~

)'e

REGULATOR LNFOHMATION DISTRIBUTION S l'EM (RIDS)

'ACCESSION NBR 8 l09040080 DOC ~ DATE ~ 84/08/27 NOTARIZED~ YES DOCKET ¹FACIL:50-410 Nine Mile Point Nuclear Stations Unit 2i Niagar a Moha 05000410

AUTH

BYNAME

AUTHOR AFFILIATION,MANGANgC,V, Niagara Mohawk Power~,-Corp,

REC IP» NAME. 'ECIPIENT AFFILIATIONSCHHENGERgA", Licens1ng Branch 2

1 'I ~

SUBJECT: Forwards. responses,to SER Open Items 9~12>Responses will beincorporated into next- FSAR amend, Affidavit encl.

DISTRIBUTION CODE! 8001D COPIES RECEIVED!LTR f" ENCL SIZE»T'ITLE! Licensing Submittal: PSAR/FSAR Amdts 5 Related Correspondence

NOTES PNL" icy FSAR~S L AMDTS"ONLY'5000410RECIPIENT

ID CODE/NAMENRR/DL/AOLNRR LB2 LA

'INTERNAL; 'AOM/LFMBIE FILEIK/DKPER/IRB 35NRR/DE/AEABNRR/DE/EHEBNRR'/OE/GB 28NRR/OE/MTEB 17NRR/OE/SGEB 25NRR/DHFS/LQB 32.NRR/DL/SSPBNRR/OS I/ASBNRR/DSI/CSB 09NRR/DSI/METB 12'-

AB22'EG,

F 04MI/MI8

EXTERNAL! AC"SOMB/DSS (AMDTS)LPOR '3NSIC 05

NOTES:

COPIESLTTR ENCL

0"0

01 1

1

0

1

2 21 1

1

1

fs 01 1

1 1

1 1

1- 1

l- 1.1 0

6l 1

1 1

1

1 1

RECIPIENTID CODE/NAME

NRR LB2 BGHAUGHEYgM 01

ELD/HDS3IE/DEPER/EPB 36

-IE/OQASIP/QAB21NRR/OE/CEB iiNRR/DK/EQB 13NRR/DE/MEB 18NRR/OE/SAB 24NRR/OHFS/HFE840NRR/DHFS/PSRBNRR/OS I'/AEB 26NRR/DSI/CPB 10NRR/DSI/ICSB 16NRR/DS I/PSB 19NRR/DSI/RSB 23RGN1

BNL(AMDTS ONLY)FEMA REP DIV 39NRC PDR 02NTIS

COPIESLTTR ENCL

1 0

1,

1 03 31

.1 1

2 21

1 1

1 1

1 1

1 1

1 1

1 1

1 1

1 1

3 3

1

1

1

TOTAL NUMBER OF COPIES REQUIRED: LTTR 55 'ENCL 47

M ll Ifl<

, Ka J;JF

M

f

M Mgla

IJ M <<L

M<

I

r

» $ lti, 1» t~'R N

'I el'

,tf< p t

L

', '-g M 4< f'tf<L,

M p, Il ->M lM 'l,u, g~ f M',q<F. l,<~ 0, I =-*l,.4'1M

f ) g,/+fthm< <'M, < gg pic <<ly'0 g M0'i<A '1<It<9'"'M'

'J

M

JJL<t <g'f,<err I $ >M M <Fr„"Mp I 'r<u( lf ',, 0 ",

<',', "

<M"I<.,»',<-'l 'I

M 4,<f g'If'." ' "fl'I ';) f

j g <lp I

"]

FJ" Mlg'I

Ml,",l < Ijj<'g r u

M]»,

'IIIg

yur)QM$

Q< l,lg

II

I K t,

I

MF $

< F I M

'A

M V Milka'A,IRA,IAfU MOoHAMKNIAGARAMOHAWKPOWER CORPORATION/300 ERIE BOULEVARDWEST, SYRACUSE, N.Y, 13202/TELEPHONE (315) 474-1511

August 27, 1984(NMP2L 0143)

Mr. A. Schwencer, ChiefLicensing Branch No. 2U.S. Nuclear Regulatory CommissionWashington, DC 20555

Re: Nine Mile Point Unit 2Docket No. 50-410

Dear Mr. Schwencer:

Enclosed for your use and information are Unit 2 responses to the NuclearRegulatory Commission's Safety Evaluation Report open items. This informationhas been previously discussed with your staff and is submitted to aid yourreview of the Unit 2 license application for the resolution of these openitems. This information includes Safety Evaluation Report open items 9, 10,11 and 12.

The enclosed will be included in the next Final Safety Analysis ReportAmendment.

Very truly yours,

NLR:jaEnclosurexc: Project File (2)

C. V. ManganVice President

Nuclear Engineering & Licensing

8409040080 8408pyADQCK 0~0004i0E

PDR

7

t

UNITED STATES OF AMERICANUCLEAR REGULATORY COMMISSION

In the Matter of

Niagara Mohawk Power Corporation )

(Nine Mile Point Unit 2) )

Docket No. 50-410

AFFIDAVIT

C. V. Mangan, being duly sworn, states that he is Vice President of NiagaraMohawk Power Corporation; that he is authorized on the part of saidCorporation to sign and file with the Nuclear Regulatory Commission thedocuments attached hereto; and that all such documents are true and correct tothe best of his knowledge, information and belief.

Subscribed and sworn to before me, a Notary Public in and for the State of NewYork and County of , this ~f+ day of QD de 198,4.

Notary Public in and fora. County, New York

My Commission expires:

yNSINKNSTN

hl ONSET Co. No. 4787687shia the State of Nsw York

Caaehhe ihrch 30, NEO

r

7

7 'IP, illa 7 ~

Ii:~7

f, ] 77

I'

117I~'.l",

)III

! '

'biC~ ~ '

Il

0 ~

Il Il~

ii

'lk/ If W

"',7 n

I7 7 , ,7 7 ", N

lllTZUABVtiZ|QPAs'f r."ll to a;~ sC cc o'"t<"IecheTL74% rH.B sphrA rd 5$dc~B,CS doM~ tauy3 r~e~o3 gQ

.i Genesis of Stresses at the Nine Mile Point Unit 2 Site

The NRC Staff has requested (No. 1, Draft SER, p. 2-53 a recalculation of thechanging stresses through time at the site, assuming less depth of burial usedoriginally in the calculations.

