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:4 V kfASA.RA" 4 PA'QhAKK
NIAGARA MOHAWKPOWER CORPORATION/300 ERIE BOULEVARDWEST. SYRACUSE, N.Y. 13202/TELEPHONE (315) 474-1511
October 3, 1980
Mr. B. J. Youngblood, ChiefLicensing Branch No. 1,Division of LicensingOffice of Nuclear Reactor RegulationU. S. Nuclear Regulatory CommissionWashington, D. C. 20555
Dear Mr. Youngblood:
Re: Nine Mile Point Unit 2Docket'o. 50-410
Your letter of July 9, 1980 requested additional information regardinggeology at Nine Mile Point Unit 2. Enclosed are Niagara Mohawk's responses toquestions Q361.26 through Q361.35 contained in the enclosure to your letter.
Very truly yours,
NIAGARA MOHAWK POWER CO RATION/g n
4c
Gerald K. R odeVice Presid nt
System Project Ma agement
PEF:jaEnclosures (25) pock
(/~<
8 020GVII $ /0
Q361.26 In'our report entitled "Nine Mile Point Nuclear Station,Unit 2, Geologic Investigation," (Vol. 1, Section 4.7,paragraph 1), you state that the intensity of the shearingon the cooling tower fault does not appear to diminishtoward the known extremities. However, it is not clearfrom your report where the southeastern extremity ofthis fault is and where either extremity of the drainageditch fault is. Accordingly, provide data which willindicate the length of the cooling tower and drainageditch faults and show their relationship, or lack ofrelationship, to each other. In your response, consideracquiring this information by running a detailed groundmagnetic survey using a field magnetometer (e.g., a protonprecession magnetometer) . This approach could be followedby trenching, if necessary. If you choose to respondwithout doing a field survey using a magnetometer, indi-cate your reasons.
RESPONSE: Figure 361.26-1 summarizes all known observations relevantto the evaluation of the lateral extent of Cooling Towerand Drainage Ditch faults. The apparent west-northwestterminations of both faults are shown on Figure 361.26-1as locations Ql and Q2. Location is consideredto be the western extremity of the Cooling Tower Faultbecause trenches 1 and 2 revealed no evidence" offaulting. These trenches were excavated 700 feet and1750 feet west of the cooling tower piping trench.Location is considered to be the western termi-nation of the Drainage Ditch Fault because the lakewater tunnels for Nine Mile Point, Unit II did notencounter the fault.
The east,-southeast extremity of the Drainage Ditch Faulthas been determined during investigations of the "compressionbuckle" disclosed during bedrock excavation for theJames A. Fitzpatrick Nuclear Power Plant. The reportentitled, "Fault Study for James A. FitzPatrick NuclearPower Plant" submitted as a supplement to the James A.FitzPatrick PSAR provided the following informationconcerning the extent of the feature:
"Examination of aerial photographs showeda lineation crossing the plant area andcorresponding to the projected trace ofthe fracture. This lineation was definedin some places by vegetation, probablybecause the fracture zone served to transmitwater. In other places it was defined by avery slight depression probably due to some.slight migration of soil downwards into theopen jointing. This feature could befollowed on the photographs approximately6000 feet to the east of the plant site, atwhich point the lineation became indistinct
Iffy I lj
Q361.26 Continued
and could no longer be seen. A test pit,No. 7, dug across the location of thelineation at this point showed only flat-lying beds with no evidence of disturbance.Refraction seismic surveys were able to definethe trace clearly in the vicinity of the plantand to a distance of 2050 feet to the east.Beyond this point, the velocity decay by whichthe trace was identified was no longer evident.Several test pits were opened along this traceat locations shown on Figure 1. Near the plantthe fracture zone was readily identified.Test Pit 5, (Ref. Figure 1) opened at, the limitto which it could be traced by geophysicalmethods, revealed a fracture about 3 incheswide, containing shattered rock, but no gouge.The rock adjacent to the fracture or jointwas closely jointed but did not exhibit thecharacteristic up-warp associated with thefracture in the station area. Test Pit 6,about 60 feet east of Test Pit 5, showed onlyintact rock with moderately closely spacedjointing. The evidence from these test pitsindicates that between the plant and Test Pit 5the buckling dies and the fracture resolvesinto a local system of close jointing.Xn a westerly direction, the trace was followedto within 90 feet of the shore of Lake Ontario,at which point: it is obscured by artificalland-fill for a parking area on adjoiningproperty."
On the basis of the above information it appears that itis appropriate to assume that the east-southeast extremityof the fault 'is somewhere around location Q3 on H.gure 361.26-1.1
The minimum lateral extent of the Cooling Tower Fault asdetermined by our investigation is approximately 3000 feet.As shown on Figure 361. 26-1, this corresponds to the distancebetween Pit 1 and the overcoring Borehole OC-2. Withthe data presently available, it is difficult to placethe east-southeast extremity of the fault. However, theCooling Tower Fault in terms of the magnitude of displace-ment and degree of cataclasis appears to be very similarto the Drainage Ditch Fault. Hence, it is difficult toenvision the later'al extent of the fault as being signifi-cantlv different, than the length of its analog. Thissuggests that the Cooling Tower Fault does not extendbeyond location @on Figure 361.26-1.
Q361.26 Continued
Investigating the length of the Cooling Tower Fault anaDrainage Ditch Fault by proton magnetometer survey hadbeen considered. However, the nature of the faultingat Nine Mile Point does not lend itself to detectionby this method. The displacement on the Cooling TowerFault is small (5 feet of vertical offset at the bedrocksurface diminishing to approximately 6 inches at a depthof 200 feet; and 3 feet, of strike slip offset) . Ad-ditionally, it is not believed that the fault extends tothe basement. Consequently, the faulting does not bringrocks with highly contrasting properties in contactwith each other and should not offer a distinct magneticcontrast or pattern by which the fault can be traced.
To illustate this, proton magnetometer surveys were con-ducted across the Cooling Tower Fault and Drainage DitchFault (Figure 361.26-1). As shown on the magnetometerprofiles (Figure 361.26-2) no pronounced gradients areapparent that would suggest the location of the faultat the surface or at a hypoth'etical projection to thebasement.
Examination of the Drainage Ditch Fault, undertaken duringthe 1977-1978 investigations for Nine Mile Point, Unit II,revealed that the structural development of the faultis essentially identical and contemporaneous with thedevelopment of the Cooling Tower Fault. This structuraldevelopment has been summarized. in the 1978 report as follows:
"The study revealed that the fault (CoolingTower) was initially developed as a vertical,left-lateral, strike-slip fault with 2 to 3
feet of stratigraphic displacement. Thefracturing occurred selectively in the strongestrocks of the stratigraphic section, namely themassive part of the Oswego Sandstone. Incontrast, the strike-slip fault zone did notdevelop within the softer rocks of theTransition Zone, and the underlying LorraineGroup. During the deformation, the fault zonewas mineralized by calcite and sulfides.Analysis of fluid inclusions from this calciteindicates crystallization temperatures rangingfrom 170 C to 120 C (corresponding to a depthof burial of 3 to 3.5 kilometers) . Moreover,fluid inclusions in quartz of the host rockindicated that the temperature reached duringdiagenesis was approximately 170 C. Fromthese data, it. is interpreted that the faultwas formed at the end of the Paleozoic Era,during the initial stage of regional uplift,
~gr.,
4
Q361.26 Continued
soon after the rocks reached a maximum depthof burial of approximately 3.5 kilometers (km) .
At a later time, during the second episode ofdeformation, the fault plane was propagateddownward as a normal fault through the TransitionZone and the Lorraine Group, with a northwarddip of 55 to 65 . The displacement alongthis structure was small, not exceeding a fewfeet. At this time, the fault zone was alsomineralized with calcite and sulfides. Fluidinclusions in the calcite yielded temperaturesof homogenization ranging from 116 C to 73 C(corresponding to a depth of burial of approxi-mately 2 to 3 kilometers) . The age of thenormal fault movement is interpreted to beLate Jurassic to Late Cretaceous.
The third episode of deformation on the CoolingTower Fault was characterized by reverse-slip,bedding plane slip, and dilation within 200 feetof the bedrock surface. Field evidence clearlyindicates that there were two phases of movement.
'The first phase preceded the deposition ofthe overburden sediments, occurring priorto 12,500 years B.P.; whereas, the secondphase post-dated the deposition of thesesediments.
