FINAL SUMMARY REPORT
EUROPEAN NUCLEAR THERMODYNAMIC
DATABASE
(ENTHALPY Project)
CO-ORDINATOR
Dr. A. DE BREMAECKER
Detached from SCK.CEN-Mol at IRSN/DRS/SEMAR
CEN de Cadarache Bât 702
BP 2
F - 13108 Saint-Paul-lez-Durance
FRANCE
Tel.: + 33 4 4225 3501
Fax: + 33 4 4225 2929
LIST OF PARTNERS
1. IRSN/DRS, Cadarache, France
2. CEA/DRN-Grenoble, France
3. AEA-Technology,Harwell, United Kingdom
4. THERMODATA, Grenoble, France
5. FRAMATOME-ANP, Erlangen, Germany
6. CEA-DRN-DTP, Cadarache, France
7. EdF, Clamart, France
8. AEKI-KFKI, Budapest, Hungary
9. SKODA-UJP, Praha, Czech republic
10. SCK.CEN, Mol, Belgium
11. ULB, Université Libre de Bruxelles, Brussels, Belgium
12. UCL, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
CONTRACT N°:
FI3S-CT1999-00001
EC Contribution:
Partners Contribution:
Starting Date:
Euro 600 000
Euro 1.125.000
February 2000
Duration:
36 months
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019 January 2004
CONTENTS
LIST OF ABBREVIATIONS AND SYMBOLS
EXECUTIVE SUMMARY
A.
OBJECTIVES AND SCOPE
B.
WORK PROGRAMME
C.
B.1
Assembling of the two existing databases & extension to new elements
B.2
Separate Effect tests
B.3
Improvement and validation of the database
B.4
Evaluation of the consequences of the uncertainties
B.5
Methodologies of coupling the database with SA codes
B.6
Edition of the database
WORK PERFORMED AND RESULTS
C.1
State of the Art Report
C.2
Assembling and extension of the database (WP 1)
C.2.1
Introduction
C.2.1.1
C.2.1.2
C.2.1.3
C.2.1.4
Selection of the elements to be included in NTD
Modelling and merging procedure
Selection of the systems to be included in NTD
Critical assessment work
C.2.2
Critical assessment and assembling (Task 1.1)
C.2.3
Extension of the database (Task 1.2)
C.2.3.1
C.2.3.2
C.2.3.3
Extension of NTDIV01 to Boron and Carbon and assembling of the
final In-Vessel Nuclear Thermodynamic database : NTDIV02
Extension of NTDIV02 to concrete elements (Al, Ca, Mg, Si).
Assembling of the final In/ex Vessel Nuclear Thermodynamic
Database : NUCLEA
Comparison calculations
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
2
C.2.4
State of the validation
C.3
Separate Effect Tests (WP 2)
C.3.1
Solidus – Liquidus temperatures for (U,Zr)O2+x (Task 2.1)
C.3.1.1
C.3.1.2
C.3.2
Tliq in Zr-Fe-O & Zr – Cr – O systems (Task 2.2)
C.3.2.1
C.3.2.2
C.3.3
Experimental
Results
Experimental
Results
Tliq in B2O3 + FeOx/ZrO2/UO2 systems (Task 2.3)
C.3.3.1
C.3.3.2
C.3.3.2.1
C.3.3.2.2
C.3.3.2.3
Experimental
Results
Fe2O3-B2O3 system
ZrO2-B2O3 system
UO2-B2O3 system
C.3.4
Tliq in UO2-ZrO2-FeOx-CaO-Al2O3-SiO2 systems (Task 2.4)
C.3.5
Experimental study of (sub)system(s) in UO2-ZrO2-BaO-MoOx (Task 2.5)
C.3.5.1
C.3.5.1.1
C.3.5.1.2
C.3.5.1.3
C.3.5.1.5
Direct determination of the phase diagram (Task 2.5.2.1)
Experimental
Results in the ternary system BaO-ZrO2-MoO3
Results in the quaternary system UO2-BaO-ZrO2-MoO3 in reducing
atmosphere at 1480°C and 1600°C
Results in the quaternary system UO2-BaO-ZrO2-MoO3 in oxidising
atmosphere at 1600°C
Conclusion
C.3.5.2
C.3.5.2.1
C.3.5.2.2
Release in thermal gradient (Task 2.5.2.3)
Experimental
results
C.3.5.3
Review of the U-Zr-Mo-Ba-O system including in irradiated fuel pins
(Task 2.5.2.4)
Solid solubility and precipitation of FP Molybdenum
Solid solubility and precipitation of FP Baryum and Zirconium
Post-irradiation observations
Review of equilibria established at the Mo/MoOé equilibrium
Conclusions
C.3.5.1.4
C.3.5.3.1
C.3.5.3.2
C.3.5.3.3
C.3.5.3.4
C.3.5.3.5
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
3
C.4
Validation and Improvement of the database (WP 3)
C.4.1
Validation based on fuel experiments and empirical models (Task 3.1)
C.4.2
Validation based on experiments (task 3.2)
C.4.3
Validation based on VULCANO/CEA and COMETA/NRI experiments
(Task 3.3)
C.4.3.1
C.4.3.2
C.4.3.3
C.4.4
Improvement by literature review (task 3.4)
C.4.4.1
C.4.4.2
C.4.5
VULCANO VE-U3 experiment
VULCANO VE-U7
COMETA / NRI test
Boiling points and vapour pressures of the elements
Thermodynamic properties of UxOy gaseous species
Validation based on Tliq and Tsol measurements in UO2+x-ZrO2 (AEA-T) and
Fe-Zr-O (SKODA), and global experiments (VERCORS, Hofmann) (Task 3.5)
C.4.5.1
C.4.5.2
C.4.5.3
C.4.5.4
UO2+x-ZrO liquidus and solidus measurements
Fe-Zr-O liquidus and solidus measurements
Fission Products release (Vercors tests)
Corium pool stratification involving Fe-O-U-Zr (+ Cr, Ni)
C.5
Influence of uncertainties
C.6
Coupling methodologies to SA codes
C.6.1
Coupling methodology of thermodynamic databases to SA codes (CROCO and
ICARE/CATHARE) (Task 5.1)
C.6.1.1
C.6.1.2
C.6.1.3
C.6.1.4
C.6.1.5
C.6.2
Tabulation of the phase diagram
Interface with the thermochemical code
Generation of the library, research and interpolation in the library
Applications
Time consuming and coupling aspects
Recalculation of TMI2 with MAAP4 and the database (Task 5.2)
C.6.2.1
C.6.2.2
C.6.2.3
Thermo-chemistry of the U-Zr-O domain
Recalculation of the U-Zr-O diagram using the NUCLEA database
Recalculation of TMI-2 using the new Tliq and Tsol
C.6.3
Simplification of the database and/or of the equilibrium code and adaptation to
SA codes (Task 5.3)
C.7
Edition of the NUCLEA database
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
4
CONCLUSION
REFERENCES
TABLES
FIGURES
LIST OF ABBREVIATIONS & SYMBOLS
CIT
Corium Interactions and Thermochemistry
COLOSS
Core Loss
DTA
Differential Thermal Analysis
EDX
Energy Dispersive Microanalysis
EPMA
Electron Probe Micro Analysis
FP
Fission Product
ICP
Inductively Coupled Plasma
LOCA
Loss of Coolant Accident
MDB
Material Data Bank ( module of the ASTEC System Code)
MCCI
Molten Corium-Concrete Interaction
NTD
Nuclear Thermodynamic Database
SA
Severe Accident
SEM
Scanning Electron Microscopy
SGTE
Scientific Group Thermodata Europe
TDBCR-IV
Thermodynamic Data Base Corium - In Vessel
THMO
Thermo-chemical Modeling and data
TMI-2
Three Mile Island Unit 2
VPA
Visual Polythermal Analysis
XRD
X-Ray Diffraction
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
5
EXECUTIVE SUMMARY
ENTHALPY is a shared-cost action where 11 partners from 6 countries succeeded to
pro- duce one unique well validated thermodynamic database for in- & ex-vessel applications.
The first step was the critical assessment and merging of the two thermodynamic
databases (THERMODATA/Grenoble and AEA-Technology/Harwell) in one database called
"NTDiv" (for Nuclear Thermodynamic Database in-vessel). The second step was the
extension of the database to Boron and Carbon, leading to the edition of the NTDiv0201
version (14 elements). In a third step, four ex-vessel elements and four new oxides
components were added. All together, the final database is based on 20 elements :
O-U-Zr-Ag-In-Fe-Cr-Ni-Ba-La-Ru-Sr-B-C-Al-Ca-Mg-Si + Ar-H
and includes in particular the 15 oxides system :
UO2-ZrO2-FeO-Fe2O3-Cr2O3-NiO-In2O3-BaO-La2O3-SrO-B2O3-Al2O3-CaO-MgO-SiO2
In view of the extension to Boron, AEKI determined experimentally 3 new phase
diagrams namely ZrO2-FeOx, ZrO2-B2O3 and B2O3 – UO2.
About the open question of the solubility of zirconia in Zr-Fe, SKODA tests on Tliq and
Tsol in the corner of low oxygen in the Zr-Fe-O system confirmed the large solubility.
The influence of the hyperstoichiometry of UO2 on Tliq and Tsol of typical corium
(U,Zr)O2 was tested by AEA-T and the results confirmed the model used in the database.
The direct construction of the complex phase diagram U-Zr-Ba-Mo-O was made in
different atmospheres (reducing conditions, and in air) as an exploratory research and showed
that in rather oxidizing atmospheres, the stability of the Ba zirconates decreases in favour of
Ba molybdates or scheelite (BaMoO4). This was confirmed by tests in thermal gradients at
UCL and by PIE at SCK.CEN on irradiated fuel pins at high burn-up.
Tliq of 10 ex-vessel mixtures (sub-systems in UO2-ZrO2-FeOx-CaO-Al2O3-SiO2)
measured by different techniques, confirmed or validated points of the ex-vessel database.
The database was further improved by THERMODATA. The thermodynamic properties
of 11 gaseous elements and of the UxOy species were specially revisited and reassessed.
The database was validated by pre- and post-calculations of experimental tasks, and by
(semi)global tests : FP release (VERCORS tests), in-vessel corium pool stratification
(SASCHA), and ex-vessel corium spreading (VULCANO).
The influence of uncertainties on the corium physical properties was studied on the
point of view of the variability of key properties from different versions of the database.
A strategy was developed by IRSN to couple the database to severe accident codes,
through tabulation of the phase diagram, generation of a library by GEMINI2 and
interpolation. This was proven to be efficient for the 4 elements system U-Zr-Fe-O.
A reactor calculation (TMI2) on the new subsystem U-Zr-O did by EdF with MAAP4
concluded that the calculation must be enlarged to a subsystem including at least iron.
The “NUCLEA” database, edited by Thermodata is now commercially available.
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
6
A. OBJECTIVES and SCOPE
For the prevention, mitigation and management of severe accidents, many problems
related to core melt have to be solved : fuel degradation, melting and relocation, convection in
the core melt(s), coolability of the core melt(s), fission product release, hydrogen production,
ex-vessel spreading of the core melt(s), etc.
To solve these problems such properties like thermal conductivity, heat capacity, density,
viscosity, evaporation or sublimation of melts, the solidification behavior, the tendency to trap
or to release the fission products, the stratification of melts, must be known.
However most of these properties are delicate to measure directly at high temperature
and/or in the radioactive environment produced by the fission products. Therefore some of
them must be derived by calculations from the physical-chemical description of the melt :
number of phases, phase compositions, proportions of solids and liquids and their respective
oxidation state, miscibility of the liquids, solubility of one phase in another, etc.. This
information are given by the phase diagrams of the materials in presence.
The phase diagrams can be experimentally determined in specific tests, or they can be
constructed by calculations made on the basis of measurements of the Gibbs energies, binary
or ternary interaction parameters, and models (the « associated » model or the « ionic »
model) and in a second step validated by application to global tests.
Results of the “CIT” & “THMO” projects (4th R&D-FW Program) were previously
obtained in this field but had to be confirmed and broadly enlarged.
In this frame, the general objective of “ENTHALPY” was to obtain one unique
European commonly agreed thermodynamic database for in- and ex-vessel applications, well
validated and with methodologies able to couple the database to Severe Accident codes used
by end-users like utilities, safety Authorities and nuclear designers.
B. WORK PROGRAMME
The work programme was organised in 6 Work Packages (WP) described below (see
also Table I). Each WP contains one or more tasks. Each task was performed by one partner.
At the mid-term assessment meeting it was agreed to merge two tasks (formerly named "Task
2.2.3 : Tliq and Tsol in UO2-ZrO2-FeO-Cr2O3" and "Task 2.4 : UO2-ZrO2/(CaO+Al2O3) both
performed by FRAMATOME ANP) , in one task named "Task 2.4 : Tliq in UO2-ZrO2-FeOxCaO-Al2O3-SiO2" entirely performed by FRAMATOME ANP, and task 2.2.2 and 3.2 in
order to re-in force the effort on the key Zr-Fe-O system (Task 2.2.1).
B.1 : Assembling of the two existing databases and extension to new elements (WP1)
The two existing nuclear thermodynamic databases had to be merged in one database,
with agreed thermodynamic models, covering the entire field from metal to oxide
(borides/carbides) for a complex multi-component chemical system).
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
7
B.2 : Separate Effect Tests (WP2)
Tests were performed in the key U-Zr-Fe-O (sub)systems and in other in- & ex-vessel
subsystems (B2O3, B, Pu, PuO2, Mo ; Si, SiO2, Ca, CaO, Al2O3 etc) including FPs with high
decay heat (Ba), in such a way that thermodynamic results (Tliq, Tsol, enthalpies, solubility
limits) were obtained.
