ML13303A700

Forwards Summary of 790403-05 Geological Site Visit

ML13303A700
Person / Time
Site:	San Onofre
Issue date:	05/17/1979
From:	Rood H Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
Shared Package
ML13303A701	List: ML13303A700
References
NUDOCS 7906250059
Download: ML13303A700 (12)

Text

16Y1al DOCKET NOS. 50-361 AND 50-362 APPLICANTS: SOUTHERN CALIFORNIA EDISON COMPANY SAN DIEGO GAS AND ELECTRIC COMPANY FACILITY:

SAN ONOFRE NUCLEAR GENERATING STATION, UNITS 2 AND 3

SUMMARY

OF GEOLOGY FIELD TRIP The enclosed memorandum summarizes the geology field trip conducted on April 3, 4, and 5, 1979, to the San Onofre site.

Ofigina I Signed by Ha RR Harky -Rood Light Water Reactors Branch No. 2 Division of Project Management

Enclosure:

As Stated ccs w/enclosure:

See next page 600

.PJA. :.L11.R. #2 DM*:.IJW.R 2

GUANAME

.. RkQ d:.ab t..

..U p j..............................

O.M.18....6.

R ad

b.

...RI...........

DATE ->

... 5/17/79 5/(7/7 NEC WORM 318 (9-76) NRCH 0240 U.S. oovaRNMnu RITN OPasuC1s o

1970sae 2a5 -79

MWY 1 7 197q Mr. James H. Drake Vice President Southern California Edison Company 2244 Walnut Grove Avenue P. 0. Box 800 Rosemead, California 91770 Mr. B. W. Gilman Senior Vice President - Operations San Diego Gas and Electric Company 101 Ash Street P. 0. Box 1831 San Diego, California 92112 cc:

Charles R. Kocher, Esq.

James A. Beoletto, Esq.

Southern California Edison Company 2244 Walnut Grove Avenue P. 0. Box 800 Rosemead, California 91770 Chickering and Gregory ATTN: David R. Pigott, Esq.

Counsel for San Diego Gas

& Electric Company and Southern California Edison Company Three Embarcadero Center, 23rd Floor San Francisco, California 94112 Mr. Kenneth E. Carr City Manager City of San Clemente 100 Avenido Presidio San Clemente, California 92672 Alan R. Watts,.Esq.

Rourke & Woodruff 1055 North Main Street Suite 1020 Santa Ana, California 92701 Lawrence Q. Garcia, Esq.

California Public Utilities Commission 5066 State Building San Francisco, California 94102

MAY 71RX Mr. James H. Drake Mr. B. W. Gi man cc: Mr. R. W. DeVane, Jr.

Combustion Engineering, Inc.

1000 Prospect Hill Road Windsor, Connecticut 06095 Mr. P. Dragolovich Bechtel Power Corporation P. 0. Box 60860, Terminal Annex Los Angeles, California 90060 Mr. Mark Medford Southern California Edison Company 2244 Walnut Grove Avenue P. 0. Box 800 Rosemead, California 91770 Henry Peters.

San Diego Gas & Electric Company Post Office Box 1831 San Diego, California 92112 Ms.

Lyn Harris Hicks Advocate for GUARD 3908 Calle Ariana San Clemente, California 92672 Richard J. Wharton, Esq.

4655 Cass Street, Suite 304 San Diego, California 92109 Phyllis M. Gallagher, Esq.

Suite 220 615 Civic Center Drive West Santa Ana, California 92701 Mr. Robert J. Pate United States Nuclear Regulatory Commission P. 0. Box 4167 San Clemente, California 92672

ENCLOSURE UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 4

RAY 3 1979 Docket Nos. 50-361 & 50-362 MEMORANDUM FOR: Robert E. Jackson, Acting Chief Goosciences Branch, DSE FROM:

Tom Cardone, Geologist Geosciences Branch, DSE Phyllis Sobel, Seismologist Geosciences Branch, DSE

SUBJECT:

SAN ONOFRE UNITS 2 AND 3 GEOLOGY FIELD TRIP On April 3, 4 and 5, 1979, representatives of the U. S. Nuclear Regulatory Commission (NRC), Southern California Edison Company (SCEC) and its consultants, and the California Division of Mines and Geology (CDMG) met to discuss and observe the regional and site geology near the San Onofre Nuclear Power Stations. A list of attendees at the April 3 meeting is enclosed. SCEC presented information which responded to NRC questions 361.35 and 361.36 in Amendment 14 to the FSAR, and addressed the geologic and seismic comments in the January 16, 1979 letter from James Davis, CDMG to J. Carl Stepp, NRC.

