Development of Thermodynamic Database for U-Zr-Fe-O-B-C-FPs System

Abstract

A thermodynamic corium database using ionic two-sublattice model for liquid was developed and stratification of molten corium, supposed to occur in in-vessel retention accident management, was analyzed. The database consists of U-Zr-Fe-O-C-B-(FP oxides) system. Fundamentally, data were obtained from existing assessed databases, such as SGTE's. The liquid phase data were reconstructed based on the ionic model and lacking data including excess energies were assessed to be consistent with existing phase diagrams. Liquidus temperatures measured under OECD RASPLAV project were analyzed with the database. In addition, an analysis of corium under a severe accident condition was carried out and demonstrates that the database gives an improved method based on thermodynamics to analyze the corium stratification.