B.3 : Improvement and validation of the database (WP 3)
This WP included the improvement and validation of the new database against global
tests.
B.4 : Evaluation of the consequences of the uncertainties (WP 4)
This WP envisaged the consequences of uncertainties on Corium physical properties.
B.5 : Methodologies of coupling the database with SA codes (WP 5)
Methodologies were developed to effectively couple the database to severe accidents
codes, and a recalculation of TMI2 with MAAP4 was made.
B.6 : Edition of the database (WP 6).
This WP included the documentation, the discussion of an agreement on property rights
and the diffusion of the database.
C.
WORK PERFORMED AND RESULTS
C.1
State of the Art Report
Before the start of ENTHALPY, THERMODATA, had developed the specific TDBCR
thermodynamic database for nuclear safety applications. It covered the entire field from metal
to oxide domains in the following multi-component system :
O-U-Zr-Fe-Cr-Ni-Ag-In-Ba-La-Ru-Sr-Al-Ca-Mg-Si + Ar-H
and was able to be used for both in- or ex- Vessel applications.
AEA-T, through external collaborations, had developed a large oxide thermodynamic
database, more oriented to Ex- Vessel applications, based on the following oxides :
UO2-ZrO2-Fe2O3-BaO-La2O3-CeO2-Ce2O3-SrO-Al2O3-CaO-MgO-SiO2.
Specific databases were also available (metal domain : U-Fe-Zr-Si-Ba-Sr-Ce-La-Ru-Te
where Cerium was introduced for simulating Plutonium ; metal oxide field : U-O-Zr-Si).
These two databases needed to be improved, specially in some key-subsystems (U-O, Zr-FeO for instance), to be extended to the absorber elements Boron and Carbon, and to be more
largely validated. The coupling of the database to SA codes was also weak. Faster and more
efficient methodologies of coupling were needed.
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
8
C.2
Assembling of the database (WP 1)
C.2.1 Introduction
The development of a common database, based on the CALPHAD method, involved the
definition of a precise methodology to assemble the data coming from the two sources.
An inventory of the content of the two databases was made and discussed. Important
decisions were taken concerning : - the elements to be included in the database, - the subsystems (binary, quasi-binary, ternary, quasi-ternary) to be critically assessed, - the standards
to be adopted (thermodynamic data for unary systems, thermodynamic models).
C.2.1.1 Selection of the elements to be included in NTD
The following elements (18 + 2) were selected for being included in NTD :
O-U-Zr-Fe-Cr-Ni-Ag-In-Ba-La-Ru-Sr-B-C-Al-Ca-Mg-Si + Ar-H
These are the elements of the main materials involved in a severe accident : UO2 (fuel),
Zr (zircaloy cladding), Fe-Cr-Ni (steel of the structural components), SIC and B4C (control
rods), Ba-La-Ru-Sr (selected fission products), Al2O3-CaO-MgO-SiO2 (concrete), H2O
(water), O (air, oxides). Argon was added only as a neutral species in the gas phase. Hydrogen
has not been taken into account in non stoichiometric solution phases.
As any metallic element can be oxidised at a given oxygen potential, the multicomponent (15) oxide system is also a subset of the whole database :
UO2-ZrO2-FeO-Fe2O3-Cr2O3-NiO-In2O3-BaO-La2O3-SrO-B2O3-Al2O3-CaO-MgO-SiO2.
(AgO and RuO2 are two oxides decomposed before melting.)
C.2.1.2 Modelling and merging procedure
The development of a thermodynamic database for multi-component system is based on
the critical assessment of the most relevant sub-systems (binary, ternary, …) i.e. the
compilation of the available experimental data (phase diagram and thermodynamic
properties), the inventory of all possible phases, the choice of suitable thermodynamic models
for each phase, and finally, the optimisation of Gibbs energy parameters.
The whole subset of Gibbs energy parameters for a given sub-system is also called a
thermodynamic database, and allows the user to re-calculate the whole phase diagram.
The list of all possible condensed solution phases was commonly built, and for each
identified solution phase, a thermodynamic model was proposed and agreed.
Common standards were also adopted for unary systems (pure elements and oxides).
C.2.1.3 Selection of the systems to be included in NTD
The thermodynamic modelling of the selected multi-component system was based on
the critical assessment of all the possible binary (153) or pseudo-binary (105) systems.
Only the most important ternary or pseudo-ternary systems (metal, metal-oxygen, oxide) were
critically assessed, due to the very high number of possible ternary systems.
C.2.1.4. Critical assessment work
For each system, the following points were carefully treated :
- The list of bibliographic references has been up-dated.
- The set of experimental data was re-checked.
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
9
- The new experimental information was included in the optimisation process
- The heat capacity of stoichiometric compounds was estimated, in order to produce
fundamental values for substances ( H°298.15 K, S° 298.15 K, Cp(T), G - HSER).
- A new optimisation was performed in order to correct any evident disagreement
between calculated and experimental values
- The calculated and experimental temperatures and compositions of the invariant
reactions or specific points have been compared in numeric tables.
- The phase diagram and specific thermodynamic properties were calculated and
compared to experimental values taken from literature on figures.
- A new set of optimised Gibbs energy parameters has been produced and included in
the new nuclear thermodynamic databases (NTDIV01, NTDIV02, NTD).
- The lack of experimental knowledge was identified
- Finally, a new quality criterion was proposed for each sub-system.
C.2.2
Critical assessment and assembling (Task 1.1)
(Assembling of a first partial In-Vessel Nuclear Thermodynamic Database :
NTDIV01)
A partial thermodynamic database for In-Vessel applications, named NTDIV01, was
first assembled, based on 14 elements : O-U-Zr-Ag-In-Fe-Cr-Ni-Ba-La-Ru-Sr + Ar-H
It included in particular the 10 oxides system :
UO2-ZrO2-FeO-Fe2O3-Cr2O3-NiO-In2O3-BaO-La2O3-SrO.
Then the Gibbs energy parameters of all possible phases were assembled by using the
thermodynamic modelling of the Gibbs energy from the assessed binary and ternary subsystems in the GEMINI2 code format (Ref. [1] & [2]).
NTDIV01 is composed of three different files :
1. The Gibbs energy parameters of the « lattice-stabilities », i.e. the Gibbs energy
difference of each element of the multi-component system in a given structure
and a reference one (SER = Standard Element Reference).
2. The Gibbs energy parameters of all possible substances referred to any chosen
reference state, provided that it is present in the first file
3. The Gibbs energy parameters of solution phases.
C.2.3 Extension of the Database (Task 1.2)
C.2.3.1 Extension of NTDIV01 to Boron and Carbon and Assembling of the final InVessel Nuclear Thermodynamic Database : NTDIV02
NTDIV01 was extended firstly to two new elements B and C and one oxide B2O3 to the
database. After assembling, the final thermodynamic database for In-Vessel applications,
named NTDIV02,was thus based on 16 elements (O-U-Zr-Ag-In-Fe-Cr-Ni-Ba-La-Ru-Sr-B-C
+ Ar-H), and included in particular the following 11 oxides system (UO2-ZrO2-FeO-Fe2O3Cr2O3-NiO-In2O3-BaO-La2O3-SrO-B2O3).
This extension involved the thermodynamic modelling of new systems. Some of them
were already accepted : B-Fe, B-Ni, C-Cr, C-Fe, C-Ni, C-Zr, C-Cr-Fe, C-Cr-Ni, C-Fe-Ni, CrFe-Ni, C-Cr-Fe-Ni. Other ones, as B-Cr, B-O, B-U, C-U, B-Zr, B-C, B-C-Fe, B-C-U, B-C-Zr,
B-Fe-U, B-Fe-Zr, C-O-U, C-O-Zr, C-U-Zr, C-O-U-Zr, were modelled by THERMODATA.
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
10
35 new binary and 13 ternary systems were re-assessed, AEA-T being more involved in
oxidic systems including B2O3, THERMODATA in metallic ones.
The oxide systems including B2O3 ,-BaO, -Cr2O3 , -FeO, -Fe2O3, -In2O3, -La2O3, -NiO, SrO, -UO2, -ZrO2 and -FeO-Fe2O3, were made by AEA-T (Ref. [3]). Experimental data for
the pseudo-binary systems B2O3 with -FeO, -Fe2O3, -UO2, -ZrO2 came from Task 2.3 (Figure
1).
12 other binaries were assessed : Al-B, Al-C, B-Ba, Ba-C, B-In, C-In, B-La, C-La, B-Ru, CRu, B-Sr, and C-Sr by THERMODATA (Ref. [4]). The two important binary systems B-U
and C-U were optimised (Ref. [5]) and the model extended in the quaternary system C-O-UZr.
NTDIV02 was assembled by the CALPHAD method on the basis of 91 binaries, 55
pseudo-binaries and 21 ternary systems. It contains 35 solution phases,191 reference
substances, 203 substances and 148 gaseous species (Ref. [6]).
C.2.3.2 Extension of NTDIV02 to concrete elements (Al, Ca, Mg, Si). Assembling of
the final In/Ex Vessel Nuclear Thermodynamic Database : NUCLEA
INTDIV02 was extended to the concrete elements for ex-vessel applications, adding four
new elements Al, Ca, Mg and Si, and four new oxide components, Al2O3, CaO, MgO and
SiO2. The final database named NTD and later “NUCLEA”, is based on 20 elements :
O-U-Zr-Ag-In-Fe-Cr-Ni-Ba-La-Ru-Sr-B-C-Al-Ca-Mg-Si + Ar-H
and includes in particular the 15 oxides system (Ref. [7]) :
UO2-ZrO2-FeO-Fe2O3-Cr2O3-NiO-In2O3-BaO-La2O3-SrO-B2O3-Al2O3-CaO-MgO-SiO2
23 binary or pseudo-binary systems were identified
- either to be checked : Al-Cr, B-Si, Ba-Si, Ca-La, Ca-Si, La-Si, Mg-O, Al2O3-BaO, Al2O3NiO, CaO-”FeO”, Fe2O3-O2Si, MgO-O2U, OSr-O2Si
- or to be re-assessed : O-Si, Si-Sr, Fe2O3-MgO, CaO-UO2
- or to be done : B-Ca, C-Ca, B-Mg, C-Mg, Al2O3-Fe2O3, B2O3-MgO.
9 ternary systems were included, either already available as :
Al2O3-CaO-O2Si, Al2O3-O2Si-O2U, Al2O3-O2Si-O2Zr, Al2O3-O2U-O2Zr, O2Si-O2U-O2Zr
or recently made as : Al2O3-B2O3-CaO, Al2O3-B2O3-O2Si, B2O3-CaO-O2Si, B2O3-FeOx.
9 ternary oxide systems were directly calculated from the binaries, but ternary
interaction parameters should be assessed in the future : Al2O3-CaO-FeO, Al2O3-CaO-Fe2O3,
Al2O3-Fe2O3-SiO2, CaO-FeO-Fe2O3,CaO-FeO-O2Si, CaO-Fe2O3-O2Si, FeO-Fe2O3-O2Si.
The following systems were evaluated or re-evaluated : Al2O3-B2O3, B2O3-CaO, B2O3O2Si, Al2O3-B2O3-MgO, B2O3-CaO-MgO, B2O3-MgO-O2S.
The experimental state of the art and thermodynamic modelling of the O-U binary
system (Figure 2) was improved using a sub-lattice model to describe the UO2+x phase (Ref.
[8]).
C.2.3.3 Comparison calculations
Calculations for selected oxide systems were performed and the results compared with
those obtained using a commercial database. The latter called MTOX has been produced as
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
11
part of a collaborative project by the NPL (National Physical Laboratory, UK) and other
industrial sponsors. The current database includes oxide systems for a range of components
(e.g.K, Na, Fe, Ca, Si, Al, Mg) and has been well validated.
Calculations of oxide systems using the MTOX database and the Gibbs energy minimisation code MTDATA were carried out (Ref. [9]). The system FeO-Fe2O3-CaO-SiO2 was
selected for the comparison exercise and 21 ternary and quaternary compositions proposed by
IRSN. The MTOX results showed that in some cases the change in the amount of liquid
phase is gradual over the temperature range whereas in others the amount increases very
rapidly over a temperature rise of a few degrees. These results are to be compared with
calculations performed by IRSN using NUCLEA and the GEMINI code. Previous code
comparison studies have shown that the results produced by the different equilibrium codes
(MTDATA and GEMINI) using the same database are in good agreement.
C.2.4 State of the validation
A quality criterion was established for each assessed sub-system:
*
Estimated ; No experimental data available.
**
Perfectible ; Some domains need more experimental information (phase
diagram or thermodynamic properties).
***
Acceptable ; The system is well known and satisfactorily modelled.
****
High quality ; The system is quite known and modelled.
The complete list of binary systems based on pure elements and oxide pseudo-binary systems
based on pure oxides are presented in (Tables II and III) respectively.
Due to the very high number of possible ternary (816) and pseudo-ternary (455) systems
only the most important ternary systems for practical applications (Tables IV and V) were
assessed at this time.
C.3
Separate Effect Tests (WP 2)
C.3.1 Solidus – Liquidus temperatures for (U,Zr)O2+x (Task 2.1)
In a severe accident the fuel in the corium will oxidise in steam, in particular for the exvessel sequence. No thermodynamic data exists for the pseudo binary system (U, Zr)O2+x .
C.3.1.1 Experimental
Tsol and Tliq measurements were measured by the thermal arrest. The PTE included
ceramography and SEM analysis.
The experimental set-up and proposed compositions were assessed first by the CEA
based on preliminary calculations performed using the TDBCR-IV 992 database.
