High temperature phase transitions of actinide dioxides

The safety of nuclear power plants is one of the major issues in nuclear materials research. In this context, this PhD thesis presents an original experimental investigation of melting behaviour of several refractory nuclear materials, whose phase diagrams are often still uncertain at temperatures exceeding 2500 K. The physicochemical properties presented for several pure and mixed actinide oxides constitute an important step forward in the understanding the behaviour of different types of nuclear fuel under extreme conditions.