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SLOW PROCESSES IN CLOSE-TO-EQUILIBRIUM CONDITIONS
FOR RADIONUCLIDES IN WATER/SOLID SYSTEMS OF
RELEVANCE TO NUCLEAR WASTE MANAGEMENT
SKIN
Tomo SUZUKI-MURESAN
Bernd GRAMBOW
PR
ES
EN
TAT
ION
OF T
HE P
AR
TN
ER
S
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 2
5 EU Member States
Laboratoire de physique subatomique et des technologies associées (SUBATECH)
Forschungszentrum Jülich (FJZ)
Karlsruhe Institute of Technology (KIT)
Stockholm University (SU)
Svensk Kärnbränslehantering AB (SKB) Chalmers University of Technology (CTH)
AMPHOS 21 Consulting S.L. (AMPHOS 21)
Loughborough University (LU)
1 Associated Country Paul Scherrer Institut (PSI)
1 Associated Partner University of Oviedo (UNIOVI)
1 Other Country Peking University (PKU)
PR
ES
EN
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OF T
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AR
TN
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Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 3
Bernd GRAMBOW, Gilles MONTAVON,
Solange RIBET, Tomo SUZUKI-MURESAN
Johan VANDENBORRE
Lara DURO, Mireia GRIVE,
Christian EKBERG, Hanna HEDSTRÖM, Natallia
TORAPAVA
Dirk BOSBACH, Felix BRANDT, Martina
KLINKENBERG
Thorsten STUMPF
Nick EVANS, John HINCHLIFF
Enzo CURTI, Dmitrii KULIK, Bruno THIEN
Daqing CUI
Kastriot SPAHIU
Chunli LIU
Manolo PRIETO
SUBATECH
AMPHOS 21
CTH
FJZ
KIT
LU
PSI
SU
SKB
PKU
UNIOVI
PR
ES
EN
TAT
ION
OF T
HE P
RO
JEC
T
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 4
General Assembly EU commision Coordinator
Executive board
WP2 WP3 WP4
Experiments Models/Theory
Synthesis
Safety analyses
Dis
se
min
atio
n, tr
ain
ing
, m
ob
ility
End user
group
WP1
Literature Field data
WP5
WP
6
ANDRA, IRSN
ONDRAF/NIRAS,
NAGRA, SSM
Modelling the kinetics of trace
element uptake in host minerals
Solid-Solution thermodynamics
Affinity law
Carbonates
Sulphates
Silicates
Cement
Oxides
H2O
sorption
dissolution
precipitation
Thermodynamic
solubility
Bulk solid
incorporation
Preexisting
Mineral/RN
No equilibrium
with bulk solid
but surface
CO
NC
EP
T O
F T
HE P
RO
JEC
T
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 5
H2O
sorption
dissolution
precipitation
Thermodynamic
solubility
Bulk solid
incorporation
Redox
capacity
Reducing:
only outer surface
equilibria assured
CO
NC
EP
T O
F T
HE P
RO
JEC
T
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 6
H2O
sorption
dissolution
precipitation
Thermodynamic
solubility
Bulk solid
incorporation
Multicomponent systems
Solid II
competing
ions
CO
NC
EP
T O
F T
HE P
RO
JEC
T
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 7
H2O
sorption
dissolution
precipitation
Thermodynamic
solubility
Bulk solid
incorporation
Solubility:
How to assure reversibility
CO
NC
EP
T O
F T
HE P
RO
JEC
T
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 8
OB
JEC
TIV
ES
– To assess the use/misuse of solubility data of sparingly soluble
tetravalent actinides
– To understand the coupling of major and trace elements chemistry
in RN migration behavior considering the extremely large exchange
pool of natural minerals present in the disposal sites
– To include irreversibility in models on the mobility of RN in the
repository environment
– To assess, in Performance Assessment, to what degree the
ignorance/non-inclusion of these studied slow processes leads to
