MODELING REACTIVE TRANSPORT IN NUCLEAR WASTE GEOLOGICAL DISPOSAL: 2 benchmark problems : -...

MODELING REACTIVE

TRANSPORT IN NUCLEAR WASTE

GEOLOGICAL DISPOSAL:

2 benchmark problems :

- Glass/iron/clay interactions

- Atmospheric Carbonation of

concrete

SES BENCH – OCT. 27 - NOV. 2 2012

O. Bildstein, P. Thouvenot, J.E. Lartigue, I. Pointeau

CEA (French Alternative Energies and Atomic Energy Commission)

B. Cochepin, I. Munier ANDRA (French Radioactive Waste Management Agency)

20 avril 2023 | PAGE 1CEA | 10 AVRIL 2012

DISPOSAL CONCEPT IN A CLAYSTONE FORMATION AT 500 m DEPTH

Current design of deep underground repository for high and intermediate level long-lived waste

S.S.BENCH - November 16-18. 2011

SeS BENCH – Taipei, Taiwan | NOV. 2012 | PAGE 2

Just a few words aboutthe glass/iron/clay

benchmark…


DRD/EAP/11-0219

HLW DISPOSAL CELL

20 avril 2023 5th Andra International Conference - Montpellier | 22 Oct 2012 | PAGE 4

• different types of material in physical contact, technological gaps

long term calculations of geochemical evolution (100 000 years)

Vitrified wastepackages

Cross section

3 cm gap steel liner

disposal package

0.8 cm gap

3 cm gap

scale

• 1D radial domain

• transport: diffusion only

• water saturated, constant porosity

• glass

Φ = 0.42 m, H = 1 m

porosity = 0.12

• metallic components

total thickness = 0,095 m,

porosity = 0.25

• connected fractured zone

0.4 * excavation diameter = 0.268 m

porosity = 0.20; Deff(25°C) = 5.2 10-11 m2/s

• undisturbed claystone (50 m)

porosity = 0.18; Deff(25°C) = 2,6 10-11 m2/s

GEOMETRY AND TRANSPORT PROPERTIES

argilites (50 m – 183 cells)

glass (21cm – 21 cells)

overpack + lining + gaps

(13,8cm – 14 cells)

5th Andra International Conference - Montpellier | 22 Oct 2012 | PAGE 5

- reactive-transport codes: Crunch/Hytec

Isothermal conditions

- H2(g) produced from anoxic corrosion p(H2)max = 60 bar

RESULTS IN THE BASE CASE (2)

20 avril 2023 5th Andra International Conference - Montpellier | 22 Oct 2012 | PAGE 6

Corrosion products (volume%, 45 000 yrs, end of corrosion)

magnetite, Ca-siderite, and greenalite dominate

(oxide) (carbonte) (silicate)

also smaller amounts of aluminosilicates

(nontronites and saponites)

no significant changes after corrosion phase

POROSITY CLOGGING

modeling vs. experimental results (Schlegel at al. 2007)

iron/claystone at 90°C for 1 year small amount of magnetite

siderite(-Ca), Fe-silicates

more phenomenological model for corrosion

Canister zone

0,1 µm

Now to theconcrete carbonation

benchmark…


DRD/EAP/11-0219

DESIGN: ILLW CELLS, SHAFTS (AND SEALS), ILLW DISPOSAL OVERPACK

Atmospheric carbonation of overpack during the operating period



• Bitumized waste• Compacted metallic waste• Organic waste

CARBONATION ISSUE FOR RADWASTE DISPOSAL



Ventilation (100 years)

DRYING AND CARBONATION PROCESSES OF ILLW OVERPACK


Dry air

(Rh = 40 %)

T = 25°C to 50°C

SlWater vapor diffusion

CO2 gas diffusion

T

Aqueous diffusion of reactants

Two phase water/air flow

Dissolution/precipitation : porosity reduction, permeability variations

Brine formation

CO2 gas dissolution

Dry air

(Rh = 40 %)

