Studies on equation of state of high temperature nuclear materials

Equations-of-state (EOS) of nuclear materials are needed for the reactor safety analysis. EOS for nuclear fuel materials such as oxides, nitrides, carbides, metal alloy and also for graphite—a moderator, are obtained based on principle of corresponding states (PCS). The total vapour pressures over the liquid region, calculated by the PCS method, are compared with experimental data obtained using an in-house developed laser-induced vaporization mass spectrometric facility for UO2, UC, ThO2 and graphite and are found to be in good agreement. Vapour pressure of PuN is the highest and that of UC is the lowest for the range of temperatures involved in the event of a core disruptive accident. The vapour pressure of the mixed carbide fuel is very close to that of the alloy fuel.