Properties of Subsurface · From SAR Section 2.5.1.2 and Calc Package GEO.DCPP.01.24. Slope Stability Theory Resisting moment o Pseudo-static Slope Stability F.S. = -----=1 q,- b

NRC/PG&E Open Meeting, San Francisco CA Diablo Canyon Independent Spent Fuel Storage Installation

Properties of Subsurface Materials Robert White

Geotechnical Engineer

PG&E Geosciences Department

U April 11, 2002

Purpose

m Characterize subsurface materials for ISFSI, CTF and Transport Route for

"* Foundation properties

"* Slope stability assessments

Subsurface Materials Assessed

"* Rock

"* Dolomite

"* Sandstone

"* Friable rock

"* Clay Beds

Subsurface Materials Properties - Rock

m Density

m Shear Wave Velocities

m Young' s Moduli and Poisson's Ratios

m Shear Strength

Rock Properties - Density

* Determined from lab tests of rock core samples of dolomite and sandstone

* 140 pcf ± 8 pcf for all rock

From SAR Section 2.6.4.3.1; Data Report I, Table 1

Rock Properties - Shear Wave Velocities

"* Obtained from suspension logging of borings at ISFSI site

"* Compared with velocities obtained in previous investigations at power block

From SAR Section 2.6.5.1.3.2 Figs. 2.6-33, 34, and 35; SAR 2.6.1.10; Data Report C

Shear wae veloy (Ips m 1000 a)

2 3 4 5 60

aS

0

7 8 9

Explanation

Upper- and kowerI I bound LTSP shear

I wame profile envelope

Rbm block baring

DDH-D (1977)

(Figure 2.6-34)

ISFSIborings

96BA-3 (1998)

98MA-1.4 (1996)

(Fir 2.6-33)

Rock shear wave velocities

From SAR Figure 2.6-35

Young's Moduli and Poisson's Ratios

m From suspension velocities for rock mass

m Compared with lab tests of rock core samples of dolomite and sandstone

From SAR Section 2.6.4.3.1; Data Report I

Results - Rock Properties

m Young's moduli

*1.3 x 106 to 1.5 x 106 psi, non-friable rock

*0.20 x 106 to 0.21 x 106 psi, friable rock

* Poisson's ratios

*0.22 to 0.37, non-friable rock

*0.23 to 0.31, friable rock

From SAR Section 2.6.4.3.1; Data Report I

Rock Strength Parameters depend on:

"* Type of rock .Dolomite, sandstone * Friable rock

"* Scale of rock mass analyzed * Large scale

+ Rock slide mass * Small scale

+ Rock wedges

Potential large scale slide mass


Large-scale Slide Mass

"* Strength controlled by rock mass

+ Discontinuities (joints, bedding planes, faults)

* Size of intact blocks

"* Strength of rock mass based on HoekBrown method

From SAR Section 2.6.5.1.2.3

NRC Request for Clarification:

* "Discuss analysis)

the technicalto justifythe

basis (data androck-mass friction

angle ofS50 degrees used to characterizethe rock-mass strength of dolomite and sandstone."

Hoek-Brown Input Parameters for Sandstone and Dolomite

m Geologic Strength Index (GSI) values as a function of discontinuity condition and spacing

m Material index (mi) values as a function of rock type and texture

m Unconfined compressive strength (ac) of intact rock samples

Distribution of Hoek-Brown Input Parameter Values

mean plus mean minus

Dolomite one sigma mean one sigma

GSI 65 56 46

m. 17 15 13

(Yci 47 32 18

mean plus mean minus

Sandstone one sigma mean one sigma

GSI 68 65 62

Mi 19 18 17

Ui 31 22 12

From Calculation GEO.DCPP.01.19

Example Hoek Brown strength envelope

tangent

T= c +On tans

10 20 30 40

Normal stress (f MPa

Figure 11.8: Plot of results from simulated full scale triaxial tests on a rock mass defined by a uniaxial compressive strength Oci = 85 MPa, a Hoek -Brown constant m, = 10 and a Geological Strength Index GSI = 45.

30

•. 20

S10O

0

Rock Mass Strength envelopes (Hoek-Brown)

range of interest

ri/ll ,11 i 11; 4 i i + i I i

i /1.5 1-

-0.5 0 0.5

71//

7

1.5 2 2.5

4

3.5--

3

•2.5

2

1.5

0.5

03 3.5 4 4.5

Normal stress (MPa)-0.5 0 0.5 1 1.5 2 2.5

Normal stress (MPa)

From SAR Figures 2.6-53 and 2.6-54; Calculation GEO.DCPP.01.19

4.5

4

3.5

1 2.5

21

0

ran-e of inte'est

_ Am-

3 3.5 4 4.5

4.5 , II l I I I ,

I - If ý, z i I I I

ýrxl 0.5

0

. I

ý7

Properties of Friable Sandstone and Dolomite

m Strength not scale dependent since relatively homogeneous (discontinuities have weathered to consistency of rock fabric)

m Samples tested in the lab measured total and effective stresses

Friable Rock Total Stress Strength envelope

0 50 100 150 200 250 300 350 400

p=1/2 (7l+G 3 ) (psi)


�1.

