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ThermoChimie guidelines

Part I: General introduction andselection process

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ANDR4Le mol~rise des d~chets wdioociils

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Ind.

A

HAVL Argile

Andra

www.andra.fr AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS

A U T H E N T I F I C A T I O N G E D

{B24597F0-9ACB-4467-BB9D-1C9107AC038B}

R-2223.2

Written by: Revised by: Validated by:

Elisenda Colàs

Cristina Domènech

Mireia Grivé

ThermoBridge ThermoChimie: Scientific

Administration

Project ANDRA-ThermoBridge Final report Task 3

Document 1 of 5

December 2012

Mireia Grivé, Elisenda Colàs, Cristina Domènech, Lara Duro

THERMOCHIMIE GUIDELINES

PART I: GENERAL INTRODUCTION

AND SELECTION PROCESS

i

Index 1.   THERMOCHIMIE, THE ANDRA THERMODYNAMIC DATABASE ..................................... 1  

1.1   PRINCIPLES OF DEVELOPMENT ...................................................................................................... 1  

1.2   CONTENTS OF THE DATABASE ....................................................................................................... 3  

1.3   SELECTION PROCESS ..................................................................................................................... 4  

1.4   THERMOCHIMIE QUALITY MANAGEMENT SYSTEM ....................................................................... 8  

2.   REFERENCES .................................................................................................................................. 10  

1

1. ThermoChimie, the Andra thermodynamic database Andra, the French National Radioactive Waste Management Agency, has organized a

dedicated program supporting the development of its own thermodynamic database,

ThermoChimie, especially designed and qualified for systems of interest for the

repository concept designed by ANDRA. This program was born from the need of using

a reliable chemical thermodynamic database to feed conceptual and numerical models

used in Performance Assessments (PA) of Nuclear Waste Repositories. These models

are mainly used in assessing the geochemical evolution of the repository both in terms

of performance of the engineering barrier system as well as the migration/retention

behaviour of radionuclides.

The ThermoChimie database was initially created in 1996. It has been continuously

updated since its creation and is supported by an experimental program on actinides

and fission products. Several groups and organizations do contribute to this continuous

update process. ThermoChimie contains data on major elements, a long list of

radioelements, such as actinides and lanthanides, chemotoxic metals and organic and

inorganic ligands.

1.1 Principles of development

The ThermoChimie database has been developed to cover six objectives with specific

surrounding conditions (e.g. disposal cells, Callovo-Oxfordian formation) in consistency

with Performance Assessment requirements:

1. Determination of radioelement and chemotoxic element aqueous speciation and

solubility.

2. Study of geochemical evolution of both the near- and the far-field of the

repository, covering the stability of clay minerals, bentonite clays, and

aluminosilicate systems.

2

3. Assessment of the process of cement degradation (considering a broad

composition range with respect to formula) to account for the stability of

cementitious phases.

4. Assessment of the process of canister corrosion.

5. Assessment of the role of ligands derived from the degradation of Natural

Organic Matter (NOM) present in the Callovo-Oxfordian argillite, as well as the

assessment of the impact of simple organic ligands on the mobilization of

radionuclides.

6. Tools and applications of the thermochemical database under different storage

scenarios.

ThermoChimie is built according to the following main requirements:

• Consistency: Thermodynamic functions included in the database are relevant

but also consistent when taken together, among thermodynamic functions for a

given chemical reaction, and between thermodynamic functions for the whole

chemical system.

• Exhaustivity: The database is exhaustive enough within its range of application,

defined with respect to elements and chemical processes of interest (i.e. input

constrain).

• Traceability: Selected data are traceable to the original source. The calculations

used to obtain the data are also traceable.

• Usability: Data values and database organization are compatible with the

numerical tools to be used at the end.

The range of application of ThermoChimie has been defined considering the

geochemical environments identified within the frame of the French underground

repository concept. The range of validity of ThermoChimie is constrained as follows:

•pH range of 5 to 14, i.e, from mildly acidic to alkaline systems.

•Eh range of -0.5 to 0.5 V, i.e., in all the redox potential range of natural waters.

•T range of 15° to 90°Cْ, i.e., in the low geochemical temperature range.

•Ionic strength up to SIT capabilities.

3

1.2 Contents of the database

ThermoChimie collects thermodynamic data on Na; K; Rb; Cs; Mg; Ca; Sr; Ba; Ra; B;

Al; C; Si; Sn; Pb; N; P; As; Sb; O; S; Se; F; Cl; Br; I; Zr; Hf; Nb; Mo; Cr; Mn; Tc; Fe; Co;

Ni; Pd; Ag; Cd; Sm; Eu; Ho; Th; Pa; U; Np; Pu; Am and Cm (Fig. 1). It covers all the

information needed to deal with radioelements and chemotoxic elements when

studying the evolution of the near- and far-field of the repository (Duro et al. 2012).

