Evaluation of HTO and selenium diffusion behavior in compacted bentonite with different lengths

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Logo

Ev a l u a t i on of HTO a n d

s e l e n i u m d i f f u s i on b e h a v i or i n c omp a c t e d b e n t on i t ewi t h

d i f f er e n t l e n g t h s

Department of Earth Sciences,

National CHENG-KUNG University, Tainan, TAIWAN Speaker: CHUAN-PIN LEE Ph.D

M.C. Wu, S.C.Tsai, T.L. Tsai, C.Y.Liu, H.J.Wei, L.C.Men Asia-Pacific Symposium on Radiochemistry (APSORC 13)

Sep. 22-27, 2013,Kanazawa, JAPAN

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Ma p of Ta i wa n ( Nu cl e a r Powe r Pl a n t s )

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Ma p of Ta i wa n ( Nu cl e a r Powe r Pl a n t s )

NPP3

NPP1NPP2 NPP4

2016^＊

－ NPP4

( ABWR)

20 2 4 19 8 4

NPP3 ( PWR)

20 2 1 19 8 1

NPP2 ( BWR)

20 1 8 19 7 8

NPP1 ( BWR)

Dec ommi s s i on Commer i c a l

Op er a t i on ( Y) UNI T

＊ under construction

＊ 5144 MWe Electrical capacity=18% in TAIWAN

＊ 4,916 tU（spent fuel）after 40 years operation

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1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5

Potential Host Rock Characterization and Evaluation

2 0 0 0 - 2 0 1 7

2 0 5 5 2 0 25 2 0 3 5

2 0 1 7

2 0 0 0

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Di s p os a l of Ta i wa n SNFD c onc e p t

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En g i n e er i n g Ba r r i e r Sy s t e m ( EBS)



Ca ni s t er



Buf f er /Ba ck f i l l Ma t er i a l ( T- H-M- C) Ther mo Cond uc t i v i t y Tes t

Hy d r a ul i c Con d uc t i v i t y Tes t Mec h a ni c a l Te s t

Ch emi c a l Tes t

＊

^La^bôrâ^tôr^y^Tes^t^sôf^Ra^dⁱônû^c^lⁱ^dê^Mi^g^râ^tⁱônôn^Bu^f^fê^r^/^ba^ck^fⁱ^l^l

MaterialandHost-rockinTaiwan(2002-current)

Transport:Migration in buffer/backfilland host-rock

Buf f er /b a ck f i l l ch emi c a l s t a b i l i t y : a d s or p t i on /d e s or p t i on

Hos t Rock Ch a r a c t er i s t i cs ( Ge ol og i c a l I nv es t i g a t i on)

2009-2013 2005-2009

2002-2005 LaboratoryTestsofRadionuclideMigrationon

Buffer/backfillMaterialandHost-rockinTaiwan

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Geol og i c a l I nv es t i g a t i on



Cr y s t a l l i n e Rock Gr a ni t e ( K & W a r e a ) Ba s a l t ( P a r ea )

Di or i t e ( K & W a r e a )



Sed i met a r yRock

Ta i wa n Mud r ock( H a r e a ) P

H K

W

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Bu f f e r Ma t e r i a l s



St ud i es h a s b ee n p er f or med i n s ev er a l count r i es ( SKB i n

SWEDEN , NAGRA i n SWI TZLAND, JAPAN i n H-12, H-1 7 Pr oj ect )



Na -Bent oni t ei s a ca nd i d a t e b uf f er f or ma t er i a l s .



MX-80 i s a ca nd i d a t e b uf f er ma t er i a l i n

Ta i wa n SNFD p r oj e ct .

2.0- 2.8 Dolomite

7.3 2-3

2 Other

0.3 0.003

0.4 0.31-

0.34 Org.Mat.

2 Gypsite

56 9.5

2 Illite

12-15

<1 Muscovite

30 0.8

<1 Kaolinite

0.3 0.5-

0.7 Pyrite

1.5 3.0-

3.5 Analcime

0.5 1-4

<1 2.1-

2.6 Calcite

4.3 2-4

5-8 2.7-

5.5 Feldspar

11.7 5

8.3 15.2

<1 29-38 Quartz

14 75.4 79

66 75

98-99 46-49

Mont.

