ML20029A318

Site Specific Response Spectra,Oyster Creek Nuclear Generating Station,Response to NRC Questions.

ML20029A318
Person / Time
Site:	Oyster Creek
Issue date:	11/30/1990
From:	Klimkiewicz G WESTON GEOPHYSICAL CORP.
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ML20029A317	List: ML20029A316 ML20029A318
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Download: ML20029A318 (33)

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I '(%' Weston Geophygca!

I November 12,1990 I I GPU NUCLEAR CORPORATlbN I One Upper Pond Road Parsippany,NJ 07054 Attention: Mr. K.Whitmore, Task Manager

Subject:

Response to US NRC RAI on the September,1989 SSRS Report

Dear Mr.Whitmore:

As authorir.ed by Change Notice No. 6 to our Contract No. PC 065216, we submit our I supplemental report in response to the US NRC's Request for Additional Information concernin our 1989 Report on Site Specific Response Spectra for the Oyster Creek Nuclear Generati Station.

Thank you for the opportunity to continue our support on your project.

Sincerely, WESTON GEOPIIYSICAL COIU) ORATION q 0 f D

George C. Klimklewicz -

Manager, Seismology Department g-GCK:ce I WGC 16190 06 Enclosures cc: Mr. S.C.Tumminelli GPUNC I

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I I TAlli.E OF CONTENTS PAGE g IJST OFTABLES LIST OF FIOURES SECTION 1 INTRODUCTION 11 SECTION 2 RESPONSE TO RAI PART(A) 21 SECTION 3 RESPONSE TO RAI PART(B) 31 Earthquake of November 14,1941 31 Earthquake of March 9,1949 33 I Earthquake ofJanuary 23,1951 34 35 Earthquake of April 25,1954 Earthquake of April 8,1901 3G Earthquake of December 10,1967 37 Summary 38 g

References 38 SECTION 4 APPENDIX US NRC RAI parts (a) and (b)

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I I 1 lST O F TAIll.ES I

No. Title RAl-la 1 SSRS f or 53 llorizontal Components, Records I from Tall Ilulldings Removed, Records with Distances > 25 km Removed RAl in 2 SSRS for 10 Horizontal Components With Distances g Reported to be > 25 km I

1.lST OF FIG UllES I No. 'I1tle RAI la 1 SSRS for 531Iorizontal Components with Distances less than 25 km RAI In 2 SSRS for 53 IIorizontal Components l vs. SSRS for 63 Components including 10 records with Distances Reported to be > 25 km I RAI In 3 Ratio of 84th pereentile SSRS 53 Component Set (all records < 25 km) vs. 63 Component I Set (including 10 records > 25 km)

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I SECTION 1 INTit0 DUCT 10N I

A request for additional infonnation (RAI) was made concerning a report on Site Speellie Response Spectra (SSRS) prepared for the Oyster Creek Nuclear Generating Station (TAC No. 68217). The ital was issued by the US Nuclear Itegulatory Commission in a letter l dated September 20,1990 (A.W. Dromerick (NitC/NItit) to E.E. Fitzpatrick (GPUNC). A copy of this letter is included in an Appendix to this report. During review of the report I prepared on SSitS for Oyster Creek (Weston Geophysleal Corporation, September,1989) the NItC staff had determined that additional Infonnation was required in order to complete their review. Ilesponsee to the Ital are provided in this supplemental report.

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I SECTION 2 ITESPONSE TO lt Al PART(A)

I The complete request for additional information is included in the Appendix to this l cupplemental report.

g RAI, part(a):

" Construct SSitS similar to those shown on figures 3.13 and 3.14 from 53 records listed I in Table 3.1, eliminating 10 records from buildings with more than four stories and 10 records from carthquakes with epicentral distances greater than 25 km, recorded at l structures with four stories or less."

l Response to part(a):

Earthquakes that produced the ten horiwntal component accelerograms, referred to in part g (a) as being recorded in buildings of 4 or fewer stories at epicentral distances greater than 25 km,inciude:

1. Northern CA Earthquake h1 arch 9,1949 29.3 km 5.2 hit.(near llollister)

2. Imperial Valley CA January 23,1951 27.5 km 5.0 hit,(near Calipatria)

I 3. Cen'ral CA Earthquake April 25,1954 30.2 km 5.4 hit,(cast ofWatsonville)

I 4. Central CA Earthquake April 18,1961 40.0 km 5.7 hit,(south ofIlollister)

5. Northern CA Earthquake December 10,1967 30.6 km 5.8 hit,(Ferndale area) l Each of these five earthquakes furnished 2 horizontal component accelerograms, thus accounting for the 10 records mentioned in part (a).