During the first phase of deformation, dilationof the bedrock strata on the hanging wall ofthe structure resulted in a reverse strati-graphic displacement that, decreases from5 or 6 feet near the ground surface to zeroat a depth of 200 feet. This deformation isattributed to a mechanism of buckling, and isbelieved to have been initiated during crustaldownwarping induced by glacial loading.
The deformation during the second phase isexpressed as two types of structures:
l. fluidized flow structures in the over-burden sediments, and;
2. folds and faults which deform the fluidi-zation structures.
This phase of deformation is attributed to amechanism of bedding plane slip which probablywas caused by changes of fluid pressure in the
„l
Q361.26 Continued
bedrock associated with water level fluctuationin the Ontario Basin during the draining ofglacial Lake Iroquois."
The identical structural character of both faults, coupledwith their contemporaneous development, indicates thatthey are related to each other. Furthermore, both ofthese faults must be a part of an integrated deformationalsystem which. is linked to a common tectonic source and/ortectonic event(s) . The April 1978 report linked thedevelopment of the faults with the tectonic developmentof the region. At that time knowledge concerninglocal geologic structure was more limited than at present.This knowledge was substantially enhanced as a result ofgeologic studies performed at the New Haven Site.Reference should be made to Figures 2.5-9 and 2.5-15of the New York State Electric 6 Gas PreliminarySafety Analysis Report for New Haven Units 1 and 2.These figures present certain aspects of the localtectonic settinq which are important in understandingthe relationship among faults and possible linkageto a common tectonic source. It appears that the .
development of the Demster Structural Zone wasaccompanied by gentle warping of the sedimentarystrata on either side of the zone. Particularlyimportant is the occurrence, in the vicinity of t:heNine Mile Point Site, of a broad syncline. As shownon New York State Electric 6 Gas Figure 2.5-9 the axisof this syncline trends north-northeast and its projec-tion is located just east of the James A. Fitz'patrickfacility. Figure 361.26-1 presents a spatial relation-ship between the Cooling Tower and Drainage Ditch faultsand the axis of the syncline. The axis appears to besituated half-way between the previously interpretedextremities of both faults. This suggests that theremay be a causative relationship between the synclineand both the faults as indicated on Figure 361.26-3.It should be recognized that the relationship, as notedabove, would account for the remarkable change in thecharacter of deformation, that is, from strike-slip tonormal. This change could be attributed to a local .
clockwise rotation of the trajectory of greatest prin-cipal stress in response to continued shortening. Oncethis trajectory assumed a position close to the pre-viously formed left lateral shear fracture then conditions.were favorable for development of normal faulting alongthis fracture.
Q361.26 Continued
REFERENCES
New York State Electric & Gas Corportation, 1979, New HavenUnits 1 and 2, Preliminary Safety Analysis Report,Docket No. STN50-596 and STN50-597.
Niagara Mohawk Power Corporation, 1978, Nine Mile Point NuclearStation, Unit 2, Geologic Investigation, Scriba, New York.
Power Authority of the State of New York, 1967, Fault Study forJames A. Fitzpatrick Nuclear Power Plant, Appendix "F"Supplement to Preliminary Safety Analysis Report.
L A JI'Z
NINE MILE POINT
NUCLEAR QENERATINQ STATON
TRKNCH I
RAOWASTE FAULT
UNIT I UNIT 2
TITENCH 2
..OI
~IT I
-E X /J'
I
I
I
IONT A8/0 II
/O2
/I /
/I
COOLING WATERSITAXE SHAFt
I
~aaEEssc 4Tcs Il
TCITvEEC
I
//
/I
I
~TTAXK ANO OISCHARGE TUNNELS
SARGE SLIP
70'TS
TEPEE FOLD
Wif
OS
JAMES A. FITZPATRICKNUCLEAR POWER IR.ANT
// /~0 ~ SS ~ NORMAL FAULT///
PLANTNORTH
~Carr
0 C00 000 sto Co FCCT
IXXX.INO TOWER
KXCAYATION MAGNETOMETER SURVEYLIKE 2
COOLINQ TOWER FAULT
TRENCH I
/~ IIAGNETOMETER SURVEY STATION
TRENCH S
OC 2
I
jNii
MAGNETOMETER SURVEYLIKE I
eTw+
0
x+
EXPLANATION:
TIILOE Of IIOO O OTEEOLT TO IIOOERLTELT OIOOIOO TTIIOOTORE
SITE LOCATKN
SHOWINS LOCATIONS Of IQIOWN WN W TIRNMH STNICTlSEO
!
RELATED TRENCHES AND EXCAVATIONS
"..ff'RKHCH KXCAYATEO TO INVESTISA'fK THK COOLIHO TOWER FAULTC9
e References Position of Inferred Syncline fran N.T.S.Electric and Cas Corp., 1979, Nev HavenUnits 1 and 2 PEAR, AsendEEEent 1, PiO. 2.5-9.
NINE MILE POINT NUCLEAR STATION
UNIT 2
NIAQARA MOHAWK POWER CORP.
FIGURE 561.26 - I
1!
I
I
SgEGS.S.
SROVP
LORRAINE
. >eg"'4qe p. 9 g]<cg4l)g
~ Cg~es
gO
l
I
Sense of Shear Strain inducedby shortening along Demster Zone
REPRESENTATION OF INITIALFOLDING AND
,RESULTING SHEAR AND EXTENSIONAL FRACTURES
REPRESENTATION OF ROTATION OF PRINCIPAL STRESSES.
SUCH THAT, EXTENSION IS PARALLEL TO ORIGINAL WNW
TRENDING SHEAR FRACTURE RESULTING IN DIP SLIP'" DISPLACEMENTS ON DISCONTINUITIES OF SIMILAR TREND
DIAGRAM OF- FOLD / FAULT RELATIONSHIPS NINE MIL'E POINT NUCLEAR STATIONUNIT 2
NIAGARA MOHAWK POWER CORP.
FIGURE 361.26 — 3
Q361.27: Indicate spatial and age relationships of the faultsat Nine Mile Point, to the geologic structures at thesite proposed for the New Haven facility and to othergeologic structures in the region. Furnish a mapand the necessary data to support your conclusions.
RESPONSE: In the region immediately around the Nine Mile PointSite (30 mile radius) there is only one structure known.This structure, located near New Haven, New York isknown as the Demster Structural Zone. Figure 361.27-1is a map showing the spatial relationship of thefaults at Nine Mile Point to the Demster StructuralZone.
Presently, there are no data available from either site whichwould permit a direct, absolute determination of the age ofdevelopment of structures at each siie. Nevertheless, theexisting data base permits a reasonable interpretation ofthe age relationship of the high angle faults at Nine MilePoint to the Demster Structural Zone. This interpretationis based upon" results of fluid inclusion studies. Thesestudies were performed independently at each site and aresufficiently broad in scope to warrant a meaningful com-parison. Clearly, the faults at each site are mineralized,and the mineral assemblages are similar. Furthermore,at both sites the mineral assemblages yielded identicalspectre of homogenization temperatures. Table 361.27-1and Figure361.27-2 present the results of fluid inclusionstudies at both sites. It appears that at each sitethe minerals occurring within fault zones precipitatedfrom fluids .whose temperatures .range from 170 C to 80 C.Based on this, it can be inferred that the developmentof the faults at Nine Mile Point (strike-slip and normalfaulting) and movements along the Demster Structural Zoneoccurred under similar depths of burial (depth of burialranging from approximately 3 kilometers to 2 kilometers)that is, in correlative geologic times. This conclusionis supported by movement plans (left-lateral) and thegeometric arrangement of faults at Nine Mile Point relativeto the trend of the Demster Structural Zone. The highangle faults at Nine Mile Point may be regarded as membersof a systematic fracture set identified onsite. This frac-ture set consists of two conjugate strike-slip shear frac-tures trending west-northwest (left lateral) and northeast(right lateral) . The trend of the acute bisectrix of theset indicates the direction of structural shortening re-quired to produce the fractures in their present arrange-ment. It can be seen from Figure 361.27-1 that the directionof shortening indicated by the Demster Structural Zone isclose to the trend of the acute bisetrix of fractures atNine Mile Point. This coincidence suggests contemporaneousdevelopments at each site and thus reinforces earlierdrawn conclusions.
In summary, the presently available data indicate anage and causative relationship between the faults atNine Mile Point and the geologic structures at New
Q361.27 Continued
Haven. These relationships appear to have beenestablished in the distant geologic past (LatePaleozoic-Early Mesozoic). As noted previously(response Q361.14), evidence of Late Cenozoic bed-rock displacement has only been encountered at NineMile Point.