Zhisin (TWN) GMZ

(CHN) Avonsel

(FRN) Motigel

(FRN) MX-80

(U.S) Kunipel

(JPN) Kunigel

(JPN) ITEM

Content

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RN Transport (Migration)

Model Parameters

Experiments

Simulation

Ob j e c t

Laboratory Tests:

Radionuclides Chemistry and Migration

1. Method establishment : batch sorption/desorption tests & Column (Through- diffusion) tests

2. Model

calibration/verification

3. Simulation & Assessment

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Ta b 1e 1. Some l ong -l i v ed r a d i onucl i d esp r od uc ed i n f i s s i on a f t er cool i ng 10y

3060 6.183

β、γ 30.1

Cs-137

0.0098 6.536

β 2.3 × 10

⁶

Cs-135

201 β、γ 0

2.06 Cs-134

0.0021 0.757

β 1.57 × 10

⁷

I-129

0.484 6.074

β 2.13 × 10

⁵

Tc-99

0.0151 0.0443

β 2.95 × 10

⁵

Se-79

Activity (TBq/tU) yield (％)

Decay Half-Life (y)

Nuclides

＊ Gregory R.Choppin et al., Radiochemistry and Nuclear Chemistry, 2002

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Ba t c h e x p er i ment s ( ASTM met hod )



ASTM D4 3 19 - 93 （2 0 01 ）

( a ) Li q ui d p ha s e s el e c t i on ： ^Sy ^nt ^h êt ⁱ ^cg ^r ôu ^nd ^wa ^t êr ⁽ ^GW) ^, ^s êa ^wa ^t êr ⁽ ^SW)

( b ) Ra d i ot r a c e r ：

⁷⁵

Se（t

₁_/2

= 12 0d ） ( c) Ca r r i er ：SeO

₂

（10

^-4

M）

( d ) Sol i d p ha s e a n a l y s i s ：Mud r ock -XRD ( Powe r X-r a y d i f f r a c t i on )

-I CP-MS ( el eme n t a l a na l y s i s of mi ner a l s ) -N

₂

-BET（s p e ci f i c s ur f a ce a r e a ）

-CEC（cat i onex c ha ng e c a p a ci t y ） ( e) Sol i d p ha s e p r ep a r a t i on ：

cr us h, s i ev e, wa s h, p r e -e q ui l i b r a t e, d r y , a n d s t or e.

( f ) Sol i d - t o-Li q ui d r a t i o: Ms / V ( g /ml )

Shaking

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Th eor y of Di f f u s i on i n p or ous me d i a

2 2

x D C

t C

a



 



B.C.

(1）C (0,t)=C

₀

(2）C (L,t)=0 I.C.

C(x,0)=0 , x > 0

•Fick’ s Law

^：

1-D Diffusion Eq. dx D dC J  

•Sol

^：



^

^ ^ ^

^





1

) ( 2

2 2

0

2 ( 1 ) ( 1 )

[ 6 )

(

2

e

^d ^t

Da n n

a a

e

Dan d D

t L L

S C t D

Q



0 L x

C

₀

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St ea d y -St a t e As y mp t ot e of t hr oug h-d i f f us i on

] ) 1

( )

1 ( 6 2

[ )

( 1

) ( 2

2 2

0 ^ ^



^ ^ ^ ^^ ²



e

^d ^t

Da n n

a a

e

Dan d D

t L L

S C t D

Q



Time

6 ] [

) (

'

⁰

a a

e

D t L

L S C t D

Q  

x

a

L t

D 

²

6

AccumulatingConc.

Steady-state asymptote Slope=m

D

_a

× t /L

²

>0.45

a d

e

mV L S

D 

a cal e

D Rf D

 

) 1

( 



_b ^d^cal

cal

K

Rf  

Apparent Diff. coe.

t

_x

Effective Diff. coe.

Retardation factor

Rf

^H/RN

=

_RN

a HTO a

D

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Col umn ex p er i me nt s

( Thr ou g h-d i f f us i on met h od )



Thr oug h -Di f f u s i on met hod

（Le e et a l , 2 00 8, 2 0 09, 20 1 0）

( a ) Li q ui d p ha s e s el e c t i on ：

Sy nt h et i cg r ou nd wa t er ( GW) , s ea wa t er ( SW)

( b ) Ra d i ot r a c e r ：

³

H ( t

₁_/2

= 1 2 y ) ；

75

Se（t

_1/2

=1 2 0 d ）

( c) Ca r r i er ： SeO

₂

（10

^-4

M）

( d ) Sol i d p ha s e a n a l y s i s ：Ben t oni t e ( MX-8 0)

