NUCLEA: A thermodynamic database validated for severe accident codes

The objective of this article is to present an overview of the validation of the NUCLEA thermodynamic database through a comparative analysis with experimental data. These examples are selected from important experimental programs (notably OECD MASCA, EC ENTHALPY) in order to cover various important topics for improving severe accident codes, especially regarding the progression of corium inside or outside the vessel. The comparison between calculations and measurements is discussed, and the main lessons learned from this extensive validation work are summarized, along with an assessment of the current relevance of the NUCLEA database concerning the thermodynamics of corium. Based on these results, the validity domain of NUCLEA is defined, and prospects for future improvement are proposed.