Exploitable results Construction of the equation of state of uranium dioxide up to the critical point The behaviour of the reactor core during rapid reactivity excursions is, to a large extent, determined by the thermodynamic properties of the molten and vaporised fuel. In the context of the analysis of the most severe accident in liquid metal fast breeder reactors, experimental and theoretical investigations have been carried out on the equation of state of oxide fuel up to temperatures of the order of 8000degreesK. This research programme, which was supported worldwide by the various fast breeder projects, was recently interrupted due to the uncertainties about the future of this type of reactor. The prediction of the behaviour of the fuel, however, at very high temperatures represents a general thermodynamic problem, independent of the reactor accident design. It is therefore worthwhile solving this problem once and for all, especially in view of future new developments in nuclear reactor design. Furthermore, recent measurements of the heat capacity of UO2 up to 8000degreesK, carried out at ITU-JRC, are casting new light on the behaviour of liquid urania at very high temperatures and provide essential data for a theoretical assessment of the thermodymamic properties of this system. These studies will be continued at the High Energy Density Research Centre in Moscow, where the necessary equipment and expertise are available, and at the Physical Technical Institute in Uzbekistan. In western Europe parallel studies will be carried out by the Institute for Transuranium Elements, Karlsruhe; the University of Warwick, Coventry; and the University of Patras. These institutions have been involved for several years in the measurement and analysis of high temperature properties of nuclear fuels and problems related to complex thermodynamic systems. The first expected results will be the compilation of a self-consistent thermophysical and thermodynamical database to be used for the construction and validation of the liquid and gaseous uranium dioxide model. The database will be corroborated by the planned measurements which some of the participants will carry out. In addition, a first model for the equation of state will be proposed providing a reasonable fitting of the database. Further refinement research is necessary at a following stage in order to consolidate the theory and produce reliable extrapolations up to the critical temperature. Searching for OpenAIRE data... There was an error trying to search data from OpenAIRE No results available