0
TABLE 36l.27-1
sAvpLE /t Tl I 21A TII 42 'TII 19 TII 39 TII 7 TII 25
38 157.2
35a l49.4
37 138.8*
40 137.8
36a 121.7
35b 103.1
36b 101.0
35c 99.2
33 98.3
24a l57.9
3la 155.4
24b 154.3
23a 141.8
3lc 138.3
3lf 137.8
31e 129.1
31d 124.3
Xnclusion¹ T C Inclusion¹ T'C
18b 159.9
15 158.3*
16 147.8
10 128.3
22b 127.2*
18a 124.6
21 124.6
22a*ll4.2*
55 179.6
59 163.8
56 155.6
S4 150.4
61c 135.2
50, 132.5
61b 116.2
44 148. 5
43 144.6
4S'28.8*46a 118.9
49 93.1
46b 92.0
42 75.7*
Inclusiong T'C Inclusiong T'C Inclusion¹ T'C Inclusion¹ T"C
6 170.4
6b 170.4
5b 155.1
9b 152.5
5a 152.0
1 12S.2
4 122.5
Mean
Std. Dev.
122.9'C
23.4
142.4 C
12.5
135.6'C
17.2
147 ~ 6 C
21.3
114. O'C
28.1
149. 7'C
19.3
Refer ..Reference:
*Xnclusions found in milk areas.
New York State Electric & Gas, 1978,Preliminary Safety Analysis Report,,New Haven Units 1 and 2, Amendment 1, Table l.
~ L A III' 0 A'A h'/0~ »»» I )it»» )t» 'h» tt»
---'=~ =- -NORMAL~FAUtTININE MILE POINT."'
NUCLEP~GENEIIATlNG-S
g/r t ( ir
j \ IJAMES A RTZPQIRIC$
h$ NUCLEAR %OWER IPLAIIT
i'h~ I
ir'" !;
( ) S)M)
;.~"g pe '-~-
c',44
)P+
LgOCl)tg'
jA,v'~4J,
r i i Vt - . ( I /)), P-COO(=I NG'QIER . 4UL
ti
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S X I C 0
R~~ Bktttg Ctott
P A',
g4"hg (PAL
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~ g 4~-'>
hhi
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'7
p )4!
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»
~ ., 1
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i t0
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*
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GEOLOGIC
Vh
STRUCTURE
MAPI:
i /I
hh 4»,„,. ),tSCALE FEET
0 I000 2000
NINE MILE
NIAGARA
POINT NUCLEAR STATION
UNIT 2
MOHAWK POWER CORP.
FIGURE 361.27 - I
80 90 100
TEMPERATURE (DEGREES CENTIGRADE)
110 120 130 140 150 160 170
PRI NARY INCLUS IONS
HOST ROCK ~ ~~ oo ~
NILKY CALCITE~4 4 OOIOOO ~ 44OLO ~ ~ 4 ~ iO
2 m
Q
CLEAR CALCITE~ ~ 08 0 oui ~ ooM 44 ~ IOOO ~ I ) ~ ~ ~ ~ ~ ~ ~ OO 0
xo oXC2
no rm
m
no
o
SECONDARY INCLUSIONS
.w BL8kA 0! IIh~aFLUID INCLUSION TEMPERATURE DISTRIBUTION
Q361.28 Indicate the relationship among the thrust faults, thecooling tour fault, and the drainage ditch fault.Specifically, indicate whether they connect as an inte-grated system and whether the thrust faults cut thethe other faults.
RESPONSE: Thus far, no direct geologic evidence has been identifiedrelevant to an unambiguous definition of age and spatialrelationships among the "thrust" faults, the CoolingTower Fault and the Drainage Ditch Fault. Presently,there are only a few exposures of the "thrust" faultsknown at the site. These are: the North Radwaste Trench,the Cooling Water Intake Shaft, Lake Water Tunnels andthe Circulating Water Piping Trench. Figure 361.28-1presents the location of all "thrust" structures known at,the site. It can be noted that these structures wererecognized only within a bedrock block bounded by thehiqh anqle faults. There is no single exposure whereinboth types of structures are present. Furthermore, theabsolute age of formation of the "thrust" faults, as wellas their relative age with respect to the reverse slipdeformation observed on the Cooling Tower Fault, cannotbe determined with certainty. Consequently, the possibleage and spatial relationships are inferred from theexisting data base.
The "thrust" fault structures appear to have been formedas a result of relief of strain energy stored in the bedrock.The strain energy is inferred to be of remanent gravi-tational and/or tectonic origin. As such, in the timescale of concern and in the tectonic environment of thesite region, the energy once relieved or reduced cannotbe replenished. That is, it is only conceivable thateither no change or a decrease in the amount of storedstrain energy occurs after the initial movement has takenplace.
The development of the "thrust fault" structures musthave been triggered (initiated) by some environmentalchange (for example, glaciation) which reduced theability of the bedrock to retain the strain energybeing stored at the time such a change occurred.The ability of a given block of bedrock to retain agiven amount of strain energy is governed by the shearresistance of block boundaries and the lateral restrainingforces. A reduction of one of these factors resultsin a reduction of the integrated restraining forceand must be followed by a reduction of strain energystored within the block. The latter reduction will beexpressed on a lengthening of the block accompaniedby the developm'ent of nonhomogeneous shear strainsalong the boundaries. The process, if continuous,
Q361.28 Continued
may be characterized as "leakage" of the strain energyinduced by the reduction of the capability of the blockto retain the stored strain energy.
Presently, there is no known direct geologic data per-mitting a firm definition of boundary conditions of thebedrock- block whose lengthening is evident in the ex-posures of the "thrust" faults. However, with theinformation presently available, it is possible topostulate reasonable boundary conditions as presentedon Figure 361.28-2. Once these boundary conditionsare assumed then it is possible to perceive the natureof the environmental change which permitted the develop-ment of the instability.With reference to the "thrust" fault structures, the factorswhich controlled the initial strain energy stored in thebedrock may be identified as:
1) the lateral restraining force provided by thebedrock which has been removed by erosion duringthe formation of the north-south trending erosionalvalley located between Nine Mile Point Units I andII (Figure 361.28-1);
2) the shear resistance of the boundaries of theblock consisting of following elements (Figure361.28-2):
a) shear resistance along boundary 1
dSl Cl + t ~l ~2')
shear resistance along boundary 2
dS2 C2 + an ~2 ddn2')
shear resistance along boundary 3
dS3= C3 + tan p3 . d~nl.In the instance of the shear resistance ofthis boundary the shear stress acting alongbedding planes (< bed) should be accounted forand thus, dS3= (C3 + tan p3 . dd nl) + bed.
As indicated by the above equations the combined shearresistance of the block boundaries is controlled bythe bedrock mass properties (C=cohesion and P=angleof sliding friction), the normal stress perpendicularto the block boundaries (0 nl and 0 nq), and the shearstress acting along the plane of bedding (g bed) .
Q36l.28 Continued
The latter two factors must have experienced significantchanges in response to gravitational loading of the litho-sphere by the continental ice sheet(s) . Other relatedphenomena were also important. They include changesof water level in the lake (fluid pressure and reductionoft'l) and shear straining of the lithosphere caused byglacially induced differential vertical movements (tiltingduring downwarping and tilting during rebound) .
Considering the foregoing, the following scenerio ofdevelopment of the "thrust fault structures can beoutlined:
(i) Downwarping of the crust. in relation to glacialadvance created conditions favorable for bucklingof the hanging wall blocks of northward dippinghigh-angle faults. This resulted in a reductionof~2 and hence reduction of dSl and dS2,.
(ii) erosional formation of the valley reducedlateral restraining force, and;
(iii) removal of the load imposed by the continentalice sheetreduced 0 n and, thus reduced dS3.Fuither reduction ok nj, and dS3 may have occurredduring the drainage of Lake Iroquois (developmentof high fluid pressure in-the bedrock) .
In summary, the present understanding of the siteconditions strongly suggests that. the "thrust faultsdo not cut the Cooling Tower and Drainage Ditch faults.It appears that the "thrust" faults together with thehigh angle faults form an integrated, but sequentialsystem of bedrock deformation. The present under-standing of the equilibrium conditions of the thruststructures implies that the development of buckling(Phase I of the reverse slip deformation) along theCooling Tower and Drainage Ditch faults contributedto the instability of the bedrock block bounded byboth faults. Additionally, it can be inferred thatthe development of the "thrust faults" post-dates thefirst phase (response 36l.30) of reverse slipmovement along the Cooling Tower Fault.