Based on this assessment the compositions of the three samples finally investigated were
UO2.00-ZrO2, UO2.08-ZrO2 and UO2.15-ZrO2 with the ratio of UO2/ZrO2 set to 80/20 wt.%.
C.3.1.2 Results
Tsol & Tliq of the three samples UO2.00-ZrO2, UO2.08-ZrO2 and UO2.15-ZrO2 were
measured (Table VI) (Ref. [10]). The results indicate that the solidus-liquidus gap for the
stoichiometric and hyperstoichiometric compositions is slightly larger than predicted and
some modifications of the model for the U-Zr-O system are required. These modifications to
the NUCLEA database have now been carried out.
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
12
C.3.2 Tliq in Zr-Fe-O & Zr-Cr-O systems (Task 2.2)
The objective is the experimental determination of Tsol (and Tliq) of one selected alloy
in the Zr-rich corner of each of the Zr-Fe-O and Zr-Cr-O systems (Zr-Fe-O alloy near 82.317.3-0.4 wt% and one Zr-Cr-O alloy near 79.6-20.0-0.4 wt%).
C.3.2.1 Experimental
6 Zr-Fe-O and 5 Zr-Cr-O alloys were prepared from pure metals (+ ZrO2). Their
chemical composition was analysed, and their hardness (HV10) measured.
The resistance furnace of the Balzers Exhalograph was adapted to the video-recording.
This resulted in a successful off-line magnified viewing of the melting process on a computer
screen. The camera & pyrometer were coupled with a PC-based image analyser.
Tsol & Tliq could be approximately determined from the off-line sequential set of images.
C.3.2.2 Results
Tsol and Tliq were measured by both the first appearances of the liquid phase (solidus)
and the complete melting manifested by formation of a drop (liquidus) (Figure 3 a, b). This
method seems to locate the solidus and liquidus with a precision of ~  15-25 C.
Tsol agreed relatively well with the values calculated using the NTDiv01 database.
The measured liquidus temperatures TLIQ for both systems were relatively close to Tsol. A
question arose : does a solid phase exist in the interior of the presumed “molten” drop or not? To
answer this question the Zr-Fe-O specimens were heated to various temperatures beyond TLIQ, i.e.
between TLIQ and ~1700 C and cooled down as rapidly as possible (~11 C/s).
The microstructure of the formed drops was investigated by both the optical metallography,
by X-ray phase analysis and by microprobe analysis. The two main phases had an appearance of
a liquid phase, the third one being cracks. A small black phase (less than 1% at TLIQ-CALC) is
~(Zr,Y)O2 originating from the Y2O3 support pad. In both specimens no ZrO2 was found. The
oxygen was found only in solid solution, either within -Zr(O) containing small amount of iron or
within the Zr-Fe matrix.
Analysis of both the cooling curves (from ~1700 C) and the recorded images of the
melting process also indicated that the main phases were liquid at TLIQ. SKODA concluded
(Ref. [11]) that the specimens were completely molten at the liquidus temperature TLIQ
(formation of spheres). This is probably valid for both systems Zr-Fe-O and Zr-Cr-O.
C.3.3 Tliq in B2O3 + FeOx/ZrO2/ UO2 systems (Task 2.3)
Boron trioxide has relatively low melting point (~450 oC), density and viscosity. Fused
B2O3 readily dissolves many metal oxides may influence fuel degradation, melting and
relocation processes. To model this influence, phase diagrams of B2O3 with Fe2O3, ZrO2 and
UO2 are needed but were lacking.
C.3.3.1 Experimental
High purity powdered Fe2O3, ZrO2, UO2 and amorphous granulated B2O3 were used as
starting materials. Due to the hygroscopic nature, boron trioxide was grinded to powder and
dehydrated.
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
13
Temperature history measurements with the test mixtures were carried out in a resistant
furnace under a protecting gas. The liquidus temperatures are signalled by a characteristic
brake on the temperature difference (T) curves of the cooling cycles.
C.3.3.2 Results
C.3.3.2.1
Fe2O3-B2O3 system
The mean values of Tliq. are summarised in Table VII. Reproducibility of the
data was estimated as ±10 oC. The phase diagram for the Fe2O3-B2O3 system could
then be constructed (Figure 4), the phase relations bellow liquidus temperatures being
taken from Makram (Ref. [12]).
C.3.3.2.2
ZrO2 – B2O3 system
The liquidus temperatures for the ZrO2-B2O3 system were determined by temperature
history and as well as from solubility measurements (Ref. [13]).
In the former experiments, test mixtures, containing 2.5 and 5.0 wt % ZrO2 were investigated.
The results are given in Table VII. In the solubility experiments, the test mixtures containing
ZrO2 in excess as compared with the saturated solution at a given temperature, were fused in a
furnace at constant temperature. The original composition of the test mixture for both
temperatures was chosen as 20 wt% ZrO2 – 80wt% B2O3.
Because the density of ZrO2 (~5,6 g/cm3) is significantly higher than that of B2O3 (~1,5
g/cm ) , during the isothermal heating at the selected liquidus temperature there is
stratification between the dense solid phase (a layer of unsolved ZrO2 deposited on the
bottom) and the liquid phase (a saturated solution of ZrO2 in B2O3).
Quenching allows to preserve the composition of the saturated liquid solution. This
composition and the isothermal heating temperature (1800° and 2000°C) determine the
position of the liquidus temperature on the phase diagram. They are given in Table VII.
3
The ZrO2 – B2O3 phase diagram (in the rich B2O3 side) is shown in Figure 5.
C.3.3.2.3
UO2 – B2O3 system
The liquidus temperatures for the UO2-B2O3 system were determined by temperature
history measurements (Ref. [14]) and are summarised in Table VII. Combining these results
with previous experimental results, the phase diagram could be constructed (Figure 5).
C.3.4 Tliq in UO2 – ZrO2 – FeOx – CaO – Al2O3 – SiO2 systems (Task 2.4)
The objective was to measure Tliq and possibly Tsol in systems relevant to SA ex-vessel
sequences.
10 temperatures (Tliq and/or Tsol) were investigated by : Visual Polythermal Alalysis in
an induction-melting furnace with a cold crucible (VPA IMCC), by VPA in the Galakhov
micro-furnace, and by classical DTA (for solidus temperature determination).
The compositions were discussed and defined together with the modelers (Table VIII).
The knowledge of Tliq allows to compare the dissolution ability of different concretes to
dissolve corium or to evaluate the viscosities of different concretes (Ref. [15]).
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
14
C.3.5 Experimental study of (sub)system(s) in UO2-ZrO2-BaO-MoOx (Task 2.5)
NB : Task 2.5.1 was merged with Task 2.4.
C.3.5.1 Direct determination of the UO2–MoO2–BaO-ZrO2 phase diagram (Task 2.5.2)
The study is subdivided into 3 subtasks, performed resp. by ULB, SCK.CEN, UCL.
C.3.5.1.1
Direct determination of the phase diagram ( Task 2.5.2.1)
Two main steps were proposed in order to understand the mechanisms of the fuel
degradation and the formation of the new phases as a function of oxygen potential :
A. The study of the pseudo-ternary system BaO-ZrO2-MoOx ( with x = 0 ,2 ,3 ) in oxidising
and reducing atmosphere giving a preliminary knowledge of the behaviour of the Mo0, Mo4+
and Mo6+ compounds in presence of BaO and ZrO2.
B. The extension of the ternary system to the quaternary system UO2-BaO-ZrO2-MoOx at
1600°C at 3 different oxygen pressures, i.e.10-16 atm, 10-9 atm and 10-5 atm..
C.3.5.1.1.1 Experimental
A major part of anneal experiments were performed in electrically heated furnaces.
Preliminary works were performed in oxidising atmosphere (air and nitrogen. Tests under
controlled atmospheres were performed in three tubular furnaces equipped either with a
zirconia oxygen sensor, either with an H2O sensor and a classic air reference zirconia gauge
operating at 700°C). Quenching was possible in two of these furnaces.
Phase identification and composition analysis were performed by optical microscope, X-RD,
X-Ray fluorescence, SEM with EDX and EPMA.
Calculations based on H2/H2O equilibria in order to check whether the effective pO2
over samples heated at 1400°C-1600°C correspond to those measured in the outlet part of the
furnace (700°C) with the zirconia sensor, demonstrated that H2/H2O equilibria are
immediately reached in all parts of the furnace so that the measured pO2 have to be corrected
at 1400°C-1600°C, owing to higher water dissociation at those temperatures. Thus, the pO2
values measured at 700°C(10–24 atm, 10–17 atm and 10–13 atm )* correspond actually to 10–16
atm, 10–9 atm and 10–5 atm at 1600°C.
C.3.5.1.1.2 Results in the ternary system BaO - ZrO2 – MoO3
a) In oxidising conditions (pO2> 10-4 atm, T<= 1600°C), BaO reacts preferably with MoO3 to
yield BaMoO4 (scheelite). For Ba/Mo ratios >1, BaO reacts with the phases BaZrO3 and
BaMoO4 to form other Ba-rich zirconates and molybdates of higher Ba order like Ba3Zr2O7,
Ba2ZrO4, Ba2MoO5 and Ba3MoO6. For the identified Mo-compounds, the stable Mo valence
is 6+; therefore solid solutions between Zr4+ and Mo6+ are limited : no Mo detected in BaZrO3;
and a maximum of 5,5 mol% of Zr in substitution for Mo in sheelite BaMoO4.
b) In reducing conditions (10-20 <= pO2 <=10-17 atm, 1200°C <= T <= 1500°C), in Mo-rich
compositions, the Mo compounds are reduced into Mo0 so that BaO reacts preferably with
ZrO2. The perovskites compounds BaZrO3 and BaMoO3 form solid solutions BaMo1-yZryO3
with y = 0,1 and BaZr1-xMoOxO3 with x = 0,08 at 1200°C.
The thermal evolution shows that the major part of BaMoO3ss disappears according to a
disproportionate reaction yielding Mo0 in a dispersed phase and Mo6+ in Ba3MoO6 while the
remainder Mo+4 is stabilised only in BaZrO3 ss. As a function of composition and temperature,
Mo0, Mo4+ and Mo6+ compounds can thus co-exist in strongly reducing conditions.
BaO volatilisation in Ba-rich compositions C and D was not observed at 1400°C.
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
15
Results in the quaternary system UO2 - BaO - ZrO2 – MoO3 in
reducing atmosphere : 1480°C/ 10-17 atm2 pO /8 & 32 h ; and
1600°C/ 10-16 atm pO2/8h
The main stability domains evidenced from the identified compounds UO2ss, ZrO2ss,
0
Mo and the perovskite phase BaZrO3ss or BaUO3ss are depicted in Figure 6.
BaO reacts preferably with ZrO2 to form the perovskites BaZrO3ss when BaO/ZrO2 2
and BaUO3ss when BaO/ZrO2  2.
Mo : appears as a dispersed Mo0 metallic phase in equilibrium with Mo4+ present mainly
in the BaZrO3ss (max 6.8 % in composition A) and BaUO3ss perovskite phases. Mo0 can
dissolve up to 1 at%Ba, 1.5 at%Zr and 0.5 at%U. Its oxygen content (up to 14%) is probably
related to oxidation upon cooling. There is no stable phase of molybdate.
UO2 matrix forms a solid solution UO2-ZrO2 which may contain up to 14 % ZrO2 at
1480°C and 26.6% ZrO2 at 1600°C. When the concentration of Ba increases, the solubility of
ZrO2 in UO2 gets reduced because of the formation of BaZrO3 ss.
The UO2 matrix dissolves a very low quantity of Ba (<1 at%) and of Mo (<2 at%).
ZrO2 : exists as a solid solution ZrO2-UO2 up to 12.8 mol% UO2 in sample F at 1600°C.
Perovskite phases BaZrO3 “or BaUO3” : The coexistence of BaZrO3ss and BaUO3ss
established at 1480°C is no longer observed at 1600°C where there is a complete miscibility
of barium uranates and zirconates in each other.
At 1600°C in sample A (with Ba/Zr = 1), the only BaZrO3 phase dissolving up to 5,8 mol% U
and 6.8 mol% Mo is observed. For much higher Ba content (samples C and D), perovskites of
uranates are found. Therefore, as in the samples as well as in irradiated nuclear fuel BaO is
never exceeding the ZrO2 nor UO2 content, the volatility of BaO in reducing conditions is
limited by its interactions with UO2 and ZrO2 (contrarily with the ternary observations).
C.3.5.1.1.3
Thus, the major effect of the UO2 matrix is to reduce the stability of the Ba molybdates :
these are reduced in Mo0 and Mo4+ with an enrichment of the Ba zirconates in U and
formation of Ba uranates.
C..3.5.1.1.4 At 1600°C in oxidizing atmosphere (pO2 10–9atm)
Stability domains evidenced from the identified compounds UO2ss, ZrO2ss, BaMoO4
(scheelite), BaZrO3ss, the MoO2-rich phase and a new uranate (Ba2U3Ox by SEM) are drawn
in Figure 6B.
BaO reacts preferably with oxidised Mo to give BaMoO4 (already observed in the
ternary system at pO2 >10–4 atm) which is present in all the nine compositions studied. Owing
to its congruent melting at 1457°C
UO2 dissolves a greater amount of ZrO2 (32% in sample F) than in strongly reducing
medium. The content of Mo and Ba in this phase is low (1% and 0.3% resp.)
ZrO2 in excess of its solubility limit in UO2 exists as a free phase of zirconia (dissolving
12.3% of UO2) in equilibrium with the matrix.
Mo : All Mo compounds are oxidised at this oxygen pressure.
The perovskite phase is limited to a Zr-rich solid solution occuring for Ba/Mo ratios
>1, in a domain including compositions B and G. In this domain, BaZrO3ss contains 18.4 at%
BaUO3 and 1.7 at% BaMoO3.
