stabilised waste - cement barrier - soil interfaces 2 july 14 2009/07... · 2009. 7. 14. ·...

Stabilised Waste - Cement barrier - Soil interfacesHans van der Sloot, Hans Meeussen, Paul Seignette, Josh Arnold, David Kosson

ECN NetherlandsECN, NetherlandsVanderbilt University, Nashville

OVERVIEW

bl d fi i iProblem definitionRelease of non-interacting species (3 layer model)Scale issues Illustration of detailed chemistryChemistry of individual layersInterface reactions (diffusion in 3 layer model)Interface reactions (diffusion in 3 layer model)Carbonation and uncertaintyConclusions

214-7-2009

POSSIBLE CHANGES IN THE TANKPOSSIBLE CHANGES IN THE TANK CLOSURE SYSTEM AT LONG TERM

TANK CLOSURE

Waste

Tank heel concentrate

Concrete

concentrate

Soil

Aging and deterioration of waste form

314-7-2009

Soilof waste form

LL WASTE VAULT W t SoilC

O2 and CO2

POSSIBLE CHANGES IN THE LOW LEVEL WASTE VAULT LONG TERM

LL WASTE VAULT Waste SoilConcreteO2and CO2

Aging and

2

Aging and deterioration of waste form

Carbonation Oxidation

CO2

carbonation front

CO2

carbonation front

CO2

carbonation front oxidation front

O2

oxidation front

O2

414-7-2009

Air void (partially water filled?)carbonation frontcarbonation frontcarbonation front oxidation frontoxidation front

Effect of Boundary Conditions Boundary ConditionsEffect of Boundary Conditions and Saturation on Release from a 3-layer System

3-Layer 1-D diffusion model for

Waste form – no flux at interior boundary (left side)Clay soil – zero concentration at external boundary (right side of clay soil)

Initial Condition3 Layer, 1 D diffusion model for non-interacting, conservative species (e.g., Na)

Waste Form Concrete Clay Soil

Initial ConditionNa only in waste form at time zero at C/C0=1

Cases1. Saturated

(1) (2) (3)

100 cm 20 cm 50 cm

2. Unsaturated (tortuosity values assumed 2x for both waste form and concrete and 3.2x for soil; available porosity assumed 0.8x for waste form and concrete and 0.16 x for soil)

Waste Form Concrete

Clay Soil(compacted)

Density (g/cm3) 1.7 2.4 1.8

and 0.16 x for soil)

3. Same as (1) but with concrete layer only and C/C0=1 at waste form-concrete interface and C/C0=0 at concrete-clay soil interface

(g/cm3)

Porosity 0.4 0.1 0.35

Tortuosity (sat’d) 5 15 2

4. Same as (1) but with waste form only and C/C0=0 at waste form boundary (waste form in infinite bath)

514-7-2009

(sat d)

Transport of non interacting species in 1 2 and 3 layer system (sat unsat)Transport of non-interacting species in 1-, 2-, and 3-layer system (sat – unsat)

614-7-2009

Flux of non interacting species at the cement soil interfaceFlux of non-interacting species at the cement-soil interface

714-7-2009

Scaling to smaller dimensions with same physical conditionsScaling to smaller dimensions with same physical conditionsNa+ release from a waste through a cementitious

barrier into a clayey soil16

10

12

14

ol/l

)

4

6

8

Na+

(m

o

0

2

4

0 0 02 0 04 0 06 0 08 0 1 0 120 0.02 0.04 0.06 0.08 0.1 0.12

depth (m)Na+ t=0.05d Na+ t=0.4d Na+ t=4d Na+ t=18dNa+ t=144d Na+ t=243d Na+ t=576d Na+ t=1222d

814-7-2009

Steady state condition established within 2 years

K l f t th h titi b iK+ release from a waste through a cementitious barrier into a clayey soil

0.45

0.5

0 25

0.3

0.35

0.4

mol

/l)

0.1

0.15

0.2

0.25

K+

(m

0

0.05

0 0.02 0.04 0.06 0.08 0.1 0.12

depth (m)depth (m)K+ t=0.05d K+ t=0.4d K+ t=4d K+ t=18dK+ t=144d K+ t=243d K+ t=576d K+ t=1222d

914-7-2009

In spite of higher K level in barrier steady state condition established within 2 years

Illustration of the importance of more detailed chemistrydetailed chemistry

Geochemical speciation modeling based on pH dependence test results taking mineral precipitation, clay interaction, sorption on g p p y pironoxides, incorporation in ettringite and interaction with particulate and dissolved organic matter into account.