Furthermore, the database includes relevant thermodynamic information for the organic

ligands oxalate (C2O42−), acetate (CH3COO−), citrate (C3H5O(COO)3

3−), EDTA

(ethylenediaminetetraacetic acid, C10H16N2O8), NTA (nitrilotriacetic acid, C6H9NO6),

gluconate (C6H11O7-), isosaccharinate (C6H11O6

-) and phthalate (C8H4O42-).

IA IIA 0

H IIIA IVA VA VIA VIIA He

Li Be B C N O F Ne

Na Mg IIIB IVB VB VIB VIIB VIIIB IB IIB Al Si P S Cl Ar

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

Cs Ba ù Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn

Fr Ra ê Ku Ha

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lrê

ù

Fig. 1. Periodic table showing in grey the elements introduced in ThermoChimie

version 8.

For each element a basic component is defined in ThermoChimie. The basic

component is usually the free cation ( e.g. Sr2+), an oxycation (e.g UO22+) or an

oxyanion (e.g MoO4-) of the element of interest.

Data included in ThermoChimie for basic components are:

• and (kJ·mol-1), and (J·K-1·mol-1) at 25ºC;

• ion interaction coefficients ε(j,k) (kg·mol-1) for the interaction of the species with

Na+, Cl-, ClO4- and/or NO3

-, when available, at 25ºC.

4

Basic components (together with e- and H+) constitute the building blocks for the

construction of the formation reactions of the remaining species and solid phases in the

database.

In ThermoChimie, aqueous species are defined by chemical reactions of the basic

components. Data included in ThermoChimie for aqueous species are:

• at 25ºC;

• and (kJ·mol-1), and (J·K-1·mol-1) at 25ºC;

• and (kJ·mol-1), and (J·K-1·mol-1) at 25ºC;

• ion interaction coefficients ε(j,k)(kg·mol-1) for the interaction of the species with

Na+, Cl-, ClO4- and/or NO3

-, when available, at 25ºC.

For solid compounds, ThermoChimie includes values for the same variables than for

aqueous species. Data on heat capacity (J·K-1·mol-1) and molar volume

(cm3·mol-1) are also provided for some of them (especially solid clays and cement

mineral phases).

All the magnitudes included in ThermoChimie are accompanied by a bibliographic

reference of the source from where the datum has been adapted and, when possible,

they have their own associated uncertainties.

1.3 Selection process

ThermoChimie takes advantage on the results of the extensive experimental program

on actinides and fission products developed by Andra. Furthermore, the data selection

process includes an exhaustive work of literature research, comparison and evaluation

of different data sources such as previous thermodynamic data compilations and open

scientific literature. Data extracted from scientific literature are analysed and tested in

front of independent values.

ThermoChimie relies on CODATA recommendations (Cox et al. 1989) for the primary

master species and the reference states of the elements. The selection process also

5

includes a revision of the thermodynamic data reported in previous databases such as

SUPCRT92 (Johnson et al. 1992), NBS (Wagman et al. 1982) or USGS Database

(Robie and Hemingway, 1995) for major elements and the IAEA (Fuger and Oetting,

1976) or the NEA-TDB’s for radionuclides. The results of the NEA-TDB project are

particularly considered in the selection, given their high quality. They have been the

basis of the selection for several of the elements included in ThermoChimie database,

as shown in Fig. 2, and enlarged when considered necessary and when possible.

IA IIA 0

H IIIA IVA VA VIA VIIA He

Li Be B C N O F Ne

Na Mg IIIB IVB VB VIB VIIB VIIIB IB IIB Al Si P S Cl Ar

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

Cs Ba ù Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn

Fr Ra ê Ku Ha

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lrê

ù

Fig. 2. Periodic table showing the elements introduced in ThermoChimie version 8 (in

grey). Selected thermodynamic data for the elements highlighted in green are based on

the OCDE-NEA-TDB publications.

Data included in ThermoChimie have been selected according to the following

procedure:

1. When possible, aqueous stability constants and solubility equilibria are selected

as main data. In some cases these data allow the calculation of Gibbs free energy of

formation of the species as far as the free energy of formation of the basic components

is available. and are thus the first parameters selected and is

calculated accordingly (Fig. 3).

6

In some cases, if this procedure cannot be applied, Gibbs free energies are calculated

from and data.

THERMOCHIMIE

NEA-TDB reviews

LogK

Literature research

ΔGf? ΔGr?

Selected TDB for auxiliary species

LogKCalculation LogK Calculation LogK

Yes

Yes

ΔGf? ΔGr?

New data?

Reliable log K

Can we calculate LogK, ΔGf ΔGrfrom estimations?

No selection No selection

Log K SELECTION/UPDATE PROCESS

Calculation internal Thermodynamic values

Yes

Yes

Yes

Yes

Yes

No

No

No No No

No

Bas

ed in

sol

ubili

ty e

xper

imen

ts

Fig. 3. Diagram showing the general procedure used in the selection of values

in ThermoChimie.