I Ten horizontal components recorded in basements, or ground levels of taller buildings,

, g referred to part (a), were produced by the following three earthquakes.

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16190 06 Weston Geophysical

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6. Torrence Gardena EQ November 14,1941 27.1 km 5.5 hi ,t Chnmber of Commerce I Bldg. (10 stories)

7. San Jose, CA Earthquake Sep. 4,1955 9.6 km 5.5 hi t. Bank of America (13 stories) l 8. San Francisco Earthquake htarch 22,1957 5.3h1L State Building (7 stories) 14.2 km Southern Pacific Bldg. (12 stories) 16.5 km g

Oakland City Hall (15 stories) 24.2 km I The complete data r,et for development of SSRS for Oyster Creek included the 20 horizontal components acqu red for the earthquakes identified above. SSRS for the complete data set l incorporating 73 horizontal component accelerograms were illustrated in the WGC September,1989 report on Figures 3.11 and 3.12. Parameters of this data set and results of l statistical analyses were summarized in Table 3.1.

Sensitivity to elimination of the 10 horizontal component accelerograms recorded in tall I buildings (e.g. earthquakes 6 through 8, above) was studied in the September,1989 report.

Results of this sensitivity computation were illustrated on Figures 3.13 and 3,14 of the SSRS report.

l Upon removal of the 10 accelerograms recorded in tall buildings, the remaining data set of 63 components included 10 necclerograms recorded at distances greater then 25 km (see pages 1 and 2 of Table 3.2, September,1989 SSRS report). RAI part (a) requests a similar g

sensitivity computation be performed on 53 components upon elimination of the 10 accelerograms (EQ No I through 5, above) recceded at distances greater than 25 km. It is I noted that the SSRS methodology employs a standard definition of the epicentral distance over which the maximum ground motion associated with an earthquake could reasonably be expected to occur. This range of epicentral distances was established in several preceding SSRS assessments, performed at other sites, to be 0 to 25 km. The identical epicentral l distance criterion of 0 to 25 km was advised by the NRC staff for development of the SSRS for Oyster Creek. The rationale for usage of several, more distant recordings will be discussed in the response to RAI part (b); this response to RAI part (a) provides results of I the requested sensitivity calculations.

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16190 06 22 I Weston Geophysical

I I Site Specific Response Spectra for the 53 horizontal component accelerograms requested to be used in RAI part (a) are illustrated on Figure RAl la.1. Shown on this iisure, as solid g

curves, are response spectra (at 5% of critical damping) corresponding to the minimum and maximum spectra in the data set, as well as the median (50th percentile) and median plus 1 I standard error (84th percentile) statistically derived response spectra. The 50th and 84th percentile spectra were computed assuming a log normal distribution of spectral ordinates.

l Plotted as a dotted curve on Figure RAl la 1 is the Oyster Creek SEP spectrum.

l To simplify observation of the effect of eliminating the 10 components recorded at epicentral distances greater than 25 km, response spectra are plotted on Figure RAl la 2 as spectral acceleration vs. frequency using linear axes. Shown on this figure are the Oyster Creek I SEP spectrum (dotted curve), the original 84th percentile spectrum (dashed curve) derived from 63 components (i.e. Figure 3.14 from the September,1989 SSRS report; 10 components from tall structures eliminated), and the recomputed 84th percentile spectrum (solid curve) derived from 53 components recorded at epicentral distances less than 25 km. The l consequence of eliminating the 10 components recorded at distances greater than 25 km is minor. The resultant 84th percentile spectrum is slightly higher at frequencies of about 4 to 20 bz, and somewhat lower at frequencies less than about 4 hz.

g In order to assign numerical values to the effects of this particular sensitivity computation, the ratio of 84th percentile response spectra was computed; this ratio is plotted on Figure RA1.la 3. The spectral ratio represents the result of using 53 components recorded at l distances less than 25 km (referred to as NEW spectrum), divided by the original result computed in the 1989 SSRS report using 63 components,10 of which were reported to have g epicentral distances greater than 25 km (referred to as OLD spectrum). At low frequencies from 0 to 4 hz, the NEW spectrum is below the OLD; the maximum reduction is about 13%

at a frequency of1.8 hz. At intermediate to higher frequencies in the band from 4 to 21.9 hz, the NEW 84th percentile spectrum marginally exceeds the OLD spectrum. The maximum amplitude of this exceedance is 4.5% at a frequency of 9.2 hz. At high frequencies of 21.9 to 25 hz the NEW spectrum islower than the OLD by less than 1%. In summary, the net effect of the requested SSRS recomputation is minor, and the maximum effect is exhibited as a 13% reduction of spectral acceleration at a low natural frequency of about 1.8 hz.