N

II 0*

0

Small-Scale Rock Wedge

"* Strength controlled entirely by discontinuities

"* Strength of discontinuities based on BartonChoubey method

Potential rock wedges


Barton-Choubey Input Parameters for Sandstone and Dolomite

"* Base friction angle (tb) based on lab tests of shear strength of discontinuities

"* Joint compressive strength (JCS).based on lab tests of unconfined compressive strength

"* Joint roughness coefficient (JRC) values based on field measurements of joints in trenches

From SAR Section 2.6.5.1.2.3)

Straight line fits: 4- 18, 33, &48'

dolomite bedding strength envelopes

14

1.2

I

S01

0.6

S04

02

0 02 04 06 0 a1 1 4

Normal stress, is g - MPP

Straight line fits: ý=-21, 31, &44'

FL sandstone bedding strength envelopes

14

1 2

0Oa

06

S04

02

02 04 06 09

Nor mal sire ns, sign - MPa

(shaded zone equals stress range of interest)

From Calculation GEO.DCPP.01.20

stres rang of inter st e-

OA@

5-. -•_

S..... .. . • •- ,, -- :

p-' A 4o,,

.,•, , .. *

12 14

5 1

Clay Bed Properties

m Density

m Atterberg limits

m Over consolidation ratio

m Shear strength

Density of Clay

m From lab tests of clay samples

m 120 pcf+ 5 pcf

From SAR Section 2.6.4.3.1; Data Report G, Table G-1

Atterberg Limits

m From lab tests of clay samples

m Representative values of Plasticity Index (PI) are between 20 to 40

From Data Report G, Table G-1

Overconsolidation Ratio (OCR)

m Estimated at several points along three clay beds from knowledge of previous ground surface

m Representative values

*2to5

From GEO.DCPP.01.31

Clay Strength

"* Strength of clay beds from lab tests on samples from tower road cut

"* Lab results correlated with published PI and OCR relationships

"* Post peak and/or large strain strengths used

NRC request for clarification:

m "Discuss the saturated undrained shear strength of the clay-bed soil."

Unconsolidated Undrained Shear Strength

Mohr failure envelope (total stress)

V -T =0

(a)

I- - <10% . .4.S =100%

a

(b)

Fig. 11.40 Mohr failure envelopes for UU tests: (a) 100% saturated clay; (b)

partially saturated clay.

From Holtz and Kovacs, 1981

T1

T =C:

l_.•_---A . . I.. Aof- - a o(total o)

L--r ---,

Consolidated Undrained Shear Strength

wj - liquid limit + Vane tests wp = plastic limit o Unconfined compression tests

From: Lambe and Whitman, 1969

Laboratory Strength Test Data

Undrained Direct Shear (Cycled) Cooper Testing Labs, Inc.

20000

15000

10000

U

an

6n

5000

0

-500"

-10000

-15000

Deformation. (Inches)

Shear Strengths of Clay Bed

(ps)

0 50 100 150 200 ... ... .. ... ... .. 200

25 Effective Shear Strength envelope 150

S20

a

2 10 •

S5

0 5 10 15 20 25 Normal effective stress on failure plane at failure - of (kSO

......................................... ... ............ .. . ...................

0

t

a

50

(ps)

100 150 200 u 200

Ir

pe 150

- loo

50

From SAR Figure 2.6-50 and 51; Calculation GEO.DCPP.0 1.31

Summary of Rock Properties

m Density: 140 pcf ± 8 pcf for all rock

"* Shear Wave Velocities: > 4000 fps

"* Young's Moduli: related to shear wave velocities

m Poisson's ratio: related to shear wave velocities

* Shear Strength:

* =- 50 degrees for slide masses

S•-18 to 31 degrees for rock wedges

Summary of Clay Bed Properties

m Density: 120 pcf + 5 pcf average

o Atterberg Limits: PI of 20 to 40

m Over Consolidation Ratio: OCR of 2 to 5

m Shear Strength:

. Effective shear strength: = 22 degrees

* Undrained shear strength:

.4 15 degrees and c - 500 psf, or

* 29 degrees

NRC/PG&E Open Meeting, San Francisco, CADiablo Canyon Independent Spent Fuel Storage Installation

Slope Stability Analysis

Joseph Sun Geotechnical Engineer


April 11, 2002

Presentation of Slope Stability

"* Hillslope above ISFSI Pads

"* Transport route and CTF

"* Cutslopes

Joseph Sun

Robert White

Jeff Bachhuber

Approach

m Select cross section for analyses

m Develop material properties

m Perform slope stability analyses

m Perform dynamic response analyses

m Estimate potential seismic induced displacements of rock masses on clay beds

Approach

"* Select cross section for analyses "* Develop material properties "* Perform slope stability analyses "* Perform dynamic response analyses

* Address NRC request for clarification on vertical ground motions

"* Estimate potential seismic induced displacements of rock masses on clay beds

/ / C'

/ /

/

RI

II,

� WI

�1

S

ON

II

Analysis Cross Section I-I1


Potential Large-scale Rock Mass Model -Upper Slope

11 North South

800 ----.. . - .-- . ...-. . . . . .. .. .. . . . .. . . .. . .. . .. ... . . . ....

MODEL I 700 /

600 . r@

1971 pre,- tower ax~ess road borrow ,..

excavation tower!

4A,•. road

SISFSI Pads A-L ""CTF 0 .. .. ..