( e)Bul k d es i t y：1. 2 g /c m

³

( f )Por i s i t y ：0. 5 5

( h) Leng t h ： 0. 25 0. 5 0, 0. 7 5, cm 1. 00, 2. 0 0, 2. 5 0 cm

PUMP

C=C₀=10^-4M

V₀=5000mL

C

V₁ V₇ V₂ V₈ V₃ V₉ V₆ V₁₂

V₅ V₁₁

V₄ V₁₀

C C C C C

0.25cm 0.5cm 0.75cm 1.0cm 2.0cm 2.5cm

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Experimental

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Sc h eme of t hr oug h - d i f f us i on t e s t s

V₁=V₂=V₃=V₄=100mL

V₅≒V₆≒ V₇≒ V₈ ≒V₉ ≒ 100mL

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Time(d)

0 50 100 150 200 250 300

CR(t)

0.0 0.2 0.4 0.6 0.8 1.0

HTO-0.25cm HTO-0.50cm HTO-0.75cm HTO-1.00cm HTO-2.00cm HTO-2.50cm Se-0.25cm Se-0.50cm Se-0.75cm Se-1.00cm Se-2.00cm Se-2.50cm

Time(d)

0 50 100 150 200 250 300

CR(t)

0.0 0.2 0.4 0.6 0.8 1.0

0.25 cm 0.50 cm 0.75 cm 1.00 cm 2.00 cm 2.50 cm y0.5 = 0.079x - 0.13

R2 = 0.94

y0.75 = 0.0035x - 0.0932 R2 = 0.98

y2.5= 0.0015x - 0.1175 R2 = 0.99

y2.0 = 0.0018x - 0.1458 R2 = 0.99

y1.0 = 0.0023x - 0.1346 R2 = 0.99

y0.25 = 0.0083x - 0.05 R2 = 0.99

Time(d)

0 5 10 15 20 25

CR(t)

0.0 0.2 0.4 0.6 0.8 1.0

0.25 cm 0.50cm 0.75 cm 1.00 cm 2.00 cm 2.50 cm y0.75 = 0.015x - 0.06

R2 = 0.99

y2.0 = 0.0114x - 0.0015 R²= 0.97

y2.5 = 0.0085x - 0.02 R2 = 0.97

y1.0 = 0.0148x - 0.085 R2 = 0.99

y0.5 = 0.0172x - 0.0038 R2 = 0.99

y0.25 = 0.0305x - 0.02 R2 = 0.99

Di f f us i on of HTO a nd Sel e ni um t hr oug h comp a ct ed MX8 0 i n SW

(a) HTO

(b) Se

(c) HTO&Se

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Time(d)

0 50 100 150 200 250 300

CR(t)

0.0 0.2 0.4 0.6 0.8 1.0

H-0.25cm H-0.50cm H-0.75cm H-1.00cm H-2.00cm H-2.50cm Se-0.25cm Se-0.50cm Se-0.75cm Se-1.00cm Se-2.00cm Se-2.50cm

Time(d)

0 50 100 150 200 250 300

CR(t)

0.0 0.2 0.4 0.6 0.8 1.0

0.25 cm 0.50 cm 0.75 cm 1.00 cm 2.00 cm 2.50 cm

y0.5 = 0.045x - 0.0925 R2 = 0.94

y0.75 = 0.0035x - 0.1614 R2 = 0.98

y2.5= 0.0013x - 0.124 R2 = 0.99

y2.0 = 0.0024x - 0.2161 R2 = 0.99

y1.0 = 0.0032x - 0.2143 R2 = 0.99

y0.25 = 0.0052x - 0.055 R2 = 0.99

Time(d)

0 5 10 15 20 25

CR(t)

0.0 0.2 0.4 0.6 0.8 1.0

0.25 cm 0.50 cm 0.75 cm 1.00 cm 2.00 cm 2.5 cm y0.5 = 0.0192x - 0.0065

R2= 0.98 y2.0 = 0.0118x - 0.02

R2

= 0.94

y2.5 = 0.0086x - 0.035 R2= 0.95

y0.75 = 0.0152x - 0.01 R2= 0.97

y1.0 = 0.0157x - 0.012 R2= 0.98

y0.25 = 0.027x - 0.0028 R2= 0.99

Di f f us i on of HTO a nd Sel e ni um t hr oug h comp a ct ed MX8 0 i n GW

(a) HTO

(b) Se

(c) HTO&Se

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Di f f u s i on Pa r a me t e r s of HTO