The uranate phase appears in a large domain where Ba/Mo >1 (compositions B, G, C
and D). This relatively homogeneous uranate whose composition is close to
Ba2(U3-xZrx)O9+y is unknown in the more recent JCPDS files but has been assigned to a
fluorite – type structure .
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
16
C.3.5.1.5
Conclusion
The major effect of increasing the pO2 from reducing (10-16 atm) to oxidizing conditions
(10-9atm) is a reduction of the stability of the Ba perovskites in favour of the formation of
stable phases scheelite (BaMoO4) and MoO2 when Ba/Mo < 1 or scheelite (BaMoO4) and a
new uranate Ba2(U3-xZrx)O9+y when Ba/Mo > 1 (Ref. [16]).
C.3.5.2 Release in thermal gradient (Task 2.5.2.3)
C.3.5.2.1
Experimental
The investigations covered the study of oxides of U, Zr, Ba and in strong temperatures
gradients and in different atmospheres.Three different powders mixtures (A, D, F) were
prepared : (mol%) : A : 80% UO2 + 7% Ba + 7% Zr + 7% Mo
D: 80% UO2 + 18% Ba + 1% Zr + 1% Mo
F: 80% UO2 + 1% Ba + 18% Zr + 1% Mo
Two types of tests were performed :
A) release of condensation particles by homogeneous heating, and
B) differential heating (in strong temperature gradients)
A) The pellets were heated up to 2400°C. Condensation particles were sampled by an
impactor .Compositions and test conditions are given in Table IX.
B) Tests in a strong temperature gradient were also performed in order to reveal possible
migrations or segregation of the different elements inside the pellet matrices. Pellets A, D
and F were submitted to a strong temperature gradient of approximately 1000-2000°C
from side to side
XRD, EDX analyses,SEM and neutron activation were performed on pellets before and
after heating as well as on the condensed particles .
C.3.5.2.2
Results
A) Release from heated pellets
Ba and Mo prevail in particles condensed from pellet A (rich in Ba and Mo). In the case
of pellet D, Ba, is most abundant in condensed particles. No Zr has been found even in the
case of pellet F, where Zr is abundant.
In the released and condensed particles, Ba and Mo(O) are closely associated suggesting
molybdates and as in the pellets, U segregates from Ba/MO, but no Zr was observed at all.
B) Behaviour in temperature gradients (7,5 mm pellets)
Grains grow up with temperature as a consequence of fusion-recristalisation.
Starting from an homogeneous distribution of U, Zr, Ba and Mo before heating, Ba and Mo
migrate to the hot zone and conversely, U migrates to (or concentrates in) the colder zone
(Figure 8). There is a marked segregation between U and Ba-Mo. Mo and Ba are strongly
associated suggesting the presence of molybdates (observed by XRD as BaMoO4, BaMo4O13,
Ba3Mo18O28). Migration of Zr from the cold to the hot zones in pellet F is compensated by U.
In hot zones of pellet F (2000°C), in opposition to the cold ones, U and Zr seem to be in close
association, probably as a solid solution or as urinates (Ref. [17]).
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
17
C.3.5.3 Review of the U-Zr-Mo-Ba-O system including in irradiated fuel
pins(Task 2.5.2.4)
The objective is to study the phase formation and the stability of the phases formed by
the FPs Ba, Zr and Mo in nuclear fuel, focused on the influence of the oxygen potential.
C.3.5.3.1
Solid solubility and precipitation of FP Molybdenum
In the actual fabrication of LWR fuels, UO2 is slightly hyperstoichiometric, and MOX is
slightly hypostoichiometric. But during and after irradiation, the initial O/M ratio increases.
Different methods to measure the real oxygen potential (or O/M ratio) were developed,
notably through the analysis of the repartition of Mo as metallic precipitates and in oxides.
Since the free energy of formation of MoO2 is slightly above that of nuclear fuel, the
measurements of the activities of Mo and MoO2 could be a method to estimate the local
oxygen potential of irradiated fuel although the basic assumption of the elevated solubility of
MoO2 in the UO2 matrix was never confirmed. Instead subsequent measurements and
theoretical work confirmed that Mo solubility limit is very low. The quantity of Mo dissolved
in irradiated UO2 is overestimated because of the contribution of submicron metallic or oxide
precipitates that are not resolved in SEM or TEM microscopes.
Nevertheless the mechanism remains partly valid : when pO raises up, Mo disappears
from metallic inclusions and is incorporated in the grey phases which are perovskite ABO3
precipitates with Ba and Zr for the A and B sites respectively. Therefore the equilibrium Mo +
O2  MoO2 is established between the Mo activity in metallic precipitates to the Mo activity
in the ABO3 grey phase. But these ABO3 particles remain too small to be analyzed directly.
C.3.5.3.2
Solid solubility and precipitation of FP Ba and Zr
The solid solubility of Ba in the oxide matrix of irradiated FBR fuel and of simulation
specimens is lower than 1,6 wt%. In LWR fuels, the ceramic precipitates are too small to be
quantitatively measured. The solubility limit of 0.2wt% for barium in oxide fuel is only
reached at a BU in excess of 45GWd/tHM only recently reached in LWR (see Table X).
At temperatures below 1200°C, the solubility of ZrO2 in UO2 is limited (<0.2wt%), but
it increases above this temperature. At 1600°C, a maximum solubility of 27.5 mol% is
reported. A continuous solid solution of ZrO2 – UO2 is obtained at temperatures >2285°C.
C.3.5.3.3
Post-irradiation observations
Given a Mo production rate of about 100ppm per GWd/tHM, Mo tends at any relevant
BU (Table 10), to precipitate from the UO2 matrix. The pO in normal LWR conditions being
lower than the Mo/MoO2 equilibrium, Mo is normally incorporated in metallic precipitates.
For the FPs Ba and Zr, the solid solubility in UO2 of both elements is limited to about
2000ppm under normal LWR operating temperatures. The solubility limit of both elements
will be reached at intermediate burn-up level (Table X). Moreover PIE of fast reactor fuels
have shown that precipitation of Ba is enhanced in the presence of dissolved Zr and that the
complex perovskite phase (Ba,Sr,Cs)(Zr,Mo,U)O3 is formed.
As long as the cladding did not fail, the conditions inside the fuel pin remain sufficiently
reducing to maintain Mo in the metallic precipitates; the ceramic precipitates are of the
general compositions (Ba,Sr,Cs)(Zr,U)O3.
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
18
C.3.5.3.4
Review of equilibria established at the Mo/MoO2 equilibrium
The experiments on the quasi-ternary system UO2-ZrO2-BaO showed complete mixing
of BaUO3 and BaZrO3 in any proportion. In the UO2-ZrO2 rich side a broad two phase field
exists, with either UO2 in equilibrium with Ba(U1-xZrx)O3 or U1-xZrxO2 in equilibrium with
BaZrO3. Since the production rate of the fission products Ba and Zr is roughly 2:1, it is most
likely that BaZrO3 is formed and is in equilibrium with (U1-xZrx)O2. In fuels with low oxygen
potentials, molybdenum will not be part of the ceramic precipitates.
At 1700°C and at the oxygen potential of the Mo/MoO2 equilibrium , in presence of Mo,
Ba(U1-xZrx)O3 solid solution can incorporate limited amounts of Mo and forms a
Ba(U,Zr,Mo)O3 perovskite phase, and the solubility of BaMoO3 in Ba(U1-xZrx)O3 depends on
the U:Zr ratio (see ( Task 2.5.2.1)
Therefore at moderate oxygen potentials, when only part of the produced (Table X) Mo
oxidizes, Mo is incorporated in the perovskite precipitates. When more Mo is oxidized,
several ceramic phases will co-exist and the formation of Scheelite type BaMoO4 becomes
possible, even when the global oxygen potential is still buffered by the Mo/MoO2 couple.
Experiments of Pascoal showed that the sole increase of pO induces a major change in
the ceramic precipitate stability : while at lower oxygen potentials Mo is in equilibrium with
BaZrO3, at more elevated oxygen potentials, it is ZrO2 that is stable against BaMoO4.
C.3.5.3.5
Conclusions (Ref. [18])
The oxygen potential controls the phase formation of the ceramic precipitates.
At low to intermediate BU and at low pO, Ba remains dissolved in the fuel matrix.
At more elevated BU and at low pO, because the fission yield of Zr is larger than that of Ba,
the perovskyte phase BaZrO3 is the preferred phase for precipitation of the fission products in
a UO2 matrix and molybdenum precipitates as a metal in metallic precipitates Mo-Pd-Rh-TcRu. The perovskyte BaZrO3 can dissolve important amounts of UO2 and various FPs.
When the pO rises, molybdenum oxidizes into MoO2 which is primarily incorporated in
ceramic precipitates BaZrO3 ; at a pO above that of the couple Mo/MoO2 scheelite BaMoO4 is
formed. This was observed in a LWR MOX irradiated fuel pin (at BU = 56GWj/tM)
The solubility limit of MoO2 in BaZrO3 also is modified : from 25mol% substitution of ZrO2
at low oxygen potentials, down to below the detection limit in more oxidizing conditions.
C.4
Validation and Improvement (WP 3)
C.4.1 Validation based on fuel experiments and empirical models (Task 3.1)
The objective of the task is to compare the predictions of fuel hyperstoichiometry using
the model in NUCLEA with the experimental data and other empirical models and thermodynamic databases adopted within the nuclear industry. The validation of the model adopted for
UO2+x in the database was carried out over the temperature range 973 to 1973 K.
Results
Agreement of the calculated values of oxygen potential for UO2+x obtained using NUCLEA,
in conjunction with GEMINI2, and the experimental data is very good across the temperature
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
19
range (Ref. [19]). For the single phase fluorite region, the calculations confirm the use of
some of the empirical models of Lindemer and Besmann, and de Franco and Gatesoupe and
show reasonable agreement between the different methods. The agreement with the Green
and Leibowitz data (only intended for use with stoichiometric and hypostoichiometric
compositions (UO2-x) at high temperatures) is logically poor for O/U ratios greater than ~2.05
and temperatures less than 1373 K.
C.4.2 Validation based on experiments (Task 3.2)
This task was dropped by a decision at the mid term assessment meeting (Ref. [20]).
C.4.3 Validation based on Vulcano/CEA & COMETA/NRI experiments (Task 3.3)
The VULCANO facility allows to heat up to 3000K and to melt roughly 100 kg of
corium composed of representative materials : UO2, ZrO2, FexOy, etc. in various proportions,
and to pour it on representative materials of ex-vessel core catchers or spreading areas.
C.4.3.1
VULCANO VE-U3 experiment
The VULCANO VE-U3 (final melt composition in wt% : 60 UO2 – 24,1 ZrO2 – 6 Fe3O4
– 0,8 Fe2O3– 8,2 SiO2- 0,7 CaO – 0,2 Al2O3) experiment has been analysed and compared
with successive versions of the nuclear thermodynamic databases (Ref. [21]).
One of the major qualitative differences between the experiments and the computations
regards the computation of the so called chernobylite phase i.e. the zircon-coffinite, which is a
silicate of mixed UO2 and ZrO2 : (ZrxU1-x)SiO4. These compounds were calculated by
different versions of the THERMODATA database coupled with the GEMINI 2 code but not
found by material analysis in the VE-U3 corium. For different quaternary systems of the exvessel corium, the uncertainties are important. For instance, in the quaternary system U-Fe-SiO, no dissolution of iron in urania-zirconia phases is considered in the databases whereas in
fact iron was observed in the urania-zirconia phase. Similarly, in the (U-Zr-Si-O) and (U-FeSi-O) systems, there are uncertainties on the miscibility limits, particularly for the
"chernobylite" phase (ZrxU1-x)SiO4 where the solubility limit, x, is not well known. Some
authors report a value up to 5% molar.
Up to version 981 included, dissolution of “USiO4” in zircon (ZrSiO4) was not
considered in the TDBCR database. When the post-test analyses of VE-U1 showed evidences
of the dissolution of uranium in zircon, i.e. the formation of chernobilyte, this dissolution was
introduced in the version 992 of TDBCR with a large solubility limit : up to 30 %mol of
uranium could be dissolved in zircon (Zr0.7U0.3 SiO4 compound. Such a high solubility seems
incompatible with the observed absence of chernobylite in the VE-U3 samples.
Now, for the reactor case a precise knowledge of the remaining free silica content is
needed (Figure 9). Testing the TDBCR versions (98,99,00), differences can go up to 26% for
the solid fraction at a given temperature. The last version is probably the most exact.
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
20
C.4.3.2
VULCANO VE-U7 experiment
VULCANO VE-U7 consisted in pouring corium over two parallel paths : one in
zirconia, the second in concrete. After spreading the global composition of the melts are very
similar : 54 UO2 – 32 ZrO2 – 7 FeO – 3 SiO2 – 2 CaO – 0,3 MgO – 0,4 Al2O3 (in wt%). FeO
is partly reduced in Fe. This presence of some iron balls gives a valuable information on pO2.
Thermodynamic calculations with the GEMINI2 code and the TDBCR001 database
predicted correctly the major phases of corium, but some discrepancies were found with the
minor phases (Fe-concrete mixtures) and the evolution of the mortar (Ref. [22]).
C.4.3.3
COMETA / NRI test
In ECOSTAR, mixtures of simulant corium of ZrO2 - Fe2O3 – concrete and prototypic
corium systems (UO2-ZrO2-Fe2O3 –concrete) were melted above 2000 K in air.



The main important results are (Ref. [23]):
For the ZrO2-Fe2O3 pseudo-binary system, the existence of the monotectic point M
implies a difference of 700 K for the “liquidus” temperature.
