ML20234E777
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{{#Wiki_filter:l i i ( 1 DRAFT I U. S. ATOMIC ENERGY COMMSISION REGION V DIVISION OF COMPLIANCE l ,J i. TO L. Kornblith, Jr., Assistant Director for Reactors DATE: A C ? ': 19G3 Division of Compliance, Headquarters FROM : G. S. Spencer, Reactor Inspector Region V, Division of Compliance TITLE: PACIFIC GAS AND ELECTRIC COMPANY - BODEGA BAY REACTOR DOCKET No. 50-205 i
SUMMARY
The proposed site of the Pacific Cas and Electric Company's Bodega Bay ,j i l Reactor, Bodega, California, was visited on August 20 and 23, 1963. The j j purpose of the visit was to accompany and observe the activities of the 1 U.S. Geological Survey team assigned to study and evaluate the excavated areas of the site for evidence of seismic faulting. The south face of the reactor building excavation has been opened to provide i I an approximate 100x120 ft. area for the proposed turbine generator basement. g on the floor of the reactor building excavation (+5 ft. elevation) an annular trench, approximately three feet wide and ten feet deep, was being dug around the proposed reactor centerline at a radial distance of 71 feet from the centerline. The purpose of the trench is to provide a reinforced concrete collar for edge-of-shoring support of the heavy equipment to be used,in excavating the 138 ft. diameter reactor shaft. Examination of the walls of the 50%-completed trencli excavation revealed l l 0709220S14 e51217 l hES -665 M l$
\\ l M (Continued) no evidence of faulting in the sediments overlying the exposed weathered quarts diorite. 1 Rwaminscion of the cores and associated logs from two recent borings drilled at a distance of approximately 70 ft. due west and southwest of the reactor centerline, indicated that hard granite'had been encountered from elevation -38.0 to -49.6 feet, and elevation -49.5 to -58.5 feet, respectively, i OttGmit 11GNID BT P, H. DIGRKDt Reviewed by: R. H. Engelken, Region V Division of Compliance i t I I a' 4 .9.
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'l f DETAILS i i I j I. Scope of Visit _ I On August 20 and 23, 1963 G. S. Spencer and R. H.'Engelken, Region V, Division of Compliance, accompanied Mr. J. Schlocker and Mr. M. G. Bonilla, i geologists from the U.S. Geological Survey, Engineering Branch, Menlo Park, California on a visit to the proposed site of the Pacific Gas and Electric The visit included: l Company's Bodega Bay Reactor, Bodega Bay, California. (a) Observation of the status of the excavation activities in pro 8ress. Observation of two core samples taken from recent borings ' drilled (b) at the west and southwest quadrants of the circumference of the proposed reactor shaft. (c) Discussion with the U.S. geologists concerning their current i observations and findings relative to the seismic activity of 4 l l l site. (d) Discussion concerning plans for the type of construction to be utilized in shoring the reactor shaft excavation. l Principal contacts during the visit were: Mr. J. Schlocker - Geologist, U.S. Geological Survey s 1 Mr. M. G. Bonilla - Geologist, U.S. Geological Survey Mr. C. Joslin - Construction Superintendent, PG&E l II. Results of Visit A. Status of Site Preparation The reactor building excavation (described in our previous report dated July 24,1963) was observed to have been further expanded in a southerly h, a, L ___-__ _ _?_?_ ~~~_?'"__f""*'"*"'**~ sw.2 u- ,-..m c._. _ _,"m " yy
II. Results of Visit (Continued) direction to provide an approximate 100 x 120 ft. area-for the proposed turbine generator basement. On the floor of the reactor building excavation (+5 ft. elevation), an annular trench, approximately three feet wide and ten feet deep, was being dug around the proposed reactor centerline at a radial distance of 71 feet from the centerline. Mr. Joslin stated that the purpose of the trench is to provide a reinforced concrete collar for edge-of-shoring support of the hoavy equipment which will be used for excavating the 136 ft diameter reactor shaft. He explained that the inside edge of the trench is 71 feet from the proposed reactor centerline and is two feet outside the reactor shaft radius of 69 feet. According to Joslin, the decision to employ the use of a concrete collar was based on a serious accident that occurred at a U.S. missile site. Apparently a large crane toppled into an excavation shaft, killing seven personnel, when the edge of the excavation gave way under the weight of the crane. Joslin said the type of shoring that will be used to support the walls of the N reactor shaft excavation will depend on the condition of the soil as it is uncovered, and could consist of I-beam ring girders with or without sheet piling, wire mesh and gunite, or nothing. k A large trench was dug along the dividing line between the excavations for the reactor building and the turbine generator basement. Mr. Joslin stated that the purpose of the trench was to provide a sump i for drainage of thq < water leakage being encountered in the two excavated ] l areas. A diesel pump was observed to be located at one end of the trench l .q with installation of the associated drain piping in progress. I 1 l -4 s 4 T T E T "I' X T 4 ~? ""~~ T '~~"~~~"~m"~"~~