38.57 1.09

0.69 1.16

0.25 40.67 1.15

0.78 1.23

0.25 1.36 1.19 1.07 1.30 1.26 1.08 1.11 1.06 1.29 0.97

Rf

1.44 1.62

2.52 1.00

6.12 1.17

1.66 0.75

0.50 2.22

2.96 2.50

0.66 2.43

4.55 2.00

1.16 1.23

1.73 0.75

1.38 0.99

1.42 GW 0.50

1.28 2.30

3.88 2.50

2.06 2.44

3.99 2.00

5.38 1.52

2.60 1.00

13.6 0.88

1.66 SW 0.50

t_d D_e×10^-10

(m

²

/s)

D_a×10^-10

(m

²

/s) Liquid

L

(cm)

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Pa r a met e r s of Se i n SW a n d GW

0.54 11.1 25.2 3.84 1.54 0.69 3.6 2.5

0.47 18.8 41.9 3.69 0.95 0.56 3.6 2.0

0.68 0.75

1.22 3.32

t_d

35.6 18.2

25.5

2K_d^H/Se 27.6

78.7 40.7

56.6

1Rf^H/Se 61.2

2.35 2.69

4.04 D_e×10^-11 2.12

(m²/s)

0.33 0.41

0.29 D_a×10^-11 0.20

(m²/s)

0.28 0.21

0.14 0.07

L/D

3.6 3.6

D

1.0 0.75

0.50 0.25

L

SW Liquid

0.50 10.3 23.4 3.33 1.26 0.69 3.6 2.5

0.53 28.9 53.1 4.91 0.86 0.56 3.6 2.0

0.60 0.60

0.89 1.56

t_d

39.7 33.1

27.3

2K_d^H/Se 42.0

87.6 73.3

60.7

1Rf^H/Se 92.7

3.28 2.69

2.30 D_e×10^-11 1.33

(m²/s)

0.29 0.24

0.23 D_a×10^-11 0.13

(m²/s)

0.28 0.21

0.14 0.07

L/D

3.6 3.6

D

1.0 0.75

0.50 0.25

L

GW Liquid

Rf^H/Se＝Da^HTO/Da^Se ；td=Da*tf/L²

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Con c l u s i on s



I n t hi s s t ud y , b a t c h a nd d i f f us i on t es t s wi t h d i f f er en t l e n g t hs ( 0. 2 5, 0. 5, 0. 7 5, 1. 0, 2. 0, 2. 5 cm) wer e cond u c t ed , r e s p ec t i v el y .



I t a l s o i nd i c a t e d t h a t t he ex p er i men t a l t i me f or SW a nd GW wa s l ong en oug h t o r e a ch s t ea d y -s t a t e d i f f us i on a t a b out 2 50 a nd 30 0 d a y s , r es p ec t i v el y .



I t wa s a l s o e v i d en t t h a t b ot h t h e

Rfand Kdof

Se i n SW wer e l ower t h a n t h os e i n GW, whi ch wa s i n a g r eemen t wi t h r es ul t s ob t a i n ed f r om t h e

b a t c h me t hod .



I n f a c t , t h e

Rfv

a l u e i n t h e 1 -D d i f f us i on h y p ot h es i s a nd t h e

Rfi

n t h e 2. 5 cm c ol umn s wer e l ower t h a n t h os e a t t he 2. 0, 1. 0, 0. 7 5, 0. 5 a nd 0. 2 5 cm c ol umns .



Ac c or d i ng t o t he p er f or ma n c e a s s es s men t f or HLW d i s p os a l , t h e hi g her

di f f us i on p a t h a nd s ol i d /l i q ui d r a t i o a p p l i ed i n t he ex p er i men t sp r ov i d e d

mor e r e a l i s t i c

Kdv

a l ues i n a r ea l g e ol og i c a l en v i r onme n t .

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Ac k nowl e d g e



The Ai m f or t he Top Uni v er s i t y Pr oj ect t o t he Na t i ona l Cheng Ku n g Uni v e r s i t y ( NCKU) , Mi n i s t r y of Ed uca t i on , Ta i wa n , R. O. C.



I ns t i t ut e of Nu c l ea r En e r g y Re s ea r c h , At omi c En e r g y Cou n ci l , Ta i wa n R. O. C.



Nucl ea r Sc i e n c e a n d Te c h n ol og y Dev el op me n t Ce n t e r , Na t i ona l Ts i ng - HuaUni v e r s i t y , Hs i n c h u , Ta i wa n



Ene r g y a n d Res ou r c e s La b or a t or i e s , I n d u s t r i a l Te c h n ol og y Res ea r c h I n s t i t ut e , Hs i n Ch u , Ta i wa n



Na t i on a l Sci e n c e Cou n c i l , Ta i wa n



Ta i wa n Powe r Comp a ny

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