The Staff has indicated a concern regarding the use of recorded maximum depthsof burial for the sediments exposed in the near subsurface at the NMP-2 sitefor the purpose of estimating stress conditions extant at the time ofinitiation of normal faulting. The Staff's concern lies with the use of thefluid inclusion studies as an indicator of maximum temperature of burial (whenused with an assumed geothermal gradient) because they may lead to an

assumption of greater burial depths and less conservative ages when assessingthe capability of a fault.

The subsequent paragraphs provide the applicants response to this request.

Conodont Color Alteration Index CAI)

Harris, et al (1978) and Epstein et al. (1977) have reported on the use ofconodonts and their color alteration with increasing depth of burial (highergeothermal temperatures) as a means of assessing the thermal maturity ofdiagenesis within an active sedimentary basin. The Staff has referred to a

CAI in the site area indicating a maximum temperature of 60'o 100'C (140 to212'F) for the Oswego Sandstone in the site region and a'eothermal gradientof 35'C/km (95'F kilometer)(Draft SER). This would be interpreted as an

estimated depth of burial of 1220 to 2440 meters (3660 to 7220 feet) of thesediments containing the conodonts at the time of maximum temperature. Itshould be noted that there have been no reported occurrences of conodonts,however, from high energy, clastic rocks such as the Oswego Sandstone in thisregion. The Staff further refers to the CAI as not requiring interpretation,as the color of the conodont as found in the rock is a direct result of themaximum temperature ranges experienced by the rock, is independent of pressureand is irreversible (Epstein et al 1977). The Staff, therefore, feels thatthe CAI is more reliable than fluid inclusion studies, which were used by theapplicant for estimating the maximum depth of burial for sediments existing atthe Nine Mile Point-2 site.

II II

CI

I

e

As shown on the attached data sheets which were obtained directly from Dr.Anita Harris (personal communication, 1984), none of the counties surroundingthe Nine Mile Point-2 site has yielded any surface or drill hole samples (one

sample) to be included in the CAI map of the Ordovician rocks in the northernAppalachian Basin. Those samples that have been studied from surroundingcounties (underlined on each of the data sheets) are Si luvian and Devonianrocks which yielded a CAI of between 2 and 3. Utilizing the lower value (2)as representative of the CAI in the site area, the suggested approximateoverburden depth at the time of fixing the color (maximum temperature) of theconodonts ranges from 8,000 to 12,000 feet (2,440 to 3,660 meters). This iscertainly consistent with the depth of burial estimates of 3.5 km (11,500 ft.)reported in Section 7, FSAR Reference 2.5-94.

Although conodont color alteration is progressive, accumulative and

irreversible (Harris, et al, 1978) and is time and temperature dependent, indiscussions with Dr. Harris, it was found that recent studies by her and hercolleagues have shown that the color alteration of conodonts is highlysensitive to the presence of mineralized solutions. Dr. Harris (personalcommunication, 1984) has estimated that the thermal maturity, as expressed inthe color alteration index, may be retarded by as much as 50K in the presenceof a closed system of circulating fluids. During and subsequent to thethermal maximum of diagenesis, the epigenetic sequence of sulfidemineralization observed at the site was deposited in a reducing (i.e., closedto the atmosphere) environment by circulating fluids (Tillman and Barnes,1983). Therefore, should the conodont color alteration index even be lessthan two in the site region, say l-l/2 to 2, the presence of circulatingfluids which is known to have occurred at the site would make any reported CAI

number of conodonts found at the site most likely on the low side. This would

suggest, therefore, that the depth of burial estimates deduced from the CAI

would be conservative.

In consideration of the above, the applicant's position is that the verythorough and systematic study of the paraganetic relationship of observedmineralization and fluid inclusion study to the genesis of faults and

fractures in the Nine Mile Point Unit 2 site area has provided a conservativeand thorough analyses of the stress genesis through time at the Nine MilePoint 2 site. Any recalculation of the stress history at the site would be

unwarranted as the differences among the estimates of depth of burial between

fluid inclusion analysis and the reported CAI would be only one to severalhundred meters.

rl* rl4 Idd

rdat » ltrll d N ~

dl I'' 'II'd> ~

w W

M

dl dh"

WI r

r

r

flrr II, ll

lw

II IIII I

V iI l Ir

I rwrr ~ W W

1 r rl

*WIW' 'N '~ Wll.

$

~I

~ tr dr

W h

d

w 'r

SThTE LATITUDE/LOHGITUDE SYSTBl (SERIES) STRhTICRhpllIC QUIT Chl

HEM YORK Hontgomery

Nagara

Ooegdd

Olltllld gd

Ontario

42 54'7436'2

55'7855'3

16'15"/73 09'45"

42 57'30"/76 26'30"

42 50'48"/75 54'55"

42 55'04"/76 14'39"

42 54'10"/77 22'10"

42 45'7721'2'48O

/77'30'rdovician

Silurian

Ordovician

Devonian

Devonian

Devonian

Devonian

Devonian

Devonian

Trenton Croup

Tully Limestone

Ludlouville Formation

Ludlouville Formation

Ludlo|dville Formation

(u)

(u)

Ccnesee Formation

Cenesee Formation

(ll) Shorehom Foist ion

(L) Reynoles Limestone

2.5-3

1.5

2.5-3

2.5

Orange

Ocsego

Rcnsselaer

42 49g /7723'1

16 1 04" /7/0 22 0 20"

41 15'07 "/74 26'12"

41 28'08"/74 15'38"

41 29'36"/74 02'12"

41 30'7402'1

27'7406'1

21'49"/74 39'53"

42 48'7443'2

49'47"/73 36'55"

Devonian (U)

Ordovician

Ordovician

Ordovician

Devonian

Dcvonioh

Devonian

Ordovician

(L)

Ordovician (H)

Ordovician

Ccnesec Formation

llolcyon Lake Cele-doloaconc

Balmville Limestone

Balmvillc Limestone

Balmville Limestone

Balmvillc Limestone

Coeymans Formation

Kalkberg Formation

Onondaga Formation

Dcepkill Shale

4 '

4.5

4.5-5

4-4.5

STATE COUNTY LATITUDE/LONCITUOE SYSTEM (SERIES) STRATICRAPUIC UNIT CAI

Albany

Cactaraugus

Clin ton

Columbia

42 28'20"/73 55'10"

42 39'7401'2

39'7354'2

00'7830'2

13'7857'2,

49'7644'2o43e39«/76o41e17

42 47'37"/76 30'20"

42 48 '24"/76 17'22"

44 48'34"/73 26'46"

44 47'47"/73 29'33"

44 50'54"/73 25'29

44 53'20 /73 26'15"

44 47'7326'2

16'28"/73 43'l4"

42 17'7331'2

22'48 /73 26'36"

42 06'30"/73 32'30"

42 06'29"/73 32'26"

Devonian (L)

Devonian (L)

Devonian

Devonian (U)

Silurian (N/U)

Silurian (U)

Devonian (N)

Devonian (H)

Devonian (H)

Ordovician (L)

Ordovician (L)

Ordovician (8)

Ordovician (M)

Ordovician (H)

U.B/L.Ord.