REFERENCE
Niagara Mohawk Power Corporation, 1978, Nine Mile Point NuclearStation, Unit 2, Geologic Investigation, Scriba, New York.
0
INTAKE AND
DISCHARGE TUNNELS
ON 7 AIIT'/0
NINE MILE POINT
NUCLEAR GENERATINGSTATION
VNIT I/I
/UNIT a
O~ / I
R ADWASTEFAULT 0 w /
~2'~ 1'
~2~~
INTAKE ANDDISCHARGE TUNNELS
6o 65m ~ NORMAL FAULT
"TEPEE FOLD"
a
I
COOLING TOWER
EXCAVATION
1 t
l
JAMES A. FITZPATRICKNUCLEAR POWER PLANT
60
COOLING TOWER FAULT
EXPLANATION:
TRACE OF MODERATELY TO STEEPLY DIPPING STRUCTURE
~2'~ BEDROCK SURFACE CONTOUR IEL'N FEETI
LOCATIONS OF OBSERVED OCCVRENCES OF STRUCTURESSIMILAR IN CHARACTER TO RADWASTE STRUCTURE
0 400 800
SCALE FEET
S IT E LOCATION MAP
SHOWING GENERAL CONFIGURATION OF BEDROCK SURFACEAND LOCATIONS OF KNOWN GEOLOGIC STRUCTURES
NINE MILE POINT - NUCLEAR STATION
UNIT 2
NIAGARA MOHAWK POWER CORP.
FIGURE 361.28-1
Drainaae Ditch FaultBounda ry Ql
~ Strain
~ restq
Cooling Tower FaultBoundary Q2
PLAN
unconso idated Latesediments ~ ~ ~ ~
~ ~
~ ~ ~ ~
Land Surface
Wisconsin to Early Holocene. W '.P
~Stra in Oswego Sandstone
Unit A of Pu laskibed
SECTION A — AI '
estdBoundary Q3
~ ~ ~
" ~n 2 ~
Land Surface
~ Top of Bedrock.. —-Oswego Sandstone
Pulaskik
Depth of instabilityDrainage Ditch Fault
Cooling Tower Faui, POSTUI ATED BOUNDARY .COMDITlONS
SECTION 8 — B' NINE MILE POINT NUCLEAR STATIONUNIT 2
NIAGARA MOHAWK POWER CORP.
FIGURE„361 ~ 28-,2
0
Q361.29: Extend coverage of the lineament map (Volume II,Plate l-l) out to a radius of at least 5 miles.Field check the lineaments to determine if they arereflections of unrecognized geologic structures.
RESPONSE: Figure 361.29-1 is a map of air photo lineaments identifiedwithin a 5 mile radius of Nine Mile Point Nuclear Station,Unit.II. The air photo lineaments were identified bytonal variations on low altitude aerial photographs(approximate scale 1:20,000) flown in 1938 and 1939. Noghoto lineaments .could be identified in many areas, includingthe area of the James A. FitzPatrick Nuclear Power Plant,because these areas were heavily forested. The lineamentswere mapped on mylar overlays to the aerial photographsand then transferred to a 1:24,000 topographic base map.The lineaments were then checked in the field to determinewhether or not they reflect unrecognized geologic structures.
II
Within the 5 mile radius, the majority of the bedrocksurface is veneered with Late Wisconsinan and Holocenedeposits. The surface topography reflects landformsrelated to Late Wisconsinan Ice. To the south of NineMile Point, long, parallel ellipitical hills or drumlinsoriented approximately N20 W are the dominant topographic0feature. The topography of the drumlins and inter-drumlinareas has been modified by erosion and deposition asevidenced by occasional knobs and ridges subparallel tothe Late Wisconsinan ice margin. Further topographicmodification occurred during Lake Iroquois and otherpre-Lake Ontario lake stages as evidenced by lacustrinedeposition and erosion, and weakly define fluvial terraces.
In general, the. lineaments identified within the 5 mileradius may be related to the following non-cultural con-ditions: 1) surface topography such as streams and ridgesnot related to bedrock conditions, 2) surface topographyrelated to discontinuities in the bedrock 3) joint orfracture patterns in the bedrock, 4) structural discon-tinuities such as folds or faults, and; 5) topographicvariations on the bedrock surface produced by preferentialglacial plucking.
Several lineaments identified on the lineament map canbe related to previously identified geologic structure.A series of N40E to N45E trending lineaments were notedfrom east of Hammonds Corner to Demster- Beach (Fig-ure 361.29-1). These lineaments are coincident withthe Demster Structural Zone and associated folds asmapped by Weston Geophysical, 1978. Location Ql onFigure 361.29-1 shows three parallel N45 E-trending>linear, dark photo tones less than 1000 feet long.
Q361.29 Continued
Although there are no bedrock outcrops in the vicinityof these lineaments, trenching completed by Weston Geo-physical in 1978 verified the existence of the DemsterStructural Zone at this location (Figure 361.27-1).Several N40 E trending air photo lineaments were iden-tified parallel to and north of and coincident with theaxis of the Demster Beach anticline. The extent of N40 Eto N45 E trending lineaments appears to be limited to0
the Demster Structural Zone as few N40 E to N45 E linea-ments were identified to the west of the known extentof this zone.
LocationQ2 (Figure 361.29-1) is a lineament nearlycoincident with the Cooling Tower Fault. However,this area is now covered with filland the natural surfaceconditions could not be field checked. This lineamentis expressed on air photos as a linear, relatively darkphoto tone, approximately 50 to 75 feet wide and 3000 feetlong. The lineament appears not to be related to surfacetopography, as it crosses topographic highs and lows.It is not observed to extend toward the southeast beyondtrench 5 and it only is noted to extend a few hundredfeet northwest of pit 1 (Figure 361.26-1) . The lineamentssouth of the main east-west road (Lake Road) and east oftrench 5 (Figure 361.29-1) are related to topographic lows.No bedrock outcrops or anomalous surface conditions werefound in this area. The same is true for the short linea-ment about 500 feet southwest of trench 5.
At location on Figure 361.29-1, Unit 1, three west-northwest trending en echelon lineaments are connectedby two north trending lineaments. This system appears torepresent bedrock topographic variations because severalbedrock outcrops were observed along the trace of theselineaments. No bedrock outcrops were found in theimmediate area away from the lineaments. The glacialdrift is apparently thinner along the trace of the linea-ments. In general, the lineaments appear to be associatedwith a topographic high. However, the relationship is notconsistent as some of the lineament segments cross topo-graphic lows. The surficial evidence is not sufficientto determine if this lineament system represents struc-tural discontinuities, joints, or bedrock topographyproduced by preferential glacial plucking.
The lineaments (Figure 361.29-1) south of the above dis-cussed en echelon lineament system represent air photo tonalvariations that cross topography. No bedrock outcrops oranomalous su~face conditions could be found in this area.At location@, a lineament approximately 1500 feetlong and 100 feet wide, relatively dark, photo tone trendsapproximately N30 E and is located east and subparallelto the Heater Bay Structure. This area is excavatedand the natural surface conditions could not be checkedin the field.
Q361.29 Continued
At Sunset Bay (location Q5, Figure 361.39-1) twolineaments were noted; one trending N60oE approximately3500 feet long cutting across topography as a relativelydark photo tone and the second trending N45oW in partparallel to a small unnamed stream. No rock outcropswere located in the vicinitv of these lineaments and,dense forest plus fillat the James A. FitzPatrickNuclear Power Plant Site prohibit checking thenatural topography in this area. Surficial evidenceis insufficient to determine whether these lineamentsreflect structural discontinuities, joints, or bedrocktopography produced by glacial plucking.
A distinct N20 W lineament trend was mapped. Theselineaments are coincident with surface topography,such as drainages and,ridges in the form of elongatedrumlins. These lineaments are also coincident withthe direction of Late Wisconsinan ice flow out of theOntario Basin toward the southeast and do not reflectunrecognized geologic structure;
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0361.30 Furnish additional discussion and documentation to supportyour conclusion that post-glacial reverse movement did notoccur below 200 feet on the cooling tower fault., Ourconcern in this matter is that if this fault had previousnormal movement as you suggest, and if the displacement onthis fault is presently zero at the 200 foot depth, thenit appears that reverse movement must have occurred belowthe 200 foot level to bring the net displacement to zero.