01 " W -O1•TF: OO -A 0 -0 A 01-A


Potential Large-scale Rock Mass Model -Intermediate Slope

IISouth


I800

700

600

500

400

300

200

100

a) C

0

0)

Potential Large-scale Rock Mass Model -Intermediate Slope

II Noah South

800_ _

MODEL 2 700

600 -- •... . 1971 pro-borrow

excavab~on topography lowe accesms ro 2D

500 ISFS1 I- - - 14--I . • C T F Pads • • • - • T-1 4

4-- - ___1

1000 .


Potential Large-scale Rock Mass Model -Lower Slope 1 11

South


North 800

700

600

500

400

4-. ci�

C 0

4

a) iJJ

300

200

100

Static Slope Stability

"* 2-D analysis using Spencer's method of slices

"* Input:

"* Geometry

"* Material properties: unit weights, strengths

"* Output:

"* Static factors of safety (F.S.)

"* Yield acceleration (ky)

From SAR Section 2.5.1.2 and Calc Package GEO.DCPP.01.24

Slope Stability Theory

Resisting moment o Pseudo-static Slope Stability F.S. = ------------ =1 q,- b

Driving moment

a ý4

w

Fig. 2. Conventional method for computing effect of earthquake on stability of a slope (after Terzaghi, 1950)

S

I

Assumptions

m Claybeds are saturated

m Tension cracks exist in the upper 20 ft

m Rock to rock contacts along the thin claybeds are neglected

m Lateral margins of potential slide massesare assumed to have no strength

From SAR Section 2.6.5.1.2.2

UTEXAS3 - Slope Stability

m Uses a 2-stage stability computation to evaluate the stability of slopes under seismic loading conditions (Duncan, Wright, and Wong, 1990)

1Ist stage: computes the state of stress along the shear surface under long term loading conditions

*2nd stage: calculates undrained shear strength based on long term state of stress and performs slope stability analysis under seismic loading conditions

Cross Section I-I" (shallow model)

I


0 -e

0m~

I©

Q

N)

00

Cross Section I-I" (deep model)


.1,

t

Results of Static Slope Stability

Slide Mass Static F.S. Yield Acc. (ky)

la 2.55 0.28

(Ib 1.62 0.20 *

2a 2.55 0.31

2b 2.16 0.24

2 c 2.18 0.19 4

3a 2.86 0.44

3b 2.70 0.39

3 c 2.26 0.25 4

3c-1 2.38 0.28

3c-2 2.28 v 0.23 From SAR Table 2.6-3

Methodology of Seismic Analysis

m Yield accelerations (ky) determined from slope stability analysis

m Response of slide masses under seismic loading evaluated using 2-D finite element method

m Displacements of slide masses calculated using Newmark sliding block approach

QUAD4M - 2D Dynamic Response

Analysis

m Input:

"* Unit weights

"* Shear wave velocities and damping values

"* Non-linear material properties

0 Output:

* Acceleration time histories of slide masses

-1.00 . I I I I I I I I I , z I I IIT

Illustration of 0.8Bock3C

-0.8 - Block 3C Ilsrto of-0.6 - Ground Motion Set 1

-04Ky= 0.25 g o0.-0.2 S0.00 Newmark 4 "5 0.2 - p

S 0.6 Sliding Block 0.8o 1.00 . . .. ... 0 5 10 15 20 25 30

Displacement Time(seconds)

Calculation 1.0

4Q 100 / o 50 a)

0 0 5 10 15 20 25 30

Time (seconds)

60

50/- Displacement= 48.9 cm

S40 a)

E 30 k~ta)

-g 20 Q.

6 10

;1 0 w 0 5 _ 10 15 20 25 30

Time (seconds)

NRC Request for Clarification

... the slope safetySAR,

evaluation presented in the

ground motion components without the vertical component, should be clarified ... 1"

which was developed using the horizontal

Effects of Vertical Ground Motions on Sliding Analysis

"* Inclination of slide planes (bedding planes)

"* Vertical motions more important for steeply dipping slide planes (greater than 30-40')

"* ISFSI clay beds typically dip less than 15' "* Steepness of slope

"* Vertical motions more important for steeper slopes

"* ISFSI hillslope is about 3:1 (H:V) and the effect of steepness of slope is incorporated in the 2-D slope stability and dynamic response analyses

Effects of Vertical Ground Motions on Sliding Analysis

m Material strength properties

"* More important for sandy material

"* Less important for clayey material

"* ISFSI slide plane material is clay beds

Ground Motion Considerations for Sliding Block Analysis

"* Direction of slide mass movements:

"* Occurs along claybeds "* Claybeds are horizontal to sub-horizontal

"* Postulated slide mass movements are influenced by horizontal motions

"* Slide plane inclination: "* Limited effect on computed displacement (less than 10%)

if the inclination is less than 20' based on Makdisi (1976) for sandy materials

"* For material similar to the ISFSI claybeds, the influence would be less

"* ISFSI claybeds typically dip less than 15'

Ground Motion Considerations for Sliding Block Analysis (cont'd)

"* Undrained shear strength of claybeds:

"* Controlled by long term overburden pressure

" Relatively insensitive to seismic loadings

"* Peak arrival time:

" Arrival time of horizontal peak is typically 1 to 3 seconds behind arrival of vertical peak based on near field recordings

"* During strong horizontal shaking, the energy (as measured by Aries Intensity) on the vertical component is typically 10% to 30% of the energy on the horizontal component

Ground Motion Considerations for Sliding Block Analysis (cont'd)

"* Standard of practice for seismic design of dams: * Evaluation of permanent displacement of

embankment dams under seismic loading is based on horizontal component of the design motion (USBR, 1989)

"* Recent studies: *Study at Cal Tech indicated that vertical ground

motions have limited impact on block movements based on numerical analysis and physical modeling Yan, et al. (1996)

Preliminary Site-Specific Study

m Evaluate effect of vertical motions on computed yield acceleration

m Evaluate effect of vertical motions on slide mass responses

m Incorporating vertical ground motions resulted in displacements varying less than 10% from calculations based on horizontal component alone

Effects of Vertical Seismic Coefficient (kv) on Yield Acc (ky)

-kv up

f

v

+kv down

kv -0.8 -0.6 -0.4 -0.2 +0.0 +0.2 +0.4 +0.6 +0.8

kh ky 0.23

0.22 0.20

0.19 0.19 0.18 0.17 0.17

0.16

Zone of applicability

Based on hand calculation of slide mass lB

Response of Block 1B Response Direction EQ

0.0uInpu 0.5

0 10 20 30 40 5

1.0• C 0. .0

2 0.0

"o -0.5 < -1.0 , (,I Average horizontal acceleration in wedg e 1 B using H+Vinput

0 10 20 30 40 50

1.0

0.5

0

0.0 4I 0 -0.5

< 10ie A r-a--q- -on_ acceleragion in Wt adge 1B ul ing directiodg of claybed (14 deg.) -1.0 " I

50

Vertical Ground Motion

Effects on Computed

Displacements

100.00

10.00

.00

CL

(U(

0.10

0.01 0.0 0.2 0.4

ky1.00.6 0.8

Conclusions on the Effects of Vertical Ground Motions

"* Effect on clay bed shear strength

* Minimal to none

"* Effect of inclination of potential slide plane

* Minimal

"* Effect on computed horizontal response of slide masses

* Minimal

"* Overall effect on computed displacements * +10%

Potential Seismic Induced Displacements on Clay Beds

:999 - node points to compute acceleration time histories

800i I

700

600

.. 3.1lft 0)500

400cc

S1.2 ft 1.4f

100 200 300 400 500 600 700 800 900

Horizontal Distance, feet

Mitigation Measures for Slide Masses

m Set back

*25 ft wide bench between cutslopes

.40 ft clearance between edge of ISFSI pads and toe of cutslope

m Debris fences

Conclusions

* The stability of the hillslope above the ISFSI pads was analyzed and the slopes have ample factors of safety under static conditions.

m The hillslope above the ISFSI site may experience small displacements when exposed to the design-basis earthquakes.

Conclusions (cont'd)

m The maximum seismic induced displacements could potentially be about 3 feet on the upper slope to about 1 to 2 feet on the lower slope.

m Mitigation measures will be implemented to minimize effects of the small displacements and protect the ISFSI facilities to perform their intended design functions.

NRC/PG&E Open Meeting, San Francisco CA Diablo Canyon Independent Spent Fuel Storage Installation

Transport Route Stability and Displacement Analyses

Robert White

Geotechnical Engineer


April 11, 2002

Transport Route Slope Stability and Displacement Analyses Steps

1. Locate critical slide mass with minimum factor of safety. Determine yield acceleration for critical slide mass.

2. Determine seismic coefficient time history for critical slide mass.

3. Determine potential earthquake-induced displacement of critical slide mass.

From SAR 2.6.5.4.2; GEO.DCPP.01.28, 29, AND 30

Stability and Yield Acceleration Analysis of Critical Slide Masses

m Three representative sections along the transport route were selected

m Affect of transporter load also evaluated

Analytical Sections

Cr,

©0

Finite Element Sections

"* Finite element meshes for Sections L-L' and E-E' were prepared.

"* A finite element mesh for Section D-D' was not prepared, as it is similar in configuration to Section E-E'.

Seismic Coefficient Time Histories of Slide Masses

m Finite element meshes for Sections L-L' and E-E' were prepared.

m A finite element mesh for Section D-D' was not prepared, as it is similar in configuration to Section E-E'.

Seismic Response Analyses Slide Masses

I % II' I I I I I I I I I I I I

Section L-L'

Vs= 1200 fps, unit weight 115 pd,

-400 -300 -200 -100 6 160 260 360 460 560 660 760 860 960 1000Horizontal Distance, feet

[From Figure 1, GEO.DCPP.01.29]

70uuI

600

50O

400-

300

200

100-

Cu

0I

100

-200-

-300-• -500

Seismic Coefficient Time Histories of Critical Slide Masses

m ILP ground motions were rotated to the direction of Sections L-L' and E-E' and input into the finite element program.

m The seismic coefficient time histories for the critical slide masses were obtained by averaging multiple nodal point time histories within the respective masses.

Earthquake-Induced Displacements of Critical Slide Masses

m The Newmark sliding block analysis procedure was used to estimate the potential displacements of the critical slide masses using the seismic coefficient time histories to estimate the potential slide mass movements.

m Potential displacements of the critical slide masses * in the three sections analyzed range from 0.5 to

1.3 feet.

