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) 27 juin 2022 | PAGE 1 CEA | 10 AVRIL 2012
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MODELING REACTIVE TRANSPORT IN NUCLEAR WASTE GEOLOGICAL DISPOSAL: 2 benchmark problems : - Glass/iron/clay interactions - Atmospheric Carbonation of concrete.
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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…
S.S.BENCH - November 16-18. 2011
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
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
S.S.BENCH - November 16-18. 2011
SeS BENCH – Taipei, Taiwan | NOV. 2012 | PAGE 32
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