RESPONSE: All available documentation and discussions supportingthe conclusion that "post-glacial reverse movement didnot occur below 200 feet on the Cooling Tower Fault" havebeen presented in the April 1978 report. Development ofadditional documentation through subsurface explorationis considered to be unwarranted. By way of summary,some of the relevant arguments are given below.
The main conclusion of the April 1978 report was thatthe latest movements observed along the Cooling TowerFault correspond to buckling of the near surface bed-rock strata forming the hanging wall block of an oldnormal fault. This buckling, termed in our report the"reverse slip deformation", should be distinguishedfrom "reverse movement". The reverse slip deformationoccurred 3.n two phases. The initial or the main phasecorresponds to the development of buckling down to a depthof approximately 200 feet. This phase of deformationoccurred "prior to the Wisconsinan glaciation and thedeposition of overburden sediments," (that is, priorto "postglacia' time) . The second phase of deformationhas been recognized only in the near-surface bedrock strataand overburden sediments. It is not known whether defor-mation related to this phase extends all the way down toa depth of 200 feet. The age of this second phase ofdeformation is Holocene, (that is, "postglacial" ) ..
The data base relevant to interpretation of the depth ofdevelopment of the reverse slip movements consists of:
(i) stratigraphic correlations across the CoolingTower Fault;
(ii) relationships between stratigraphic separationand depth, and;
(iii) results of detailed examinations of rock coresextracted from the fault zone.
The data clearly indicate that:(i) the stratigraphic separation resulting from the
reverse-slip movements varies in a linear mannerwith depth. Figur'es 361.30-1 and 361.30-2 present
Q361.30 Continued
the relationship of stratigraphic 'separation anddepth. It can be seen that downward the sepa-ration becomes progressively smaller. At a depthof approximately 200 feet there is no relativedisplacement of the strata;
(ii) below a depth of approximately 200 feet the senseof fault displacement is nor'mal; and
(iii) the occurrence of a deformational fabricattributable to the reverse-slip deformationappears to be restricted to the upper 200 feet ofthe fault zone.
Combining the above observations, it can be concludedthat the stratigraphic separation varies linearly withdepth indicating that there must be a limiting depthbelow which the reverse-slip deformation is notpresent. Assuming that the normal fault separationis not large (smaller than 5 feet), it followsthat this limiting depth does.not exceed 400 feet.Additionally, the occurrence of deformation fabric(attributable to the reverse slip deformation),selectively within the upper 200 feet of the faultzone suggests that the limiting depth does not exceeda value of approximately 200 feet.
Further means of estimating a value of the limiting depthcan be obtained from Figure 361.30-3. Before this can beaccomplished the following points should be recognized:
(i) the reverse-slip deformation and/or separationis a result of buckling of strata forming thehanging wall block. The buckling occurredagainst the old fault whose inclination isapproximately 60 toward the north, that istoward the hanging wall block;the wavelength of each individual buckle islimited by the wavelength of the uppermostbuckle (Ll on figure 361. 30-3), and theinclination of the fault.
(iii) buckles whose wavelength LM0 require layerparallel normal stress gg H ~ 'in order tobe formed. This relationship is depicted onFigure 361.30-4.
Considering the above points, it follows from Figure 361.30-3that the maximum possible depth of occurrence of the re-verse-slip deformation, D , is less than a value given
Q361.30 Continued
by the following equation:Ll
Dtan (90-4 )
where: 4 = inclination of the fault;=. wavelength of the upper deflections
FromPigure 361.30-5 it can be seen that Ll does notexceed a value of 130 feet. Hence, D is equal toapproximately 225 feet. The actual depth of therreverse slip deformation must be less than thisvalue.
0
SOUTH SIDE IS UP AIO NORTH SIDE IS UP AHOFNILT slsPUcfNK L mUiT 0ls UcBIE 1 15
IS NORMAL HIGH ANGLE REVERSE
STRATIGRAPHIC SEPARATION IN FEET
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0 ~
s
4
c
0
EXPLANATION <
~ Stratlgrophlc displacement measured odJocont to tha (nuit plane.o stratlgrophlc displacement measured 20 (aet ovoy (rcm ohe (suit plane.
NOTE:
(I) Dlsplocements sheen neer top o( the bedrock ora based on observationsnode In trench
(2) Olsplocements sheen ln unccnsolldatod sodlamnts Includes monocllnol(loxure over the (nuit.
DIAGRAM SHOWING RELATIONSHIP BETWEEN STRATIGRAPHIC
DISPLACEMENT AND DEPTH IN BORINGS T-5- I THROUGH T" 5-10
NINE MILE POINT NUCLEAR STATIONUNIT 2 .,
NIAGARA MOHAWK POWER CORP.
FIGURE 361. 30-1
SOUTH SIDE IS UP ANOFAUI.T DISPLACEMENTIS NORMAL
NORTH SIDE IS UP ANOFAULT DISPLACEMENT ISHIGH ANGLE RETERSE
STRATIGRAFHIC SEPARATION IN FEET
2 J d
TOP OF BEDROCK
~ 0
0 ~
0 ~
0 ~
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~ fEXPLANATI ON t
~ Stretlpraphlc displacement e»asured odJacent to tho tault plane.0 StrotlGraphlc dlsplacenent a»soured 20 toot arsy tron tho fault plane.
NOT Et
Ill Olsplacomonts sheen near top Ot the t»drock aro based on observationsnode In trench a,
DIAGRAM SHOWING RELATIONSHIP BETWEEN STRATIGRAPHIC
DISPLACEMENT AND DEPTH IN BORINGS T-4- I THROUGH T -4 - l2
NINE MILE POINT NUCLEAR STATIONUNIT 2
NIAGARA MOHAWK POWER CORP.
FI6URE 361. 30-2
DEPTH0
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4. L4Dr4
-200
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tI= t2=t3=t4; LI > L2 > L) > L)HENCE:
LI /tI > L~/t2 > LP/tg > Lg/tg
Dr4= MAXIMUMPOTENTIAL DEPTH OFREVERSE-SLIP DEFLECTION.
(DEPENDS UPON LI, AND IS
CONSTANT FOR A SPECIFIC SYSTEM.)
L =WAVELENGTH OF DEFLECTION
Or=DEPTH OF REVERSE-SLIP DEFLECTION
t= THICKNESS OF STRATA
DEVEL'OPMENT OF MAXIMUM POTENTIAL DEPTH OF
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NINE MILE POINT NUCLEAR STATIONUNIT 2
NIAGARA MOHAWK POWER CORP.
FIGURE 361. 30-3
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A
b,L/,RANGE OF SLENDERNESS RATIOOF THE UPPER INITIAL DEFLECTIONS
MINIMUM POSSIBLE SLENDERNESSRATIO CORESPONDING TO MAXIMUMPOTENTIAL DEPTH OF'THEREVERSE - SLIP DEFLECTIONS
RELATIONSHIP OF LAYER--PARALLELSTRESSTO SLENDERNESS RATIO ASSUMED NECESSARY
TO CAUSE BUCKLING ON THE COOLING TOWER FAULT
NINE MILE POINT NUCLEAR STATIONUNIT 2
NIAGARA MOHAWK POWER CORP.
FIGURE 361.30-4
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175
ZONE OF DIRECTSHEAR DISPLACEHENT
WHETSTONE GULFFORHATION
200
225
250
REVERSE SLIP DISPLACEMENTSDUE TO BUCKLING ON
COOLING TOWER FAULT
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NINE MILE POINT NUCI.EAR STATIONUNIT 2
NIAGARA MOHAWK POWER CORP.
FIGURE 361 ~ 30-5
Q361.31: In Section 3.2 of the Executive Summary, you concludethat future displacements along the deformation struc-tures at the site will involve vezy low strain rates. Usingthe data available for these structures, provide a discussionas to why past Quaternary movements and possible futuremovements should be classified as slow (i.e., creep) versusrapid (i.e., seismic).
