SUZUKI-MURESAN GRAMBOW - European Commission · Suzuki-Muresan et al. EURATOM Disposal Programme...

$: SUZUKI-MURESAN GRAMBOW - European Commission · Suzuki-Muresan et al. EURATOM Disposal Programme Dissemination Workshop 21 Modeled fractionation coefficient of Sr in calcite (a) and$
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

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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)

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ES

EN

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OF T

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TN

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S


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


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


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


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


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


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


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


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


Solubility of pure BaSO4

1.70 m²/g 0.17 m²/g

AP

PR

OA

CH

ES F

OR

MO

DE

LIN

G


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


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


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


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


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


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


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)


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


Using literature data

Irreversible processes

New solubility

and

Sorption data

WasteWaste

ContainerContainer

BentoniteBentonite

GraniteGranite

Sink_endSink_end


DiffusionDiffusion

DiffusionDiffusion

AdvectionAdvection

WasteWaste

ContainerContainer

BentoniteBentonite

Cement plugCement plug

GraniteGranite

Sink_endSink_end

Sink_2Sink_2


DiffusionDiffusion

DiffusionDiffusion

DiffusionDiffusion

AdvectionAdvection

SorptionSorption

DesorptionDesorption

Sink_3Sink_3

SorptionSorption


Sink_1Sink_1

SorptionSorption


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


-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


-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








this work


5 < pH < 6


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


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


• 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


AC

KN

OW

LE

DG

ME

NT

European Atomic Energy Community's Seventh Framework

Programme (FP7/2007-2011) under grant agreement n° 269688


SUZUKI-MURESAN GRAMBOW - European Commission · Suzuki-Muresan et al. EURATOM Disposal Programme...

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