULATORY COMMISSION Washington, D. C. 20555

Dear Mr. Denton:

DOCKET NO. STN 50-502 HAVEN NUCLEAR PLANT SEISMIC RISK EVALUATION Appendix 2K of the Haven Site Addendum provides results of seismic risk calculations which are used to estimate the average recurrence interval of the Operating Basis Earthquake (OBE) at the Haven site. These calculations were performed using various attenuation laws described in Appendix 2K.

During review of these calculations, we have determined that two of the three equations used for attenuation contained errors which resulted in overestimation of average OBE recurrence intervals at the Haven site.

In addition to these errors, refinments in seismic risk calculations have been developed since the original analysis was performed. The calculations have been redone using revised equations representing the present state-of-the-art and a method suggested by the NRC Staff. The reanalysis indicates an average recurrence interval of 419 years conpared to the original value of 1595 years. The recurrence interval of 419 years, while lower than the original estimate, confinns that the OBE acceleration value chosen for the Haven site is conservative and there is no need to change plant design.

The results of the seismic risk calculations are enclosed as Table 1. This table will be incorporated in Appendix 2K of the Haven Site Addendum at an appropriate time.

Very truly yours,

/

• Sol Burstein Exe utive Vice President Enclosure 0\

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Copy to Service List s I --

7009110

i UtilTED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION l Before the Atomic Safety and Licensing Board l In the Matter of i WISCONSIll ELECTRIC POWER Docket flo. STil 50-502 COMPN 1Y, ET AL. ,

I Haven fluclear Plant I

SERVICE LIST Chairman Robert H. Gorrke, Esq.

Atomic Safety and Licensing Board Wisconsin Electric Power Company U. S. !{uclear Regulatory Comission 231 West Michigan Street Washington, D. C. 20555 Milwaukee, Wisconsin 53201 Mr. Glenn 0. Bright Mr. Sol Burstein Atomic Safety and Licensing Board Executive Vice President U. S. Nuclear Regulatory Comission Wisconsin Electric Power Company Washington, D. C. 20555 231 West Michigan Street Milwaukee, Wisconsin 53201 Dr. E. Leonard Cheatum Route #3 Mr. William Charles Hanley Box 350-A President Watkinsville, Georgia 30677 Safe Haven Ltd.

P. O. Box 40 Steven C. Goldberg, Esq. Kohler, Wisconsin 53044 Office of the Executive Legal Director David E. Beckwith, Esq.

U. S. Nuclear Regulatory Comission Foley & Lardner Washington, D. C. 20555 First Wisconsin Center 777 E. Wisconsin Avenue Docketing and Service Section Milwaukee, Wisconsin 53202 Office of the Secretary U. S. Nuclear Regulatory Commission Mr. Richard W. Henneger Washington, D. C. 20555 Bureau of Legal Services Department of Natural Resources Thomas A. Lockyear, Esq. Box 7921 Assistant Chief Counsel Madison, Wisconsin 53707 Public Service Commission of Wisconsin Hill Farms State Office Building Madison, Wisconsin 53702 Gerald Charnoff, Esq.

Shaw, Pittman, Potts & Trowbridge 1800 M Street, N.W.

Washington, D. C. 20036

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l TABLE 1

. ANALYSIS OF EARTHQUAKE INTENSITY AT SITE _ _ __ _ .._ _ _ _

~

Annual Risk at the Site of Exceeding Intonsity Attenuation Rato Rono Law # 10 b (km) _

VI VII VIII Brazee 0.001 4 7.0 0.845 40 6.75 x 10-4 0.0 0.0 0.001 4 7.5 0.845 40 1.18 x 10 -3 7.10 x 10-5 0.0 0.001 4 8.0 0.845 40 1.77 x 10-3 2.09 x 10

• 0.0 0.001 6 7.0 0.247 40 2,78 x 10-3 0.0 0.0 0.001 6 7.5 0.247 40 4.11 x 10-3 2.47 x 10

-4 0.0 0.001 6 8.0 0.247 40 5.67 x 10-3 6.70 x 10-4 0.0 Gupta & 7.0 5.78 x 10 -4 6.78 x 10 -5 -6 0.536 4 0.845 23 163 x 10 Huttli 0.536 7.5 -4 1.22 x 10 *

-# -0 4 0.845 . 23 7.81 x 10 7.74 x 10

-3 -#

0.536 4 8.0 0.845 . 23 1.03 x 10 1.79 x 10

• 2.10 x 10-5 0.536 6 7.0 0.247 23 2.39 x 10-3 2.80 x 10-#* 6.73 x 10

-6 0.536 6 7.5 0.247 23 2.72 x 10 -3 4.25 x 10-4 2.70 x 10 -5 0.536 6 8.0 0.247 23 3.29 x 10-3 5.74 x 10-4 6.73 x 10-5 Howell & 0.64 7.0 0.845 25.5 8.38 x 10

• 9.98 x 10 -5

-6 4 4.63 x 10 1.16 x 10-3 1.72 x 10 -4 Schultz 0.64 4 7.5 0.845 25.5 1.41 x 10-5 0 64 4 8.0 0.845 25.5 1.53 x 10-3 2.60 x 10-#* 3.09 x 10-5 0.64 -6 7.0 0.247 25.5 3.46 x 10-3 4.12 x 10-4 1.91 x 10 -5 4.05 x 10 -3 0.64 6 7.5 0.247 25.5 5.98 x 10

• 4.93 x 10 -5

-3 a

.k 0.64 6 8.0 0.247 25.5 4.91 x 10 8.33 x 10 -4 9.91 x 10 -5 Risk Per Year Aveiage 2.38 x 10-3 2.90 x 10-#* 1.94 x 10-5 Maximum 5.67 x 10-3 8.33 x 10-4 9.91 x 10-5 Mininum 5.78 x 10-4 0.0 0.0 Return Period (Years)

Average 419 3448 51,546 Maximum 1730 - -

Minimum 176 1200 10,091 Sheet'l of 2

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s TABLE 1 (cont'd)

ANALYSIS OF EA}tTifQUAKE INTENSITY AT SITE Attenuation Laws Brazee I = 3.387 + I. - 0.894 Inn - 0.00289R Gt.pta & I = 3.7 + I, - 1.173 inR - 0.00lIR Nuttli llowell & I = 3.278 + I, - 0.989 InR - 0.0029R Shultz Definitions P is standard deviation I g, is lower bound intensity of source area I S is upper bound intensity of sourco area

_g Hate is annual rate of occurence of earthquake ? I o -

[.[ Rone is radius from epicenter for which there is no attenuation w

Sheet 2 of 2 .