over-conservative evaluations, or in few cases, even too optimistic
evaluations
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 9
OU
TL
INE
S
HLW
Ra
SO4
(Ra,Ba)SO4
Se
CaCO3
Solid-Solution
Modeling
U
Fe-oxyhydroxides
Retention
Release
Biosphere
EBS – Host rock
ThO2
Analogue
UO2
Solubility
Ca(CO3)(1-x)(SeO3)(x)
Substitution
10 Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop
RA
DIO
BA
RIT
E S
YS
TE
M
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 11
Ba2+ : Baaq (mainly 134Ba, 135Ba and 138Ba)
Corrosion of spent fuel
Ra2+ : decay chain of 238U in spent fuel
SO42- : ground water
1.70 m²/g
0.17 m²/g
Ra2+aq
BaSO4(s)
Ba2+aq
SO42-
aq
barite
RA
DIO
BA
RIT
E S
YS
TE
M:
UP
TAK
E O
F R
A
• Macroscopic studies
• Microscopic studies
– Homogenous incorporation of Ra in barite determined via TOF-
SIMS measurements of powders
– Morphological evolution indicates a replacement of barite BaSO4
by radiobarite Ba1-xRaxSO4
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 12
Solubility of pure BaSO4
1.70 m²/g 0.17 m²/g
AP
PR
OA
CH
ES F
OR
MO
DE
LIN
G
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 13
1.E-09
1.E-08
1.E-07
1.E-06
1.E-05
0 100 200 300
time [days]
[Ra
] /M
IDEAL SOLID SOLUTION
REGULAR SOLID SOLUTION (WG=2000 J/mol => a0=0.8)
REGULAR SOLID SOLUTION (WG=-2000 J/mol => a0= -0.8)
IDEAL SOLID SOLUTION
REGULAR SOLID SOLUTION (WG=2000 J/mol => a0=0.8)
REGULAR SOLID SOLUTION (WG=-2000 J/mol => a0= -0.8)
Predicted time-dependency of aqueous
Ra concentration due to formation of Ra-
barite from a solution with 5×10-6 M initial
Ra concentration at
growth rates = 2 µmol m-2d-1
growth rates = 80 µmol m-2d-1
Ba – Ra exchange within the crystal volume Curti et. al. (2010)
Ra – Ba exchange ≈ Ba – Ba exchange at close to equilibrium conditions
Ra crystallizes as Ra – Ba sulfate from solution on the barite surface
→ solution controlled Ra-sorption
SE(I
V) –
CA
RB
ON
AT
ES
• Selenium(IV) coprecipitation with calcite
– Aragonite – Calcite recrystallization
– Selenite substitutes 1 carbonate ion upon incorporation into
calcite
• Substitution scheme:
– Ca(CO3)(1-x)(SeO3)(x)
• Thermodynamic solid solution
model for Se(IV) in calcite: on going
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 14
wait NaCl 0.1mol/L Se(IV) 10-4 mol/L
Aragonite Se-Calcite
reaction progress monitored by XRD
solid- and liquid phases composition analyzed by ICP-MS, EXAFS, XAS
CO
-PR
EC
IPIT
AT
ION
U(V
I)-F
E(I
II)
• Aim:
– Study of Fe(III)-U(VI) coprecipitation and its evolution with
ageing time
– Ageing processes will influence the retention/release of uranium
from the coprecipitates
• U(VI)-Fe(III) co-precipitates (XRD, EXAFS, XANES)
– Ferrihydrite-like structure
– Evolution from 2-L to 6-L ferrihydrite-like structure with time.
• Uranium measurements
– The retention of U(VI) within the structure of a ferrihydrite
remains effective after 5 weeks of suspension and after 9 years
of a dry-stored sample
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 15
CO
-PR
EC
IPIT
AT
ION
U(V
I)-F
E(I
II)
• Aim:
– Study of Fe(III)-U(VI) coprecipitation and its evolution with
ageing time
– Ageing processes will influence the retention/release of uranium
from the coprecipitates
• U(VI)-Fe(III) co-precipitates (XRD, EXAFS, XANES)
– Ferrihydrite-like structure
– Evolution from 2-L to 6-L ferrihydrite-like structure with time.