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I i 'II. 'Results of visit (Continued) 4 ) Landscaping of tho' sloped and benched areas of the open cut i excavation sectors of the reactor site was observed to be in progress and q appeared to be nearly completed from elevation +50 feet to the top of the cut (elevation +130 feet). -{ B. Examination of Annular Trench Excavation i Mr. Schlocker, U.S. Geological Survey geologist, stated that his l l objective during the two visits covered by this report was to map the major i faults observed'in the weathered quartz diorite exposed in the north-northeast quadrant of the trench. He explained that when the trench .j excavation is completed along the south quadrant of the are he would be looking to see whether these faults carried into the sediments exposed in the south quadrant. By the end of the second visit, excavation of the trench was approximately 50f, completed and mapping of this portion essentially completed by the U.S. geologists. The inspectors accompanied Messrs. Schlocker and 1 l Bonilla into the trench where the following observations were made, as 1 pointed out by the U.S. geologists. quarts diorite was exposed from the bottom (elevation -5 feet) l to the top (elevation +5 feet) of the trench over a distance of 58 feet along the trench. The bulk of the exposed granite was located in the l northeast quadrant of, the trench and sloped off to a point where it disappeared'below the bottom of the trench 34 feet west and 90 feet east of the northern estension of the north-south centerline of the reactor. l 's m, 1....,w,~.y.,,.m,.- ._.,,,.,, - w y..m ,,....y ..w y, ..,7 .,,.7, r-,_..3..... ,, 7 .g, a1
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- 11. Results of Visit (Continued)
I l The granitic material observed in the northeast quadrant consisted of i granular quartz diorite which became weathered quartz diorite in the due I 1 north section of the are formed by the trench. This in turn melded into grey clay in the northwest quadrant. Schlocker voiced the opinion that the granular quartz diorite would maka a good foundation material due to its' porosity and incompressibility..The sediments overlying the slope of the ~ quartz diorite in the northwest quadrant were observed to consist of grey-l and mottled brown coarse sandy clay with no sign of bedding. No evidence of offsetting or other disturbances was noted in this clay. A distinctive bed of grey gravelly, sandy clay was observed from a point 45 feet (along the are) northwest of the north-south centerline, to the western termination of the excavated portion of the trench. In Schlocker's opinion, this clay was less cohesive then the material underlying it. He also indicated ^ that the absence of any offsetting in the clay could be considered further 1 conclusive evidence that no faulting had occurred. j Many shears and fault zones were observed in the quartz diorite exposed in the walls of the trench. These were marked by pale blue clay i l gouge zones one to three inches thick. According to Schlocker, there was no dominant direction of dip to the fault veins. 1 Following their examination of the excavated section of the trench, Schlocker and Bonilla stated that theit; study of the site to date has revealed no evidenc's of recent faulting. l i.J l m...__._......
-f II. Results of Visit (Continued) C. Results of Recent Borinas Mr. Joslin, PG&B Construction superintendent, stated that.two I exploratory borings were recently drilled at the wes*. and southwest quadrants of the circumference of.the proposed reactor shaft.. He said that the purpose of the borings was to further define the bedrock surface at those locations. The core samples and associated boring logs were eramined by the inspectors and the U.S. geologists. Hr. Bonilla, geologist with the U.S. Geological Survey, observed that the direction of the faults evidenced in the samples taken at the quartz diorite level.showed a steep vertical orientation rather than the horizontal displacement associated with the San Andreas Fault. He indicated that this was further evidence that the boundaries of the San Andreas Fault did not extend into the site. The following information was extracted from the log of the. borings. Reference to the coordinates may be found in Plates 1 or 2, Amendment No. 3, Part IV D of the application. p Borina Due West of Reactor Centerline N 20,000 E 9921.68 El. 4.76 Elevation 44.76 to -10 feet: Grey sand Elevation -10 to -15.5 feet Grey sand or sand and clay Elevation -15.5 to -36.0 feet: Grey clay with quarts and feldspar Elevation -36.0 to ~38.0 feet Partially decomposed quartz'diorite Elevation vS8.0 to -4916 feat Hard granite e O ~7-o ______-_-_____-_______-_-___I
II. Results of Visit (Continued) Borinz Southwest of Eeactor Centerline N 19,942 E 9927.2 E1. 3.26 Elevation +3.26 to -18.5 feet: Alluvial sand i Elevation -18.5 to -23.5 feet: Grey sand or clay, or combination Elevation -23.5 to -48.5 feet: Grey clay with quartz and feldspar crystalo Elevation -48.5 to -49.5 feet . Soft partially decomposed granite Elevation -49.5 to -58.5 feet: Hard granite i l \\' 'l LI
I i MEMO ROUTE SLIP 5** m* about this. For Concurr&dat. FC# action, Pbrrn A EC-t3 (Rav. May14. 1947) Nots and return. For sign.tturs. For Information. i, s-d') (Nafne t unit) INIT1.43 REMARKS I sEds G. se
SUBJECT:
PACIFIC GAS & SLECTRIC CO. (BODEGA BAY) f th DOCKET No. 50-205 / (/ 016 Attached is a draf t copy of a report by our field 1 TO (Name and unit)
- emALS REMARKS
/ inspector of recent visits to the proposed site of f t the subject facility. Normal distribution of this ./..- om ~ report will follow. .l TO (Na,me and unit) NC TIALS AEMARKS l . // om
Attachment:
Cpy rpt by G. S. Spencer 5 L dtd 8/30/63 FROM (Name and unit) REMARKS B. H. Grie'r CO 177 1 i I ras = om T/4 ) i m - m n dhi e-r 1 M ' A s.o 3
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