Phase diagram of the UO 2 -FeO 1+x system

AbstractPhase-relation studies of the UO 2 –FeO 1+x system in an inert atmosphere are presented. The eutectic point has beendetermined, which corresponds to a temperature of (1335 ± 5) C and a UO 2 concentration of (4.0 ± 0.1) mol.%. Themaximum solubility of FeO in UO 2 at the eutectic temperature has been estimated as (17.0 ± 1.0) mol.%. Liquidus tem-peratures for a wide concentration range have been determined and a phase diagram of the system has been constructed. 2006 Elsevier B.V. All rights reserved. 1. IntroductionThe conventional fuel used in modern nuclearpower plants, e.g., PWR and BWR reactors, isbased on UO 2 , therefore the behaviour of theUO 2 –metal oxide systems is the object of extensivestudies (see the comprehensive inventory presentedin [1]). The knowledge of the UO 2 –FeO 1+x systemis essential for the analysis of physicochemical phe-nomena taking place at a severe accident involvingthe core meltdown and, in particular, for the ex-vessel stage of accident progression, because ironoxides are present in the sacrificial materials usedin core catchers [2–5].However the published data of the UO