ML19305D375
| ML19305D375 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay |
| Issue date: | 03/21/1980 |
| From: | Locke R PACIFIC GAS & ELECTRIC CO. |
| To: | Lazo R Atomic Safety and Licensing Board Panel |
| References | |
| NUDOCS 8004150003 | |
| Download: ML19305D375 (6) | |
Text
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o PACIFIC GAS AND ELECTR,IC C O M PANY bbW2' l
77 BEALE STREET,31ST FLOOR. S AN FR ANCISCO, C ALIFORNI A 94106 (415) 781 4211
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March 21, 1980
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Robert M.
Lazo, Esq., Chairman
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Atomic Safety and Licensing Board Panel U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Re:
In the Matter of Pacific Gas and Electric Company (Humboldt Bay Power Plant, Unit No. 3) Docket No. 50-133, License No. DPR-7
Dear Mr. Lazo:
In accordance with the Board's Order of June 19, 1979, Pacific Gas and Electric Company ("PGandE") hereby submits a Report by its consultants, Woodward-Clyde Consultants, outlining the status of the geologic and seismic investigations involving the Humboldt Bay Power Plant, Unit No. 3 together with an outline of the work accomplished during January-February 1980.
The tasks identified in this Report are more fully described in a document entitled Scope of Work for Geological and Seismological Studies in the Humboldt Bay Region, dated September 1, 1979, which was attached to PGandE's pending Motion to Hold in Abeyance filed on September 26, 1979.
Very truly yours, MALCOLM H.
FURBUSH PHILIP A.
CRANE RICHARD F.
LOCKE By RICHARD F.
LOCKE RFL:sls cc:
Bruce Norton, Esq.
Enclosure 8004150 oQ
'v UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter of
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PACIFIC GAS AND ELECTRIC COMPANY
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Docket No. 50-133 l
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License No. DPR-7 (Humboldt Bay Power Plant, Unit No. 3)
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l CERTIFICATE OF SERVICE The foregoing document of Pacific Gas and Electric Company has been served today on the following by deposit in the United States mail, properly stamped and addressed:
I Linda J. Brown, Esq.
- Robert M.
Lazo, Esq., Chairman 100 Van Ness Avenue, 19th Floor Atomic Safety and Licensing San Francisco, CA 94102 Board Panel U.S.
Nuclear Regulatory Commission
- Steve Goldberg, Esq.
Washington, D.C.
20555 Office of Executive Legal Director Mr. Gustave A.
Linenberger, Member BETH 042 Atomic Safety and Licensing U.S. Nuclear Regulatory Board Panel Commission U.S.
Nuclear Regulatory Commission Washington, D.C.
20555 Washington, D.C.
20555
- Secretary Dr. David R.
Schink U.S. Nuclear Regulatory Department of Oceanography Commission Texas A & M University
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Washington, D.C.
20555 College Station, TX 77840 Attn:
Docketing and Service Section Michael R.
Sherwood, Esq.
Sierra Club Legal Defense Fund, Inc.
311 California Street, Suite 311 San Francisco, CA 94104 Dated:
March 21, 1980 J
RICHARD F.
LOCKE Attorney h
Pacific Gas and Electric Company
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Woodward Clyde Consultants
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415-956-7070 13976F-5216.1,5216.2 156 March 14, 1980 Mr. Frank Brady Pacific Gas and Electric Company 77 Beale Street, Room 2611 San Francisco, California 94106
Dear Frank:
Subject:
Progress During January and February, 1980 -
Geologic and Seismologic Studies, Humboldt Bay Review This report summarizes the geologic and seismologic investigations for the Humboldt Bay Power Plant during January and February,1980.
During the period, regional age dating, late Quaternary studies, deep boring at the site, and acquisition and analysis of strong motion data continued.
Seismologic data analysis and earthquake ground motion studies were begun.
The purpose of the studies was to obtain additional information on the geologic structure at the site and its relationship to regional tectonics.
Specific tasks included the following:
1)
Regional Geologic Mapping and Age Dating 2)
Late Quaternary Geologic Studies and Fault Capability Evaluation 3)
Identification of Faults in the Site Locality 4)
Geophysical Data Analysis 5)
Seismologic Data Analysis 6)
Site Specific Earthquake Characteristics 7)
Earthquake Ground Motion These tasks are described in the Scope of Work for Geological and Seismological Studies in the Humboldt Bay Region, dated September 1,1979.
The progress made during the period on each of these tasks is summarized below.
Regional Geologic Mapping and Age Dating Work continued on radiometric dating, trace element analysis, and the preparation of interim summaries of existing data.
Recently purchased seismic data has defined offshore structural features, and a review of the literature concerning the origin of these structures was begun.