In the ZrO2-FeOx-SiO2 system, a miscibility gap is observed between 2423 K and 2073
K whereas the thermodynamic data calculates a full liquid domain (Figure 10).
In the UO2-ZrO2-Fe2O3 –concrete systems, a monotectic temperature was experimentally
identified at 2223K whereas the calculated Tliq is 2200K. Between 2623K and 2223K, two
liquids were observed whereas GEMINI 2 computed only one liquid phase.
C.4.4 Improvement by literature review (Task 3.4)
C.4.4.1
Boiling points and vapour pressures of the element
Thermodynamic properties of all gaseous metallic elements were revisited and
reassessed, mainly at high temperature. A survey of the boiling points of 11 metallic elements
(Table XI) with the related vapour pressures was made (Ref. [24]).
A critical assessment was used to optimise of the thermo-chemical properties of gases in
consistency with SGTE data for condensed species.
C.4.4.2
Thermodynamic properties of UxOy gaseous species
The gaseous binary O-U system is complex. Tests to determine pvap over UO2 are very
difficult because the non-congruent vaporisation of the ceramic and its non-stoichiometry.
The specific heats were taken from the last work made in Glushko THERMOCENTER.
After the analysis of more than 150 scientific papers concerning the composition of the
gaseous phase in equilibrium with urania, a critical assessment and optimisation of the
thermodynamic properties led to a new set of thermodynamic data. The validation of that new
data was made by comparison between calculations and experiments (Figures 11, 12) .
A new set of thermodynamic data are available for the OxUy gaseous species (Ref. [25])
but experimental information are still needed.
C.4.5 Validation based on Tliq & Tsol measurements in UO2+x–ZrO2 (AEA-T) and
Fe-Zr-O (SKODA), & on global experiments (VERCORS, Hofmann) (Task 3.5) (Ref. [26])
C.4.5.1
UO2+x – ZrO2 liquidus and solidus measurements
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
21
Pre-calculations were performed with the experimental conditions of the UO2+x – ZrO2
tests foreseen at AEA-T in closed cell, i.e. at constant volume, with x = 0 – to 0,10 (Task 2.1).
All calculations were performed with the GEMINII2 code and 2 databases TDBCR-iv 992
and NTDiv01, able to take into account the UO2 hyper-stoichiometry.
The pre-calculations made for the two extreme compositions proposed by AEA-T( x = 0
and 0,1) showed that an intermediate composition like x = 0.05 is not hyper-stoichiometric
enough to be sensitive to a change of Tliq from the stoichiometric composition. Therefore the
hyperstoichiometries tested by AEA-T were fixed to x= 0 - 0.08 - 0.15.
The AEA-T test results are in general good agreement with the calculations (Figure 13)
: the difference in liquidus temperature are less than 50K which is acceptable.
These pre-calculations became validation calculations of the NTDiv012 database.
C.4.5.2.
Fe-Zr-O liquidus and solidus measurements
Pre-calculations on the Zr-O-Fe system, made in support of the SKODA tests (WP2 task
2-2) were performed with the SKODA “measured” compositions called “chemical analysis”
(with a clear uncertainty about the oxygen concentration).
Different databases, provided by Thermodata (NTDiv01 Tdbcr991 and Tdbcr992) or
CEA (DPC/01), corresponding to different Zr-O-Fe models were used to calculate Tsol and
Tliq . A good agreement between measurements and calculations is obtained for Tsol.
For Tliq, depending on the database, measurements are 300 to 1300 K lower than
calculations. NTDiv seems to be the best database but with still 300 K discrepancy .
The visual Tliq measurement method consisting to observe the temperature at which the
sample forms a droplet, is probably less sensitive than methods related to sign of the last crystal presence (as TDA or VPA), giving an order of magnitude, located between Tliq and Tsol.
Calculations about the phase proportion evolution versus temperature showed that with
the Thermodata database, in a very small range of temperature (~ 50K), 80% of the mixture is
melted. This could be interpreted a Tliq with the visual method used by SKODA.
According to calculations, the last phase to be dissolved in the liquid, is the zirconium
rich solution phase (HCP) for NTDiv and DPC/01, or the ZrO2 phase for Tdbcr992.
Furthermore for TDBCR992, depending of the oxygen content in the alloy, the primary
crystallization phase is the zirconium rich solution phase (HCP) for a low oxygen content
(~2at%) or the ZrO2 phase for higher oxygen content (~7.8at%). This is not the case for the
other databases, whatever the oxygen content between 2 and 7.8at%.
The real oxygen composition of the alloy is thus an important parameter .
C.4.5.3
Fission Products release (Vercors tests)
The aim of VERCORS is to quantify the release rate of FPs from pieces of irradiated
fuel pins heated up to 2800°C.
It is assumed in the calculations made with GEMINI2 that all the elements are oxidized.
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
22
Moreover the quantity of oxygen necessary to form corresponding stable stoichiometry
oxides (UO2, ZrO2, LaO, BaO, RuO2, SrO) is taken into account for the calculations.
The composition of the gas is taken into account only to determine the pO. The
equilibrium temperature was considered as the maximum temperature of the test (2300°C).
The comparison between measured releases and the calculation results are summarized
in Figure 14 A and 14 B with several databases.
The release of baryum is important for both atmosphere. There is an agreement between
calculation and measurement whatever the atmosphere is.
The release of lanthanium is small for both atmosphere. There is an agreement between
calculation and measurement whatever the atmosphere is.
Calculated Ru releases in oxidizing atmosphere are very elevated compared to the
measured releases.
The discrepancy concerning the U release in oxidizing atmosphere has several origins:
 The thermodynamic data of the UO3 gaseous species are very uncertain and must be
improved later on in the NUCLEA database.
 UO3 is taken into account in the databases since 1998 (TDBCR 981 & after), not in
1997 (TDBCR 971); UO2 is considered as stoichiometric in TDBCR 971 and 981; it is
only since 1991 (TDBCR991 and after) that UO2+/- x is described. The presence of
UO3 enhances significantly the U release, even in the database where the
stoichiometry of UO2 is no described (TDBCR 971 & 981).
The discrepancy concerning the Sr release in reducing atmosphere (Figure 14 A) has
several main origins:
 The presence in the database of some Sr condensed phase like SrUO3 (TDBCR 991,
992, 001) or solid solution (Sr xBa 1-x)UO3 (NTDiv01 and 02), reduces strontium
release by trapping some Sr in the condensed state but this is not enough.
 The calculated release is very sensitive to the oxygen quantity taken into account in
the initial mass balance.
 The calculated release can be divided by 2 if the gas volume taken into account is
limited to the plateau at 2300°C instead of the total volume of gas flowing over the
pellets above 1300°C.
C.4.5.4
Corium pool stratification involving Fe-O-U-Zr (+Cr, Ni)
In 1976 Hofmann performed small scale experiments to study the melting behavior of
fuel (UO2) with its clad (Zircaloy 4) and the structure (stainless steel).
The AX1 (Table XII) test showed the presence of 2 immiscible liquids with the metallic one,
iron rich also enriched in uranium and zirconium.
This miscibility gap behavior in the liquid phase has also been experimentally observed in the
U-O-Zr-Fe quaternary system in the Isabel 1 installation.
Thermodynamic calculations were performed with NTDiv01 with theGemini2 code, the
previous databases TDBCR971, 991, 992, 2000-1 with the GEMINI2 code, the 4 elements
Fe-O-U-Zr DPC/01 database developed by CEA/DPC with the Thermocalc code.
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
23
TDPC/01 and TDBCR97 calculate an important content of U in the metallic liquid
phase. This is not the case for tdbcr991, 992, 2000-1 nor for NUCLEA. The discrepancy
between measurement and calculation is more important for the metallic phase than the oxide
one : in the metallic liquid Zr and O in DPC and Zr, Fe, O in TDBCR are not correctly
calculated.
Almost no experimental results exist in the metal-oxide part of the U-O-Zr-Fe system. It
explains why there are so many differences between the DPC and Thermodata databases. This
shows that the metallic description of these databases need to be improved.
C.5
Influence of uncertainties (WP 4)
The first step was devoted to the uncertainties still present in the nuclear
thermodynamic data bases. Six cases (reactor case or R&D case) were chosen : a
VULCANO spreading experiment (VE-U3), the TMI2 corium composition in reducing
atmosphere, a typical EPR composition, the gaseous substances produced during MCCI,
gaseous substances for in-vessel corium and U1-xZrxO2+y hyperstoichiometric
compositions. Uncertainties on thermodynamic outputs (Tliq, Tsol, solid, liquid mass
fractions during solidification, enthalpy) were assessed from the user’s point of view.






Some general rules were drawn (Ref. [27] [28]) :
the uncertainties on the thermodynamic outputs are decreasing with the latest versions
of the databases
all the thermodynamic outputs don’t have the same uncertainties ;
the uncertainties on the enthalpy, Tliq and Tsol are low for the successive databases,
the uncertainties of the composition of liquids are low,
between Tsol and Tliq, the uncertainties on the nature and the proportions of the existing
substances are increasing;
the uncertainties on the nature and the quantities of the existing gaseous substances are
increasing.
It’s possible to define a general rule to qualify a thermodynamic calculation in
relation with the quality of the binary systems that constitute the corium composition :


if all the pseudo-binary systems that constitute the corium composition have
rankings higher than ***, uncertainties on temperature will be less than 50K
if one or more pseudo-binary systems constituting the corium have rankings equal
to *, an uncertainty on the temperature of  100 K could be expected.
In the U-Zr-O system, with the previous modeling, without experimental data,
uncertainties for O/M>2.00 were important. The last modeling is now correct.
Another part of the task was related to the relevance of subsystems for the nuclear
thermodynamic databases (Ref. [29]). 290 were assessed . 12% of them are the most
important. The main elements of the in-vessel corium (U, Zr, Fe, O) belong to the most
relevant subsystems. The knowledge and modeling of these subsystems is good except
for the subsystems with iron oxides : for the binary and the ternary systems including
iron oxides, there’s a need of reliable thermodynamic data for the end-users of NTD.
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
24
C.6
Coupling methodologies to S.A. codes (WP 5)
C.6.1
Coupling methodology of thermodynamic databases to SA codes (CROCO and
ICARE/CATHARE) (Task 5.1)
Different strategies for coupling the thermo-chemical databases for corium with severe
accident codes were investigated by IRSN. They can be broadly separated into two groups :
either a direct coupling between a thermo-chemical code and the severe accident code, either
''tabulation'' strategies where the phase diagram is ''pre-calculated'' and implemented in the
severe accident code.
The thermo-chemical databases for corium contains the description of the Gibbs energy
G, for all the phases able to appear in an accidental transient for a given number of elements.
The Gibbs energy may exhibit a very complex form. Therefore the presence of metastable
minimum is often encountered. The thermo-chemical codes on the market use different
algorithms to solve the difficult problem of research of the stable equilibrium in a multicomponent and non ideal system.
On the basis of this analysis, it is not reasonable to directly couple a thermochemical
code with a severe accident code in order to treat the corium thermodynamics.
C.6.1.1 Tabulation of the phase diagram
The feasibility of an automatic tabulation of the complex phase diagrams and its
implementation in severe accident codes was investigated. The main advantage of this
approach is to prevent the numerical problems inherent to the determination of the stable
equilibrium in a complex thermodynamic system.
This automatic pre-calculation consists in a meshing of the concentration domain
followed by the calculation, for each point of this meshing, of the thermodynamic properties,
as a function of temperature. The implementation of this strategy of coupling by meshing of
the phase diagram requires four separate steps :




the meshing of the composition and temperature domain,
the interface with the thermo-chemical code,
the generation of the tabulation,
the development of tools allowing to get for any composition and any temperature, the
value of the thermodynamic properties.
This was done for the U-Zr-Fe-O system.
C.6.1.2 Interface with the thermochemical code
The FORTRAN version of the thermo-chemical code GEMINI2 was modified to make
it more readable and to reduce the time of each call. (A factor of 10 was gained ). With this
improvement, the tabulations up to 7 elements could be performed in few days.
C.6.1.3 Generation of the library, research and interpolation in the library
For each node of the tabulation (x), GEMINI2 is called in order to compute the useful
thermodynamic quantities : Tsol, Tliq, the temperature of apparition of the gas phase,
the liquid fraction, the solid fraction, the gas fraction, the enthalpy, the composition of the
solid phase, the composition of the liquid phase, the composition of the gas phase.
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
25
For each node of the meshing (x), one stores the different thermodynamic properties
(previously mentioned) in a file (the format of this file respecting the MDB requirements). All
these files constitute the associated material library.
With the concentrations meshing and the corresponding material library, it is possible to
get the properties of any material by interpolation. For obvious reasons of computation time,
it is excluded to do a loop over all the elements of the composition mesh. The retained
solution is to research the closest mesh nodes of the point to interpolate and then to research,
the good ''element'' over the elements associated with these closest points, that is to say, the
elements containing one or more of these points. Once the element containing the M point
determined, the thermodynamic properties at M, have to be interpolated over the nodes of the
considered element. The interpolation is performed firstly in the temperature tabulation and
after in the composition field.
C.6.1.4 Applications
The U-Zr-O phase diagram meshing has been restricted to the composition sub-domain
included in the triangle the UO2-ZrO2-Zr triangle. This meshing contains 289 nodes. Some
compositions have been chosen in order to validate the approach. As example, some
reconstructions of different thermodynamic properties for the composition UO2-ZrO2-Zr = 11-1 in moles were calculated : the enthalpy, the liquid fraction, the liquid composition (Figure
15) and the solid composition, and compared with the GEMINI2-NUCLEA “referenced”
results. A good agreement is obtained.