RESPONSE: The amount of seismic energy radiated as a result of slipalong a fault in a given bedrock environment is a functionof the stress drop and the source dimensions. Furthermore,for an earthquake to occur (the amount of seismic energyradiated is large) the stress drop must attain a valuewhich is appreciably greater than zero. Typically,earthquakes are accompanied by stress drops ranging from50 to 100 bars (approximately 750 pounds per square inchto 1500'ounds per square inch) . Moreover, the earth-quake related reduction of the in situ stress must beaccomplished within a very small time interval, say 10seconds., In other words, the change in stress with re-spect to time must be relativesly large.In the April 1978 report. it. has been stated that the slipconditions accompanied by large, relatively fast stresschanges can be only conceived during the development ofthe rotated bedrock sliver (see Sections 7.0 and 8.0Volume I). Furthermore, it has been demonstrated thatit is not possible to form another rotated bedrock sliverbelow a depth of approximately 160 feet.From the present understanding of the site conditions andthe mechanism of Quaternary deformation, it cannot beruled out that minor, near-surface adjustments mayoccur in the future. These adjustments are consideredto be related to:
Further increase in amplitude of individualdeflection within the depth interval of .140 to200 feet, (below the rotated bedrock sliverwhere the stress drop was relatively small). Theprocess will be arrested and/or mitigated bythe higher deflections whose stress drop wassignificant.Development of swelling strains in areas where theearlier deformational processes reduced the con-fining pressure below a given value of the firststress invarient (see response to Q361.34). Itis expected that the occurrence of these strainswill be limited to a rock mass above a depth of160 feet.
(iii) Viscous "flow" of the bedrock in areas where thestress gradient is sufficiently large.
Q361.31 Continued
(iv) Reduction of the ability of bedrock, surroundingthe perturbation, to maintain a given stressgradient. This reduction is related to the timedependent increase of the water level in the OntarioBasin. This increase will have a minor negativeeffect on the shear strength of bedding and thus,may facilitate further reduction of the existingstress gradient.
All the above mentioned processes are related to eitherrheological properties of the bedrock (viscosity and swell)or to the time dependent environmental changes (porepressure) . The resulting strains must also be time'dependent. The strain rates, associated stress drops,as well as the rates of stress drops are infinitestimallysmall. The existing stress gradients will be decreasing,resulting in a time dependent reduction'f the strainrates-
In summary, following the reasoning presented above,as well as that presented in the April 1978 report,it can be concluded that should any future adjustmentsoccur in the vicinity of the Cooling Tower Fault, itis expected that they will involve very limited volumesof the bedrock as well as very low strain rates. Theseadjustments are of no consequence in the context ofvibratory ground motion.
REFERENCES
Brune, J.N.,1970, "Tectonic Stress and the Spectra of,Seismic Shear Waves from Earthquakes," Journalof Geophysical Research, Volume 75, pages 4997-5009.
Niagara Mohawk Power Corporation, 1978, Nine Mile Point NuclearStation, Unit 2, Geologic Investigation, Scriba, New York.
Q361.32 Our position regarding the dating of the age of thelast movement on the faults based on an apparent temper-ature of mineralization is that this method should beused with caution. Accordingly, provide your basis fordiscounting the possibility that frictional heat on thefault planes, generated during deformation, could causethe observed fluid inclusion temperatures. Further,indicate your basis for discounting the possibilitythat, fluids which deposited the calcite were heatedabove the ambient geothermal gradient.
RESPONSE: We recognize and agree with your position regarding theneed for caution when utilizing data from paleogeo-thermometry and paleogeobarometry to interpret the ageof latest displacement along a fault. Indeed, the databy themselves do not provide direct information per-taining to their time of origin. Instead, one mustinfer this information based upon other data regardingthe samples, their origin and local geologic (structural)relationships, and knowledge of the regional tectonicframework. Where these supplementary data are notavailable, paleotemperatures can be equivocal.
It was with this potential ambiguity in mind that thefault and fracture fillingminerals were assessed as totheir emplacement mechanism, environment and time oforigin in the 1978 report (Niagara Mohawk Power Corporation,1978; Geologic Investigations Nine Mile Point NuclearStation Unit 2; Volume I).Since the completion of that report all availablefluid inclusion data for northern New York State andsoutheastern Ontario, Canada were reviewed. Additional=-data have been obtained from investigations for a Pre-liminary Safety Analysis Report for New Haven which isapproximately 5 miles to the southeast of the Nine MilePoint Site. These newer data were reviewed and assessedin responses to Questions 361.13 and 361.14 which weresubmitted in June 1980. Comparison of these resultswith those reported in Section 2.2.4.2 of the 1978report reveals that the majority of regional tempera-tures of homogenization are consistently in the rangeof 65 Centigrade (C) to 178 C. These values (a) are inexcellent agreement with the data from the Nine MilePoint Site, and (b) represent temperatures. obtainedfrom specimens from a variety of specific settingsincluding joints, beds, and stylolites, as well asfaults. Intuitively, the quantity of frictional heatgenerated by shearing along these other features incomparison to faults would be minimal. Hence, oneshould be suspicious of the possible explanation thatheat from frictional resistance to shear accounts forthe high temperatures calculated from fluid inclusions.
Q361.32 Continued
There are two lines of evidence indicating that thetemperatures of homogenization recorded by the calciteand quartz (in the host rock) represent heat from asource or sources different from the heat of friction.Dr. H.L. Barnes reported (Appendix E, Volume, I, NiagaraMohawk Power Corporation, 1978) the occurrence of certaineuxinic sulfides accompanied with calcite along beddingas well as fracture planes; among them are mackinawite(FeqS8) and troilite (FeS) . These minerals are thoseto be expected from the aging of sedimentary iron sul-fides, and have limited stability ranges. Mackinawiteis unstable at temperatures above'40 -150 C (Appendix E,Niagara Mohawk, 1978); however, if buried to depths of2 kilometers or more the stability limit increases to155 C-160 C. This is completely compatible with the160 C temperature values from fluid inclusions in re-crystallized quartz from the host rock.
The other line of evidence is the discovery of calcitedeposited by groundwater flowing along the Radwaste Fault,and Lake Water Tunnel faults as reported in the responseto Question 361.1(d) submitted in, June, 1980. As re-ported, this calcite contained fluid inclusions withdecrepitation temperatures of less than 40 C. Dr. Barnesindicates that, in one specimen collected from thethrust fault in the tunnel, low-temperature calciteas matrix encloses breccia fragments of sandstone andmilky calcite such as identified from the Cooling TowerFault. Because the liquid-to-vapor ratio of the milkycalcite inclusion clasts is approximately the same asthat for the in situ milky calcite, no alteration orre-crystallization occurred when the low-temperaturecalcite was formed. Because the earliest generationof groundwater calcite always exhibits cataclastictexture, and because the texture, character of inclusions,their temperature values and the mineral paragensisall suggest that the groundwater calcite grobablycrystallized at temperatures less than 40 C, it is highlyunlikely that frictional heat adversely affected inclusionentrapment temperatures in the calcite.A further argument from a mechanical standpoint may bemade that friction on the Cooling Tower Fault could nothave contributed a significant, quantity of heat suchas would influence the entrapment temperatures of fluidinclusions. Price (Appendix L, Volume III, Niagara Mohawk,1978) indicated that:
1) The rocks were saturated with brines.2) The minimum fluid pressure likely to be
attained over long time periods is that ofhydrostatic head.
3) Mineralization of the fault can lead one toinfer that the fluid pressure exceeded thehydrostatic state.
Q361.32 Continued
In other 4ords, with progressive sedimentation in theAppalachian Basin, the ratio ( ~ ~ of fluid pressure tothe vertical geostatic pressure commonly approached avalue of 1.0 and locally could exceed this value undercertain conditions. It can be shown that normal faultscould develop and that the normal stress across suchfaults would be negative, that. is the fault planeswould be "open" thereby permitting flow of fluids alongthe faults with consequent precipitation of vein-fillingminerals. Under these circumstances, the contributionof friction to the value of shear resistance would beminimal. One can extend this argument to include thethrust faults. These faults were formed later thanthe normal faults, and at. higher levels in the crust.as evidenced by abundant dilation of beds affectedby the deformation. In this instance, the value ofshould have been much lower than at the time of normalfaulting. Hence, one would expect the friction to havebeen relatively greater during thrust-type slip, thanduring normal-slip. However, the paleotemperatureswere apparently less than 40 C. Therefore, one canonly conclude, once again, that frictional heat had anegligible effect upon the inclusion entrapment temper-atures. The temperatures more likely reflect the ambientgeothermal gradient at the time the minerals were formed.