Sorption parameters for particulate and dissolved organic matter for U and Th based on the generic parameters derived by Milne t l 2003 f th Ni D d let al, 2003 for the Nica Donnan model.

1014-7-2009

Standardisation:

Characterisation leaching tests

GRANULAR MATERIALS

or pH DEPENDENCE TEST BATCH MODE

Standardisation: CEN/TC292, ISO/TC190, CEN/TC345, CEN/TC351, SW846

PERCOLATION LEACHING TEST CEN TS 14405 or EPA method 1314

TEST: BATCH MODE ANC, CEN/TS 14429, or EPA method 1313or, COMPUTER CONTROLLED CEN/TS

MONOLITHIC MATERIALS

CO O C / S14997

TANK LEACH TEST MONOLITH CEN/TS

15863 and EPA method 1315 and COMPACTED

GRANULAR LEACH TEST

Same as granular + GRANULAR LEACH TEST

(NEN 7347 and EPA method 1313).

Chemical speciation aspects Time dependent aspects of release

+

1114-7-2009

Chemical speciation aspects Time dependent aspects of release

LeachXS StructureLeachXS Structure

In the modeling mineral dissolution, sorption on hydrated ironoxides, clay interaction, interaction

1214-7-2009

g , p y , y ,with particulate and dissolved organic matter and incorporation in ettringite solid solution.

Cement Stabilised Waste Mix

[Th+4] as function of pH Partitioning liquid-solid, [Th+4] Th+4 fractionation in solution Th+4 fractionation in the solid phase

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

Con

cent

rati

on (

mol

/l)

1.0E-131.0E-12

1.0E-11

1.0E-101.0E-09

1.0E-08

1.0E-07

1.0E-061.0E-05

1.0E-04

Con

cent

rati

on (

mol

/l)

20%

40%

60%

80%

100%

Frac

tion

of

tota

l co

ncen

trat

ion

(%)

p

20%

40%

60%

80%

100%

Frac

tion

of

tota

l co

ncen

trat

ion

(%)

1.0E-091 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

[Th+4]

1.0E-141 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Free DOC-bound POM-bound Thorianite

0%1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Free DOC-bound

0%1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

POM-bound Thorianite

[UO2+] as function of pH

1.0E-04

/l)

Partitioning liquid-solid, [UO2+]

1.0E-05

1.0E-04

/l)

UO2+ fractionation in solution

100%

)

UO2+ fractionation in the solid phase

100%

1.0E-09

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

rati

on (

mol

/

1.0E-13

1.0E-12

1.0E-11

1.0E-10

1.0E-09

1.0E-08

1.0E-07

1.0E-06

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

rati

on (

mol

/

0%

20%

40%

60%

80%

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Frac

tion

of

tota

l co

ncen

trat

ion

(%)

0%

20%

40%

60%

80%

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Frac

tion

of

tota

l co

ncen

trat

ion

(%)

[UO2+] Free DOC-bound POM-bound Carnotite Schoepite Free DOC-bound POM-bound Carnotite Schoepite

[Cu+2] as function of pH

1.0E-05

1.0E-04

on (

mol

/l)

Partitioning liquid-solid, [Cu+2]

1.0E-05

1.0E-04

ion

(mol

/l)

Cu+2 fractionation in solution

60%

80%

100%

of t

otal

ti

on (

%)

Cu+2 fractionation in the solid phase

60%

80%

100%

of t

otal

ti

on (

%)

1.0E-07

1.0E-06

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

rati

o

SWD_SR2 (P,1,1) [Cu+2]

1.0E-08

1.0E-07

1.0E-06

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

rati

Free DOC-bound POM-bound FeOxide Cu[OH]2[s]

0%

20%

40%

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Frac

tion

oco

ncen

trat

Free DOC-bound

0%

20%

40%

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Frac

tion

oco

ncen

trat

POM-bound FeOxide Cu[OH]2[s]

1314-7-2009

Information also relevant for stabilisation of contaminated soil

Granulated blast furnace slag – fly ash cement mortar

[Th+4] as function of pH Partitioning liquid-solid [Th+4] Th+4 fractionation in solution Th+4 fractionation in the solid phase[Th+4] as function of pH

1.0E-07

1.0E-06

1.0E-05

Con

cent

rati

on (

mol

/l)

