Thermodynamic analysis of radioactive graphite reprocessing by incineration in air and oxidation in molten salt

Reactor graphite waste of nuclear industry contains various radionuclides. This study deals with the behaviour of radioactive elements during thermal treatment of waste. Two thermal processes were simulated: incineration of graphite in air and oxidation of graphite in a molten salt, containing Na 2 CO 3 + K 2 CO 3 + 20 mass% PbO. Carbon oxides CO and CO 2 , containing radioactive 14 C, are the main components of the gaseous phase with partial pressures approximately 10 4 Pa in both cases. More gaseous radionuclides are observed during incineration of graphite in air than during oxidation of graphite in the molten salt. In the latter case radionuclides are in the condensed state in the melt of sodium and potassium carbonates.