On April 3 geology presentations were made by the SCEC staff and consultants. The information presented was an elaboration of the data and information cont ned in the March 16, 1979 submittal to NRC by SCEC. Dr. Perry Ehlig described the geology and tectonics of the Capistrano Embayment area and the Newport-Inglewood Fault Zone.

Dr. Roy Shlemon presented the results of his study of coastal de formation rates based on an evaluation of the elevation of Late Quaternary (70,000-125,000 years before present) stratigraphic markers.

Jim McNey described minor unmapped faults located in the Capistrano Embayment which were discovered during the aerial photolineament analysis and provided answers to each of CDMG's written comments to NRC. A copy of the CDMG letter is enclosed. A brief summation of SCEC's answers to the CDMG questions were as follows:

1. SCEC believes the feature common to Horno and Dead Dog Canyons, which are approximately one quarter of a mile apart, is.a land slide and is at least 125,000 years old, since it is truncated by Terrace I as discussed by Roy Shlemon. The Target Canyon planar features are unrelated to deformation in the area and to the the features seen in Horno and Dead Dog Canyons. They are the result of differential consolidation and landsliding.

R. MAY 97

2. The features found during excavation (A, B, C, and 0 features) are not significant to the seismic design. They are all trunca ted by Terrace 1 and are, therefore, not capable within the meaning of Appendix A to 10 CFR Part 100.

3. Vibroseis studies could not detect small offsets on possible faults associated with the moderate earthquakes that occur in the region.

4. Sulphur Creek does show a change in the direction of stream flow. The evidence indicates that landslides dammed Sulphur Creek, causing the change in direction of stream flow.

5. SCEC agrees with CDMG that aeromagnetic data does not show a change in the basement rock complex across the Christianitos fault as was indicated on page 12 of "Recent Geotechnical Studies, Southern Orange County, California, February 16, 1976, Vol. II," by SCEC.

6. SCEC agrees that the Bouguer gravity data does change across the continent-ocean boundary..However, SCEC still believes the Mesozoic subduction zone is a valid theory.

CDMG did not-indicate a need for additional information at this time and we believe that SCEC's answers were generally adequate and should aid us in responding to Dr. Davis's questions to NRC.

Dr. Ehlig discussed current uplift and regional compressional patterns and indicated that he had not found any active faults in the embayment during mapping or as-a result of ground truth assessment of the lineament study. Jack West reviewed data relating to subsurface structure in the site area and concluded that most tectonic movement was pre-Pliocene, and that all movement was pre-late Pleistocene based on his interpretation of oil well logs and seismic reflection profiles.

On April 4 we took a helicopter overflight of the area and a bus and foot tour of the areas of interest. During the helicopter reconnaissance we observed Target and Horno canyons, the Christianitos fault, the bluffs along the coast that contain the marine terrace markers, the Newport Inglewood fault zone, the Cherry Hill fdult, the Pelican Hill fault zone, and the Shady Canyon fault. On the bus tour we observed:

R. AY 3 1979

1. An outcrop of Capistrano siltstone.

2. Several previously unmapped faults found in the Capistrano Embay ment.

3. Landfill consisting of material from the San Mateo formation in contact with continental sediments, which had given the appearance of the possible presence of recent faulting near the construction site. The emplaced landfill sand had recompacted itself to appear very much like the original San Mateo deposit which occurs in the area.

4. Outcrops of the stage 5e sea level (Terrace 1) (age - 70,000 to 80,000 y.b.p.) above the San Mateo formation north of the plant along the beach.

5. Channel features in the sea cliffs at San Clemente State Beach.

6. Terrace deposits and shoreline angles at Dana Point.

On April 5 we walked to Horno, Dead Dog, and Target canyons. At Horno and Dead Dog canyons, SCEC interpreted the features observed in both canyons as the backscarp of a landslide based on the normal displacement toward the sea.

CDMG geologists indicated that these fractures could be associated with a fault which extends through the three canyons and might control the straitness of the shoreline in this area..It was also observed that these offset features, which are approximately 6 miles from the site, whether due to either landslide or faulting, are capped by Terrace 1 which is at least 125,000 years old, and are not capable faults within the meaning of Appendix A to 10 CFR 100.