Partitioning liquid solid, [Th+4]

1 0E-13

1.0E-12

1.0E-11

1.0E-10

1.0E-09

1.0E-08

1.0E-07

1.0E-06

1.0E-05

Con

cent

rati

on (

mol

/l)

Th+4 fractionation in solution

20%

40%

60%

80%

100%

Frac

tion

of

tota

l co

ncen

trat

ion

(%)

Th+4 fractionation in the solid phase

20%

40%

60%

80%

100%

Frac

tion

of

tota

l co

ncen

trat

ion

(%)

1.0E-081 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

[Th+4]

1.0E-14

1.0E 13

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

CFree DOC-bound POM-bound

0%1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Free DOC-bound

0%1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

POM-bound


1.0E-05

l)


1 0E 06

1.0E-05

/l)


100%


100%

1.0E-11

1.0E-10

1.0E-09

1.0E-08

1.0E-07

1.0E-06

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

rati

on (

mol

/l

1.0E-12

1.0E-11

1.0E-10

1.0E-09

1.0E-08

1.0E-07

1.0E-06

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

rati

on (

mol

/

0%

20%

40%

60%

80%

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Frac

tion

of

tota

l co

ncen

trat

ion

(%)

0%

20%

40%

60%

80%

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Frac

tion

of

tota

l co

ncen

trat

ion

(%)

p

[UO2+]Free DOC-bound POM-boundEttringite Tyuyamunite Uranophane

p

Free DOC-bound

p

POM-bound Ettringite Tyuyamunite Uranophane


1.0E-06

1.0E-05

n (m

ol/l

)


1.0E-06

1.0E-05

n (m

ol/l

)


60%

80%

100%

f to

tal

on (

%)


60%

80%

100%

f to

tal

on (

%)

1.0E-09

1.0E-08

1.0E-07

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

rati

on

HOL12 (P,1,1) [Cu+2]

1.0E-09

1.0E-08

1.0E-07

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

rati

on

Free DOC-bound POM-bound FeOxide Tenorite

0%

20%

40%

60%

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Frac

tion

oco

ncen

trat

io

Free DOC-bound

0%

20%

40%

60%

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Frac

tion

oco

ncen

trat

io

POM-bound FeOxide Tenorite

1414-7-2009

Cement mortars and concrete not inorganic: non-negligible organic matter content!

CLAYEY SOIL

[Th+4] as function of pH Partitioning liquid-solid [Th+4] Th+4 fractionation in solution Th+4 fractionation in the solid phase[Th+4] as function of pH

1.0E-09

1.0E-08

1.0E-07

1.0E-06

Con

cent

rati

on (

mol

/l)

Partitioning liquid solid, [Th+4]

1 0E-13

1.0E-12

1.0E-11

1.0E-10

1.0E-09

1.0E-08

1.0E-07

1.0E-06

1.0E-05

Con

cent

rati

on (

mol

/l)

Th+4 fractionation in solution

20%

40%

60%

80%

100%

Frac

tion

of

tota

l co

ncen

trat

ion

(%)

Th+4 fractionation in the solid phase

20%

40%

60%

80%

100%

Frac

tion

of

tota

l co

ncen

trat

ion

(%)

1.0E-101 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

[Th+4] - L/S=10 [Th+4]-L/S=0.2

1.0E-14

1.0E 13

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

CFree DOC-bound POM-bound

0%1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Free DOC-bound

0%1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

POM-bound


1 0E 04

1.0E-03

l)


1 0E 06

1.0E-05

)


90%

100%


100%

1.0E-10

1.0E-09

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

rati

on (

mol

/l

1.0E-13

1.0E-12

1.0E-11

1.0E-10

1.0E-09

1.0E-08

1.0E-07

1.0E-06

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

rati

on (

mol

/l)

0%

10%20%

30%

40%50%

60%

70%

80%90%

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Frac

tion

of

tota

l co

ncen

trat

ion

(%)

0%

20%

40%

60%

80%

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Frac

tion

of

tota

l co

ncen

trat

ion

(%)

p

[UO2+] [UO2+] - L/S=0.2

pH

Free DOC-bound POM-bound Clay

p

Free DOC-bound

p

POM-bound Clay


1.0E-03

1.0E-02

1.0E-01

1.0E+00

ion

(mol

/l)


1.0E-05

1.0E-04

1.0E-03

1.0E-02

n (m

ol/l

)


60%

80%

100%

f to

tal

on (

%)


