Improvement of the European thermodynamic database NUCLEA in the frame of EU-funded experiments

Modelling of coriumbehaviour during a severe accident requires knowledge of the phases present at equilibrium for a given coriumcomposition, temperature and pressure. The thermodynamic database NUCLEA in combination with a Gibbs Energy minimizeris theEuropean reference tool to achieve this goal. Within SARNET, this database has beenimproved thanks to the analysis of bibliographical data and to EU0funded experimentsperformed within the SARNET network, PLINIUS as well as the ISTC CORPHAD and EVAN projects. To assess the uncertainty range associated with Energy Dispersive X-ray analyses, a round robin exercise has been launched in which a UO2-containing coriumconcrete interaction sample from VULCANO has been analyzed by three European laboratories with satisfactorily small differences.