Ordovician (L)

Ordovician (L)

Ordovician (L)

Ordovician (11)

Coeymans Formation

Coeymsns Formacion

Onondaga Formation

Oseaeyo Formation

Cobbleskil1 Limestone

Ludloeeville Formation

hedloeeville Formation

Ludlowvill» Formation

Providencc Island Dolostone

Spelimsn Formation

Day Point Limestone

Day Point Limestone

Clens Falls Limestone

Scuyvessnt Falls formation

Scockbridge Croup

Scockbridge Croup

Copake Limestone

Baimville Limestone

2-2.5

2-2.5

2.5

4-4.5

4.5

3-3. 5

5-5.5

4. 5-5

5-5.5

0 ~References - Genesis of Stresses

U.S. N.R.C.; Draft Safety Evaluation Report, Section 2.5, Nine Mile PointUnit 2, Final Safety Analysis Report, February 16, 1984.

Harris, Anita G., L.D. Harris and J.B. Epstein; 1978; Oil and Gas Data fromPaleozoic Rocks in the Appalachian Basin: Maps for Assessing HydrocarbonPotential and Thermal Maturity (Conodont Color Isograds and OverburdenIsopachs); Miscellaneous Investigation series Map I-917-E; U.S. GeologicalSurvey.

Epstein, A.G., J.B. Epstein and L.D. Harris; 1977; Conodont Color Alteration-an Index to Organic Metamorphism; U.S.G.S. Prof. Paper 995, 27p.

Niagara Mohawk Power Corp.; 1982; Final Safety Analysis Report; Vol. III, FSAR

Reference 2.5-94.

Tillman, J.E. and H.L. Barnes; 1983; Deciphering Fracturing and Fluid MigrationHistories in Northern Appalacian Basin; AAPG Bull., Vol. 67, No. 4, April1983.

~U„' .Wkf .,'>W,. ' ''UUU'I'i~

't-((U "'1 " ', ' ' "' l ~ - o ~~ o"

~ I ''at"W<" ',"' 'Il "v "

W

'

~ ~ >Uvh ~ ~,, C ~

WL(lh»

I ~W W

~

~ I ~«U I I''

Il lv 'W( UWW p UW t' ~" ~ ll II ~ tl, ~ W W, ~ ~

~ (

II.U

Ut''v hl, f I h ht f „U 3 v ~ 4

, i .'W', (AU, I Il f f) ) < Uv ll W;

f v

~ 'W

~Stresses Observed in Bedrock in the Re ion Surroundin the Nine Nile Point Site

The NRC Staff has generally agreed with the applicant that the latest movement

on the Cooling Tower Fault is nontectonic in origin and, therefore, noncapablein the meaning of Appendix A to 10 CFR 100. However, because they believethat this conclusion is not completely demonstrated by field data, they have

requested additional information. Specifically, they have requested (No. 2,P. 2-53 of the Draft SER) "An evaluation of the significance of the decoupledregional stress regime" (SER Open Item No. 10). Subsequent paragraphs providea discussion of the regional stress field around the NNP-2 site).

The Staff has discussed and summarized their observations regarding theregional stresses around the NNP-2 site on pp 2-35 to 2-37 in the draft SER.

In this summary, they have expressed several reservations about theorientation and magnitude of the regional stresses that they feel requiredadditional clarification. These reservations include:

1) the omission of in-situ stress measurements by overcoring and

hydrofracturing at several localities on the north shore of Lake

Ontario from the FSAR (Lee, 1981, Table 1) and the apparent exclusionby the applicant of several deeper focal plant solutions in theregional data set and limiting stress and strain data observations tothose in the upper 85 feet of the crust.

2) the impact and importance of deep hydrofracturing tests at theDarlington site, some 190 km west-northwest of the NNP-2 site, on thenorth shore of Lake Ontario. The results of the deep hydrofracturingtests showed a maximum horizontal compressive stress of about 2200

psi in the Ordovician rocks oriented N70'E and about 2800 psi in theunderlying crystalline Precambrian rocks, oriented N23'E (Haimson and

Lee, 1980).

3) a concern regar ding the importance of the "decoupled" stress regime(as measured at Darlington) on the potential for vibratory groundmotion at the NMP-2 site.

The subsequent paragraphs provide a reiteration of data and discussionscontained in the FSAR and FSAR references as well as a discussion regardingnew data available since the submission of the FSAR.

f s I'h li llI Vj

t ~~

II V"

II ~ fl f

Il Ilh '

l'll

s s

II

lvf I

f PII

H Ik

h

'f ~ I I V'l 'j

f fl

~'I

Iffi

h

'll 'f

ilI"

"l(

I

II

1 Il

f V I f II

I s I'

Ii s s 's f IJr I fl',

Omission of Data in the FSAR

The applicant presented a thorough discussion and analysis of the regionalstress field operative in the region surrounding the NMP-2 site as of mid-1978

in Volume III of FSAR Reference 2.5-94. Data included in this analysis were

all available measurements of both stress and strain indicators, such as

deeper stress measurements (up to 1700 ft.) by hydrofracturing; shallower (up

to 85 ft.) measurements of stress by overcoring; earthquake focal mechanisms;

pop-ups; and surface strain measurements.

Item 2 on p. 2-36 of the Draft SER describes the concerns of the NRC Staffregarding the omission of certain classes of in-situ stress data from theFSAR. These included:

2)

excluding focal mechanisms from deeper foci earthquakes in the

region; and

restricting observations of stress and strain data to the upper 23 m

(85 feet) of the crust.

The applicant has included deeper focal mechanisms in their analysis. The

event questioned by the Staff was a swarm of small magnitude earthquakes which

occurred near Blue Mountain Lake, N.Y., between May and November 1971. The

authors of the paper (Sbar, et. al., 1972) considered that the composite focalmechanism for the shallower foci ( < 2 km) events was more reliable than thatof the deeper foci (between 2 and 3.5 km). The applicant therefore, did notconsider the composite focal mechanism for the deeper swarm any further in itsregional analysis. All of these data are reported in Table 2.3 of Volume IIIof FSAR reference 2.5-94.

