ML20118D269
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UNITED STATES GOVERNMENT Memorandum
$EP. c a Edson G. Case, Assistant Director U*
To for Facilities Licensing Division of Licensing and Regulation L. Kornblith, Jr., Assistant Director N
Division of Complianca
-/], M FROM f r Reactors y
PACIFIC CAS AND ELECTRIC CCtiPANY (BODEGA BAY)
SU BJE.CT DOCKET NO. 50-205 At a ched is a report by our field inspector of recent visits to the subject proposed facility site. A draf t copy of this report was forwarded to you on September 4, 1963.
Our inspector had the following additional consnents:
" Subsequent to the visits coverert in this report, we were informed by Schlocker that t\\te trench was 757. completed but that cave-in problems were being eicountered as the trench excavation progressed into loose sandy soil in the southeast To counter this further excavation progress was quadrant.
limited to 40 feet at a time and concrete pours completed section before continuing to excavate the next 40 for thatSchlocker intimated '. hat this was interfering with feet.
his fault mapping activities somewhat, but.not to a degree he considered to la significant. Focewarning of the cave-in problam was evidenced to us during our second visit when we observed that a cave-in had occurred at the last location we were studying during~ our first visit. Fortunately no one was in the trench when this occurred.
"All comments made to us by the U. S. geologists in the course of their study of the site excavations to date indicate a consistent picture of fault-free sediments overlying the bedrock on which the reactor will be built. Schlocker and Bonille plan to ccatinue mapping the reactor excavation down to the ~73 ft.
elevation and to transpose the mapped data onto a plastic model of the shaft."
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Attachment:
Rpt by G. S. Spencer dtd 8/30/63 h
j j Distributiou:
J. R. Sears, Region I (2)
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1 M. L. Erns t, Region 11
\\f H. D. Thernburg, Region III V
s J. W. Flora, Region IV R. H. Engelken, Region V e fh
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G. S. Spencer, Region V NJ,;.1 \\
C. A. Nelson, INS, w/o attach.
L.LEJ-ile 9210120055 920!20 PDR ORG NRCHIST 6338 een
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U. S. ATONIC ENERGY CCHKISSION ~
REGION V-i, DIVISION ' OF COMPLIANCE 1
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Ly-G. S. Spencer, Reactor Inspector August 30 1961 3
Region V, Division of Compliance a
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PACIFIC CAS AND ELECIRIC COMPANY - BODEGA BAY _ REACTOR.
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D,0CKET NO. 50-205 t
SUMMARY
l Tae proposed site of the Pacific Gas and Electric Company's Bodega Bay s
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- Reactor, Eodega, California, was visited on August 20 and' 23,1963. The parpose of the visit was to accompany and observe the activities. f the U. S. Geological Survey team assigned to study and evaluate the excavated I
areas of the site'for evidence'of seismic faulting.
i The south face of the reactor. building excavation-has been' opened co provide l
an approximate. 100 ( 120 f t. -area for the proposed turbine generator basemett.
On the floor of the reactot building excavation (+5 f t, elevation) 'an annular l
- tench, approximately three feet vide and ten feet' deep, was being. dug around the proposed reactor centerline at a radial distance of 71 feet fr:s the centerline. ihr purpose-of the trench is to provide a reinforced conettri
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collar for edge-of-shoring support of f the heavy equipment to be used in e
excavat1ng.the 138 ft, diameter reactor shaft.- Examination of the-walls c.f the 50%-completed trench excavation _ revealed no evidence of faulting in t
the sediments overlying the expoced weathered q"trtz diorite, i
cxamination _of the coren and associated -logs from two recent borings drilled l.
at a distante of approximately 70 f t.'due west and southwest of the reactor j-ccnterline, indicated that hard granite.had.been encountered-from elevation
-38,0 to -49.6 feet, and elevation -49.5 to -58.5 feeti respectis sly.
DETAILS 1.
Seone of-Visit i.
l On August 20 and 23, 1963 G. S. Spencer and R. H. Engelken, Region V; Division of Compliance, accompanied Mr. J. SchlockerL and Mr. M. G. Bonill A, geologists from the U. S. Geological Survey,f Engineering Branch, Menlo Patk.
California on'a visit to the proposed site' of the Pacific Gas and Electric C7r.pany's Bodega Bay Reactor, Bodega Bay,_ California. The visit included:
(e) Observation of the-status of the excavation activities uin progrtsi.
l (S) - Observation of tuo core samples taken from recent-borings drt11+d -e
.hs west and southwest quadrants of the circumference of the' ;rciatsd f
ree tor shaft.
(continued)
2 Scope _of Visit (continued) i Discussion with the U. S. geologists concerning their current l
(c) observations and findings relative to the scismic aativity cf site d
(d) Discussion concerning plans for the type of construction to be utilized in shoring the reactor shaft excavation.
Principal contacto during the visit were:
Mr. J. Schlocker - Geologist, U. S. Geological Survey Mr. M. G. Bonilla - Geologist, U. S. Geologic 1 Survey Mr. C. Joslin - Construction Superintendent, PG&E i
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 expcnded in a southers direction to provide an approximate 100 x 120 f t. area for the proposed turbi-generator basement. On the floor of the reactor building excavation (+5 ft.
