European Nuclear Thermodynamic database for in- & ex-vessel applications (ENTHALPY)

QUENCH workshop, 13-15 Octobre 2003, Karlsruhe

A. De Bremaecker (1), M. Barrachin, F. Jacq (2), F. Defoort (3), M. Mignanelli (4), P.Y. Chevalier, B. Cheynet (5), S. Hellmann, F. Funke (6), C. Journeau, P. Piluso (7), S. Marguet (8), Z. Hózer (9), V. Vrtilkova, L. Belovsky (10), L. Sannen, M. Verwerft (11), P-H. Duvigneaud, K. Mwamba (12), H. Bouchama, C. Ronneau (13).

The ”European Nuclear Thermodynamic Database for in- and ex-vessel applications” (ENTHALPY) Project lasted from 1 February 2000 to 31 January 2003, and was performed by twelve partners : AEA-T-Harwell, AEKI, CEA-Grenoble, CEA-Cadarache, EdF-Clamart, Framatome-Erlangen, IRSN, SCK.CEN-Mol, SKODA-UJP, Thermodata, UCL, ULB.
The main aim of the project was to produce one unique commonly agreed and well validated thermodynamic database able :

a) to be used for in- and ex-vessel applications, and
b) to be linked in the future and after simplifications, to severe accident codes.

From thermodynamic data it is possible to calculate the phase diagrams, and from the data of phase diagrams (number and composition of the phases, proportion of liquids and solids, miscibility and solubility limits) it is possible to deduce physical properties like viscosity, thermal conductivity, evaporation, stratification, that are essential to describe the fuel degradation, relocation of melts, fission product release, hydrogen production, etc.
The most outstanding issues of the project were :

- to compare, critically assess and merge the two databases existing in Europe, one at THERMODATA (more oriented to in-vessel systems), the other at AEA-T (this one being oriented to ex-vessel systems) into one database
- to extend the database to new elements : B, C, and the elements of the concrete (Si, Ca, Mg, Al)
- to perform Separate Effect Tests (SET) in order to improve the phase diagrams of systems not known (the pseudo-binaries B2O3 – FeOx / ZrO2 / UO2 ; the UO2-ZrO2-BaO-MoOx phase diagram) or poorly known (corium-concrete sub-systems)
- to validate the database with very different tests (FP release tests likeVERCORS, pre-calculation and post-calculation of tests on hyperstoiciometric corium (U,Zr)O2+x, spreading tests of corium like VULCANO, etc.)
- to develop fast coupling methodologies between the database and SA codes (specially by meshing the compositions vs temperature, tabulation of the thermodynamic properties, and interpolation)

The project fulfilled all these objectives : the “NUCLEA” data base was issued, validated against several in- and ex-vessel tests, and documented.
It contains the following elements : -U-Zr-Fe-Cr-Ni-Ag-In-Ba-La-Ru-Sr-B-C-Al-Ca-Mg-Si + Ar-H
The multi-component (15) oxide system
UO2-ZrO2-FeO-Fe2O3-Cr2O3-NiO-In2O3-BaO-La2O3-SrO-B2O3-Al2O3-CaO-MgO-SiO2
is also a subset of the whole database.
An effective and fast coupling methodology with SA codes was developed, that can be applied for 5-elements subsystems. This method was applied to recalculate a reactor case (TMI2).
The commercial name of the database is “NUCLEA”. More information on NUCLEA can be get on the web site of Thermodata : http://thermodata.online.fr/

(1) : SCK.CEN detached at IRSN (F)
(2) : IRSN, Cadarache (F)
(3) : CEA/DEN, Grenoble (F)
(4) : AEA-T, Harwell (GB)
(5) : THERMODATA, Grenoble (F)
(6) : FRAMATOME-ANP, Erlangen (D)
(7) : CEA/DEN/DTP, Cadarache (F)
(8) : EdF/D-R&D (F)
(9) : KFKI/AEKI, Budapest (H)
(10) : SKODA-UJP, Praha (CZ)
(11) : SCK.CEN, Mol (B)
(12) : ULB, Brussels (B).