Additionally, it should be mentioned that the applicant has not restrictedstress and strain data to the upper 24 m (85 ft.) of the earth's crust in itsregional analysis. The data reported in Tables 2.2 and 2.3 of Volume III ofFSAR reference 2.5-94 cover a range of depths for all types of stress and

strain indicators from the surface (pop-ups of quaternary age and surficialstrain relief measurements) to over 20 km deep (focal mechanism solutions).Figure 2.5-20 in the FSAR provides additional focal mechanisms through 1982.

All of these data show a remarkable consistency in orientation of the maximum

horizontal compressive stress operative in the region, which is between N70'E

and N80'E.

jj 1ll I

H

I

n ~tt'l

It

tf I II

The data referred to by the Staff as having been omitted from the FSAR

analysis (Lee, 1981 and Haimson and Lee, 1980) do not change theseobservations.

Additional Re ional Stress Measurements and Focal Mechanisms

Since the submission of the FSAR in January 1983, additional data have become

available with which to compare earlier data. These are the October 7, 1983

Goodnow, N.Y. earthquake and aftershocks (m = 5.2) and the results of deep

(1.6 km) hydrofracturing in a test well at Auburn, N.Y., about 50 km SSE ofthe NMP-2 site.

The focal mechanism available for the main shock of the Goodnow, N.Y. sequence

shows nodal planes striking NW to NNW with a mixed reverse/oblique sense ofmotion. The NNW striking plane, st'eeply dipping to the west, best fits theaftershock distribution. The axis of the maximum principal compressive stressis oriented ENE with a gentle plunge, in agreement with the available regionaldata (Lamont Doherty, 1984).

A composite focal mechanism available for a swarm of aftershocks of theGoodnow, N.Y. main shock also strongly supports NW to NNW trending modal

planes and a NE to ENE trend to the maximum horizontal stress. The solutionalso indicates a mixed reverse/oblique sense of faulting (Woodward Clyde,1984).

A series of deep (1.6 km) hydrofracture tests was conducted in a geothermal

exploration well in Auburn, New York, some 50 km SSE of the site. The resultsof the hydrofracturing indicate that (Hickman, et. al., 1983):

2)

the minimum horizontal principal stress increases in a nearly linearfashion from 99 + 2 bars at 593 meters depth to 306 + 2 bars at 1482

meters depth;the maximum horizontal principal stress increases in a somewhat lessregular fashion from 138 + 10 bars to 490 + 12 bars over the same

depth range.

a ~

0 ~

4

~ ~

3)

4)

orientation of hydraulic fractures induced at 593 M and 919 M

indicate that the azimuth of the maximum horizontal principal stressis N83'E + 15'. The total stress regime indicates conditions thatwould be favorable for strike-slip faulting, if stress levels were

high enough.

none of the deviatoric stresses measured in this well were of a

magnitude sufficient to cause failure along previously existing,favorably oriented fault planes.

The results at the Auburn site confirm what observations have already been

made regarding the orientation of the horizontal maximum compressive stressfor the region about the site. More importantly, the low deviatoric stressesobserved throughout the 1.6 km deep well completely support the relativelyaseismic nature of the region around the site.

Observations Re ardin Stress "Decou lin " and Hi h Re ional Stresses

One of the Staff's concerns regarding the regional stress regime around theNMP-2 site was the reporting by Haimson and Lee (1980) of a possibledecoupling of stresses in the Paleozoic rocks from underlying Precambrian

rocks as measured at the Darlington Nuclear Power Plant site, some 190 km WNW

of the NMP-2 site.

Stresses measured by the hydrofracturing method in a 300 m deep test hole atthe Darling Site showed a consistent N70 E orientation of the maximum

horizontal stress in Ordovician rocks with an average magnitude value of 2200

psi. Several tests in the underlying Precambrian rocks showed, however, a

counter-clockwise rotation of the maximum horizontal stress orientation toabout N23'E with an increase in magnitude of stress to about 2800 psi. Thisdifference in magnitude and orientation of the "principal stresses" has been

attributed to a "decoupling" (presumably, a physical discontinuity) between

the Ordovician and Precambrian interface. A plausible explanation given, butnot elaborated on, by Haimson and Lee (1980) on p. 48 is simply that thecurrent stresses measured at the Darlington site in the Precambrian rocks arethe composite result of the superposition (through time) of two or more

separate stress conditions.

C1

fl

Iltt

If

tl ''lII

I

l tf 'I

I'

II t

4 ~Note that this situation is achieved with no restrictions or condition on the

interface. It may be (but, more probably, is not) "decoupled." A decoupled

condition may or may not exist equally if the stresses have 1) the same

orientation and/or 2) the same magnitude in both the Paleozoic and Precambrian

rocks.

To date, there have been no reported observations of stress "decoupling" inthe NMP-2 site region. Furthermore, there is no reason to believe thatdecoupling of stresses, if in fact it exists, is necessarily associated withthe release of stored strain. All that is required to satisfy the failurecriterion is a stress field properly oriented and sufficient deviatoricstresses to overcome the strength of previously existing faults or fractures.This is not the case in the NMP-2 site region, attested by the almost absence

of preceptible seismic activity.

In various parts of the FSAR and principal FSAR references supportingconclusions reached in the FSAR regarding the nature and characteristics ofthe regional stress field, the applicant has made mention of the presence of"high horizontal rock stresses" in the region. High, in all cases, refers tostresses that exceed those expected from gravitational loading (lithostatic)alone. The stresses measured at the site are not anomalous with respect tostresses measured at similar depths in similar rocks within the region about

the NMP-2 site. Essentially, all near-surface (0-1.5 km) stressdeterminations indicate significant horizontal stresses (of the order ofseveral hundred to several thousand psi). In North America and in other partsof the world, this condition is definitely more usual than a low horizontalstress condition. Thus, the existence of such horizontal stresses near thesurface is not anomalous.

I,

Hitt

I

» I

II

~ S

~ ~

References - Stresses Observed in Bedrock

U.S. Nuclear Regulatory Commission; Draft Safety Evaluation Report, Section

2.5; Nine Mile Point Unit 2, Final Safety Analysis Report; February 16,

1984.

Haimson, B.C. and C.F. Lee; 1980; Hydrofracturing Stress Determinations atDarlington, Ontario; in proceedings, 13th Canadian Rock Mechanics

Symposium (The H.R. Rice Symposium), special Volume 22, pp. 42-50.