The meshing of the quaternary phase diagram U-O-Zr-Fe (with 1576 nodes) has been
also investigated and the “tabulation” approach remains feasible and suitable (Ref. [30]).
C.6.1.5 Time consuming and coupling
The generation of the tabulation of the different ternary phase diagrams, takes less than
1 hour, and for the quaternary phase diagrams, only a few hours. Phase diagrams with 6 or 7
elements should request a few days. In any case, it means that the tabulation can be easily and
quickly re-generated with each new version of the database.
For the quaternary phase diagram, the calculation of a thermodynamic property at a
given composition and given temperature is 1000 times more rapid than a call to the
GEMINI2 code. This time is reasonable, regarding the coupling with SA codes.
The tabulation of the quaternary phase diagram occupies 22 Mbytes. Phase diagrams
with 6 or 7 elements could occupy 1 Gbytes, which can be prohibitive. Further analysis must
be performed for phase diagrams with such high number of elements.
The implemented approach will be included in the MDB module of the ASTEC Code.
C.6.2 Recalculation of TMI2 with MAAP4 and the database (Task 5.2)
EDF uses the EPRI MAAP integral software in order to calculate SA sequences for
PSA level 2. MAAP4 models thermal-hydraulics and FPs behaviour in the primary circuit,
steam generators, containment, and auxiliary buildings. In this code is implemented the
MATPRO thermo-chemical.
The effect on plant applications of the new properties given by NUCLEA was
investigated (Ref. [31]).
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
26
C.6.2.1 Thermo-chemistry of the U-Zr-O domain
The general process of degradation is strongly governed by the formation of the U-Zr-O
eutectic. The effect of the melting temperature of the U-Zr-O mixture can be investigated by
the opportunity of two models implemented in MAAP4 .
C.6.2.2 Recalculation of the U – Zr – O diagram using the NUCLEA database
The two pseudo-ternary diagrams of U-Zr-O were recalculated using the NUCLEA
database. Tliq and Tsol of the leading points of the diagrams were evaluated, postulating a
similar shape between the leading points as in the previous MATPRO database.
The differences between MATPRO and NUCLEA for Tliq are summarised in Table XIII. The
calculations were done with the GEMINI Gibbs minimizer. For several points, temperatures
are very close (less than 30 K, sometimes much less).
There are some large differences such as Tliq of corium but this corium contains no Zirconium
and is therefore mainly non prototypic.
C.6.2.3 Recalculation of TMI-2 using the new Tliq and Tsol
The new calculation, made with NUCLEA data for U-Zr-O was compared with a
previous calculation of the TMI-2 sequence run for the CIT project (in the 4th Framework
Program).
The two main physical parameters investigated are the total mass of hydrogen produced
during the accident (300 kg were produced before quenching and 150 kg after the quenching)
and the mass of molten materials. With the initial reference calculation made with MATPRO,
the total mass of molten materials is notably too low : 25 tons instead of 60 tons. With the
new figures extracted as explained above from the U-Zr-O subsystem of the NUCLEA
database, the calculated mass of molten materials is of the same order of magnitude (25 tons).
The trend of the H2 production is also the same for both calculations.
C.6.3
Simplification of the database and/or of equilibrium code and adaptation to SA
codes (Task 5.3)
Users are interested by simplifying the NTD-GEMINI2 global thermodynamic approach
for specific applications, in order to decrease significantly the calculation time for one
thermo-chemical calculation, and also to guarantee the convergence of their codes at 100 %,
i.e. the robustness. Specific subsets may be extracted from the global NTD user’s request.
In this respect the Fe-O-U-Zr database was assembled and delivered to IRSN, EDF, CEA.
Concerning this « key » quaternary system, improvement works were documented :
 boiling points and vapour pressure of Fe, U and Z
 critical assessment of some systems Fe-U, U-Zr, O2U-O2Zr, shared between
THERMODATA and AEA-T (Ref. [32]),
 improved version using a sublattice model to describe the UO2+x.
The partial FeOUZr Thermodynamic Database for In- and Ex-Vessel applications,
contains the 4 + 2 following elements : O-U-Zr-Fe + Ar-H, and includes in particular the 4
oxide system : UO2 -ZrO2 -FeO-Fe2O3. Hydrogen was added because it is a major component
of the system, but the dissolution of hydrogen in condensed solid and liquid solutions is not
taken into account at this time.
The FeOUZr Thermodynamic Database can be considered as well validated.
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
27
C.7
Edition of the database
All the binary systems and many ternaries were checked, and the data base as a whole
too. The database for in- and ex-vessel applications was named “NUCLEA”
A commercial agreement was signed between THERMODATA and AEA-T on the
property rights.
CONCLUSION
As outcome of the extensive efforts, started in the 3rd Framework Programme for R&D
of the European Commission, through the 4th and 5th FWP (the present ENTHALPY Project) ,
the NUCLEA database is now available. This tool is unique in the world to calculate the
phase diagrams of most of the corium materials involved in severe accidents (Ref. [33]).
This was reached by merging the two databases existing in Europe at the beginning of
ENTHALPY, and by extending it to key new elements. The database was feed up with
experimental results for many important systems that were unknown or badly known. The
database was validated against many types of experiments. Methodologies were developed to
link it with different SA codes in a fast and reliable way.
The database is fully documented and commercially available; more information can be
get on the web-site : http://thermodata.online.fr/nuclea/Nuclea03-1.htm
The next step, beside the necessary updating of data, should be the introduction of the
following new elements : Mo, Pu, Cs.
The ENTHALPY partners thank the European Commission for its thorough scientific
and financial support to the Project.
REFERENCES
[1]
Chevalier P.Y., Fischer E., Assessment and assembling of the systems for the Nuclear
Thermodynamic Database NTDiv01, ENTHALPY Report SAM-ENTHA(01) P003
(February 2001)
[2]
THERMODATA, NTDiv01 Nuclear Thermodynamic Database for In-Vessel
applications, ENTHALPY report SAM-ENTHA(01) D001 (February 2001)
[3]
Mason, P.K. Mignanelli M.A, Extension of the oxide components of the nuclear
thermodynamic database for in-vessel applications, ENTHALPY report SAMENTHA(01) P007 (November 2001)
[4]
Chevalier P.Y., Fischer E., Nuclear Thermodynamic Database for In-Vessels
applications. Extension to B and C, ENTHALPY report SAM-ENTHA(02) P009
(February 2002)
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
28
[5]
Chevalier P.Y., Fischer E., B – U and C – U : Thermodynamic assessment,
ENTHALPY report SAM-ENTHA(02) P010 (February 2002)
[6]
THERMODATA, Nuclear Thermodynamic Database. 2nd version for In-Vessels
applications, ENTHALPY report SAM-ENTHA(02) D002 (February 2002)
[7]
Mason P.K. and Mignanelli M.A., Extension of the oxide components of the nuclear
thermodynamic database for ex-vessel applications, ENTHALPY report SAMENTHA(02) P013 (June 2002)
[8]
Chevalier P.Y., Fischer E., Progress in the thermodynamic modelling of the O-U
binary system, ENTHALPY report SAM-ENTHA(02) P012 (May 2002)
[9]
Barrachin M., Mignanelli M., Chevalier P.Y., Comparison exercise between the
thermo-chemical databases NUCLEA and MTOX regarding the pseudo-quaternary
phase diagram FeO-Fe2O3-CaO-SiO2, ENTHALPY report SAM-ENTHA(03) P017
(March 2003)
[10]
Punni J.S., Mignanelli M.A., Determination of the Solidus and Liquidus temperatures
of uranium-zirconium oxides, ENTHALPY report SAM-ENTHA(01) D004 (August
2001)
[11]
VrtílkováV., Novotný L., Belovsky L., Solidus temperatures in Zr-Fe-O and Zr-Cr-O
systems, ENTHALPY report SAM-ENTHA(01) D005 (November 2001)
[12]
Vasáros L., Jákli Gy, Pintér A., Hózer Z., High Temperature Investigation of the Iron
Oxide-B2O3 Systems, ENTHALPY report SAM-ENTHA(01) D008 (January 2001)
[13]
Vasáros L., Jákli Gy, Windberg P., Matus L., Nagy I., Pintér A., Hózer Z., Phase
Transition Investigation in the ZrO2 -B2O3 system, ENTHALPY report SAMENTHA(01) D009 (January 2003)
[14]
Vasáros L., Jákli Gy, Hózer Z., Phase Transition Investigation in the UO2 -B2O3
system, ENTHALPY report SAM-ENTHA(01) D010 (January 2003)
[15]
Hellmann S., Lopukh D., Liquidus in subsystems UO2-ZrO2-(Al2O3-SiO2-CaO-FeOCr2O3-BaO), ENTHALPY report SAM-ENTHA(03) D011 (March 2003)
[16]
Duvigneaud P.H., Kitembo Mwamba, Phase relationships in the BaO-ZrO2-MoO3UO2 system, ENTHALPY report SAM-ENTHA(02) D013 (July 2002)
[17]
Bouchana, H., Cara J., Ronneau Cl., Behaviour of UO2-MoO2-BaO-ZrO2 at high
temperature (element migration and release, influence of gases), ENTHALPY report
SAM-ENTHA(01) P006 / SAM-ENTHA(01) D015 (June 2001)
[18]
Verwerft M., Vos B., Van den Berghe S., Review of the U-Zr-Mo-Ba-O quinary
system, ENTHALPY report SAM-ENTHA(03) D016 (January 2003)
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
29
[19]
Mason P.K., Mignanelli M.A., Comparison of the model for UO2+x in the NTD with
empirical correlations and experimental data, ENTHALPY report SAM-ENTHA(02)
D017 (August 2002)
[20]
Barrachin M., Minutes of the third progress meeting, Budapest 5-6 July 2001,
ENTHALPY report SAM-ENTHA(01) M005 (July 2001)
[21]
Journeau Chr., Piluso P., Interpretation, with GEMINI2 and TDBCR992 of the corium
cooling in the VULCANO test VE-U3, ENTHALPY report SAM ENTHA(00) P001
(August 2000)
[22]
Journeau Chr., Interpretation of the VULCANO VE-U7 data using GEMINI2 and the
TDBRCR001 database, ENTHALPY report SAM-ENTHA(02) P016 (December
2002)
[23]
Piluso P., Validation of the European thermodynamic database with the experiments
performed at NRI-REZ on the (U,Zr)O2 – Fe2O3 system, ENTHALPY report SAMENTHA(03) D020 (January 2003)
[24]
Cheynet B., Chaud P., Boiling points and vapour pressures of elements. Improvement
from literature, ENTHALPY report SAM-ENTHA(02) D021 (February 2002)
[25]
Cheynet B., Chaud P., Thermodynamic properties of gases in the O-U system,
ENTHALPY report SAM-ENTHA(03) D22 (March 2003)
[26]
Defoort Fr., Pre-calculations of UO2+x–ZrO2 (AEA-T) and Fe-Zr-O (SKODA) Tliq and
Tsol measurement; Validation of the database based on global experiments (Vercors
test and Hofmann tests), ENTHALPY report SAM-ENTHA(03) D023 (January 2003)
[27]
Piluso P., An evaluation of the uncertainties of the thermodynamic database,
ENTHALPY report SAM-ENTHA(02) D024 (February 2002)
[28]
Piluso P., Consequences of the uncertainties in the database, ENTHALPY report
SAM-ENTHA(03) D025 (March 2003)
[29]
Piluso P., Relevance of subsystems for the nuclear thermodynamic databases,
ENTHALPY report SAM-ENTHA(02) P015 (September 2002)
[30]
Barrachin M., Jacq F., Coupling of the corium thermo-chemical database with the
severe accident codes, ENTHALPY report SAM-ENTHA(03) D026 (January 2003)
[31]
Marguet S., Calculation of TMI-2 using new Liquidus and Solidus temperature of UZr-O, ENTHALPY report SAM-ENTHA(03) D027 (March 2003)
[32]
THERMODATA, FeOUZr Thermodynamic database, ENTHALPY report SAMENTHA(03) D028 (March 2003)
[33]
THERMODATA, NTD Nuclear Thermodynamic Database for In- and Ex-Vessel
Applications, ENTHALPY report SAM-ENTHA(03) D003 (March 2003)
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
30
Table I : Summary of WPs, tasks and partners in the ENTHALPY project.