• Uranium measurements
– The retention of U(VI) within the structure of a ferrihydrite
remains effective after 5 weeks of suspension and after 9 years
of a dry-stored sample
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 16
0
50
100
150
200
250
300
350
400
450
500
10 30 50 70 902 Theta
rela
tive
cp
s
Coprecipitate 3 weeks (present work)
Coprecipitate 9 years (present work)
2-L ferrihydrite (Zhao et al. 1994)
6-L ferrihydrite (Zhao et al. 1994)
CO
-PR
EC
IPIT
AT
ION
U(V
I)-F
E(I
II)
• Identification of U-Oeq2 at a distance of 2.85-2.90 Å
• Distance decreases with time
– Approaching to schoepite-like distance
• Observation of U-Fe at 3.41-3.46 Å
• Consistent with an edge-sharing bond between U(VI)
and ferrihydrite.
• Measurement of U-U distance at 4.0-4.3 Å
• Distance decreases with time
– Approaching to schoepite-like distances
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 17
U-Oeq2
U-Fe
U-U
• Measurements are consistent with a regrouping of the uranium
content
• Assessment of the efficiency of this retention process at these time
frames would be given by the schoepite solubility limit.
MO
DE
LIN
G T
HE U
PTA
KE O
F T
R IN
HO
ST M
INE
RA
LS
• Models of time-dependent metastable Tr uptake in host minerals
– SEMO = surface (growth) entrapement model
– SRKM = surface reaction kinetic model
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 19
SEMO (Watson, 2004)
• Assumption: a growing crystal takes
the composition of its surface, unless
diffusivity in thin near-surface region
is effective during growth.
• Surface enrichment/depletion of Tr is
due to adsorption equilibrium between
the crystal surface and the bulk aqueous
solution.
• Upon growth, the surface layer is
“buried” and Tr ions are trapped in the
newly-formed lattice, resulting in Tr
concentrations between the Aq-SS and
Aq-surface equilibrium distributions.
MO
DE
LIN
G T
HE U
PTA
KE O
F T
R IN
HO
ST M
INE
RA
LS
• Models of time-dependent metastable Tr uptake in host minerals
– SEMO = surface (growth) entrapement model
– SRKM = surface reaction kinetic model
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 20
CaRf
CaRb
TrRb
TrRf aq.
mineral
SRKM (de Paolo, 2011)
• Originally developed for describing
isotope fractionation in calcite
• Based on the concept of a dynamic
precipitation-dissolution process
• Represented as a competition of gross
forward Rf and backward Rb rates of
the host or trace Tr component
• Rf = Rb: the system is in equilibrium
UP
TAK
E B
Y C
O-P
RE
CIP
ITA
TIO
N IN
CA
LC
ITE
• “merged” model
– SEMO and SRKM merged into 1 model
– Implementation into GEMS-Selector geochemical code
– Realistic description of the rate dependency of Tr fractionation
coefficient
• Implemented model automatically adjusts for changing composition of
the aqueous solution
– aqueous speciation, saturation index, and ion activities
0
0.02
0.04
0.06
0.08
0.1
0.12
-10.00 -9.00 -8.00 -7.00 -6.00 -5.00 -4.00
log10 R p
ΔS
r,C
a
Exp
Model
(a)
0.80
1.00
1.20
1.40
1.60
1.80
2.00
-9.00 -8.00 -7.00 -6.00 -5.00 -4.00
log10 R p
log
10 Δ
Cd
,Ca
Exp
Model
(b)
21 Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop
Modeled fractionation coefficient of Sr in calcite (a) and Cd in calcite (b) as a function of precipitation rate (mol/m2/s). Experimental data (Lorens, 1981).