Sbar, M.L., J. Armbruster and Y.P. Aggarwal; 1972; The Adirondack, N.Y.,Earthquake Swarm of 1971 and tectonic Implications; Bull. seis. soc. Amer.

V. 62, No. 5, pp. 1303-1317.

Lamont-Doherty, 1984; in LAMONT, A close-up view of Intraplate seismotectonicsin the Adirondacks 2 pp.

Woodward-Clyde Consultants, 1984; Personal communication with C.T. Statton.

Hickman, S.H., J.H. Kealy and M.D. Zoback; 1983 In-Situ Stress, Natural

Fracture Distribution and Borehole Elongation at Depth in the Auburn

Geothermal Well, Auburn, N.Y.

*»( f II „pi yI I

~ ~

Cf 'I ',S"

a lli' „'Ill,'f. f fa' )f

II !I''I »4» <4' f I f C>I f 'I.'f< < ''II ~ ~ ~< '' f Ak'~

ll>.f,k',4, Cf, 'f ',. '-g ~ ~, "„<If»'' V

~ ~ II~ fIi 4 I ~ C P C ~ 4'

I I III . f' ~ II » ~

~ ~ ll

I~ ~ ~ ~ 4 ~ ~ »

C

~ 0The Ori in of Dia iric Structures in the Re ion Surroundin the NMP-2 Site

As described on p. 2-54 of the Oraft SER at item (3), the Staff has requested"an assessment of sedimentary structures to determine if they are of seismic

origin" (SER Open Item No. 11). The Staff regards further evaluation ofsedimentary structur es observed at the NMP-2 site important in furtherconfirming the noncapabi lity of the Cooling Tower Fault.

The subsequent paragraphs discuss the observational character of the sediments

and deformational structures at the NMP-2 site in comparison to other similarobservations in the general site region. Additionally, the modes of origin ofthese types of structures, both seismic and aseismic, are presented.

Com arison of Overburden Sediments and Oeformational Structures at NMP-2 Siteto Similar Observations in the Re ion

As discussed in detail in FSAR Section 2.5.1.2.2 and in Section 4.5.2 ofVolume I, FSAR Reference 2.5-94, the general character of the overburden

sediments where observed on site consist of (from youngest to oldest):

1)

2)

3)

4)

5)

recent organic soil;massive, medium-gray silty sand;thin-bedded, rippled and cross-bedded silty fine sand of the Sandy

Creek stage;Lake Iroquois laminated, clayey silt; and

gray mottled proglacial lake fill grading downward to glacial till.

The diapiric or "flame" structures depicted on FSAR Figure 2.5-32 are found

primarily within the massive or thinly-bedded silty fine sands of the Sandy

Creek stage sediments (deposited on top of the Lake Iroquois lake sediments).

These sediments are shallow water deposits of thin bedded silt, fine to medium

sand and clay. Bedding varies from planar to wavy rippled to ripple driftcross laminated.

The ripple drift cross laminations include totally preserved climbing ripples,which is indicative of rapid deposition from suspension and is attributed toturbidites, point bar deposits and fluvial flood deposits (Vol. II, FSAR Ref.

2.5-94). These sediments grade finer upward into a massive silty fine sand

and silt deposit, representing a fining-upwards sequence during the Sandy

Creek Stillstand.

W I

I~ r w ~

CH

itli ',

a iIIH Ii l I Ci r' '" ',

I ll

~ I I fi

~ ~ ~ ~ ' ~ i'

~ H,r

«I

I I rli I

I''lC

~ IilW

~W

I I

'll H* I

'9 I'.,

I''l'j'«,9»ffr' WH ~ I ".W WtH,»

HWf, I'Wil

CCK fk'lH«

W

The diapirs, or "flame" structures, occur very close to and below the

gradational contact between the more permeable cross bedded and rippled finesands and the upper, massive si its and silty fine sands. This gradational

contact is seen as representing a permeability gradient within the sediments-the permeability of the lower, fine silty sands being greater than the

overlying massive silts and silty fine sands. Photos taken of these diapirsduring trenching of excavations at the NMP-2 site, the contacts between the

fine sands intruded into the overlying si its are wispy and not well defined.This would indicate a very fluid type of flow under completely saturatedconditions. It should be noted, however, that none of these structures istruncated or shows signs of significant erosion, indicating that the

deformation did not take place at the water/sediment interface but rather atsome depth where confining pressure and sediment permeability or viscositygradients may have had more influence in forming the diapirs.

The deformational structures reported on by H empton and Dewey (1983, Figures 1

and 2), although similar in form and appearance to those seen at the NMP-2

site, have much sharper contacts between the sands intruded into finer-grainedsilts and clays, which may be indicative of a greater vertical velocity ofescape of the fluidized sediments. Additionally, they are much larger and

many of the "flame" structures appear to be truncated, indicating that theywere at or close to the surface when they were formed.

Observations of Similar 'Structures in the Re ion

A very well documented and thorough reconnaissance of deformed guarternerysediments within the St. Lawrence lowlands in New York and parts of adjoiningCanada was carried out in 1975 by an interdisciplinary team of geoscientists(Coates, 1975). The purpose of their reconnaissance was to "identifyquaternary sediments that meet the criteria for earthquake-induced structuresand to evaluate the applicability to the St. Lawrence lowland of studying thedeformed features as a means of better defining earthquake recurrence rates."(Coates, 1975)

Their findings were that the St. Lawrence lowland contains a vast arr ay ofsoft sediment deformation from folding and faulting, to diapirs, decollement

structures and fluidization features. A great majority of sedimentary

structures they observed could be attributed to causes related to glaciation

N4 N

N'

11

0

1

and deglaciation. However, after establishing certain minimum criteria thatexcluded causes by glaciation, they found that certain localities contained

quaternary deformation structures with the greatest promise of being relatedto seismic events. (Coates, 1975; Figure 1.) These areas were:

Alexandria Bay: This area was found to contain the maximum number of deformedstructures observed at any locality visited in the St. Lawrence lowland.Because of the magnitude of deformation and its widespread continuity,diapirism of ~man units, thixotropy and form similarities with structuresobserved in seismically active areas (such as California), a reasonablehypothesis for their development must include triggering by vibratory groundmotion.

Malone - Constable Area: Delta-type sediments and lake clays (lower most) arepresent sn a roa cut near Malone. Deformation structures observed were:1) widespread thixotropy of clay beds; 2) diapirism and 3) vertically directeddeformation.