Transport Route Displacement Analyses

100.00

10.00

01.3 S1.00

0.10

0.01 1.0

From Figure 6, GEO.DCPP.01.30

0.2 o.-).46k o." 0.80.0

Conclusions

m Three representative sections along the transport route were evaluated for static and seismic loading conditions

m The sections are stable under transporter loads

m Displacements of 1.3 feet or less were calculated for slide masses subjected to the ILP ground motion

NRC/PG&E Open Meeting, Diablo Canyon Independent Spent

San Francisco, CA Fuel Storage Installation

Stability Analysis of Cutslopes

Jeff Bachhuber Engineering Geologist

William Lettis & Associates

April 11, 2002

Purposes

m Evaluate static and dynamic stability of proposed ISFSI pad cutslopes against possible smaller-scale rock block (wedge) failures

m Develop conceptual cutslope rock anchor support

, ftw s

S. S* PS~v

V.W,-,

............--- ......... L E1,149,000 Limitof7To PograPhic

S. . . . . . " - -

-27

k ý57.

A..

""-'E Backcut - " .

n profile.

//

/ / 4. I , T-, 6G

(SAR Figure2.6-3.2) /'

-' .1

4

50 100 150 200 -L_-_i -- _L- - I -J

5-

so's/

i

I North

MODEL 2

ISFSI CTF Pads

Reservoir

1971 pre-borrow excavation topography

II South

800

700

600

S500 4

0 • 400 a,

300

200

100

tower access

1'

TofbDoinltori

BACK CUTSLOPE

7' restricted

area fence

25' wdde bench a el.329.75'

S' security fence

ISFSI PAD

raw water wrm ervc

Cask setback from toe of cut

(SAR, PG&E, 2001)

0 50 too 150 200 250

400

350

250

200

300 350

K -'A /

/

/

/ /

S - .T-16

' ' ' '/ "T 1 B '• ". ,/ ,/ "

DS- ",1T- - "b (in road cut),-/ / ," /

<p 2 , .' -S "1"- 11A ./ ,'" 9 '". / ,, . " T 1 A," " " " , Yf/slo / . . -/ . I,"/' / /" . . -. "11..

SReport F Figure F-l) .: '., :. " ' ,

4'T-•/ i...OA..---. -7--:

/~ i5-0- .. -?-t-o o 100 150 200

" -- .. - - Contour interval = 5 feet

• . / J , . - ."•/ .c , -",. .• i.t t./.:., - ' j ,

• .,- , , -. .. ... ,.' ,,,- . ; " - ... ,1" ."'

T -"x.,. Tý T-14A7 "

," :• - , T-'I B. . ,, ./

E 1,149,000

+

�grP"

"N \,

x•,•_• -" • ..

Rock Mass Discontinuities

4:1

"40L

14.00

12.00-

S10.00

CU 8.00 0

ct) S6.00

.3

"0 4.00 0 UI)

2.00FI I

T-1 T-2 T-3 T-4 T-5 T-6 T-11 T-12 T-13 T-14 T-15 T-17 T-18 T-20 T-21

(Data Report F) Test Pit I Mean Discontinuity Spacing (ft)

I Standard Deviation (ft)

S-Maximum Spacing (ft)

Approach

"* Kinematic Analyses:

"* Identify potential failure modes

"* Select model for pseudostatic analyses

"* Pseudostatic Analyses: "* Deterministic Factor of Safety

"* Evaluate Sensitivity of Input Parameters

* Determine Anchor Force Requirements

"* Evaluate Mitigation Options

Assumptions For Analyses m Stability controlled by rock mass discontinuities m Discontinuity shear strength is represented by the

frictional component of the median Barton shear strength envelope

m We assume no benefit from cohesion m Groundwater/rainwater collects in discontinuities

up to half-height of the wedge m Wedges are limited within the outermost 20 to 25

feet of slope m Tension cracks exist at the top of the cutslope

Software

m Qualified software

o Kinematic Analyses - DIPS Version 5.041(Rocscience,

m Pseudostatic

1999)

Analyses - SWEDGE Version

3.06 (Rocscience, 1999)

Kinematic Analyses Input Parameters "i Geologic mapping data "i Discontinuity surveys in trenches and cuts

"* Bedrock bedding

"* Joints

* Faults

Set

1

Southern Hemisphere Projections

Set 1

Set 3

t2$

C. Wedge sliding hazard (high hazard)

(SAR, PG&E, 2001)

B. Planar sliding hazard (low to moderate hazard)

Results Kinematic Analyses

Planar Wedge Pseudostatic Mitigation Cutslope Topple Sliding Sliding Analyses Required?