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In addition to the effects on the 84th percentile SSRS noted above, parameters of the 53 component NE'W spectrum differ from those of the original 63 component OLD spectrum supplied in Table 3.2 of the 1989 SSRS report. These differences include:

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16190 06 Weston Geophysico!

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NEW Spectrum OLD Spectrum (53 components) (63 components)

Mean Magnitude 5.2 Mt. 5.3 Mi, (standard error) 0.3 0.3 I Mean Epicentral Distance 11.0 km 14.4 km (standard error) 5.0 9.4 Median PGA 74.80 cm/s/s 75.85 cm/vs I 84th percentile PGA 156.00 cm/s/s 158.13 cm/s/s Pseudo-Velocities I hz (84th percentile) 5.48 in/s G.09 in/s l 10 hz (84th percentile) 25 bz(84th percentile) 2.03 in/s 0.42 in/s 1.95 in/s 0.42 in/s I The above summary of parameters demonstrates that removal of the 10 more distant accelerograms(> 25 km) has resulted in lowering of the mean magnitude of the data set, as I well as the low frequency end of the SSRS. These changes result from the relatively high magnitude and high amplitude spectra associated with the 10 more distant components.

. Parameters of the 10 components recorded at distances greater than 25 km are summarized on Table RAl-la 2. Characteristics of this data cet, eliminated to produce the NEW SSRS, include:

Mean Magnitude 5.5 Mi, I (standard error) 0.2 Mean Epicentral Distance 32.7 km (standard error) 4.9 I Median PG A 81.62 cm/s/s 84th percentile PG A 175.90 cm/s/s I

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16190 06 Weston C+20 physical

I Pseudo Velocities I hz(84th percentile) 8.15 in/s

- 10 bz(84th percentile 1,56 in/s I 25 bz (84th percentile) 0.46 in/s l This summary supports the conclusion that although the 10 components were recorded at distances reported to be greater than 25 km, they nonetheless generated response spectra 3

that ranked among the most conservative assembled for the purpose of developing an SSRS g

for Oyster Creek. Blind application of the 0 to 25 km epicentral distance constraint was questioned during preparation of the 1989 SSRS report. Instead, data were incorporated I such that a mean magnitude, equivalent to the target magnitude of 5.3 (+/ 0.5, or less),

was achieved. This procedure necessitated the incorporation of several marginally more i distant, higher magnitude events.

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. PROG 2AH AVGRS: Response SpeCtrua Statistics .

. OUTPUT FILE: HLT25KM. CUT .

. CATE: 27-3LT-9C TIMI: 11:03:52 PAGE 2 .

2L N DE SC RI P110N.. : 55R5 fer DCNG5: Spectra > 25 km. and free buildings >4 stories reeoved File E ar tbov ek e Ic en ti fic a tion Coer on en t Hs2nitude Gistance Docth PGA PSRV (in/sec)

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. 30TPUT FILE: HLT25KM. CUT .

. CATE: 2T-0CT-9C TIME: 11:03:52 PAGE 3 .

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N I M M M M M M M M M M M M M M M M M Table RAl-1a-1 (Cont'd)

. PRJG 2 AH AVGRS: R a spon s e Spectrua Statistics .

. JUTPui FILE: HLT25KH. CUT .

PAGE 4 .

. CATC: 2T-0CT-90 TIME: 11:03:52 RLM 3 ESC 21PTICN..: 55R5 for 3CNGS- Spectra > 25 k m. and from bulloinas >4 stories resowed Magnitude Cistence Docth PGA  ?$RV (in/sec)

File E ar tb au ak e Identification Component ha 25 to 1 Kr HL ke entsec/ set 50 OE 5.2 8.9 3.0 115.62 0.40 2.06 11.30 l WC0k83AH2.050 CONVICT CREEK MAMMOTH LAKE 5 EARTHJUAKE JANUARY 6, 198 00 DE 5.1 13.5 5.0 15.78 C.15 0.76 4.89 wCHP!V3H1.050 C3ALINGA CHP (TAPE FILE 26)

COALInGA AFTER5 HOCK (Ewent 83) JUNE 10.

90 DE 5.1 13.5 5.0 14.9T C.15 0.75 4.89 WC HPE V 3 H2. 0 5 0 C3ALINGA CHP (TAPE FILE 26)

C3ALINGA AFTERSHOCK (Ewent 83) JUNE 10.