2. Secondly, enthalpies or entropies are selected. When a value has been selected

for two of these three variables ( , and ), the rest of the data are internally

calculated using eq. 1 and eq. 2.

  ∆𝑓𝐺𝑚0 = ∆𝑓𝐻𝑚0 −  𝑇+𝑆𝑚,𝑖0

𝑖

eq. 1

  ∆𝑟𝐺𝑚0 = ∆𝑟𝐻𝑚0 −  𝑇∆𝑟𝑆𝑚0 eq. 2

7

3. ThermoChimie primes SIT (specific ion interaction theory) for activity corrections

to the derivation of the stability constants to the standard state.

The SIT approach (as described in Grenthe et al. (1997) and recommended by the

NEA guidelines Grenthe and Wanner (2000)) takes into account short-range non-

electrostatic interactions by adding terms to the Debye-Hückel expression, as shown in

eq. 3. The use of SIT could provide adequate ionic strength corrections of data up to 6-

10 mol/kg, depending on the particular system and the ionic media considered.

∑+⎟⎟⎠

⎞⎜⎜⎝

⎛

+−=γ

kkm

mi

m2ii )mIk,(i,

IBa1IA

zlog ε)(

eq. 3

Many interaction coefficients are already available in the NEA compilations, and others

are available in the open literature. If individual, reliable and consistent ε are available,

it is possible to calculate values accordingly. If the individual interaction

coefficients are not reported, it is possible to calculate values using stability

constants at different ionic strengths ( ), by interpolating and Δε from a

lineal regression (Fig. 4).

Fig. 4. SIT Relationship among SIT equations, and Δε values.

4. Sometimes, either because of the absolute lack of experimental data or because the

inappropriateness of the existing ones, estimations are needed in order to fill in

8

important data gaps. The estimation procedures can be applied to obtain different

types of thermodynamic data, such as , or ε(j,k) values. The validity and the

accuracy of the estimations depend on each particular case and must be individually

evaluated.

1.4 ThermoChimie quality management system

As previously mentioned the thermodynamic data selection process involves different

groups and organizations and includes an exhaustive work of experimental and

literature research. This continuous process results in a high amount of information

going into the database. It is then necessary to guarantee that all the information

achieves the quality standards of the database and its four main requirements of

consistency, exhaustivity, traceability and usability.

The different processes summarized in Fig. 5 must be fulfilled previous to inclusion,

elimination or modification of any value in the database.

Data  selection

Internal  calculations

ACCESS  database

Consistency  checking

Documentation

ValidationUser

Uncertainty

Estimations

Fig. 5. Summary of the process to maintain the quality, consistency and traceability of

the database in the ACCESS format.

9

Those processes are summarized in a series of brief guidelines related to the following

procedures:

-Estimations;

-Uncertainty assignment;

-Consistency checking;

-Data integration and documentation.

10

2. References Cox, J.D., Wagman, D.D. and Medvedev, M.A. (1989) CODATA Key Values for

Thermodynamics, New York Hemisphere Publishing Corporation.

Duro, L., Grivé, M. and Giffaut, E. (2012), ThermoChimie, the ANDRA thermodynamic

database, in ‘Scientific Basis for Nuclear Waste Management XXXV, MRS

Proceedings’, Vol. 1475.

Fuger, J. and Oetting, F.L. (1976) The chemical thermodynamics of actinide elements

and compounds: Part 2. The actinide aqueous ions, Vienna: International Atomic

Energy Agency 1976, 65p.

Grenthe, I., Plyasunov, Andrey V. and Spahiu, K (1997) Estimations of medium effects

on thermodynamic data. In Modelling in Aquatic Chemistry. OECD NEA (Grenthe, I.

and Puigdomènech, I. eds.) OECD 1997.

Grenthe, I., Wanner, H. (2000) TDB-2: Guidelines for the extrapolation to zero ionic

strength. Version of 6th January 2000 NEA OECD

Johnson, J.W., Oelkers, E.H. and Helgeson, H.C. (1992) SUPCRT92: A software

package for calculating the standard molal thermodynamic properties of minerals,

gases, aqueous species, and reactions from 1 to 5000 bar and 0 to 1000 ºC;

Computers and Geosciences 18, 899-947.

Robie, R.A., Hemingway, B.S. (1995): Thermodynamic properties of minerals and

related substances at 298.15 K and 1 bar (105 Pascals) pressure and at higher

temperatures; U.S. Geological Survey Bulletin 2131.

Wagman, D.D., Evans, W.H., Parker, V.B., Schumm, R.H., Halow, I., Bailey, S.M.,

Churney, K.L. and Nuttall, R.L., (1982) The NBS tables of chemical thermodynamic

properties, selected values for inorganic and c1 and c2 organic substances in SI units.

J. Phys. Chem. Ref. Data, V. 11, supp. 2, 392p.