Canton Area: Coates (1975) feels that deformation structures observed in thisarea have the greatest possibility of having been induced by vibratory groundmotion. The deformation is widespread and continuous through distances ofseveral hundred feet in individual strata. The most convincing evidence was:

1) truncation of diapirs, indicating that sediments were at the surfacewhen deformed;

2) widespread, vertically induced thixotropic structures; and3) widespread continuity of deformation

Colwell Gravel Pit - Watertown, NY: This pit contains deltaic deposits abouty ee sc , ws abun an cross bedded, ripple drift sand sequences and

siltier units occurring below. Deformation structures observed were: 1)truncated diapirs; 2) thixotropic deformation structures; and 3) widespread,continuous deformation.

It is noted that because of the rapid deposition of the coarser grained topset beds, the lower finer grained silts may not have reached sedimentarystability. The weight could have been sufficient to incude the thixotropicstructures. An earthquake related source for a causal mechanism could not beruled out, however.

Modes of Ori in of Dia iric Structures

Obvriously, one of the potential causes of diapiric or "flame" structuresbeing discussed here has to include a triggering mechanism caused by vibratoryground motion. Much discussed in the literature, liquefaction potentialgenerally involves around several characteristic criteria: 1) grain size and

sorting; 2) void ratio; 3) initial confining pressure; and 4) intensity and

duration of ground shaking (Seed and Idriss, 1971). Studies of theliquefaction process generally have been conducted on homogeneous, undrained

noncohesive sediments. As Karcz and Enos (in Coates, 1975) have pointed out,

11

II

a I

II

1

"I1

11

l

I~I

11

11 III,

e

~ ~

problems that can develop on trying to attribute the origin of these diapiricstructures to seismic shaking are:

2)

how and at what rate pore pressures are dissipated in stratifiedsystems; and

how stratified systems of varying lithology and properties (i.e.,porosity and permeability) behave or respond to pore pressure

accumulation and dissipation at different r ates.

Karcz and Enos (in Coates, 1975) further point out that in natural stratifiedsystems, soft sediment deformation depends mainly on the stability of thesediment as well as the nature, magnitude and rate of the deforming stress.The less stable a sediment is, the less energy is required to induce

deformation. Fine grained sediments (i.e., silts), can gradually build up

strain internally during deposition, and thus get to a critical metastablestate if internal drainage is retarded during deposition. It is evident thatany disturbing event need not be large at all to trigger soft sediment

deformation. Such disturbing events can be a small, local earthquake or as

innocuous as a pore pressure differential (water escape mechanism). Gi llespie(1977) states that "seismicity, as a unique cause of deformation, can only be

established if all other initiating causes can be eliminated."

Aseismic causes of soft sediment deformation can be attributed to severaldifferent classes of physico-chemical processes, including:

1) Settling and flow shear;

2) Inverse density stratification; and

3) Consolidation and fluidization

~Settlin — when a suspension of fine grained partioles begins to settle out,the decline in settling velocity is caused by the upward moving fluid beingdisplaced by the settling particles. As the sediment enters into a

compression stage upon settling out, small-scale convection (caused by theactual compression of consolidation or more complex physico-chemical processes

such as dilatancy or thixotropy) can occur, creating miniature diapirs or "mud

volcanoes."

WPW

Nl

»

~ ~ »

P't [

P IIN

PN i

~ Nr cir

N

l 4

N»l

4

P

4„ f ', »' II

»

4 f

44' P'

II

'NW4

I 4 I ~ IS II PNf jW

I

~)»,'

Pl I" " 'Ii'

fl

ilf Il '.NN r»P f scc

fl' I, 4 s» ( P NNWN

I

c~ C

~ ~Flow -Many investigators have considered the effects of flow drag on

deformation of soft sediments. Some attribute the deformation to the pressuredifference between ripple crest and trough, leading to an upward suction on

the crest (Keunen, 1968a, 1968b). Others suggest that fluid and sediment dragexerts sufficient shear to induce deformation.

Inverse Density Stratification - This process may occur through a number ofways, either through differences in lithology or differences in porosity and

permeability. When a denser material overlies a less dense material,instability results. Once a certain threshold is exceeded, be it excess porepressure, compaction, etc., deformation begins. The final geometry depends on

sediment properties and the continuity of the horizon. Figure 2-8 in Coates

(1975) shows a remarkable similarity to the diapirs seen at the NMP-2 site.

Consolidation and Fluidization - These processes can create deformationstructures in soft sediments through the normal process of sediment dewateringduring compaction. In certain fine grained sediments, rapid compaction (andliquefaction) will create an instability in the sediments when rapidlyexpelled fluids reach a critical velocity sufficient to start fluidization.Deformation structures such as diapirs, flow folds, etc. can result if theprocess is operative over a long enough time.

Com arisons of NMP-2 Site Dia iric Structures to Earthquake Induced SoftSediment Deformation Criteria of Coates 1975)

As has been discussed in the previous pages, most of the deformationalstructures in soft sediments in the St. Lawrence Lowlands can be explained as

to their mode of origin by a variety of external causes, both seismic and

aseismic. Coates ( 1975) most succintly put it "the law of equifinality mustbe borne in mind at all times... that structures that visually appear to be

almost identical may have been formed by different processes."

The diapiric and fluidization structures structures observed in quaternarysediments in excavations made for the Cooling Tower Fault investigation appearto be confined to the vicinity of the fault. This is an apparent, not a

causal association, because the sediments are only preserved in those portionsof the site. The structures observed in the overburden sediments at the NMP-2

site may have been caused by vibratory ground motion; however, aseismic causes

A 0

0"

0

lt ~

««

's'

I, y

« I «

W

I II

W

WI I

""(IW

(WW

~ ~

could have been equally (perhaps more plausibly) responsible for theirinformation. Glacial processes or mechanisms such as ice push or thrust,static loading and compacting, collapse by ice melt-out, collapse near freestanding ice margins or frozen ground phenomena could all have an integralpart in the deformations observed at the NMP-2 site.

As discussed in Vol. I, Section 8.0 of FSAR Reference 2.5-94, the diapiricstructures observed in quaternary sediments at the NMP-2 site are believed tohave formed due to abnormal pore pressure differentials existing in thebedrock and sediments after the rapid dewatering of Lake Iroquois to theAdmiralty stage. The field evidence obtained during the investigation of theCooling Tower Fault does point to this as a plausible explanation, especiallywhen viewed in light of Coates (1975) criteria of association of sedimentarystructures to seismic disturbances in the St. Lawrence Lowlands. A comparison

of field observations at the NMP-2 site to the general criteria are: (Note:the underlined portions of the numbered items below are the general criteriaestablished in Coates (1975) as being indicative of earthquake-induced

sediment deformation; the statements following each underlined criteria are

field observations from the Nine Mile Point Unt 2 site.)