90 DE 5.3 11.1 1C.0 153.4! C.42 3.46 1.36 l W C H PE V 4 H 1. 0 5 0 C3ALINGA CHP (TAPI FILE 28)

CDALINGA AFTERSHOCK (Event e4) JULT 9 00 CE 5.3 11.1 1C.0 172.24 0.44 2.39 2.21 W C HPE V 4H 2. 0 5 0 COALINGA CHP (TAPE FILE 23)

C3ALINGA AFTER$HDCK (Event s4) JULY 9.

90 DE 5.0 8.3 10.0 205.65 C.55 3.04 3.49 WC HPE W 6H1. 0 5 3 CCALINGA CHP (TAPE FILE 32)

CDALINGA AFTER$ HOCK (Event e6) JULY 21.

00 DE 5.0 8.3 10.0 115.99 0.33 1.21 1.75 WCHPEV6H2.050 COALINGA CHP (TAPE FILE 32)

C3ALINGA AFTER$HCCK (Ewant e6) JULY 21.

7.0 22.04 0.C9 0.56 0.81 WCHPEV3H1.050 00ALINGA CHP (TAPE FILE 36) 90 DE 5.3 9.3 C3ALINGA AFTER5 HOCK (Event e8) S E PTE M B E 00 CE 5.3 9.3 7.0 ;1.12 C.06 0.41 0.73 W C H PE V 8 H2. 0 5 0 C3ALINGA CHP (TAPE FILE 36)

C3ALINGA AFTERSHOCK (Event #8) SE P TE N SE 360 3.4 14.0 309.62 C.80 2.42 12.47 WC ePK 3 60.0 5 0 COMG 24400 Los ancelos Ote*2on Park 5.3 uhi t tie r Aftershock Oct 04, 8.4 14.0 323.2f 0.86 3.27 5.12 WC SP(2 T0.0 50 00HG 24400 L os Anceles Deregon Park 270 5.3 Whi t t ier Aftershock Oct 04, I

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5' 5.2 11.0 9.6 14.50 0.21 0.94 2.35 3 median values standard devistions: .86 t h percent 11es 0.3 5.3 59 155.00 0.42 2.03 5.45 O

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. P RJG R A M AVGR5! Response Spectrus Statist 1CS .

. JUTPUT FILI: H25KM.OUT .

. CATE: 2 T-JCT-90 IIMI: 12:3E:22 PAGE 1 .

OLN DE SCRIPTION..: 55RS For Scectra (10 c o m po n e n t s 3 with Cistences > 25 ke File E ar th qu ak e Identification Component MaRottude Castance Dacth PGA P5RW (in/sec)

HL km km cm/sec/sec 25 10 1 Hr WL301H1.050 U301 PUSLIC LIBRARY. HOLLISTER. TALIF h89W 5.2 29.3 16.0 153.61 0.51 1.43 7.75 NJRTHERN CALIFCENIA EARTHQUAKE HAR 9 Et301H2.050 U301 PUBLIC LIBRARYe HDLLISTER, CALIF $01W 5.2 29.3 16.0 119.44 0 30 0.92 5.95 N3RIMERN CALIFORNIA EARTHJUAKE MAR 9, W1287H1.050 T287 EL CENTRC. IPPE RI AL V ALL EY IRRIG NORTH 5.6 27.5 16.0 20.35 C.05 0.30 2.49 IMPERIAL VALLEY EARTHJDAKE JAN 23 195 W12 87H 2. 0 5 0 T287 EL CfNTRO. IPPERI AL V ALLEY IRRIG EAST 5.6 27.5 16.0 27.56 C.07 0.26 2.52 IMPERIAL VALLET EARTHQLAKE JAN 23. 195 Ob 3 05 H 1. 0 5 0 U305 PUBLIC LIBRARY. H OLLI STE R. CALIF N89W 5.4 36.2 If.G 12.02 C.13 0.40 1.91 CENTRAL CALIFORNIA 2ARTHQUAKE APR 25.