TO
WA
RD
S T
HE S
AF
ET
Y A
NA
LYS
ES
• Compartmental modelling
approach
• Three steps
1. Define a Reference case
and calculate the model
using previous parameter
values
2. Recalculate the model
using new data obtained in
SKIN project
3. Compare results obtained
using literature or SKIN
project data
• Concentration of Np, Ra, Se, Tc,
Th and U
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop
Based on the SKB system
22
WasteWaste
ContainerContainer
BentoniteBentonite
GraniteGranite
Sink_endSink_end
IRFIRF DissolutionDissolution
DiffusionDiffusion
DiffusionDiffusion
AdvectionAdvection
Water reach the waste
after 50 000 years
IRF during first year of
water entrance +
Congruent matrix
dissolution
Discretization
Diffusive fluxes
Solubility
Sorption control
Discretization
Advective fluxes
Solubility
Sorption control
Surroundings of the
system
TO
WA
RD
S T
HE S
AF
ET
Y A
NA
LYS
ES
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 23
Using literature data
Irreversible processes
New solubility
and
Sorption data
WasteWaste
ContainerContainer
BentoniteBentonite
GraniteGranite
Sink_endSink_end
IRFIRF DissolutionDissolution
DiffusionDiffusion
DiffusionDiffusion
AdvectionAdvection
WasteWaste
ContainerContainer
BentoniteBentonite
Cement plugCement plug
GraniteGranite
Sink_endSink_end
Sink_2Sink_2
IRFIRF DissolutionDissolution
DiffusionDiffusion
DiffusionDiffusion
DiffusionDiffusion
AdvectionAdvection
SorptionSorption
DesorptionDesorption
Sink_3Sink_3
SorptionSorption
DesorptionDesorption
Sink_1Sink_1
SorptionSorption
DesorptionDesorption
Determining the impact of the studies done in the frame of the SKIN
project over the calculations that support safety assessment procedures.
DE
CR
EA
SE O
F U
NC
ER
TAIN
TIE
S:
EX. O
F T
HO
2
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 24
-16
-15
-14
-13
-12
-11
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
-1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
- log [H+]
log
[T
h]t
ot
Rai et al., RCA, 2000 Heisbourg, PhD, 2003 Jernström, report, 2002
Neck et al., RCA, 2002 Bitea et al., Coll. and Surf. A, 2003 Rai et al., RCA, 2000
Heisbourg, PhD, 2003 Moon, Bull. Kor. Chem. Soc., 1989 Neck et al., RCA, 2001
Ryan et al., Inorg. Chem., 1997 Nabivanets et al., Ukr. Khim. Zh., 1964 Rousseau et al., RCA, 2006
Felmy et al., RCA, 1991 Felmy et al., RCA, 1991 Rai et al., RCA, 2000
Neck et al., RCA, 2002 Landesman et al., MRS, 2004 this work
ThO2(cr) ThOx(OH)y(H2O)z(am)
this work
oxide forms hydroxide forms
5 < pH < 6
[Th]aq = “Local solubility”
Site accessibility
[Th]aq = “Thermodynamic solubility”
Site accessibility =
DE
CR
EA
SE O
F U
NC
ER
TAIN
TIE
S:
EX. O
F T
HO
2
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 25
-16
-15
-14
-13
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-11
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
-1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
- log [H+]
log
[T
h]t
ot
Rai et al., RCA, 2000 Heisbourg, PhD, 2003 Jernström, report, 2002
Neck et al., RCA, 2002 Bitea et al., Coll. and Surf. A, 2003 Rai et al., RCA, 2000
Heisbourg, PhD, 2003 Moon, Bull. Kor. Chem. Soc., 1989 Neck et al., RCA, 2001
Ryan et al., Inorg. Chem., 1997 Nabivanets et al., Ukr. Khim. Zh., 1964 Rousseau et al., RCA, 2006
Felmy et al., RCA, 1991 Felmy et al., RCA, 1991 Rai et al., RCA, 2000
Neck et al., RCA, 2002 Landesman et al., MRS, 2004 this work
ThO2(cr) ThOx(OH)y(H2O)z(am)
this work
oxide forms hydroxide forms
5 < pH < 6
[Th]aq = “Local solubility”
Site accessibility
[Th]aq = “Thermodynamic solubility”
Site accessibility =
Pyrolytic C
SiC
Low density C
sphere
ThO2 sphere
DE
CR
EA
SE O
F U
NC
ER
TAIN
TIE
S:
EX. O
F T
HO
2