Mod. To Mod. To Eastcut Low High Yes Yes

High (3 sets)

S~High

acut Low Low to Mod. (4 sets) Yes Yes

We steutHigh Low Very Low No No

(

Pseudostatic Analyses Input Parameters

m Barton mean shear strength values

m Laboratory direct shear test results

m Seismic loading of 0.5g acting as a uniform horizontal force

m Cutslope geometry from design drawings

m Wedge intersections from kinematic analyses

m Variable wedge geometry, shear strength

max height of ISFSI cutslope at el. 361.5'

max height of ISFSI cutslope at el. 361.5'

Itension crack at drainage ditch at back of bench

7,: 18"

4.-

modeled "average" slope profile without benches for fullheight failure wedges

-cutslope

profile

height 52.3' I

0.5 g Horizontal Seismic force

Single bench wedge

SWEDGE analysis

I Ii

tension crack tension distance crack

18"

4-

0.5 g Horizontal Seismic force

Total cut-height wedge as modeled by SWEDGE program

(From SAR, Fig.2.6-60)

Dynamic Factor of Safety= 1.3 Capacity 34 kips Length 23 feet + Bond

Critical wedges

Backcut Dynamic factor Anchor of safety characteristics

critical wedge without with per anchor anchor weight support support capacity* length

1784kips 0.62 1.3 33.9 kips 13 feet 4475 kips 0.63 1.3 32.1 kips 23 feet

40 kips 0.0 1.4 18.6 kips 7 feet 10 kips 0.3 1.7 9.4 kips 4 feet

Eastcut Dynamic factor Anchor of safety characteristics

critical wedge without with per bolt anchor weight support support capacity length

34 kips 0.54 1.3 9.0kips 3.5 feet

23.8 kips 0.0 1.4 8.4 kips 3.5 feet

5' x 5' pattern

Fault-Jed margin

Perspective view

Mitigation

" Rock anchor

" Drainage

"* Debris fences

" Shotcrete

* Setback

8' security area fence

8' security fence

raw water reserfvir

(From SAR, Figure 2.6-60)

ISFSI PAD

- •. Cask seth from tooc

BACK CUTSLOPE

7' restricted area fence 400

25' wide bench

at el. 329.75'

cutalope at el. 361.5' 350

onRock MxhDrain anchor

-A Drain Rock anchor

back Df cut

250

200 2033 00 200 250 300 350

Distance (feet)n 50 100 150

I-411 -

Conclusions - Cutslope Geology

"- Proposed ISFSI cutslopes will be excavated in dolomite, sandstone, and friable rock

"* Rock mass discontinuities control cutslope stability

"* Discontinuity spacing limits size of potential blocks to less than 20 to 25 feet

Conclusions - Cutslope Stability

"* Stability analyses shows that cutslopes exhibit high likelihood for wedge failure

"* Rock anchors will effectively stabilize cutslopes to achieve a dynamic, saturated Factor of Safety of 1.3

.34 kip anchors at 5' X 5' spacing

* Penetration lengths of up to 25'

* Proposed mitigation measures provide high margin of safety

Conclusions - Cutslope Stability

m Stability analyses shows that cutslopes exhibit high likelihood for wedge failure

m Rock anchors will effectively stabilize cutslopes to achieve a dynamic, saturated Factor of Safety of 1.3

.34 kip anchors at 5' X 5' spacing

*Penetration lengths of up to 25'

*Proposed mitigation measures provide high margin of safety

NRC/PG&E Open Meeting, San Francisco, CA Diablo Canyon Independent Spent Fuel Storage Installation

Response to NRC question

William D. Page

Senior Engineering Geologist


April 11, 2002

Question: Explain Degree of Confidence in

Results

m Input parameters used for modeling potential large-scale rock mass movements are realistic and conservative

m Confidence in predicted foundation conditions at CTF, ISFSI Pads and ISFSI cutslopes

Input Parameters for Modeling

m Geometry of clay beds well understood

m Groundwater conditions known, clay beds assumed saturated

Dip Direction

I Clay Beds lorth > 1/4 ±100ft.

0 100lFeet 1/8 to1/4 ± 50 ft. < 1/8 ± 25 ft.

V=H

1971 pre-borrow topography

CTF ISFSL. ..- T -1.1-F.D-

TCTF 01-H

Change in dip " .

direction- -

700

600

500

'--'400 a1) UI-,

0 16 300 a)

w

200

100

..... .. Tofb-i . . . . Dolmilte

v


II

SouthN

j�N �

- � -. �- - r 'F

-

0

zoo

U

-U-

I Clay Beds 11 North South

> 1/4 +±100 ft. 700 100 Feet 1/8to1/4 -,±-501ft.

Scale < 1/8 ±+25 ft. V-H

600

Temporary perched water 500 on clay beds after storms 0.A

S400 C FIS F S ... 01-F.. • _ • • ' _! "._: .• ._- • - 1.• ' •_• .• ... . , .. ,..

CTFT-1D . Reservoir Road , T1- 11

.0 01-CTF-A / 01-A __

S 300

200t Totb-2

Sandetone

100

0

Main water table(From SAR, Figure 2.6-18)

-A �1

Large-scale Mass Movements

m Geologic interpretations of extent of clay beds is conservative, but not extreme

m Potential slide planes are chosen to follow the full extent of more extensive clay beds and step between clay beds, this assumes minimum rupture of rock

m Rock to rock contact along potential slide plane along clay beds not factored into model, this would increase the clay strength from that used

Clay Beds Not Continuous

Clay Beds North South

> 1/4 ±100ft. 700 0 100Feet 1/8 to1/4 ±50 ft.

Scale <1/8 +25 ft.