T = 25°C to 50°C

SlWater vapor diffusion

CO2 gas diffusion

T

Aqueous diffusion of reactants

Two phase water/air flow

Dissolution/precipitation : porosity reduction, permeability variations

Brine formation

CO2 gas dissolution


MODELING ISSUES



• CO2 gas diffusion and reactivity

MODELING ISSUES



benchmark emphasizes the coupling aspects

• CO2 gas diffusion and reactivity

GEOMETRY

1D Cartesian – 5.5 cm divided in 11 x 5 mm cells

Boundary conditions (EOS 4)


Concrete

Symmetry axis

Dry air Dry air

Wall package 110 mm


CASE 1DRYING OF CONCRETE OVERPACK


DRD/EAP/11-0219

DRYING PHENOMENON (TOUGHREACT EOS4)

Flow law: Generalized Darcy law

Lowering of the dew point due to capillary effects (Kelvin equation in EOS 4)

Water relative permeability (Van Genuchten)

Gas relative permeability (Corey)

Klinkenberg effect (gas flow at low pressure)


)(

gPkkF r

))(ln()( lrw

wrcap ShM

RThP

21

11)(

m

mrrrrl SSSk

lrls

lrlr SS

SSS

22 ˆ1ˆ1 SSk rg grlr

lrl

SS

SSS

1

ˆ

rgg kp

kk

1int


DRYING PHENOMENON (TOUGHREACT)

Air and water gases diffusion

CO2 and other gases

Aqueous diffusion

Effective diffusion

Tortuosity


15,273

15,273,, 000,,0,,0

T

P

PTPdTPd ii

M

RT

PNd

RTd i

8

23 2,,0

TR

Edd a

KOHi

1

15,298

1exp15,298,,,0 2


0,,0, ii dD

baS 0

DRYING PHENOMENON (TOUGHREACT)

Air and water gases diffusion

CO2 and other gases

Aqueous diffusion

Effective diffusion

Tortuosity


15,273

15,273,, 000,,0,,0

T

P

PTPdTPd ii

M

RT

PNd

RTd i

8

23 2,,0

TR

Edd a

KOHi

1

15,298

1exp15,298,,,0 2

0,,0, ii dD

baS 0


DRYING PHENOMENON : PARAMETERS IN REFERENCE CASE

BHP CEM I


ROCK1

Density (kg/m3) 2700

Porosity 0.12

Intrinsic permeability to liquid (m²) 1e-19

Intrinsic permeability to gas (m²) 1e-17

Relative permeability m – Slr – Sls - Sgr

0.424 – 0.0 – 1.0 – 0.0

Capillarity pressurem – P0 (MPa) – Pmax (MPa) 0.424 – 15 - 1500

Molecular diffusion coefficient in gaseous phase (m²/s)

2.4e-5

Molecular diffusion coefficient in aqueous phase (m²/s)

1.9e-9

Millington-Quirk a parameter 2

Millington-Quirk b parameter 4.2

Klinkenberg parameter (MPa) 0.45


RESULTS


Drying results


RESULTS with RICHARDS’ EQUATION


Drying results


OK to use Richards’ equation for benchmarking exercise

CASE 2CARBONATION WITH CONSTANT SATURATION


DRD/EAP/11-0219

PHENOMENOLOGY

Constant saturation but unsaturated + diffusion of gas


Sliq = 0.3

CO2 gas diffusion

Diffusion of aqueous species

Dry AirRH = 60%

25°CpH = 13

CO2 dissolution

Precipitation/dissolution reactions

Sliq = 0.3

CO2 gas diffusion


Dry AirRH = 60%

25°CpH = 13

CO2 dissolution


Sliq = 0.3

CO2 gas diffusion


Dry AirRH = 60%

25°CpH = 13

CO2 dissolution



CHEMICAL PARAMETERS

Primary phases

Secondary phases

Kinetics of dissolution / precipitation

nnnn Akr 1

15,298

11exp15,298 TR

EkTk a

n

Phase Volume %

Calcite 72.12

Portlandite 5.73

CSH 1.6 13.76

Monocarboaluminate 2.26

Ettringite 3.60

Hydrotalcite 0.39

Hydrogarnet-Fe (C3FH6) 2.05

Phase type Phases

Oxides Magnetite, Amorphous silica

Hydroxides Brucite, Gibbsite, Fe(OH)3

Sheet silicates Sepiolite

Other silicates CSH 1.2, CSH 0.8, Straetlingite, Katoite_Si

Sulfates, chlorides, other salts Gypsum, Anhydrite, Burkeite, Syngenite, Glaserite, Arcanite, Glauberite, Polyhalite