WP
WP 1
Task 1.1 & 1.2
WP 2
Task 2.1
Task 2.2
Task 2.3
Task 2.4
Task 2.5.1
Task 2.5.2.1
Task 2.5.2.2
Task 2.5.2.3
WP 3
Task 3.1
Task 3.2
Task 3.3
Task 3.4
Task 3.5
WP 4
WP 5
Task 5.1
Task 5.2
Task 5.3
WP 6
Description of WP and tasks
Assembling & extension
-Critical assessment ,assembling; extension
Separate Effect Tests
-Hyperstochiometry in UO2+x - ZrO2
-Tliq in Zr - Fe - O and Zr - Cr – O
-Tliq in B2O3-FeOx-ZrO2-UO2
-Tliq in UO2-ZrO2-FeOx-CaO-Al2O3
-Tliq in UO2 – BaO
-UO2-ZrO2-MoO2-BaO phase diagram
-Release in ,, in T gradient
-Comparison with damaged irrad. fuel pins
Validation and improvement
-From fuel experimental & empiric models
-Based on ACE experiments
-Based on VULCANO, COLIMA
-Based on literature
-Based on UO2+x-ZrO2 test , Vercors etc
Influence of uncertainties
Coupling methodologies to SA codes
-To CROCO, ICARE/CATHARE
-Recalculation of TMI1 with MAAP4
-Simplification of database & equilibr. code
Edition of the database
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
Main partners
THERMODATA , AEA-T
AEA-T
SKODA-UJP
AEKI
FRAMATOME ANP
FRAMATOME ANP
ULB
UCL
SCK.CEN-Mol
AEA-T
IRSN (ex-IPSN)
CEA/DRN/DTP
THERMODATA
CEA-Grenoble
CEA/DRN/DTP
IRSN
EdF
IRSN
THERMODATA
January 2004
31
Table II : State of the validation of the binary systems
N°NAME
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
Ag-Al
Ag-B
Ag-Ba
Ag-C
Ag-Ca
Ag-Cr
Ag-Fe
Ag-In
Ag-La
Ag-Mg
Ag-Ni
Ag-O
Ag-Ru
Ag-Si
Ag-Sr
Ag-U
Ag-Zr
Al-B
Al-Ba
Al-C
Al-Ca
Al-Cr
Al-Fe
Al-In
Al-La
Al-Mg
Al-Ni
Al-O
Al-Ru
Al-Si
Al-Sr
Al-U
Al-Zr
B-Ba
B-C
B-Ca
B-Cr
B-Fe
B-In
B-La
B-Mg
B-Ni
B-O
B-Ru
B-Si
B-Sr
B-U
B-Zr
Ba-C
Ba-Ca
Ba-Cr
S QC
O
T
T
T
T
T
T
C
T
T
T
T
T
T
T
T
T
T
T
O
O
T
O
O
T
O
O
C
T
O
T
T
O
T
T
T
T
O
T
T
O
O
T
T
T
T
T
T
T
T
T
***
*
***
**
**
*
***
***
***
**
***
***
***
***
***
**
***
**
**
***
***
***
***
***
**
***
**
*
**
***
**
**
*
*
**
*
**
***
*
**
***
***
*
**
**
*
**
***
*
***
*
N°
NAME
S QC
N°
NAME
S QC
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
Ba-Fe
Ba-In
Ba-La
Ba-Mg
Ba-NIi
Ba-O
Ba-Ru
Ba-Si
Ba-Sr
Ba-U
Ba-Zr
C-Ca
C-Cr
C-Fe
C-In
C-La
C-Mg
C-Ni
C-O
C-Ru
C-Si
C-Sr
C-U
C-Zr
Ca-Cr
Ca-Fe
Ca-In
Ca-La
Ca-Mg
Ca-Ni
Ca-O
Ca-Ru
Ca-Si
Ca-Sr
Ca-U
Ca-Zr
Cr-Fe
Cr-In
Cr-La
Cr-Mg
Cr-Ni
Cr-O
Cr-Ru
Cr-Si
Cr-Sr
Cr-U
Cr-Zr
Fe-In
Fe-La
Fe-Mg
Fe-Ni
C
T
C
T
T
T
C
C
C
C
C
T
O
O
T
T
T
O
T
T
O
T
T
O
T
T
T
T
O
T
T
T
T
T
T
T
O
T
T
O
O
O
T
O
T
T
T
T
T
O
O
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
Fe-O
Fe-Ru
Fe-Si
Fe-Sr
Fe-U
Fe-Zr
In-La
In-Mg
In-Ni
In-O
In-Ru
In-Si
In-Sr
In-U
In-Zr
La-Mg
La-Ni
La-O
La-Ru
La-Si
La-Sr
La-U
La-Zr
Mg-Ni
Mg-O
Mg-Ru
Mg-Si
Mg-Sr
Mg-U
Mg-Zr
Ni-O
Ni-Ru
Ni-Si
Ni-Sr
Ni-U
Ni-Zr
O-Ru
O-Si
O-Sr
O-U
O-Zr
Ru-Si
Ru-Sr
Ru-U
Ru-Zr
Si-Sr
Si-U
Si-Zr
Sr-U
Sr-Zr
U-Zr
T
C
O
C
C
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
C
T
C
O
T
T
O
T
T
T
O
T
O
T
T
T
T
C
T
T
T
T
C
C
C
C
C
O
C
C
C
FINAL SUMMARY REPORT "ENTHALPY"
**
***
**
**
**
**
*
**
**
*
*
*
***
***
*
**
*
***
*
***
***
*
****
***
*
*
**
**
***
**
*
*
**
***
*
*
****
*
**
*
****
***
**
***
*
***
**
***
***
**
****
SAM(ENTHA)04-P019
January 2004
32
***
***
***
*
**
**
***
***
****
**
*
***
***
*
*
**
***
*
**
**
*
***
*
**
*
*
***
**
*
**
***
***
***
**
**
***
*
**
*
***
***
**
*
***
***
***
**
**
*
*
***
Table III : State of the validation of the pseudo-binary systems
N°
NAME
S QC
N°
NAME
S QC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
Al2O3-B2O3
Al2O3-BaO
Al2O3-CaO
Al2O3-Cr2O3
Al2O3-FeO
Al2O3-Fe2O3
Al2O3-In2O3
Al2O3-La2O3
Al2O3-MgO
Al2O3-NiO
Al2O3-SrO
Al2O3-SiO2
Al2O3-UO2
Al2O3-ZrO2
B2O3-BaO
B2O3-CaO
B2O3-Cr2O3
B2O3-FeO
B2O3-Fe2O3
B2O3-In2O3
B2O3-La2O3
B2O3-MgO
B2O3-NiO
B2O3-SrO
B2O3-SiO2
B2O3-UO2
B2O3-ZrO2
BaO-CaO
BaO-Cr2O3
BaO-FeO
BaO-Fe2O3
BaO-In2O3
BaO-La2O3
BaO-MgO
BaO-NiO
A
C
O
T
T
C
T
C
C
T
T
C
C
C
A
A
A
A
A
A
A
A
A
A
A
A
A
T
T
C
T
T
C
T
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
BaO-SrO
BaO-SiO2
BaO-UO2
BaO-ZrO2
CaO-Cr2O3
CaO-FeO
CaO-Fe2O3
CaO-In2O3
CaO-La2O3
CaO-MgO
CaO-NiO
CaO-SrO
CaO-SaO2
CaO-UO2
CaO-ZrO2
Cr2O3-FeO
Cr2O3-Fe2O3
Cr2O3-In2O3
Cr2O3-La2O3
Cr2O3-MgO
Cr2O3-NiO
Cr2O3-SrO
Cr2O3-SiO2
Cr2O3-UO2
Cr2O3-ZrO2
FeO-Fe2O3
FeO-In2O3
FeO-La2O3
FeO-MgO
FeO-NiO
FeO-SrO
FeO-SiO2
FeO-UO2
FeO-ZrO2
Fe2O3-In2O3
C
T
T
C
T
O
C
T
C
O
T
T
O
C
C
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
C
T
T
**
***
***
**
***
**
*
.**
**
.*
**
**
***
***
**
**
**
**
**
**
**
**
**
**
**
**
**
*
*
***
**
**
**
**
**
**
**
***
**
*
**
*
***
***
**
**
***
**
***
**
**
*
***
**
*
*
*
*
*
***
*
*
*
**
**
**
**
**
*
N°
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
NAME
S QC
Fe2O3-La2O3
Fe2O3-MgO
Fe2O3-NiO
Fe2O3-SrO
Fe2O3-SiO2
Fe2O3-UO2
Fe2O3-ZrO2
In2O3-O3LA2
In2O3-MgO
In2O3-NiO
In2O3-SrO
In2O3-SiO2
In2O3-UO2
In2O3-ZrO2
La2O3-MgO
La2O3-NiO
La2O3-SrO
La2O3-SiO2
La2O3-UO2
La2O3-ZrO2
MgO-NiO
MgO-SrO
MgO-SiO2
MgO-UO2
MgO-ZrO2
NiO-SrO
NiO-SiO2
NiO-UO2
NiO-ZrO2
SrO-SiO2
SrO-UO2
SrO-ZrO2
SiO2-UO2
SiO2-ZrO2
UO2-ZrO2
C
C
T
C
C
C
C
T
T
T
T
T
T
T
C
T
**
C
C
C
T
C
O
C
C
T
T
T
T
C
T
C
C
C
C
**
**
**
**
*
*
*
*
*
*
*
*
*
*
***
*
**
**
***
**
***
***
**
***
*
*
*
*
**
**
***
***
***
***
Table IV : State of the validation of the ternary systems
N°
1
2
3
4
5
6
7
NAME
S QC
N°
NAME
S QC
N°
NAME
S QC
B-C-Fe
B-C-U
B-C-Zr
B-Fe-U
B-Fe-Zr
C-Cr-Fe
C-Cr-Ni
T **
T **
T **
T **
T
*
O ***
O ***
8
9
10
11
12
13
14
C-Fe-Ni
C-O-U
C-O-Zr
C-U-Zr
Cr-Fe-Ni
Cr-Fe-O
Cr-Fe-Zr
O ****
T **
T **
T
*
T **
T **
T **
15
16
17
18
19
20
Cr-Ni-O
Fe-Ni-O
Fe-O-U
Fe-O-Zr
Fe-U-Zr
O-U-Zr
T **
T **
T **
T **
T **
T ***
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
33
Table V : State of validation of the pseudo-ternary systems
N°
1
2
3
4
5
6
7
NAME
S QC
N°
NAME
Al2O3-CaO-FeO
Al2O3-CaO-Fe2O3
Al2O3-CaO-SiO2
Al2O3-SiO2-UO2
Al2O3-SiO2-ZrO2
Al2O3-UO2-ZrO2
SiO2-UO2-ZrO2
*
*
C ***
T **
C **
C **
C **
8
9
10
11
12
13
14
Al2O3-FeO-Fe2O3 Al2O3-FeO-SiO2 Al2O3-Fe2O3-SiO2 CaO--FeO-Fe2O3 CaO--FeO-SiO2 CaO-Fe2O3-SiO2 FeO-Fe2O3-SiO2 -
NOTE :
N°
NAME
S
QC
S QC
*
*
*
*
*
*
*
N°
NAME
S QC
15
16
17
18
19
20
21
Al2O3-B2O3-CaO
Al2O3-B2O3-SiO2
B2O3-CaO-SiO2
B2O3-FeO-Fe2O3
Al2O3-B2O3-MgO
B2O3-CaO-MgO
B2O3-MgO-SiO2
A
A
A
A
A
A
A
Order number
Name of the system
Source : T = Thermodata, A = AEA-T, O = open literature, C = common (T-AEA-T)
Quality criterion (*, **, ***, ****).
Table VI : Solidus and liquidus temperatures for UO2+x-ZrO2 mixtures
Sample mixture (80/20 wt%)
UO2.00-ZrO2
UO2.08-ZrO2
UO2.15-ZrO2
Composition
U0.65Zr0.35O2.000
U0.65Zr0.35O2.052
U0.65Zr0.35O2.098
Solidus (C)
2590
2550
2482
Liquidus (C)
2678
2638
2561
Table VII : Liquidus temperatures measured in the B2O3/ FeOx/ ZrO2/ UO2 systems
B2O3–Fe2O3
Fe2O3
Tliq
(wt %)
(°C)
5.0
885
7.5
1010
10.0
1065
15.0
1130
18.0
1165
25.0
1225
37.5
1320
B2O3–ZrO2
ZrO2
Tliq
(wt %)
(°C)
2.5
1130
5.0
1300
1800
6.5  0.5
2000
13.51.0
FINAL SUMMARY REPORT "ENTHALPY"
B2O3–UO2
UO2
Tliq
(wt %)
(°C)
2.5
1130
5.0
1300
7.5
1330
10.0
1460
SAM(ENTHA)04-P019
January 2004
34
**
**
**
**
**
**
**
Table VIII : Compositions, Tliq and Tsol of the ex-vessel mixtures tested
Sample
1
2
3
4
5
6
7
8
9
10
Compositions (wt%)
UO2
43.3
42.1
33.8
37.9
33.6
41.7
41.4
0.3
61.9
3.5
24.2
ZrO2
17.8
13.9
14.5
13.5
13.5
16.4
15.5
39.5
14.9
9.5
7.9
Others
28.9 FeO – 10.0 Cr2O3
31.4 FeO – 12.6 Cr2O3
30.1 FeO - 14.1 SiO2 - 7.5 Cr2O3
16.9 FeO - 1.1 SiO2 – 12 Cr2O3 - 7.6 CaO
26.4 CaO - 26.5 Al2O3
41.5 FeO – 0.4 Al2O3
12FeO -13.6SiO2 - 4.2Cr2O3 -7Al2O3 - 6.3CaO
28.8FeO-12SiO2-3.6Cr2O3-13.1Al2O3-2.7CaO
23.2 CaO
33.5 CaO - 25.5 SiO2
33.8 CaO - 9.1 FeO - 25 SiO2
Experimental results
Tliq (°C)
Tsol (°C)
1710-1760
1600-1640
1660-1700
1770
1800-1860
1800-1860
1800-1880
1890-1980
1800-1860
1800-1880
1420
1360-1400
1390±30
1340
1350
1250
1320
1860-1870
1460-1520
1240-1360
Table IX : Compositions and test conditions of heated samples from
the U-Zr-Ba-Mo-O system
Oven ΔG(O2) Samples & test
T (°C) kJ/mol
conditions
1500 ~ - 25 A : 30 min/1500°C
D : 30 min/1500°C
F : 3 min/1500°C
Nitrogen N57 1500 ~ - 250 A : 60 min/1500°C
D : 60 min/1500°C
F : 60 min/1500°C
Nitrogen N57 1500 ~ - 450 A : 60 min/1500°C
+ 20 ppm H2
D : 60 min/1500°C
F : 60 min/1500°C
Ar N50
2000 ~ A : 30min/ 2000°C
(AAS oven)
1000
D : 30min/ 2000°C
F : 30 min/ 2000°C
Emission
gaz
Air
Results : Compositions of pellets after
heating
A : UO2,U3O8,BaMoO4,MoO3, traces ZrO2
D : UO2,U3O8,Ba,BaO,BaMo4O13,traces ZrO2
F : UO2,U3O8, U4Zr11O32, traces ZrO2
A : UO2,25, traces ZrO2
D:UO2+x, Ba, traces ZrO2
F : U3O7, traces ZrO2
A : UO2, Mo, BaMoO4, BaZrO3
D : UO2,BaZrO3, Ba2UO2O7
F : UO2, BaZrO3, ZrO2,Ba3Mo18O28
A : UO2,25, Mo, U, Zr, Ba
D:UO2,U,Zr,Ba,trace Mo
F : unknown cubic U/Zr?