V-H 600

500 1971 pre-borrow topography 00 - ",A

T8400 T .----- "F

0 01-CTF-A 01-A- =01 -

-II Tadb

--- _D o lom ite * . . Tofb-2 -01

San dotonb----- V.• --- "•r_.___ 100 .

0

9-


-T

-1

Clay Bed Extent Based on Thickness

0 100 Feet 1/8 LU tol/ ± ±u .t.

Scale[ <1/8 +±25 ft.

V=H

1971 pre-borrow

topography

IS FS1l. "01-F 01-H I_..- " I SHSI -•,, al-F

700

600

500

"--400 a)

0 N 300 a) w

200

100

R2 -- '" - q,

no-..•I

- .- - -- OOBAT-14A

a-01

Tofb-1 ---.. . . Dolomite

I-

v


I North

Clay Beds

>1/4 --- ±1001ft. 1 /0 f-1. ]A - trf% £f

II South

Tofb-: Sandstor

0

K

Thin areas where rock contactoccurs across clay bed

Thick areas of clay bed

Potential slide plane smoothes Shears offset clay bed undulations of clay bed by breaking through rock

Potential Slide Plane Breaks through Rock along Clay Bed

Evidence of No Landslides at ISFSI

m No evidence on pre-1971 air photos

m No evidence in studies for and excavation of borrow site

m No evidence of any fissures or fissure fills in trenches for ISFSI

Assumed Displacement of LargeScale Slide Mass* Fractures in the slope larger than 3 to 4

would have left a record on the slope

* No vegetation lineaments (similar to of intense growth in filled trenches)

inches

the zones

* No open fractures or soil-filled fractures in trenches on slope

"* Hillslope is 430,000 years old

"* Subjected to many large earthquakes

* Assumed 4 inches would occur in one slideevent

Ab1

~ 5 'K/ CD -~ - CL

/ - /~LL

It~~I al

Ka

LL

.V,

//N-'

a -0

N co

Slope 430,000 years agowo 900 - -

1971 slope

Q4

70- Q 5

Marine wave-cut

platform olderthan 430,000

Marine wave-cut platform years

(430,000 years old)

Hill Slope is 430,000 Years Old,

but degraded a Few Tens of Feet

North Clay beds at base of South

700 0100 Feet modeled large-scale

V=H movements extrapolated 600 to pre-1971 slope

500 1971 pre-borrow topography

S400 I~~~SFS1 ."o-_• 400 CTF .. • -T-1 1 D -- . -- , ----- .. ---

"" Reservoir Road F H

C ad 1t- "OOBA-3 0-4•••.•''--•L.- "•-•• t••*

0 01-CTF-A, 01-A -

S300

Lii

200 Totb-It,

T•fb.-2 -.

Sandston- '

100

0(From SAR, Figure 2.6-18)

Results of Sensitivity Study Clay Bed Strengths

200 --a-pMedianJdDeep

Model stress range N, Model -800 psf/215 deg

U) tres - 3000 psf / 22 deg 150 Shallow-800 psf / 36 deg

co Model stress range psf/4deg

" 1O0-range.2500 psf /23 deg

j:100 U _--800 psf / 26 deg

-0 psf /37 deg c 50 Strength ) 5used

study 0

0 50 100 150 200 250

Normal Stress (psi)

Confidence in Predicted Foundation Conditions at CTF, ISFSI Pads and Cutslopes

m High confidence in rock types predicted

*Sandstone

*Dolomite

*Friable Sandstone

" Friable Dolomite

" Clay beds

Interpretations with Less Certainty

m Locations and percentage of rock types not known with certainty

m Friable diabase may be encountered and is expected to have the same properties as friable sandstone

m Attitude of clay beds uncertain, more clay beds may be exposed

m Precise location of faults uncertain, other shear zones are expected

Conclusion

m High degree of confidence that there will be no significant surprises

m Features will be mapped during construction

m Planned mitigation measures will be applied as appropriate

WV �c.

April 9, 2002

Diablo Canyon ISFSI Site Tour

1 March, 2002I

1a c , 2 0

,4 4 , " , I, , -; f -3

Diablo Canyon Dry Cask Tour Agenda April 9., 2002

8:00- 8:25

8:30-8:35

8:35- 9:30

9:30 - 9:40

9:40 - 10:40

Maintenance Shop Building Training, Badging, Dosimetry

Canyon Room (Breakfast provided) Intro by Jearl Strickland, USFP Manager

Canyon Room

Part 50 and Part 72 Presentations

Break

Canyon Room Geotechnical Presentation

2 March, 2002

Diablo Canyon Dry Cask Tour Agenda April 9, 2002

10:45 - 12:15

12:15- 1:00

1:05 -4:00

4:00 - 5:00

Board bus in front of Training Building Geosciences Tour

Training Building, Room 123 Lunch

Board bus in front of Training Building Field/ISFSI Site Inspection (Outside Protected Area)

Training Building, Room 123 Closure Activities, Q&A

3 March, 2002

Process for Loading Used Fuel into Dry Storage

4 March, 2002

Transfer Cask Placement in Fuel Handling Bldg

V

F-`IL

�EI

5 March, 2002

S•!'• •F•F' i

NO

Transfer Cask Upending in Fuel Handling Bldg

6 March, 2002

Cask Transport Frame Stabilizer

1IMI Tension Links

7 March, 2002

FUEL HANDLING BUILDING CRANE

AUXILIARY LIFT

FHB CUANE MAIN HOIST

TOP BLOCK PIN

121 JOYCE SCREW JACK

PI L : "I '

PIN. J--7

8 March, 2002 I A*~I

Transfer Cask Removal From the Cask Transport Frame

N- I ',l ý[",,L IN K •

March, 20029w -Wwý

Transfer Cask Placement in the Cask Washdown Area

L I U! I I-- FP E TP• T -7 .