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 26
-16
-15
-14
-13
-12
-11
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
-1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
- log [H+]
log
[T
h]t
ot
Rai et al., RCA, 2000 Heisbourg, PhD, 2003 Jernström, report, 2002
Neck et al., RCA, 2002 Bitea et al., Coll. and Surf. A, 2003 Rai et al., RCA, 2000
Heisbourg, PhD, 2003 Moon, Bull. Kor. Chem. Soc., 1989 Neck et al., RCA, 2001
Ryan et al., Inorg. Chem., 1997 Nabivanets et al., Ukr. Khim. Zh., 1964 Rousseau et al., RCA, 2006
Felmy et al., RCA, 1991 Felmy et al., RCA, 1991 Rai et al., RCA, 2000
Neck et al., RCA, 2002 Landesman et al., MRS, 2004 this work
ThO2(cr) ThOx(OH)y(H2O)z(am)
this work
oxide forms hydroxide forms
5 < pH < 6
[Th]aq = “Local solubility”
Site accessibility
[Th]aq = “Thermodynamic solubility”
Site accessibility =
Pyrolytic C
SiC
Low density C
sphere
ThO2 sphere
DE
CR
EA
SE O
F U
NC
ER
TAIN
TIE
S:
EX. O
F T
HO
2
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 27
Crushed ThO2 spheres
ThO2 powder
synthesized at 1300°C
Initial ThO2 spheres
ThO2 powder
synthesized at 700°C
Crystalline
surface state
Initial
dissolution Rate
Amorphous phase
grain boundaries
SY
NT
HE
SIS
/CO
NC
LU
SIO
N
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 28
• SKIN project
– Large number of individual studies related to slow processes close to
equilibrium
– Experimental, Theory-Modeling, Impact of uncertainties in the PA
• Dynamic exchanges close to solubility equilibrium
– Isotopic exchange: ThO2, TcO2, silicates
– Bulk phases vs. specific surface sites on solubility control
• Incorporation of Tr in host minerals
– Case of Ra in barite: data explained using the GEMS-Selector code
– Incorporation requires diffusion and/or recrystallisation: very slow
processes
• Sorption/Desorption processes
– Often reversible but some case irreversible (Cs in illite)
– Ageing can influence the retention and the release of the co-precipitate of
U/Fe(III)
• Modeling
– SEMO / SRKM : successfully tested
– SEMO + SRKM: implemented in GEMS-Selector geochemical code
• Uncertainties in the solubilty and sorption
– Compartmental modelling approach
– Reference case: waste, container, bentonite, granite, sink
DIS
SE
MIN
AT
ION
• F. Brandt, M. Klinkenberg, K. Rozov, G. Modolo, D. Bosbach; Goldschmidt’2012
Conference, Montreal, Canada
• B. Grambow (France, Germany, Sweden, Spain, Sweden, Switzerland, United Kingdom,
China); 13th International Conference on the Chemistry and Migration Behaviour of
Actinides and Fission Products in the Geosphere, Beijing, China
• H. Hedström, I. Persson, G. Skarnemark, C. Ekberg; Submitted to Radiochimica Acta.
• Hinchliff J, Felipe-Sotelo M, Drury D, Evans N D M, Read D; NUWCEM 2011 1st
International Symposium on Cement-based Materials for Nuclear Wastes 2011 Avignon,
France
• K. Holliday, A. Chagneau, M. Schmidt, F. Claret, T. Schäfer, T. Stumpf; Dalton Trans., 2012,
41, 3642-3647.
• M. Klinkenberg, F. Brandt, K. Rozov, G. Modolo, D. Bosbach; Goldschmidt’2012
Conference, Montreal, Canada
• D.A.Kulik, B.Thien, E.Curti; Goldschmidt’2012 Conference, Montreal, Canada
• Tomo Suzuki-Muresan, Bernd Grambow; Euratom-China cooperation 2011 workshop,
Beijing, China
• Tomo Suzuki-Muresan, Bernd Grambow, Johan Vandenborre, Abdesselam Abdelouas;
13th International Conference on the Chemistry and Migration Behaviour of Actinides and
Fission Products in the Geosphere, Beijing, China
• Tomo Suzuki-Muresan, Johan Vandenborre, Abdesselam Abdelouas, Bernd Grambow; 4th
ASRC International Workshop, Ibaraki, Japan
• B.Thien, D.A.Kulik, E.Curti; Goldschmidt’2012 Conference, Montreal, Canada
Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 29