wL305H2.050 0305 PUBLIC LIBRARY. POLLISTER. C ALI F 3D1W 3.4 36.2 16.0 48.14 0.12 0.42 3.66 CENTRAL CALIFORNIA EARTHQUAKE APR 25 W A 018 H 1. 0 5 0 A019 HOLLISTER CITY HALL Sold 5.7 40.0 11.0 (3.41 0.17 0.56 7.39 H3tLISTER EARTHQUAKE AP2 8. 1961 - 23 W A 013 H 2. 0 5 0 A018 HOLLISTER CITY HALL h89W 5.7 40.0 11.0 115.52 C.45 1.39 8.07 H3LLISTER EARTH 3UAKE AP2 S, 1961 - 2' UL 312 H 1. 0 5 0 U312 CITY HALL. FE2NDALE, CALIFORNIA h46W 5.8 30.6 15.0 1L3.07 C.29 1.31 7.72 FERNDALE, CALIFORNIA. EARTHJUAKE DEC CO 312 H 2. 0 5 0 0 72 CITY HAtt. FERNDALE, CALIFORNIA 544W 5.8 3C.6 15.0 212.07 0.61 2.34 5.57 FL t NDAL E. CALIFORNIA. C A R T H OUA K E DEC g _-._----______..._.___ _____..__.._______________________.__ ..____________________ ________._. .._._... .._____.__..____._

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O 2 median values 5.5 32.7 14.8 11.52 0.21 0.73 4.69 q) s t an o ir d oeviationst .84t h percent 11es 0.2 4.9 2.0 115.9E C.46 1.56 8.15 m

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I SECTION 3 I RESPONSE TO RAI PART(B)

I RAI part (b) was transmitted as follows:

(Provide) "A more detailed discussion and pertinent documentation to substantiate l the statement on page 13 which resulted in a change of epicentral distances from more than 25 km to less than 25 km for twelve earthquake records."

I The verbatim statement on page 13 in the September,1989 SSRS report that prompted RAI part(b)is:

"A review of available data libraries identified 73 records generally meeting the l applicability criteria for OCNGS with epicentral distances of 0 to 40 km reported in standard catalogs. Twelve of these accelerograms, although having reported epicentral distances of greater than 25 km are determined to be applicable due to epicenterlocation uncertainty. Re-calculation of distance using alternative published locations resulted in epicentral distances in the speellied range of 25 km, or less."

The twelve earthquake records that have become the topic of RAI part (b) include the two horizontal component accelerograms generated by each of the carthquakes numbered 1 through 6 and previously listed in the response to RAI part (a). These earthquakes are l discussed individually in this response to part (b).

Earthquake of November 14,1941 This earthquake occurred in Los Angeles County, CA in the Torrence Ostdena area; hence I the event is usually referred to as the Torrence-Gardena earthquake. The maximum Modified Mercalli Intensity was evaluated to be VII-VIII; the magnitude for this event is 5.4 Mi.. Strong ground motion for this earthquake was recorded in the basement of the Los Angeles Chamber of Commerce Building, a 10 story, steel frame structure.

I To technically support the statement made on page 1-3 and respond to RAI part (b), location coordinates of the recording station, epicenter coordinates for the earthquake published in 16199 06 31 Weston Geophysical

available catalogs, and references for these coordinates, are recapitulated below. Also, epicentral distances between the accelerograph station and the various published epicenters are provided.

Accelerograph Station:

Los Angeles Chamber of Commerce:

Location: 34.04 N Latitude: 118.26 W Iongitude (Swita.er et al.,1990)

I Earthquake Epicenters:

Latitude longitude Distance (km) References j 1. 33.783 N 118.25 W 28.52 USEQ (1941)

Chang (1978)

2. 33.80 N 118.10 W 30.46 NUREG/CR 1660 EERL 76-02

3. 33.80 N 118.20 W 27.19 Krinitsky and Chang (1977)

NUIEG/CR 1660 The distance listed on Table 3.1 (WGC,1989 SSRS report) for this carthquake was 27,1 km; the reference for this distance was Krinitsky and Chang (1977). The small difference is I distance between that which was listed in the 1989 report and that recomputed above may result from more precision in coordinates of the station location used in this response. It is reiterated that this event, which was recorded in a 10 story structure, was included in the 73 component complete data set. This record, however, was not used in the 63 component data set including only records from low rise structures (4 stories, or less), nor was this record included in the 53 component data analyzed in response to RAI part (a).

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I l 16190 06 32 Weston Geophysical

I Earthquake of March 9,1949 I This rnagnitude 5.2 Mt, earthquake occurred in north-central California and produced a maximum intensity of VII at llollister. Strong ground motion was recorded at the Public Library Building in IIollister. Currently, the one story library building is re occupied as the Hollister City IIall. The accelerograph is located in the basement of the structure.