At Target canyon, the fault offset type features observed differ somewhat in character from those observed in the other two canyons.

The Target canyon features are more linear which could argue against a landslide origin and appear to offset by approximately 2 inches the 125,000 year old terrace deposits. These offsets appear to be small and are about 6 miles from the site. SCEC indicated that this feature also has a landslide origin and even if they have a fault origin the distance from the site precludes them from being significant to the seismic design of the San Onofre plant structures.

R.

MAY 21979 In summary, through oral presentations and helicopter, bus and foot reconnaissance, SCEC presented analyses of a number of significant geologic structures which had not been address during the CP review, but which have been extensively studied during the OL review.

Tom Cardone, Geologist Geosciences Branch Division of Site Safety and Environmental Analysis Phyllis Sobel, Seismologist Geosciences Branch Division of Site Safety and Environmental Analysis

Enclosures:

As stated cc: w/enclosure H. Rood L. Heller L. Reiter J. Greeves P. Sobel T. Cardone PDR Local POR

nf~ O:Le 1. ALendance at April 3, 1979 I-RC site visit o

-an Onofro 2 and 3-Geology SCE 1M.0.

1.'e d fo rd J. L.

McNey P.

J. West Jim Beoletto David R. Pigott Shawn Biehler, consultant H. Gene Hawkins J. S. Andres H. Peters Roy Schlemon, consultant P. Ehlig, consultant J. L. Smith, consultant J. C. West, consultant NRC Tom Cardone Phyllis Sobel H. Rood S.S. Philbrick (ACRS)

Gary R. Quittschreiber (ACRS)

CDMG Perry Y. Ajqimoto Siang S. Tan GUARD Phyllis M4. Gallagher, atty.

FOE Grey Garrett for Richard Wharten

TAIE CF C.'i<

,.A l-7 E~Y E

P

)EPAT.-INT OF CGONSF;:vA1iON

)1VISION OF MINES AND GEOLOGY

)IVISION HEADQUARTERS 416 NINTH STREET, RCOM 1341 3

ACRAPENTO, CA 9L314 Phone 91 t 1

.4Ik25j janu 11ry 16, 1979 J. Carl Stepp, Chief Geology and Seismology Branch Division of Site Safety and Environmental Analysis U.S.

Nuclear Regulatory Commission Washington, D.C.

20555

Subject:

San Onofre Nuclear Station Review

Dear Carl:

The comments on the geologic and seismic review of reports on San Onofre Nuclear Station were prepared by our staff, Siang S.

Tan (geologist) and Gordon W. Chase (geophysicist).

The reviewed reports were the following:

1. Amendment #11 PSAR (Preliminary Safety Analysis Report)

March, 1972, SCE and SDG & E.

2. Recent Geotechnical Studies -

Southern Orange County California, Vol.

1 and 2, February,

1976, SCE and SDG 5 E.

3. Final Safety Analysis Report, Vol. 3 -

App. 2.5, March, 1977, SCE and SDG & E.

4.

Final Safety Analysis Report, Vol. 4 -

App. 2.58, SCE and SDG S F.

5. Geotechnical Studies No. San Diego County, California, October, 1977, SCE and SDG 5 E.

6. Amendment #52, Final Safety Analysis Report, December, 1977, SCE and SDG.&

E.

7. Analysis of Geological Features at the San Onofre Nuclear

-Generating Station, July, 1974, Fugro.

8. Analysis of C & T Type Features at the San Onofre Nuclear Generating Station, November, 1974, Fugro.

9. Final Report on Geological Features at the San Onofre Nuclear Generating Station Unit 2 and 3, August, 1976, Fugro.

1f.

Safety Evaluation of the Geological Features at the Site of the San Onofre, July, 1975, USNRC.

Carl Stepp, Chief J3 o EI

3. Further studies aire suggested to deterine whether the reported r~

(pr - t.I n

S IU J c

'l

n 1 J F:: t 2

t

t. IY l o Canyon area, S miles south of the reactor site, (as reported by Fugro, Inc.

and P.

L. Ehlig) are definitely created by landsliding and not by faulting or a combination of tectonic and subsequent landsliding.

Is the ancient landslide feature exposed at the sea bluff?