Carbonates Calcite, Nahcolite

Other Hydrotalcite-CO3, Ettringite, Dawsonite

CHEMICAL PARAMETERS

Primary and Secondary phases characteristics

Phase Kinétic

Constant (298.15 K)

Activation Energy

(kJ.mol-1)

Specific Surface (m2.g-1)

C3FH6 1 10-12 30 1

Calcite 1.6 10-6 23.4 1

CSH 0.8 1.6 10-9 50 1

CSH 1.2 1.6 10-9 50 1

CSH 1.6 1.6 10-9 30 1

Ettringite 1.6 10-9 30 1

Gibbsite_am 1.6 10-9 30 1

Gypsum 1.6 10-5 20 1

Hydrotalcite 1.6 10-9 30 1

Iron Hydroxyde 1.6 10-8 30 10

Monocarboaluminate 1.6 10-9 10 1

Portlandite 1.6 10-8 20 1

Sépiolite 1.6 10-12 50 10

Amorphous SiO2 1.6 10-9 30 1

Straetlingite 1.6 10-9 50 1


CASE 3FULLY COUPLED CARBONATION


DRD/EAP/11-0219

Input parameters

CARBONATION RESULTS

pH decrease, portlandite dissolution and calcite formation over a thickness of about 2 cm after 100 years

CARBONATION RESULTS

Dissolution of CSH 1.6, ettringite, monocarboaluminate and hydrotalcite on 2 cm after 100 years

Precipitation of CSH 1.2, CSH 0.8, straetlingite, amorphous silica and gypsum on the same thickness

Precipitation of small amounts of sepiolite, gibbsite and katoïte-Si is also predicted

CARBONATION: CPU CONCERNS…

CO2 diffusion (gas phase) and reactivity are very fast!

No SIA small time steps CPU times go up!

POSSIBLE EXTENSION:SATURATION DEPENDENT REACTIVITY

Considerable reduction in the amplitude of carbonation (less dissolution of portlandite and CSH 1.6 and less precipitation of amorphous silica and other secondary CSH)

Lower reactivity accompanied by a greater penetration of carbonation front due to lower consumption of CO2 at the surface

Effect of water content on reactivity (Bazant type function)

CONCLUSIONS

Drying process of 11 cm thick waste packages depends strongly on the concrete nature and slightly on the flow model (Richards or full multiphase)

Considering full multiphase model, carbonated depth is about 2 cm after 100 years for the Intermediate Performance Concrete. degraded thickness is totally carbonated (total dissolution of primary mineral phases)

If we consider a chemical reactivity depending on the liquid saturation (Bazant type function), a considerable reduction in the amplitude of carbonation and a greater penetration of carbonation front are observed.

Progress areas include:

• taking into consideration a protective effect of secondary minerals

• improving knowledge on kinetics parameters and thermodynamic data, especially for CSH with low Ca/Si ratio

• coupling this system with corrosion of rebars

NUMERICAL RESOURCES



And now: - EOS9- Crunchflow- Hytec- … more?

Direction de l’Energie Nucléaire

Département des Technologies

Nucléaires

Service de Modélisation des Transferts et

de Mesures Nucléaires

Commissariat à l’énergie atomique et aux énergies alternatives

Centre de Cadarache | 13108 Saint Paul-lez-Durance

T. +33 (0)4 42 25 37 24 | F. +33 (0)4 42 25 62 72

Etablissement public à caractère industriel et commercial | RCS Paris B 775 685 01920 avril 2023

| PAGE 33

CEA | 10 AVRIL 2012

AcknowlegementToughreact development team (LBNL)

C. Steefel (LBNL, Crunchflow)

Hytec developement team (Mines Paristech, PGT consortium) for technical support on codes

THANK YOU FOR YOUR ATTENTION

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