Accelerograph Station:

Hollister Public Library (also City llall):

I Location: 36.85 N Latitude;121.40 W Longitude (Switzer et al.,1990)

Earthquake Epicenters:

Latitude Longitude Distance (km) References I 1. 37.00 N 121.50 W 18.88 EHUS,ISS (1949)

2. 37.02 N 121.48 W 20.17 SMC AT (1.1)

USEQ (1949)

NUREG/CR 1660 l 3. 37.10 N 121.30 W 29.14 Chang (1978)

An epicentral distance of 29.3 km was listed in Tables 3.1 and 3.2 of the 1989 SSRS report.

The reference for the distance was Chang (1978). Recomputation of the epicentral distance using the epicentral coordinates given by Chang (1978) and the station coordinates (Switzer I et al.,1990) resulted in a slightly reduced epicentral distance of 29.14 km. It is noted that several other references list epicenters that result is distances that would fall within the 0 to 25 km epicentral distance constraint. The fact that the smallest epicentral distance was not routinely used during preparation of the 1989 SSRS report is discussed in the Summary l provided at the end of this section.

I 16190 06 33 W25!On GeophySICO!

Earthquake of January 23,1951 This earthquake occurred in southernmost California, near Calipatria. The maximum intensity was VII for this magnitude 5.6 MI, event. An accelerogram was recorded at ground level in the Imperial Valley Irrigation District building, a 2-story reinforced concrete facility. Currently, this installation has been incorporated as Station 9 of the El Centro Accelerograph Array.

Accelerograph Station:

g Imperial Vhlley Irrigation District (El Centro, Station 9):

Location: 32.794 N Latitude:115.549 W Longitude (Switzer et al.,1990)

Earthquake Epicenters:

l Latitude Longitude Distance (km) References 35.86 I 1. 33.12 N 115.57 W USEQ (1951)

NUREG/CR-1660 Vanmarcke and Lai(1977)

2. 33.20 N 115.70 W 47,19 ISS

3. 33.10 N 115.60 W 34.27 EHUS, SMC AT (1.1) g

4. 32.98 N 115.73 W 26.69 NUREG/CR-1660 EERL,Vol U Chang (1978)

As for the previous event, the standard catalog compiled by Chang (1978) was used as a reference for the epicentral distance of 27.5 km listed in the 1989 SSRS report.

Recomputation of the epicentral distance using the Chang's epicentral coordinates and Switzer's more precise station location, resulted in an epicentral distance of 26.69 km,just 16190-06 34 Weston Geophysical

I beyond the 25 km limit imposed for SSRS analyses. Other published epicenters resulted in greater distances, ranging to about 47 km.

Earthquake of April 25,1954 This earthquake occurred in central California, east of Watsonville. The maximum intensity was VIII for this magnitude 5.4 Mt, event. An accelerogram was recorded at the Hollister Public Library. This station was previously discussed in the section on the earthquake of March 9,1949.

Accelerograph Station:

g Hollister Public Library (also City Hall):

Location: 36.85 N Latitude; 121.40 W Longitude (Switzer et al.,1990)

Earthquake Epicenters:

Latitude 1 ongitude Distance (km) References

1. 36.93 N 121.68 W 26.49 USEQ (1954)

NUREG/CR 1660 ISS (1954) l SMCAT (1.1)

2. 36.80 N 121.80 W 36.11 Chang (1978) g Again, Gnang's standard catalog was used to assign an epicentral distance of 36.2 km to this I- earthquake. Recomputation, using more precision, resulted in an epicentral distance of 36.11 km. The alternative epicentral location, given by several references, results in an epicentral distance close to the 25 km limit for SSRS analyses.

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I 16190-06 35 Weston Geophysical

I Earthquake of April 08,1961 I This earthquake occurred about 13 miles south ofIlollister on the San Andreas Fault. The maximum intensity was reported to be VII and the magnitude was computed to be 5.7 M1,.

As for the earthquakes on March 9,1949 and April 25,1954, this event produced a strong motion record at the llollister Public Library.

Accelerograph Station:

IIollister Public Library (also City IIall):

Location: 36.85 N Latitude;121.40 W Longitude (Switzer et al.,1990)

Earthquake Epicenters:

Latitude Longitude Distance (km) References 1, 36.59 N 121.71 W 40.00 NUREG/CR-1660 EERL 76-02

2. 36.67 N 121.30 W 22.19 Chang (1978)

SMC AT (1,1)

3. 36.683 N 121.30 W 20.87 USEQ (1961)

ElIUS I The epicentral distance of 40 km, given in the 1989 SSRS report for this earthquake, was adopted from documentation accompanying California Institute of Technology, EERL, Vol II strong motion data. Recomputation of the epicentral distance provided the identical result. Epicentral coordinates given in other references result in substantially shorter epicentral distances, which conform to the SSRS distance criterion.