In the 1978 report, based upon the work performed byDr. Barnes, it was concluded that the paleotemperaturesrecorded by the minerals were elevated initially due toincreased heat flow caused by dehydration reactionstypical of the zone of transition from hydrostatictemperature/pressure to lithostatic temperature/pressure conditions in the Appalachian Basin, analogouswith the Gulf Coast Basin. It was postulated thatthese fluids of elevated temperature caused. the de-velopment of a transient thermal gradient of as much as40 C/kilometer for a period of a few tens of millionsof years. It was also stated (pages 6-14 of Volume I)that there were two other potential causes of anelevated geothermal gradient: localized magmaticprocesses and crustal thinning associated with tectonicprocesses. The closest known evidence of paleo-magmaticactivity is in Syracuse, New York where several Jurassickimberlite dikes are known. Batholithic intrusions ofthe Monteregian Hills, Canada are known to be Cretaceous.However, no clear evidence of hydrothermal mineralizationdue to igneous activity was found in the site region.Similarly, because progressive sedimentation in the nor-thern Appalachian Basin continued through the Mississippianperiod, it is improbable that crustal thinning wasoccurring beneath the basin rather than beneath theuplands. Therefore, no firm reason to support thesupposition that the fluids from which fault-fillingminerals precipitated could have been heated abovethe ambient geothermal gradient can be offered.
Q361.33 In Appendix I-G of your report, you present resultsof uranium/thorium (U/Th) disequilibrium dates fromsamples of fault-plane calcite. Indicate how thisevidence affects your assessment of the most recentmovements on the fault. Discuss why the ages of 80,000and 170,000 years before the present as determined bythis technique, are not consistent with ages of faultingdetermined by other methods. Our concern is that ifthere is sufficient uranium present in the sample toestablish a U — Th disequilibrium date, then there shouldbe sufficient uranium and lead for a U-Pb, Pb-Pb, orU-fission track date. Any one of these methods wouldbe much more sensitive and meaningful if the calciteis older than 200,000 years. If possible, provide areliable date by one or more of the methods cited aboveif the 80,000 year date is to be discounted as youclaim.
RESPONSE:Conclusions regarding 'the nature and age of specimensSW-1 and SW-2 which yielded the Th/U dates of 80,000and 170,000 years, have changed in light of detailedadditional geological investigations performed at theNine Mile Point Site since 1978. Subsequent work atthe Nine Mile Point Site has revealed the occurrenceof a generation of calcite which crystallized at alater time and at lower temperatures than the varietiesof calcite identified in the 1978 report. The newercalcite has been found to be present in association withzones of deformation of the low-angle thrust faults inthe North Radwaste Trench, in the Intake Shaft and EastLake Water Tunnel, as well as bedding plane slip zoneselsewhere on site. The occurrence of this calcite hasbeen documented, and specimens were collected for fluidinclusion and paragenetic analyses by Dr. H.L. Barnes.
Calcite specimens were collected from three locales:
1) the Circulating Water Piping Trench to therelocated cooling tower,
2) the North Radwaste Trench, and;
3) the East Lake Water Tunnel
Additionally, radiometric dates and stable isotope analyseswere obtained to help interpret the absolute age of thecalcite. Results are outlined herein and full detailsdocumenting the occurrence, analyses, and conclusionswill be presented in a report to be submitted at a laterdate.
Dr. Barnes'aragenetic studies have distinguished asmany as six varieties of calcite in the entire parageneticsequence which is presented schematically in Figure 361.27-2.
Q361.33 Continued
Dr. Barnes also identified two additional stages of defor-mation based upon microscopic mineral textures. He termedthese stages D5 and D6. The mineral types are briefly de-scribed below.
alent, but Type 2 was only recognized at one locality,the Circulating Water Piping Trench. Type 1 consistsof fine-grained clear calcite which has been brecciatedand recemented by later calcite. Typically, clasts ofbroken bedrock are incorporated within it. Para-genetically, this group apparently is the oldest of thissequence, but its texture and isotopic compositionindicate that it post-dates the clear calcite associatedwith Mesozoic normal faulting identified in the 1978report. Fluid inclusions were rarely found in Types 1or 2. The intense cataclasis of this calcite apparentlyliberated any inclusions which may have formed. Thisgroup of calcite is always found on shear planes of theRadwaste and East Lake Water Tunnel thrust faults, andalong brecciated zones of bedding-parallel slip onsite.Dilated openings in the bedrock, associated with thesezones of shear deformation where this mineralizationoccurred, suggested a near surface origin of Type 1calcite.Travertine: Many forms of very fine-grained, travertinewere observed and this mineral group is parageneticallyrelated to Type 1 calcite in that, although never foundtogether with Type 1, it always underlies or is infilledby later forms of calcite, as in the case of Type 1. Thetravertine was deposited above the water table. Type 1crystallized below it. The travertine is found on dilatedbedding planes and joints in the zone of deformation ofthe Radwaste Fault, and has been deformed.
very fz.ne-grained calcareous material containing abundantpyrite and siliceous detritus, deposited on travertine andcovered by Type 3 calcite. This is not a dominant formof mineralization at the site.T~pe 3: The sperry calcite is found in a variety ofhabet.ts, and occurs in fractures and openings in the Type 1breccias and travertines, and are therefore younger thanthe age of deformation of Type 1 (D5). Type 3 calciteis the only one of the =lower temperature calcites thatcommonly contained fluid inclusions. They are predomi-nantly liquid-phase inclusions, but have high liquid-to-vapor ratios when a vapor phase is present. The fluidhas a very low salinity, (5 to 6 percent NaCl by weight) .Ths maximum filling temperatures of these inclusions is40 C. Minor healed fractures in Type 3 have been observed(D6) plus chips of Type 3 have been seen to be healed bybrown calcite.
Q361.33 Continued
Brown Calcite: This mineral lies on top of sparry, Type 3calcite, but is present only irregularly, being both dis-continuous and of varied thickness. This mineral isinterpreted to be younger than D , and is parageneticallythe youngest variety of calcite.
A e of the Calcite: During the investigation, the absoluteage of the major forms of calcite were analyzed and evalu-ated utilizing stable isotope ratios of «3C and O plusabsolute dates by the 14C and 230TH/234U methods. Theresults are summarized in Table 361.33-1.
Additionally,'specimens of the drusy calcite dated by theTh/U method from the Cooling Tower Fault study werereassessed in light of the new data from the parageneticstudies on groundwater calcite. As a result of this work,the following conclusions can be drawn with respect toType 1 calcite, Travertine, and Type 3 calcite.1. Type 1 calcite is apparently the oldest of the ground-
water calcites. It is younger than calcite found atthe time of normal faulting (Mesozoic) because of itsnear-surface origin and lower inclusion temperatures.Carbon and oxygen isotope results (Table 361.33-1) indi-cate a typically marine source for the carbon, but afresh.ma~ source for oxygen if the carbonate isyounger than Triassic. A marine origin of the car-bonate oxygen would be unlikely in Triassic timebecause the site area was emergent and erodingthroughout the Mesozoic. (ence, fresh eater appa=entlyleached the older marine C from the site bedrocP,thereby explaining the greater than 36 000 year C
age (sample HK-1). For this reason a TH/ 34Udate, to determine the actual age of calcite crystalli-zation, was performed by Dr. T.L. Ku of the Universityof Southern California. His analysis yielded a lessthan 300,000 year age.
2. The travertine was found to be a vadose precipitateyielding a C age of 14,180+550 year age. This ageis somewhat compatible with that yielded by shellsfrom sample SL-10 from the
$gcustripI overburden at thesite (Table 361.33-1). The C and 0 ratios indicatea superficial source of both carbon and oxygen infresh waters of relatively shallow circulation.Inasmuch as glacial ice covered the site 14,000 yearsago, the travertine likely formed at a later time.This is because it formed above the water table.
Q361.33 Continued
Small quantities of older carbon leached fromPaleozoic carbonate clasts by water percolatingthrough till in the overburden could have beenincorporated into the travertine, thus settingback the 14C age. Nevertheless, the travertineis of Late Wisconsinan age, and the parageneticstudies showed that it is deformed and fracturesin it are filled by Type 3 calcite.
3. An insufficient aTgunt of Type 3 calcite was collectedfor a successful C date, but the 13C ratio showsthat the carbon is also from a fresh water source(Table 361.33-1) . This calcite is the same age oryounger than the travertine, namely Late Wisconsinanaa
Dr. Barnes re-examined the data from specimens JT-13,43 and 44 collected from the same material which yieldedthe TH/U dates reported in the 1978 report (SamplesSW-1 and 2) . He has concluded that the clear calcitein these samples is actually Type 1 calcite for threereasons:
1. They contain single phase inclusions andinclusions with high liquid-to-vapor ratios,yielding temperatures well below 100 C.
2. The occurrence of sulfides (marcasite, pyrite)in JT-44 closely corresponds to those seen inthe Type 1 calcites ( Table 361.33-1) .