60%

80%

100%

f to

tal

on (

%)

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

rat

Zinc_Soil (P,1,2) [Cu+2] - L/S=10Zinc_Soil (C,1,1) [Cu+2] - L/S=0.2

1.0E-10

1.0E-09

1.0E-08

1.0E-07

1.0E-06

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

rati

on

Free DOC-bound POM-bound FeOxide Clay

0%

20%

40%

60%

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Frac

tion

oco

ncen

trat

io

Free DOC-bound

0%

20%

40%

60%

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Frac

tion

oco

ncen

trat

io

POM-bound FeOxide Clay

1514-7-2009

Soil system dominated by dissolved and particulate organic matter interaction

PROFILE WASTE- CEMENTITIOUS BARRIER - SOIL

I t ifi tiDiffusion Case Stabilised Waste - CEM II GBFS-FA - Soil OXIDISED/ CARBONATEDLayer overview

Material Stabilised waste GBFS-FA-Mortar SoilLength 5 00 2 00 5 00 cm

Input specification

Length 5.00 2.00 5.00 cmPorosity frc 0.40 0.10 0.35Tortuosity 3.00 10.00 2.00Density 1.70 2.40 1.70 kg/dm³

H 10 1 11 5 6 5pH 10.1 11.5 6.5

pe 15 15 15

In the modeling mineral dissolution, sorption on hydrated ironoxides, clay interaction, interaction with particulate and dissolved organic matter and incorporation in ettringite solid solutionsolution.

Typically 44100 variables, 192565 expressions, 118 equations

1614-7-2009


Distribution profile for Al+3 after 6 days Distribution profile for Ca+2 after 6 daysp y

1.0E-03

1.0E-02

1.0E-01

1.0E+00

1.0E+01

on (

mol

/l)

Stabilised Waste Concrete Soil

p y

1.0E-02

1.0E-01

1.0E+00

1.0E+01

1.0E+02

tion

(m

ol/l

)


1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

Con

cent

rati

o

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0.00 0.01 0.03 0.04 0.05 0.06 0.08 0.09 0.10 0.11

Con

cent

ra

1.0E-090.00 0.01 0.03 0.04 0.05 0.06 0.08 0.09 0.10 0.11

depth (m)

Free DOC-bound POM-bound Clay Ettringite AA_Gibbsite Albite[low] Kaolinite

depth (m)Free DOC-boundPOM-bound ClayEttringite AA_2CaO_Fe2O3_SiO2_8H2O[s]AA_Calcite AA_Gypsum

Distribution profile for Sr+2 after 6 days

1.0E-01S bili d W C S il

Distribution profile for Na+ after 6 days

1.0E+02Stabilised Waste Concrete Soil

1.0E-04

1.0E-03

1.0E-02

rati

on (

mol

/l)


1.0E-02

1.0E-01

1.0E+00

1.0E+01

trat

ion

(mol

/l)


1.0E-08

1.0E-07

1.0E-06

1.0E-05

0.00 0.01 0.03 0.04 0.05 0.06 0.08 0.09 0.10 0.11

Con

cent

r

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0.00 0.01 0.03 0.04 0.05 0.06 0.08 0.09 0.10 0.11

depth (m)

Con

cent

1714-7-2009

depth (m)

Free DOC-bound POM-bound FeOxide Clay Ettringite BaSrSO4[50%Ba] Strontianite

depth (m)

Free DOC-bound POM-bound Clay Albite[low]


Distribution profile for Th+4 after 6 days

1.0E-04

1.0E-03


Distribution profile for UO2+ after 6 days

1.0E-03

1.0E-02


1.0E-09

1.0E-08

1.0E-07

1.0E-06

1.0E-05

entr

atio

n (m

ol/l

)

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

entr

atio

n (m

ol/l

)1.0E-13

1.0E-12

1.0E-11

1.0E-10

0.00 0.01 0.03 0.04 0.05 0.06 0.08 0.09 0.10 0.11

Con

ce

1.0E-13

1.0E-12

1.0E-11

1.0E-10

1.0E-09

0.00 0.01 0.03 0.04 0.05 0.06 0.08 0.09 0.10 0.11

Con

ce

depth (m)

DOC-bound POM-bound Thorianite

depth (m)

Free DOC-bound POM-bound Carnotite

Association with DOC important for release

1814-7-2009

p

Predominance diagrams

Projected very long t

Technetium

term condition –carbonated and a doxidised

Initial condition –alkaline and reducing

1914-7-2009

Carbonation leads to alterations in the releaseCarbonation leads to alterations in the release behaviour as a result of the pH change that is brought about

CarbonationCarbonationThe effect of carbonation on release is illustrated by

CO2CO2CO2

modeling, including an evaluation of uncertainty in the model prediction.