1) Dia irs, es eciall when truncated - Diapirs occur in Sandy Creek

stage sediments at a gradational contact between overlying massive

si its and silty sands and underlying silty fine sands. They are nottruncated, nor are they laterally continuous over large distances.They only occur at one horizont.

2) Horizontal continuity of deformed units - The deformed horizon is notcontinuous over large distances. Diapirs appear to be concentratedin the area near the Cooling Tower Fault but do occur elsewhere inthe sediments away from the fault.

3) Presence of thixotro ic features - There are no observed thixotropicstructures in association with the diapirs at the NMP-2 site. The

deformation in the Sandy Creek stage sediments is confined to one

horizon only.

4) Verticall -directed distortion - The nature of the diapirs or "flame"structures seen at NMP-2 give the indication that distortion was

directed vertically.

yI

I h

C

I

I'l,

g $ h iI

Ifhl fh

~ .

~ I lj hi

« ff' ll f h i!

~ I I jj Sh

hf,h, .I If

II I» jj I I y lj h

rill I Il'l'',I j

I h

~ \

5) Absence of lacial rocesses - The ice margin was far removed from

the site when the Sandy Creek sediments were laid down.

6) Character of overburden - The massive silts and silty fine sands

directly overlying the cross-laminated, rippled fine sands of Sandy

Creek stage are thought to have provided both a viscosity and

permeability gradient instability during or immediately followingdeposition.

If one wer e to look at the criteria established by Coates (1975) a's being

absolute, then the diapiric structures observed in Sandy Creek stage sediments

at Nine Mile Point would most likely be associated with other exteralinitiators than from vibrator y ground motion as a triggering mechanism.

Gi llespie (1977), one of Coates'tudents at S.U.N.Y. Binghamton, examined indetail two of the areas singled out by Coates'1975) St. Lawrence report as

having soft-sediment deformation most likely originating from seismic activityin the St. Lawrence region. He studied both the Canton, NY Landfill and the

Newberry Sand and Gravel Pits at Alexandria Bay, NY. These locations are

about 91 and 58 miles distant from the NMP-2 site, respectively. The Canton'itehas sediments of roughly correlative age to the NMP-2 site and a similar

deltaic nature of depositional environment. The conclusions reached byGillespie for this site (Canton) were that deformation structures (see Figures33 and 34 in Gi llespie, 1977) are most intense along the edges ofdistribuatory channels and areas of rapid point-bar growth and primarilycaused by water escape (as deduced at the NMP-2 site). His most importantconclusions, however, were:

2)

that lateral continuity of deformation cannot be considered as an

indicator of seismic triggering of deformation (one of Coates, 1975,

criteria) as lack of deformation in one area might mean that thesediments there were not in an unstable state; and

seismicity, as an unique cause of soft-sediment deformation, can onlybe established if all other external initiating causes can be

eliminated.

l '

II 1

~ 0 ~ 4

I

I'

I I'

lfII hl

~ ~

~ ( In summary, the current state-of-the-art does not allow us to readilydifferentiate between various external triggering mechanisms of soft sediment

deformation in the region surrounding the NNP-2 site, including seismic

events. It is considered that the Cooling Tower Fault, because of: 1) itsnature of development as a buckle of limited vertical extent;2) nonassociation with a basement-related tectonic structure; and 3) limitedlateral extent was not responsible for the development of the diapiricstructures as seen at the site.

While the diapiric structures observed at the site were of interest inunraveling the history of development of the sediments at the site, theirsignificance to the likelihood of vibratory ground motion originating from the

Cooling Tower Fault is essentially meaningless.

~ p„"

Rhfh

t h"h,,tl„( + h II lych

~, WP

i I Jihad h

~ ~

~ 'oolin Tower Fault and Monitorin

The Staff has recommended a monitoring program (No. 4, p. 2-54 of the DraftSER) of the Cooling Tower Fault designed to ascertain the strain ordisplacement rate on the fault (SER Open Item No. 12).

The NRC Staff has agreed that the Cooling Tower Fault is most likelynontectonic and, therefore, noncapable (Draft SER, p. 2-40). However, theycontinue to have several concerns relating to the interpretation and

conclusion about the Cooling Tower and related faults. These concerns are:

2)

3)

Neither the length nor the depth of the Cooling Tower Fault has been

completely explored or determined;The mechanism postulated for reverse slip displacement, that ofbuckling, is not fully supported by field evidence;The possibility that small, intrastratal diapiric structures in finegrained sediments overlying the cooling tower fault may have been

formed as a direct result of vibratory ground motion.

These concerns have led the staff to recommend an extended period ofmonitoring the displacement on the Cooling Tower Fault during plant licensingand operation.

Subsequent paragraphs provide a discussion and summary of available evidenceregarding the latest history of movement on the Cooling Tower Fault and thechronologic development of trench exposures of this structure. Discussionsregarding the diapiric structures are found in the response to SER Open Item

No. 11 and will not be repeated here.

Chronolo ical Excavation and Investi ation of the Coolin Tower Fault

In late September 1976, a nearly vertical apparent strike-slip fault trendingabout N70'W was discovered in the west wall of the Cooling Tower piping trenchduring bedrock surveillance mapping (routine examination of all bedrockexposures after excavation).

W

h

~ E

f Et

~ )r >I 1 ~ ','f

II ~]

W

W

W

h f wr~E,, r

Pit 1 was excavated approximately 50 feet west of the exposure of the Cooling

Tower Fault in the Cooling Tower piping trench between October 15 and 21,

1976. This was the first of the six man-made exposures designed to define thelateral extent of the Cooling Tower Fault. Pit 1 was approximately 45 feet indiameter and exposed the Cooling Tower Fault in the bedrock, with an observed

orientation of about N77'W, some 7 variance to the exposure in the CoolingTower piping trench (see Figure 2.5-28A).

Between October 21 and October 28, 1976, a 470 foot long, north-south orientedtrench was excavated through the overburden to bedrock about 1750 west of the

Cooling Tower piping trench and was referred to as Trench 1. This trench,along with Pit 1, was observed by NRC Staff geologists during their site visiton November 4, 1976. The Cooling Tower Fault was not observed in the Trench 1

exposure (see p. 1-4, FSAR Reference 2.5-94, Yolume 1). Trench 1 was excavated

in such a fashion so that the slight vari ation in orientation of the CoolingTower Fault between the Cooling Tower piping trench and Pit 1 could be

accommodated in the length of Trench 1 so that the Cooling Tower Fault, would

be observed, if it were present (see Figure 2.5-28A).