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36 I 16190 06 Weston Geophysical

Earthquake of December 10,1967 The December 10,1967 earthquake occurred near the coast of northern California and was felt principally in Humboldt County. The magnitude of this carthquake is 5.8 Mt. Strong ground motion was recorded at ground level of the Ferndale City Hall, a two story, wood.

frame building. Currently, the Ferndale City Hall accelerograph installation is one element of the Eel River Valley strong motion array, operated by the U. S. Geological Survey.

Accelerograph Station:

I Ferndale City Hall (also Eel River Valley Array station)

Location: 40.576 N Latitude;124.262 W Longitude (Switzer et al.,1990)

Earthquake Epicenters:

Latitude Longitude Distance (km) References

1. 40.50 N 124.60 W 29.90 NUREG/CR-1660 USEQ (1967)

Chang (1978)

EHUS I 2. 40.58 N 124.53 W 22.70 NUREG/CR-1660 USGS (78-941)

3. 40.49 N 124.69 W 37.50 NUREG/CR-1660

4. 40.50 N 124.70 W 38.10 SMC AT(1,1)

As for several previous earthquakes, the epicentral distance of 30.6 km given in the 1989 l SSRS report, was taken from the Chang catalog. Recomputation of the distance using the epicenter published by Chang resulted in a distance of 29.90 km. Other published I 16190 06 37 weston Geophysicci

I epleenters result in epicentral distances that fall within and beyond the 25 km distance g limit.

Summary I

The previous discussions highlight the epicentral location uncertainty associated with older h events which were used in derivation of SSRS in the September,1989 report. Tables included in the SSRS report contained a single epicentral distance, typically taken from standard published catalogs, such as Chang (1978), or the California Institute of Technology

_l reports that accompany a particular accelerogram data tape. The most accurate epicentral location, and consequently the resulting most reliable epicentral distance to an individual accelerograph site are not easily selected from the differing published locations. The procedure followed in SSRS derivations was to acknowledge that epicentral uncertainty I- crists, that the "true" location is not known, and likely cannot be further refined based on the number and distribution of seismographs that existed from 50 to 20 years ago. Given l this situation, a record was ultimately selected for use in the SSRS analyses on the basis that certain determinations of epicentral distance, were within, or very close (i.e. about 10%) to the specified distance limit of 25 km.

References CODE Reference

, Chang (1978)' Chang, F.K.,1978, Catalog of strong motion earthquake records, Western United States, Vol.1, State of the Art for Assessing Earthquake Hazards in the United States, Report 9, U.S. Army Waterways Experiment Station, Vicksburg, MS,28p.

EERL 76 02 Strong Motion Earthquake Accelerograms, Index Volume,1976, Caltech, Report No. EERL 76-02,72 p.

EHUS Coffman, J.L., von Hake, C.A., and Stover C., Earthquake History of the United States, Publication 41-1, US. Department of Commerce, NOAA, and the US Department of the Interior, Geological Survey, 208 p.

I 16190-06 38 weston Geophysical

I I. ISS International Seismological Summary, 1949, 1951, 1954, International Geodetic and Geophysical Union, Association of Seismology, I Krinitsky and Krinitsky, E.L. and Chang, F.K.,1977, Specifying Peak Motions for Chang (1977) Design Earthquakes, State of the Art for Assessing Earthquake h Hazards in the United States, Report 7, U.S. Army Waterways Experiment Station, Vicksburg, MS,34 p.

l I NUREG/CR-1660 Crouse, C.B., Hileman, J.A.. Turner, B.E. and Martin, G.R.,1980, Compilation, assessment and expansion of the strong earthquake ground motion data base, Seismic Safety Margins Research Program (SSMRP), NUREG/CR 1660, UCRL 15227, prepared for Office of I Nuclear Regulatory Research, US Nuclear Regulatory Commission, Washington, DC,125 p.

SMCAT(1.1) Row, L.W. III,1989, An carthquake strong motion data catalog for personal computers, SMCAT, release 1.1, World Data Center A for Solid Earth Geophysics, National Geophysical Data Center,47 p., (3) 51/4" magnetic disks.

I USEQ Unites States Earthquakes, 1941,1949,1951,1954,1961,1967, US.

Department of Commerce, Coast and Geodetic Survey, Washington, DC.

I Vanmarcke and Vanmarcke, E.H. and Lai, S.S.P.,1977, Duration characteristin of horizontal components of strong motion earthquake records, I Lai(1977)

Publication No. R77-16, MIT,32 p.