CO2CO2CO2The data are placed in perspective to actually measured test data for > 70

carbonation frontcarbonation frontcarbonation front different cement mortars (Portland as well as different types of blended cements)

2014-7-2009

Stochastically varied input parameters for modeling of pH dependence leaching test data for cement mortars

• Total available concentration (10%)

• pH (0.1 unit)p ( )

• Pe (2 units)

• All reaction constants (15%)

• Ionic strength (20%)

• Gaussian distribution

• 2000 simulations in the pH range 2-13

2114-7-2009

2000 simulations in the pH range 2 13

Solubility of Ca in cement mortars as function of pH

With CarbonateWithout Carbonate100000000100000000

10000000

a] (µ

g/l)

10000000

a] (µ

g/l)

1000000

[Ca

1000000

[Ca

1000002 4 6 8 10 12

pH

1000002 4 6 8 10 12

pH

2214-7-2009

Solubility of SO4 as S in cement mortars as function of pH

Without Carbonate With Carbonate

100000

1000000

100000

1000000

10000

100000

S] (µ

g/l)

10000

100000

[S] (

µg/l)

1000[S

1000

[

1002 4 6 8 10 12

pH

1002 4 6 8 10 12

pH

2314-7-2009

Ettringite

Solubility of Si in cement mortars as function of pH

Without Carbonate With Carbonate

1000000

10000000

1000000

10000000

10000

100000

[Si]

(µg/

l)

10000

100000

[Si]

(µg/

l)

100

1000

2 4 6 8 10 12100

1000

2 4 6 8 10 12 2 4 6 8 10 12pH

2 4 6 8 10 12pH

2414-7-2009

CONCLUSIONSCONCLUSIONS- Both physical and chemical changes in the waste form and cement barrier are of importance to properly assess release to thebarrier are of importance to properly assess release to the environmental.

- For non-reacting species a steady state condition of release through the barrier develops within a few years for saturated conditions Forthe barrier develops within a few years for saturated conditions. For unsaturated conditions this takes in the order of a hundred years.

- Carbonation and oxidation lead to important changes in release b h i f b A h l d i f i ibehaviour of substances. As these processes lead to moving fronts it is difficult to capture the release in a Kd describing contaminant behaviour of the entire waste form, the barrier or the soil.

2514-7-2009

CONCLUSIONSCONCLUSIONS- Gaining insight in more detailed chemical interactions is of importance as mobilisation in the form of dissolved complexes mayimportance as mobilisation in the form of dissolved complexes may occur. Currently, organic matter interaction is not considered.

- The binding potential of hydrated ironoxide (formed in situ upon oxidation of reduced Fe in both waste and barrier) for radionuclides ofoxidation of reduced Fe in both waste and barrier) for radionuclides of interest is important for retention within the containment under oxidised/carbonated conditions.

U d Th i h d l li i d d f h- U and Th in the present model runs are preliminary and need further verification by measurement of actual release behaviour from size reduced stabilised waste. In case of U and Th, this is possible with stable isotopes For Tc this is obviously not possiblestable isotopes. For Tc this is obviously not possible.

- Therefore, carrying out a pH dependence test on cement stabilised radioactive waste is highly recommended to provide better insight in

2614-7-2009

release controlling processes.

CONCLUSIONSCONCLUSIONS- More detailed chemical characterization provides the means to design for retention of contaminants in the waste or the design of adesign for retention of contaminants in the waste or the design of a chemical barrier in addition to physical containment.

- Although calculation times with complex chemistry are long compared to Kd type calculations it is possible to model release under definedto Kd type calculations, it is possible to model release under defined conditions along the projected path as defined in a pe – pH diagram (resulting from carbonation and oxidation). More complete consideration of chemical processes also provides more robustconsideration of chemical processes also provides more robust understanding of non-linear process coupling and for improved design.

- Optimization of calculation efficiency. Balance complex models with simplified models Preferably justified simplification based onsimplified models. Preferably justified simplification based on understanding the underlying processes.

2714-7-2009

stabilised waste - cement barrier - soil interfaces 2 july 14 2009/07... · 2009. 7. 14. ·...

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