3. Ku's analyses of Type 1 in TU-1 (analyzed recently)and SW-1 and 2 (analyzed previously) showed thereto be excess Th in the calcite because of theinheritance into Type 1 calcite of older clastsof milky calcite.
Additionally, fluorescence techniques applied to analysisof the Type 1 calcite has revealed that Type 1 consistsof several compositional types of calcite indicative ofthe inheritance of older epigenetic calcites. Thismeans that Type 1 calcite is prejudiced for older dates.Consequently, dating by the U-Pb, Pb-Pb, and probablythe U-fission track methods is precluded because of themixing'of young and old calcite.Hence, one can conclude from these new data that the clastsof breccia in Pit 1 were coated by a drusy form of low-temperature Type 1 calcite at the bedrock/till interfaceto be distinguished from the high-temperature epigeneticcalcite which was found in every surface exposure of andthroughout the cores obtained from the zone within the
Q361.33 Continued
Cooling Tower Fault. Moreover, the results of age-datingstudies show that the Type 1 calcite is less than 300,000years old. Therefore, the results of the 80,000 and 170,000year dates are no longer discounted. Furthermore, thetravertine and Type 3 calcite are approximately the same ageas the later stages of glacial Lake Iroquois, (approximately11,000 years before present) .
From geological evidence (Niagara Mohawk, 1978, Volume 1,Section 4.0), it is known that the main stage of bucklingoccurred prior to deposition of the Wisconsinan overburdenand that buckling caused dilation of the upper 200 feetof the bedrock section. It is known now that dilationand crystallization of Type 1 calcite are also associatedwith the development of the thrust faults. Therefore,the time of buckling on the Cooling Tower Fault could becorrelative with the beginning of thrust fault development,which, because of the postulated mechanism of deformationfor this sytem of structures, must have occurred. duringthe final stages of an interglacial period (refer toresponse Q361.28; and to Sections 7.0 and 8.0, Volume 1and Section 7.0 Volume III, Niagara Mohawk Power Corporation,1978) .
TABLE 361.33-1
RADIOMETRIC AND ISOTOPIC ANALYSES
Number:
Sample:
14 Age (years)
13C 00
HK-l, TU-1
TYPE 1Calcite Breccia
36 g 000 (HK 1)
+ 3.1 (HK-1)
HK-2
Travertine
14,180 + 550
7.5
HK-3
TYPE 3Sparr Calcite
4.7
SL-10*
Mollusk Shells
12,545 + 330
6.9
18O ( /00)
230 /234 (years)
+ 21.1 + 0.2 (HK-1)
300,000 (TU-1)
+ 22.6 + 0.2
*From Niagara Mohawk Report, 1978, Uolume II. Collected frommarl in overburden along Circulating Water Piping Trench.
0,
Q361.34 Substantiate the argument presented in Section 2.6 ofyour Summary that swelling stresses may have resultedfrom fluctuations in water level in Lake Iroquois. Showthat rocks at the site can develop a swelling stress underconfined conditions with water pressure varying from 1 to10 atmospheres. Estimate how rapidly Lake Iroquois musthave drained so that residual pore pressues could approachlithostatic pressures. In this evaluation, use thepermeabilities determined by pumping test in the upper200 feet of rock in this area.
RESPONSE: In order to characterize the swell behavior of the bedrockat the Nine Mile Point site, various swelling tests wereperformed. These tests included free swell tests (uncon-fined swell) as well as oedometer ring swell tests (con-fined swell) . The results of the free swell tests werepresented and discussed in the April 1978 report. Itwas concluded that the development of swelling strainsis conditioned by the accessibility of water, and thereduction of confining in situ stress below a givenvalue.
The results of the oedometer ring swell tests are pre-sented on Figures 361. 34-1 through 361. 34-8. The Figuresshow the relations of the swell rates as a function of thefirst stress invarient, which is the. sum of the principalstresses. The rock units within which the Cooling TowerFault is developed were tested for swelling potential.The following conclusions can be reached, based on thedata presented:
(i) the swell strain rates are dependent upon thefirst stress invarient. The rates decreaselinearly with the increase of the stressinvarient;
(ii) there exists a limiting value for the firststress invarient beyond which swell rate isequal to zero. The limiting value indicatedby the results appears to be larcener thanapproximately 450 pounds per square inch (firststress invarient corresponding to hydro taticpressure equal to 10 atmospheres) .
Hence, it follows that rocks present at the site candevelop a swelling stress under confined conditionswith water pressure varying from 1 to 10 atmospheres.However, in order to develop these strains, the in situ
'edrockstress must be reduced below the limiting value ofthe stress invarient. From observations of bedrockdilations onsite, it is clear that the required reductionoccurred simultaneously with the deformation. The residualpore pressure may have been important in triggering thisdeformation.
Q361.34 Continued
The deformation must have been accompanied with astress drop and the development of a stress gradient.As a consequence of the deformation, permeabilityof the bedrock was substantially increased and thepore pressure was reduced. Following that, theswelling of the bedrock could have taken place, pro-vided that access to water was maintained.
Available data regarding the drainage of Lake Iroquoisdo not allow a more precise estimate than already pre-sented in Plate 1-14 of Volume II of the April 1978 report.Calculations of the rate of drainage would be hiahlvspeculative, requiring knowledge of the outlet crosssectional area and inflow rate. Additionally, changesin bedrock permeability occurred as a result of thedraining of Lake Iroquois as evidenced by the presenceof lacustrine deposits on bedding planes and fracturesto below 200 feet. Therefore, it would be inappropriateto utilize present. permeability values determined in theupper bedrock units. It is felt that the load castsand sand dikes observed in the Sandy Creek sedimentsabove the Cooling Tower Fault provide sufficient evidencethat, Lake Iroquois drained relatively quickly and porepressures probably did approach lithostatic pressures.
'
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ESTIMATED UPPER BOUND
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FIRST STRESS INVARIANT (PSI)
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HORI7.ONTAL SWELL STRAIN RATEV.S. FIRST STRESS INVARIANT- PULASKI B & C
NINE MILE POINT NUCLEAR STATIONUNIT 2
NIAGARA MOHAWK POWER CORP.
FIGURE 361 ~ 34-5
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SMELL STRAIN/STRESS TESTS
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ESTIMATED UPPER BOUND
ESTIMATEDAVERAGE
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Ao VERTICAL SWELL STRAlN RATEV.S. FIRST STRESS INVARIANT- PULASKI 8 5 C
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0 FREE SWELL TESTS DATAON SHALE SAMPLES FROM PULASKI C
(TEST NOS. TD-1"13,TD-1-14, TD-1-16)
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ESTIMATED UPPER BOUND
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STRAIN/SWELL STRESS TESTS
ESTIHATED UPPER BOUND
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VERTICAL SWELL STRAIN RATE'V.S. FIRST STRESS INVARIANT- WHETSTONE GULF FORMATION
700 Soo
Q361.35: If the draining of Lake Iroquois provides a plausibleexplanation for the Quaternary movement along thedeformation structures at the site, then similar featuresshould exist at other locations similarly affected by thedraining of Lake Iroquois. The existence of similarstructures only at such locations would provide evidencefor your hypothesis. Accordingly, determine the knowndistribution of such structures from a literature searchand present a discussion as to whether this distributionfavors your hypothesis.
RESPONSE: In the region affected by the draining of Lake Iroquois,numerous buckles of postglacial age were reported (NiagaraMohawk Power Corporation, 1978, Volume I, Section 2.0,and Volume II, Section 3.0) . It was also reported(Volume I, Section 2.2.3.5) that the buckles were of twotypes: chevron-style, and sinusoidal. Sutton's (1951)work in western New York State indicated that a chevon-style buckle:
"typically coincides with a pre-existingfracture or fault, which is situatedalong the axial plane."
A classic example of the relationship between bucklesand faults is the structure exposed at Thirtymile Pointnear Lyndonville, New York.
The locations of postglacial deformational features inthe Lake Ontario region are illustrated on Figure 2-4,Volume I of the April 1978 report. None of the defor-mations reported appears to be as complex as that notedalong the Cooling Tower Fault, but the lack of significantbedrock exposures along the southern shore of Lake Ontarioprecludes a detailed assessment of the distribution andcomplexity of similar structures.
REFERENCES
Niagara Mohawk Power Corporation, 1978, Nine Mile Point NuclearStation, Unit 2, Geologic Investigation, Scriba, New York.
Sutton, R.G., 1951, Stratigraphy and Structure of the BataviaQuandrangle, Proc. Rochester Acad. Sci., v. 9, p. 348-408.