Switzer, J. Johnson, D., and Maley, R.,1990, Western Hemisphere Accelerograph Station List,1990, United States Department of the l Interior, Geological Survey, Open File Report.

I I 16190 00 39 Weston Geophysico!

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APl'ENDIX A US NitC 11Al parts (a) and (b)

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I I WCSton Geophysical

/,$pa esegI4., UNITED sT ATEs t ,y

i er j NUCLEAR REGULATORY COMMISSION WW A$HINGTON. D. C. 20665 September 20. 1990

%....*/ ,,; n MO Docket No. 50-219 g

Hr. E. E. FitzPatrick I Vice President and Director Oyster Creek Nuclear Generating Station P. O. Box 388 l Forked River, New Jersey 08731

Dear Mr. FitzPatrick:

f

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION CONCERNING SITE SPECIFIC RESPONSE SPECTRA - OYSTER CREEK NUCLEAR GENERATING STATION (TAC MO. 68217)

-l By letter dated October 11, 1989, GPU Nuclear Corporation provided a report j prepared by Weston Geophysical Corporation entitled " Site Specific Response Spectra - Oyster Creek Nuclear Generating Station" for our review. The staff i has reviewed the information and has determined that additional information is required in order for the staff to complete its review. The specific information requested is presented in the enclosure. , , ,

We request that the information be provided within ',0 days of receipt of this letter. If you have any questions regarding this request, please contact me.

, The reporting and/or recordkeeping requirements contained in this letter 4 affect fewer than 10 respondents; therefore; OMB clearance is not required under PL.97-511.

-J-l '

Sincerely, I ,

u42s4 Alexander W. Dromerick, Senior Project Manager Project Directorate I-4 Division of Reactor Projects - 1/11

'I

Enclosure:

Office of Nuclear Reactor Regulation As stated cc w/ enclosure:

DISTRIBUTE TO: bhO VW4 kA6k JOB FILE 6 EL X MB D'A PT CHRONO. Cf VM X KB DG MJ ACCT G RH X PF JR

.I Cl FILE OA FILE X LD ER KS PS GH PH GK )( !

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Mr. E. E. Fitzpatrick Oyster Creek Nuclear

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j Oyster Creek Muclear Generating Station Generating Station

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cc:

Ernest L. Blake, Jr. Resident Inspector I shaw, Pittman, Potts and Trowbridge 2300 N Street, NW Washington, D.C. 20037 c/o U.S. MRC Post Office Box 445 Forked River, New Jersey 08731 I I. H. Jolles, Executive Vice President Cosmissioner New Jersey Department of Energy s

GPU senior Corporation ig 100 Interpace Parkway 101 Commerce Street ju Newark, New Jersey 07102 Parsipanny, New Jersey 07054 i Regional Administrator, Region 1 Kent Tosch Chief i New Jersey, Department of Environmental U.S. Nuclear Regulatory Commission Protection )

475 Allendale Road King of Prussia, Pennsylvania 19406 Bureau of Nuclear Engineering CN 415 Trenton, New Jersey 08625 -

BWR Licensin Manager

GPU Nuclear orporation 1 Upper Pond Road '

! Parsippany', New Jersey 07054

Mayor Lacey Township 818 West Lacey Road Forked River, New Jersey 08731 Licensing Manager Cyster Creek Nuclear Generating Station '

j I Mail Stop: Site Emergency 816g.

P. 0. Box 388 Forked River, New Jersey 08731  !

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l l' ENCLOSURE I

REQUEST FOR AD01T10tlAL INFORMATION I SITE SPECIFIC RESPON5E SPECTRA OYSTER CREEK NUCLEAR GENERATING STATION Criteria recomended by the NRC for developing the Oyster Creek Site Specific Response Spectra (SSRS) specified the use of earthquake records from earthquakes

-E with epicentral distances of 25 km or less. Table 3.1 of the below referenced 5 document lists 12 records of earthquakes with distances greater than 25 km.

+

'Please provide the following additional information:

I '

(a) Construct SSRS similar to those shown on figures 3.13 and 3.14 from 53 records listed in Table 3.1, eliminating 10 records from buildings with more than four stories and 10 records from earthquakes with epicentral distances greater than 25 km, recorded at structures with j four stories or less.

!B (b) A more detailed discussion and pertinent documentation to

E substantiate the statement on page 1-3 which resulted in a change of

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epicentral distances from more than 25 km to less than 25 km for

, as twelve earthquake records.

'J Reference Document: Weston Geophysical Corporation Report " Site Specific -

I Oyster Creek Nuclear Generating Station" September,1989.

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