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de e elevation), an annular tr(ach, approximately three feet wide and ten feet was being dug around the proposed reactor centerline at a radial distan e ef 71 feet from the centerline Mr. Joslin stated that the purpose of the cri '-
of tc4 is to provide a reinforced concrete collar for edge-of-shoring support heavy equipment which will be used for excavating the 138 ft. diameter :ca:---
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shaft. He explained that the inside edge of the trench is 71 feet frem th+
proposed reactor centerline and is.two feet outside the reactor shaft r+cies of 69 feet. According to Joslin, the decision'to employ the use of a c:nev 4
collar was based on a serious accident that occurred at a U. S. misJ11e s i -
l Apparently a large crane toppled into an excavation shaft, killing seven personnel, when the edge of the excavation gave way under the weight cf otte Joslin said the type of shoring that will be used to support the w, crcne.
of the reacter shaf t em.avation will depend on the condition of the soil a; it is uncovered, and could consist of I-beam ring girder; with or without l
sheet piling, wire mesh and gunite, or nothing.
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- 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 aump for drainage of the water leakage being encountered in the two excavated A diesel pump was observed-to be located at one end of the trcnen areas.
with inste11ation of the associated drain piping in progress.
Landscaping of the sloped and benched areas of the open cut exc7rst sectors of the reactor site was observed to be in progress and appeared to t -
nearly completed from elevation +50 feet to the top of the cue (elevation
+130 feet).
(continued)
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Results of,yisit (certinued) 1 l
B.
Examination of_ Annular Trench Excavation stated that Mr. Schlocker, U. S. Geological Survey geologist, tis objective during the two visits covered by this report was to map the major faults observed in the weathered quartz diorite_ exposed in 4
the aorth-northeast qvadrant of the trench. He explained that when the j
trench 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 j
approxirc.ately 507, completed and mapping of thia portion essentially completed by the U. S. geologists. The inspectors accompanied F.cssrs. Schlocker and Bonilla into the trench where the following observations were made, as pointed out by the U. S. geologista.
i Quartz diorite was exposed from the bottom (elevetien -5 foet) to the top (elevation +5 feet) of the trench over a distence of 50 feet The brik of the exposed granite was located in the along the trench.
l northeast quadrant of the trench and sloped off to a point where it dis-appeared below the bottom of the trench 34 feet west and 90 feet. east of the northern extension of the nor*h-south centerline!of the reactor.
The granite material observed in the northeast quadrant consisted of 1
j granular _ quartz dioritt which became wea;hered quartz diorite in the due north section of the arc fonaed by tha trench. This.in turn melded into l
grey clay in the northwest quadrant. Schlockac voiced the opinion that the granular quartz diorite would make.a good foundation material due to its porosity and incumpressibi.11ty. The sediments overlyingLthe-_ slope of the quartz diorite in the northwest quadrant were observed to consist of grey and mottled brown ccarse 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 cbServed 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 Schiccker's He j
j opinion,.this clay was less cohesive than the material underlying it.
also indicated that the absence of any offsetting in the clay could be con-sidered further conclusive evidence that no 'f aulting had occurred.-
Many sh n s and f ault zones were observed in the quartz diorite l
exposed in the astis of the trench. The-:e were marked by pale blue clay gouga. anes one to three inches thick. According to Schlocker, there was no dominant direction of dip to the fault veins.
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(continued) t I,
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, actuits of ns.: (c ont inued)
Folleving their examination of the excavated section of one trinch, Schlocker cod 22n111a stated that their study of the site to date has revealed no evidence of recent faulting.
C.
Results of Recent Boring Mr. Jeslin, PG&E Const uction Superintendent, stated that two ap' oratory bo a gs were recently drilled at tht. west and southwest quadra.ts ef the circ =ftrence of the proposed reactor shaf t.
lie said that the purpose nf the horir.,;s -as to further define the bedrock surface at those locations.
T.ie c re sa:rpl:s and associated boring logs were examined by the inspectors ud the U. S. ge:logists.
Mr. Bonilla, geologist with the U. S. Geological i
. n ef,,.A s e rv e : that the direction of the faults evidenced in the samples ahen at
'e qs.artz diorite level showed a steep vertical orientatien rnher thr. the horize tal displacement associated with the San Andreas Fa;lt. He indicated that Pis was f arther evidence that the boundaries of *he San kr.dtc as Fault did not ex;end into the site.
The following informatior. was extrscted from the log of the borings.
!sf err.ce to the coordinates may be found in Plates 1 or 2. Amendme.t No. 3, Par: I7 3 of the application.
BoriQe West _c f Reactor Centerline N 20,0T)
E 9921.6B El. 4.76 Elevation -:-4.76 to -10 feet:
Grey sand j
Elevation -10 to -15.5 feet:
Grey sand er sand 4.nd clay Elevation -15.5 to -36.0 feet:
Grey clay with quartz and f eldsp ar I
Elevation -36.0 to -3S.0 feet:
Partially decomposed quartz diorite Elo'ntion -38.3 to -49.6 feet:
Hard granite Borim Southwe st2 Reactor Centerline i
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i N 19,941 E 9927.2 El. 3.26 Elevatten +3.26 t
-18.5 feet:
Alluvial sand l
Zla:ition -18.5 to -23.5 feet:
Grey sand or city, or co.bir r
rievet'on -23.5 to -48.5 feet:
Grey clay with qutrtz rd f
- er l
crystals Elevat ion -48.5 to -49.5 feet:
Soft partially decespose.d grar ': s l
Elevatten -49.5 to -58.5 feet:
Hard granite t
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