Or is it thought to be concealed by one of the younger slope failures at the sea cliff?

If it is considered to be of tectonic origin, it may not be exposed at the sea bluff as it parallels the shoreline.

Similarly, any fault trending parallel to the coast could not be exposed anywhere else since as a vast area along the coast of this region is underlain by thick terrace deposits which are not intersected by drainage channels, deeply eroded into the underlying bedrock, except for the two canyons where these features were reported.

It is important to consider the possible occurrence of faults along the coastline as they parallel the offshore southern extension of the Newport-Inglewood fault zone.

These possible faults may be related to the late Quaternary displacements found more to the south, in the Target Canyon.

Any feasible geophysical exploration (such as deep seismic profiling, vibro seismic, etc.) and digitized method of providing computerized printout of seismic data showing continuous geologic structure along the profile, which allows the interpretation of structure underneath the coastal terrace deposits, will be very useful in evaluating the possibility of the presence of onshore faults paralleling the Newport-Inglewood fault zone.

2.

The nuclear stations are underlain by a couple of sets of.fractures and shear joints, particularly Unit 1. These features. are exposed at the surface after up to 85 feet overburden was removed; they may experience greater seismic shaking effects than when they were still buried, although they do not separate different lithologies.

It seems that many of these joint features are well cemented and are normally not open fissures, but no careful study of the characteristics of these failure features which.

relates them to potential rupture due to seismic shaking was ever performed.

3. Offshore subsurface studies of the CaDistrano embayment. indicate that several significant faults may underlie the general vicinity of the site, as reported by J. C. West. Although these faults do not show any evidence of HQlocene or Pleistocene movement or high seismicity, more detailed subsurface studies, deep seismic or vibroseismic exploration and computerized profiles of seismic data showing continuous structure may reveal some explanation of the origin and significance of small earthquakes in the.region.

i sii1call active t"s may not cko:: any distinct Holocene

.>COFCJ~~~~~~~~~t evck c

],t10--

L

-- ~>:

-ls" ll erh Zr 1

C a

Carl Stcpp, Chief 3

4. Some geomorphologic fCatures indicatinp possible recent uplift mov:: nts 1:-

pr7Cnt in the C2>, st 1--

t The Sulphur Creek seems to have changed its strelm flow direction and drainage. course but this phenomenon could also be explained by a blockage of drainage due to land sliding.

Further studies of these features as related to recent tectonics are recommended.

5. On page 12 in "Recent Geotechnical Studies, Southern Orange County, Calfiornia, February 1976, Vol. II, portions of enclosure A" the following statement is made:

"The aero magnetic map indicates there is a change in the basement rock complex from the east to west side of the Christianitos fault."

The amount of aeromagnetic data east of the fault is not sufficient to develop this conclusion.

6.

Regarding "(Amendment No.

11 to PSAR Unit 2 and 3, March 1972)"

the offshore gravity and magnetic data do not appear to con flict with the associated acoustic sections.

Using current geologic interpretations, the term "Southern California Mesozoic Subduction Zone" (gravity map and text) may be doubtful at this time.

The Bouguer gravity data generally has a transformation from minus to plus values across the continental to oceanic boundary.

We hope these comments will be helpful in the preparation of your forthcoming geologic review on San Onofre Nuclear Station.

Sinc ly, Jr cm s F. Day s tate Geologist cc:

Priscilla Grew Perry Y. Amimoto

Meeting Summary Docket File J. Knight NRC PDR S. Hanauer Local PDR R. Tedesco TIC R. Bosnak NRR Reading S. Pawlicki LWR #2 File F. Schauer E. Case K. Kniel D. Bunch T. Novak R. S. Boyd Z. Rosztoczy D. F. Ross W. Butler D. B. Vassallo V. Benaroya D. Skovholt R. Satterfield W. Gammill V. Moore J. Stolz M. Ernst R. Baer F. Rosa

0. Parr R. Denise S. Varga EP Branch Chief C. Heltemes G. Chipman W. Haass J. Collins R. Houston W. Kreger L. Crocker G. Lear D. Crutchfield B. Youngblood F. J. Williams L. Hulman R. J. Mattson NRC

Participants:

R. DeYoung T. Cardone Project Manager -

H. Rood P. Sobel Attorney, ELD S. Philbrick J. Lee G. Quittschreiber IE(3)

ACRS(16)

R. Denise L. Rubenstein