Table X : ORIGEN-2 calculation of production rates of fission products Zr, Mo and Ba
expressed per GWd/tHM, for BWR fuel of a BU of 56GWd/tHM.
Zr
UO2
(U,Pu)O2
113
80
Mo
Wt ppm produced per GWd/tHM
105
97
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
Ba
48
45
January 2004
35
Table XI : Tboiling of 11 elements of the database after literature overview
Boiling temperatures (in Kelvin) of 11 elements of the database
Element Hulgren Kubashewski Janaf
TCras
SGTE This work
Ag
2430
2432
2437
2430
2435
Ba
2210
2167
2118
2210
2080
Cr
2953
2952
2952
2953
2768
Fe
3122
3133
3133
3125
3122
3163
In
2290
2343
2295
2290
La
3713
3730
3686
3713
Ni
3118
3169
3156
3130
3118
3366
Ru
4633
4612
4633
Sr
1635
1635
1685
1635
1656
U
4457
4440
4470
4457
4149
Zr
4700
4630
4702
4630
4700
4886
max
5
130
185
208
248
29
308
256
Table XII : Global compositions of Isabel 1 and Hofmann AX1 tests
Fe
Global composition in at%
U
Zr
ISABEL 1 [GUÉNEAU, 1999]
50
17
18
15
HOFMANN AX1 [HOFMANN, 1976] C14 U/ZR=1.2
20.3
15.3
19.4
45
(+Cr+Ni for Hofmann)
O
Table XIII : Liquidus temperatures as calculated with MATPRO and NUCLEA (limited
to the elements U, Zr, O) and the GEMINI2 Gibbs minimiser
Point MAAP
XO
XU
XZr
TMAAP (K)
TNUCLEA (K)
a
b
c
d
e
f
g
h
k
l
m
n
p
q
r
0.666
0.6666
0.6666
0.59
0.59
0.46
0.44
0.40
0.25
0.40
0.10
0
0
0.07
0.6666
0.3333
0.1666
0
0.41
0.27
0.54
0.13
0.09
0
0
0
0
1
0.93
0.13
0
0.1666
0.3333
0
0.14
0
0.43
0.51
0.75
0.60
0.90
1
0
0
0.2033
3113
2800
2911
2740
2673
2740
2673
2338
2403
2338
2243
2125
1406
1406
2850
3119
2849
2984
2759
2652
2766
2458
2357
2424
2408
2254
2127
1407
2899
2851
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
36
Figure 1 : Calculated phase diagrams for the Fe2O3 -B2O3 with a few experimental points
Figure 2 : Assessment of the O-U phase diagram (spec. in the UO2+/-x region)
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
37
Cu
1100
1500
600
800
1000
500
Ag
950
450
900
400
850
A
800
Solidus-A
Solidus-B
Liquidus-A
Liquidus-B
HV-10
B a)
C
D
E
F
Zr-Fe-O
Temperature [ C]
550
Hardness HV-10
Temperature [ C]
1050
1400
700
1300
600
1200
500
1100
400
Cu
1000
350
900
300
800
300
Solidus-A
Liquidus-A
HV-10
b)
Solidus-B
Liquidus-B
200
Zr-Cr-O
A
B
C
0
0.2
0.4
D
E
0.6
0.8
Hardness HV-10
Ni
100
1
0.2 0.4 0.6 0.8
1.2
Fig. 10 0: Solidus
and liquidus1 temperatures
of the tested alloys versus nominal
Nominal
oxygen content
Nominal
oxygen
content
]
oxygen
content.
The[wt%
dashed
ellipse marks
the required
alloy.[wt% ]
a) Zr-Fe-O
b) Zr-Cr-O
Figure 3 : Measured Tsol & Tliq and hardness versus nominal oxygen content
of Zr-Fe-O & Zr-Cr-O alloys
1600
1800
1500
Liq. Fe2O3 + Liq. B2O3
1400
1700
1600
1300
1500
1200
1100
1400
Solid Fe2O3 + Liq. B2O3
o
T, C
1200
900
Fe2O3
+
Fe3BO6
700
Solid Fe3BO6
+
Solid FeBO3
Solid Fe2O3
+
Solid FeBO3
600
1100
1000
Solid FeBO3 + Liq. B2O3
FeBO3
Fe3BO6
800
Solid Fe3BO6 +Liq. B2O3
T, K
1300
1000
900
500
800
Sintered Fe2O3 + B2O3
700
400
Solid Fe2O3 +Solid B2O3
600
300
0
10
20
30
40
50
60
70
80
90
100
B2O3, wt %
Experimental,
Interpolated,
Lit. [4]
Figure 4 : Phase diagram for the Fe2O3 – B2O3 system with the 8 experimental points
(red circles) gained in the ENTHALPY project
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
38
Figure 5 : Experimental ZrO2-B2O3 (left;B2O3 side ) & UO2–B2O3 (right) phase diagram.
The red circles are experimental points
Liquidustemperaturverlauf bei der Mischung einer Schmelze aus 75 w% UO2 und 25 w% ZrO2
mit den 3 definierten Portlandzementtypen
Viskositätsverlauf beim Aufschmelzen von PZ-Betonen
3000
1000000
SI-PZ 15 - liquidus
FESI-PZ 15 - liquidus
2800
100000
EO-PZ 15 - liquidus
2600
10000
Viskosität [Pas]
Temperatur [K]
2400
2200
1000
100
2000
10
1800
1
1600
1400
0
10
20
30
40
50
Anteil Beton [Gew%]
Calculated liquidus temperatures for
dissolving different concretes in 75%
UO2-25% ZrO2
60
0,1
1000
SI-PZ15
FESI-PZ15
EO-PZ15
1100
1200
1300
1400
1500
1600
1700
Temperatur [°C]
Calculated viscosities of different
concretes with 15% Portland cement
upon heating
Figure 6 : Examples of benefits from the knowledge of Tsol and Tliq: calculation
of the liquidus of different mixtures of ex-vessel corium mixtures (left)
and of the viscosities of different concretes
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
39
B
a
O
0
1
0
0
K
=
2
4
;
1
6
0
0
°
C
1
0D
B
a
U
O
+
U
O
3
s
s
2
s
s
9
0
2
0
B
a
M
o
O
8
0
3
6
C
3
0
B
a
Z
r
O
2
4
7
0
B
a
U
O
+
M
o
+
U
O
3
s
s
2
s
s
B
a
Z
r
O
4
0
3
2
7
B
a
Z
r
O
35
0
B
a
Z
r
O
+
U
O
3
s
s
2
s
s
6
0
B
m
B
a
M
o
O
3
5
0
B
G
B
m
z
6
0
4
0
A
7
0
8
0
3
0
B
a
Z
r
O
+
M
o
+
U
O
3
s
s
2
s
s
2
0
Z
r
O
+
U
O
2
s
s
2
s
s
9
0
1
0
0
0
Z
r
O
2
1
0
M
o
+
U
O
2
s
s
F
B
a
Z
r
O
+
Z
r
O
+
M
o
+
U
O
3
s
s
2
s
s
2
s
s
E
0
1
02
03
04
05
06
07
08
09
01
0
0M
o
O
(
x
=
0
)
x
B
a
O
0
1
0
0
K
=
1
7
;
1
6
0
0
°
C
1
0D
9
0
(
U
,
B
a
)
O
+
U
O
x
2
s
s
2
0
B
a
Z
r
O
2
4
3
0
B
a
Z
r
O
4
0
3
2
7
B
a
Z
r
O
+
(
U
,
B
a
)
O
+
U
O
3
s
s
x
2
s
s
B
a
Z
r
O
0 G
35
B
a
Z
r
O
+
U
O
3
s
s
2
s
s
6
0
B
a
M
o
O
+
B
a
Z
r
O
+
(
U
,
B
a
)
O
+
U
O
4
s
s
3
s
s
x
2
s
s
B
a
M
o
O
8
0
3
6
C
7
0
B
a
M
o
O
2
5
6
0
B
B
m
B
a
M
o
O
4
5
0
B
m
z
A
3
0
B
a
M
o
O
+
M
o
O
+
U
O
4
s
s
2
s
s
2
s
s
8
0
2
0
B
a
M
o
O
+
Z
r
O
+
U
O
4
s
s
2
s
s
2
s
s
9
0
F
0
Z
r
O
2
B
a
M
o
O
+
U
O
4
s
s
2
s
s
4
0
B
a
M
o
O
2
7
7
0
1
0
0
B
a
M
o
O
+
(
U
,
B
a
)
O
+
U
O
4
s
s
x
2
s
s
1
0
E
0
1
02
03
04
05
06
07
08
09
01
0
0M
o
O
(
x
=
2
)
Z
r
(
M
o
O
)
4
2
Z
r
O
+
U
O
2
s
s
2
s
sB
a
M
o
O
+
Z
r
O
+
M
o
O
+
U
O
4
s
s
2
s
s
2
s
s
2
s
s
x
M
o
O
+
U
O
2
s
s
2
s
s
b)
Figure 6 : UO2 80wt% cut in the pyramid of the pseudoquaternary UO2-BaO-ZrO2MoOx system at 1600°C under pO2 = 10–k atm with
a) k=16 (~-580kJ/mol) i.e. in reducing conditions
b) k=9 to 5 i.e. in oxidizing conditions
Phases stability domains relative to the UO2 80wt% matrix (in red) show substantial
differences with respect to equilibrium phases evidenced at 1400°C (a) and 1600°C (b) in
ternary BaO-ZrO2-MoOx system (in black dashed lines).
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
40
Mo
Ba
Cold
Hot
zone
Zr
U
50 µm
Figure 8 : Mapping of the pellet A as a function of temperature
Silica in liquid phase
Scheil Gulliver TDBCR981
Equilibrium TDBCR981
Scheil Gulliver TDBCR 992
Equilibrium TDBCR 992
%mol SiO2 in liquid phase
50%
45%
40%
35%
30%
25%
20%
15%
10%
5%
0%
1200
1400
1600
1800
2000
2200
2400
2600
2800
Temperature K
Figure 9 : Evolution of the silica fraction in the liquid phase using the two versions of the
database for equilibrium or Scheil-Gulliver cooling below 2270 K
(VULCANO-VE-U3 spreading experiment)
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
41
Figure 10 : Proposed miscibility gap in the pseudo-ternary system ZrO2-SiO2-FeOx
UO2(G)
4
2
0
logP(atm)
-2
-4
-6
-8
-10
-12
0,0001
Szwarc 68 UO1.94
DeMaria 60
Ohse 66 (Ptot)
Ohse 78 (Ptot)
Ackerman 56
Babelot 86
Hoch 87
Benezech 74 : UO1.953
Long 80
Pattoret 68
Ackermann 69
Green 81
NTDiv00
Winslow 75
This work
0,0002
0,0003
0,0004
0,0005
0,0006
0,0007
1/T(K)
Figure 11 : Ratio of the partial pressure of gaseous UO2 over condensed UO2 :
comparison calculations vs experiments
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
42
In red : UO (G)
In blue : UO2 (G)
In pink : U (G)
In green : UO3 (G)
In turquoise : O (G)
Figure 12 : Speciation of the gas over UO2
Calculation with the assessed data : T = 2500K.
Figure 13A : Solidus temperature versus hyper- Figure 13B : Liquidus temperature versus hyperstoichiometry x : calculations with 2 versions of
stoichiometry x : calculations with 2 versions of
the database and measurements
the database and measurements
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
43
Figure 13 : Solidus (left) and Liquidus (right) temperature versus hyper-stoichiometry x
: calculations with 2 versions of the database and measurements
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
44
70
60
50
40
30
20
10
ea
su
re
td
bc
r9
71
Td
bc
r9
81
Td
bi
vh
99
1
Td
bi
v9
91
Td
bc
r9
92
td
bi
v0
01
N
td
iv
00
1
nt
di
v0
21
0
VERCORS 4
90
80
BA
70
SR
60
RU
50
U
40
LA
30
ZR
20
U
BA
RU
LA
SR
ZR
10
0
su
re
Td
bc
r9
71
Td
bc
r9
81
TD
BI
Vh
99
1
TD
BI
V9
91
td
bi
v9
92
TD
BI
V0
01
N
TD
iv
01
N
TD
iv
02
1
80
FP released in Vercors 5 (oxidizing)
ea
(FP in the gas phase) / (FP initial)
90
100
m
FP released in Vercors 4 (reducing)
M
(FP in the gas phase) / (FP initial)
100
VERCORS 5
Figure 14 : Measured and calculated FP release in VERCORS 4 (left)
and VERCORS 5 (right)
Titre:
Auteur:
Aperç u:
Cette image EPS n'a pas été enregis trée
avec un aperç u intégré.
Commentaires:
Cette image EPS peut être imprimée s ur une
imprimante PostScript mais pas s ur
un autre type d'imprimante.
Figure 15 : Liquid composition reconstruction from the tabulation versus GEMINI2NUCLEA results [Molar composition :(ZrO2, UO2, Zr)=(1,1,1)]
FINAL SUMMARY REPORT "ENTHALPY"
SAM(ENTHA)04-P019
January 2004
45