Beginning about November 9, 1976, Trench 2 (Figure 2.5-28A) was excavated

about 700 feet west of and along the projected trend of the Cooling Tower

Fault as observed in the cooling tower piping trench. Again, the CoolingTower Fault was not observed either in the exposed bedrock or the overlyingglacial sediments (see p.l-4, FSAR Reference 2.5-94, Yolume 1).

In late November 1976, Trenches 3 and 4, located 5200 and 1300 feet farthersoutheast of the cooling tower piping trench respectively, were excavated

through the overburden to bedrock and both exposed the cooling tower fault.As seen in Figure 2.5-28A, Trench 3 began to the south of the projected trendof the Cooling Tower Fault and was excavated to the north until the fault was

observed. Conversely, Trench 4 was begun to the north of the projected trendof the Cooling Tower Fault and excavated in a southerly direction unti 1 thefault was exposed. In this manner, any minor change in orientation of the

Cooling Tower Fault, either in a northerly or southerly direction, would stillhave allowed the fault to have been observed.

Lastly, Trench 5 was excavated in January 1977 about 900 feet farthersoutheast of Trench 4 and also exposed the Cooling Tower Fault.

hn

44

I(

1'ih

$ 'l4'i

4

4

~ ill ji '4

«H

K ~ ~ C ~ tw

~ » I, IiIH»»h th, 'H ',,„'.,'

4

4

( t '~ «h A

I ii

,» Ht'I Il«,

,', I,'I «H 1

'H

» «Hi

~ ) '«4th \'H

«

~ ~

Develo ment of the Buckle Associated with the Coolin Tower Fault

The field evidence gathered in the various trenches and from drill holes thatpenetrated the Cooling Tower Fault at the NMP-2 site all suggests that the

youngest deformation at the site is the buckle that has produced reverse slipdeformation on the Cooling Tower Fault.

The evidence supporting buckling r ather than reverse faulting in brittle rocks

is overwhelming. This can be summarized as:

2)

The latest high angle reverse slip movement is accompanied by

displacement which increases upward (see Plates 5-4, 5-5, 5-6 and 5-7

of Vol. I, FSAR Ref. 2.5-94); if the displacements had been initiatedin the under lying Precambrian rocks, they would have been eitherconstant or increasing downward.

The observed displacements have not resulted from frictional slidingon the structure.

Typical reverse faulting would have produced a relatively small amount ofbedding plane dilation as compared to the accumulated displacement. What isobserved is that dilation is 6 feet greater on the hanging wall than the same

stratigraphic horizon on the footwall.

Additionally, displacement of strata on one side of the structure in relationto the corresponding stratigraphic horizon on the opposite site of the faultwould not significantly decrease away from the structure. What is observed isthat displacement progressively decreases and becomes smaller with depth

between two points (see Plates 5-7 and 5-8, Vol. I of FSAR Ref. 2.5-94). This

phenomenon occurs almost entirely within strata on the hanging wall.

Moreover, if the observed displacements were the result of reverse faulting,there would be, most likely, a continuous and relatively large shear

displacement at the present bedrock surface. This is not observed, which

indicates that the observed dilation in the hanging wall rocks is not a

residuum of a larger and older reverse-slip displacement eroded away to tepresent bedrock surface.

';s«„"« I f I ~~ '.". I» «

h

H

s « I I«

.H

»,I I

If I ~, III « I II

I f H

H

U «h

I ~ 'd «

I Hhr '«I

««« S) t,t I'1 t '

„,I I»h

~ " ~ H H' I« ~ II

lr«I

~ II I I Is I

IH

While the Staff has considered all of the structures in the vicinity of thesite (i.e., the Cooling Tower Fault, the Drainage Ditch Structure and theBarge Slip Fault) together as to their origin and significance, there is a

distinct difference between the Cooling Tower Fault and Drainage DitchStructure as compared with the Barge Slip Fault in how they responded to theregional stress regime extant during glaciation. The orientation of theCooling Tower and Drainage Ditch Faults (70 dip to the north) to the stressesoperative during glaciation and deglaciation in the site area provided shearstress resistance (not related to cohesion on the fault), thus allowing thedevelopment of buckling instability. The Barge Slip fault, because it was

dipping to the south, was not in a favorable orientation to the regionalstress regime, which is why buckling did not develop on this structure.

Although it was concluded that future small movements within the buckled zone

of the Cooling Tower Fault may occur (Section 8.6, Vol. I of FSAR Ref.2.5-94), the movements, if they occur, will involve only slow strain rates and

only limited volumes of the rock mass (certainly not a rate or volume of rockthat would sustain a seismic event). The Cooling Tower and all otherstructures on site are sufficiently far removed from the Cooling Tower Faultthat would preclude any impact as the result of these small movements shouldthey occur.

Additionally, the buckle developed on the Cooling Tower Fault is not capableof generating movements sufficient to cause vibratory ground motion.Therefore, any program designed to monitor small adjustments in the rock mass

. and even if they were measured, would only be confirming what is potentiallyexpected; it would not provide any evidence for, nor alter our conclusionsregarding, the noncapability of the Cooling Tower Fault.

P

Lastly, the Cooling Tower Fault is not associated with basement-relatedtectonic structure. Even if it were, the likelihood of the structure (becauseof its size and orientation to the stress regime extant in the eastern U.S.)being the locus of seismic energy release would be extremely small.

r ~I I II fl I ', fir wlrH '

e ~ ~

F I"''

~" ti

t I ~ t lw tl C,W

f f tt

~ I IiI ~

",ifit

fi,f

Writ 'If a H" "'

f I

~,i I ~ .,'fl 1, I"

$

fC IC

Reference - Coolin Tower Fault and Monitorin

U.S. Nuclear Regulatory Commission; Draft Safety Evaluation Report, Section2.5, Nine Mile Point Unit 2, Final Safety Analysis Report; February 16,

1984.

Niagara Mohawk Power Corp.; 1982; Final Safety Analysis Report, Vol. III, FSAR

Reference 2.5-94.

Tillman, J.E. and H.L. Barnes; 1983; Deciphering Fracturing and Fluid MigrationHistories in Northern Appalachian Basin; AAPG Bull., Vol. 67, No. 4, April1983.

~ ~

~ ~

~ ~ ~ ~

44