Preparations were made for field mapping and sample collection which will resume in March.
l Consulting Engineers. Geologists and Environrnental Scientists Offices in Other Pnncipal Cit es i
Mr. Frenk Brcdy Woodward Clyde Consultant 3 March 14, 1980 Page 2 Late Quaternary Geologic Studies and Fault Capability Evalution s
Geologic data from the Trinidad and Goose Lake exploration localities were synthesized and the results of the detailed mapping, topographic profiling, and trenching at these sites were summarized.
Soil test pits were excavated on the displaced late Quaternary marine terrace at the McKinleyvi]1e airport 28 km north of the plant site.
Two overlapping trenches, 3 to 5 m deep and having a combined length of 90 to 95 m, were excavated across the 6-to 8-m-high fault scarp.
The soil profiles exposed in the test pits were described and sampled, and the trenches were logged.
Soil test pits and two 18-meter-long trenches were also excavated and logged at College of the Redwoods 5 km south of the Humboldt Bay Power Plant.
The 3-to 5-m-deep trenches cross a topographic lineament and the projected trace of a steeply dipping contact between clay and gravel that was observed in outcrops.
The trenches exposed a low angle thrust fault.
Analysis of aerial photographs to identify lineaments that may be coincident with late Quaternary faults continued at the McKinleyville area and along the Little Salmon Fault between Hydesville and the plant site.
Large scale lineament maps were being compiled for each of the fault capability exploration localities.
A smaller scale map showing the regional pattern of lineaments will be compiled from high-altitude U-2 imagery.
Identification of Faults in the Site Locality Drilling operations continued in the site vicinity during the reporting period.
Boring WCC-12 (previously designated Boring 9 in the Scope of Work) in the Fields Landing area was completed to its revised target depth of 3148 feet.
South of Fields Landing, Boring WCC-18 (previously designated, but unnumbered in the Scope of Work) was drilled to its revised target depth of 1750 feet at its revised location northeast (rather than southeast) of Boring A-3.
Suites of geophysical logs have been obtained in the borings; spontaneous potential, resistivity, gamma ray, and caliper logs have been obtained in both borings, and sonic, neutron, formation density and high resolution dipmeter logs have also been obtained in Boring WCC-12.
Geophysical Data Analysis The data collected in November 1979 at the site and at Fields Landing were processed between December 1979 and February
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Mr. Frank Brady Woodward.Clyde Consultants March 14, 1980 Page 3 y
1980.
Stacked sections were prepared by a consulting processing group in Denver and line 21 near the plant was m ig ra ted.
The sections of ref2ection data on lines 10, 11, 12, and 21 were being interpreted using the logging data from the available wells to mark horizons.
The 250 miles of reflection data offshore from Humboldt Bay obtained from Western Geophysical were interpreted in January and February.
Four horizons were selected, and were tracked along profiles and tied along cross lines to produce phantom horizon sections.
Structures interpreted as faults were identified on each profile and were connected between lines where suggested by the data.
Areas where there was an absence of structure were also mapped on each platform horizon.
Contour maps of the bathymetric data, water bottom reflectors and beds conformal with the Hookton and Wilcat were prepared.
Seismologic Data Analysis The analysis of the crustal structure in the region including the plant site and the Mendocino escarpment was continued by refining the analysis of the refraction velocities obtainad from the offshore blasts, and by including selected earthquake sources located at the northeast and southeast corners of the region containing network control.
Data were obtained from Tera Corporation in Berkeley to begin assessing the crustal parameters and details of the seismicity in the vicinity of the plant site.
Selected focal mechanisms have been reviewed and identified for further study.
Site Specific Earthquake Characteristics Collection and analysis of strong motion data has continued with a reduced number of recording stations.
Five of the recorders were removed from the recording network in order to prepare two instruments for the down-hole versus surface (free field) recording experiment near HB3.
The remaining digital event recorders are undergoing system maintenance consisting of calibration and repairs.
A preliminary analysis on all of the data for the period from October 1979 through January 1980 neared completion.
Results of corrected digital records for selected earthquakes which occurred prior to October 1979 were being reviewed and verified based on the outcome of calibration studies being completed with input from the instrument supplier.
Earthquake Ground Motion A review of previously obtained Standard Penetration Test (SPT) data was begun to assess the need for additional SPT 1
Mr. Frenk Brcdy Woodward Clyde Consultants March 14, 1980 g
Page 4 data at the plant site.
Specifications and procedures were being prepared for the in situ shear wave measurement program.
Data recorded during the October 1979 Imperial Valley earthquake were being obtained.
This data will be incorporated with other appropriate worldwide data and the site data to assess ground motions.
SCHEDULE Age dating of the Hookton formation and installation of the free-field strong motion accelerometers is now scheduled to begin during the next reporting period.
The identification of f aults at the North Spit of Humboldt Bay and in the Elk River Valley have been postponed until a later phase of work.
Identification of faults south of Fields Landing by deep drilling will commence in the next period as will studies of fault formation and propagation.
If you have any questions or require further information, please do not hesitate to call me.
With rega 4,1. A Ash k S.
Patwardhan e-ASP:ss
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