Note: Main hook not shown, but is engaged

Note: Seismic Restraint is not current version in this slide

10 March, 2002

Attachment of Impact Limiter

11 March, 2002

WALL P AE•E Cask (6PAE\ \Washdown

L"'"Area

Seismic Restraint

ONL•REAR 5LiNSS %•VN F-P l'AR T'

CONTROLLEO LOW

-Ri liON MATERIAL

Impact Limiter -

12 March, 2002

MPC and Annulus Filling

Note: Seismic restraint is not current version in this slide

13 March, 2002

Transfer Cask Removal from Frame

Note: Main hook is engaged, but not shown

Note: Seismic Restrain is not current version in this slide

14 March, 2002

TRANSFER CASK READY FOR

HORIZONTAL MOVEMENT TO

SFP

15 March, 2002

* SPENT FUEL POOL STRUCTURAL FRAME DETAIL

DETAIL (TYP. 4 CORNERS)

16 March, 2002

Transfer Cask Placement in Pool after Engaging in SFP Frame

17 March, 2002

Spent Fuel Loading into MPC

18 March, 2002

MPC Lid Installation

SNPC LID ,,RES TRAINT

Notes: Main hook is engaged, but not shown

Final lid restrain will differ

19 March, 2002

MPC Lid Installation


March, 200220

March, 2002

UIFT

TRANSFER CASK READY FOR

HORIZONTAL MOVEMENT TO

CWA

11a"21

Placement of Transfer Cask in Cask Wash Down Area

Note: Main hook is

engaged, but not shown


22 March, 2002

MPC Lid Welding

23 March. 2002-- w- I EL, %ml -1

MPC Lift Cleat Installation

L 1 r- T :I L E ',- -

24 March, 2002

Transfer Cask Readied for Horizontal movement


Note: Seismic Restrain is not current version in this slide

25 March, 2002

Transfer Cask Removal from Frame

Note: Main hook is engaged, but not

shown


26 March, 2002

Transfer Cask Placed on Transport Frame


correctly

27 March, 2002

Transfer Cask Downending Using Impact Limiter

28 March, 2002 I ��!& �

28 March, 2002 lktl&l;

Transfer Cask movement to Transporter

29 March, 2002

Transporter Rigging

LIFT INL] :R'ACiKE T S,

H 0lIP I ZFP N

March,1200230#

Tc1r)

Hi-Storm Overpack Lowered into Cask Transfer Facility

32 March, 2002I

Hi-Storm Overpack with Mating Device

"NET -HD R'vL:\T

33 March, 2002

Transfer Cask Upended (Transporter not Shown)

F]:L L

,'-- P ;Ir.! F' K • • F ] ' T , • :

34 March, 200271

Transfer Cask movement to CTF

35 March, 2002

Placement of Transfer Cask over Storage Cask

MarcLhU L2F

March, 200236

AT C TF WIO TRA NSPOR TER SHOWN

LIFTIN tPL ATT jts

J,-!, t÷ T t- t -r -• u rJ Icit e c04 r-e st r-oa in t ý , c,t. 1• 4r,

37 March, 2002

Transfer of MPC into Storage Cask

March, 200238

Transfer Cask Removal from CTF

C ASK T " ,r1,FER FACILITY , NEIT SHOWN)

39 March, 2002

Storage Cask Lid Placement

40 March, 2002

Overpack Raised out of CTF

•,(•~ K- ; • ,, i•..

41 March, 2002

I

Overpack Transported to Storage Facility

42 March, 2002

Overpack Placement on Storage Pad

43 March, 2002

I

J

Overpack Loading OperationsActivity Part 50 Part 72

1. Move empty cask and MPC into Impact on N/A FHB and prepare for loading structure

2. Empty transfer cask and MPC being Heavy load N/A placed in SFP drop

3. Load fuel assemblies into MPC Spent fuel Fuel TSs movement in

pool 4. Remove transfer cask from SFP Heavy load Thermal

drop on req's structure

5. Decontamination Existing N/A processes

6. Welding, leak testing and prepare for Releases and Fuel movement SSIP conditions/

closure req's 7. Transfer cask movement in FHB Heavy load N/A

drop on structure

8. Transfer cask movement outside Effect on Transporter FHB plant SSCs stability44

Part 50 and 72 Scope

* Part 50 - Crane modifications

- Heavy load drop structural analyses - Cask seismic restraints - Affect on facility during transport

* Part 72(Holtec CoC 1014) - Cask structural limits (drops, missiles, etc) - Criticality analysis during cask handling - Thermal analysis during cask handling

45 March, 2002

Documents

Properties of Subsurface · From SAR Section 2.5.1.2 and Calc Package GEO.DCPP.01.24. Slope Stability Theory Resisting moment o Pseudo-static Slope Stability F.S. = -----=1 q,- b